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@article{nokey,

title = {Covalent Organic Framework Bipolar Pseudocapacitive Electrodes in an All-Organic Symmetric Lithium-Ion Battery},

author = {A Singh and P Bhauriyal and L Quincke and D Bl\"{a}tte and R Guntermann and J L Rupp and T Heine and T Bein},

url = {\<Go to ISI\>://WOS:001544766400001},

doi = {10.1002/aenm.202501494},

issn = {1614-6832},

year  = {2025},

date = {2025-08-06},

journal = {Advanced Energy Materials},

abstract = {Covalent organic frameworks (COFs) have emerged as promising active materials for secondary-ion battery electrodes, owing to their robust porous structure and the flexibility in selecting redox-active building blocks. Here, a novel highly crystalline, electro-active, bipolar-type WTTF-COF, obtained by integrating p-type N,N,N ',N '-tetrakis(4-aminophenyl)-1,4-phenylenediamine (W) and 4,4 ',4 '',4 '''-([2,2'-bi(1,3-dithiolylidene)]-4,4 ',5,5 '-tetrayl)tetrabenzaldehyde (TTF) molecular building blocks via n-type imine linkages, is reported, serving as a Li-ion battery electrode. In Li-ion half cells, WTTF-COF as a cathode features 12-electron dual-ion redox chemistry per unit cell within a stable, unusually wide potential window of 0.1-3.6 V versus Li/Li+, corresponding to a high theoretical capacity of 315 mAh g-1, with an experimental reversible specific capacity of 271 mAh g-1 at 0.1 A g-1. The hybrid redox features coupled with the long-range ordered nanostructure of WTTF-COF enable an efficient pseudo-capacitive charge-storage mechanism. Different diffusion pathways and diffusion coefficients for Li+ and PF6- transport are established through detailed diffusion measurements and theoretical modeling. Among hybrid storage electrodes, WTTF-COF is reported to offer the option to serve as both anode and cathode up to a high rate of 200 mV s-1, as demonstrated in fully organic symmetric cell tests. Summarizing, judiciously designed COFs are suitably established for efficient bipolar electrode applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optimized Oxidation Temperature Enhances OER Performance of IrO2-Loaded SnO2 Nanofibers - Role of Charge Carrier Percolation Pathways},

author = {M Kost and J F Dushimineza and K M\"{u}ller-Caspary and T Bein},

url = {\<Go to ISI\>://WOS:001527460600001},

doi = {10.1002/admi.202400997},

issn = {2196-7350},

year  = {2025},

date = {2025-07-14},

journal = {Advanced Materials Interfaces},

volume = {12},

number = {14},

abstract = {The potential for reducing iridium content in large-scale proton-exchange membrane (PEM) electrolysis is examined using a fibrous support morphology to enhance electron percolation. Focusing on high activity, stability, and conductivity, ultra-small, interconnected IrOx/IrO2 nanoparticles anchored to electrospun SnO2 nanofibers (IrOx/IrO2@SnO2) are investigated, with particular attention to the crystallinity of the iridium phase. Scanning transmission electron microscopy (STEM), conducted both before and after use as an electrocatalyst for the oxygen evolution reaction (OER), reveals how the oxidation temperature impacts the crystallinity and stability of the iridium oxide phase. The results suggest that further reductions in iridium content may be achieved by optimizing synthesis parameters. Here, the highest iridium utilization is achieved at an oxidation temperature of 375 degrees C, with improved conductivity and electrochemical activity. Transmission electron microscopy (TEM) indicates that higher oxidation temperatures result in fragmentation of conduction pathways, negatively affecting catalyst performance. Furthermore, TEM reveals the onset of IrO2 crystallization between 365 and 375 degrees C, with cyclic voltammetry (CVA) emphasizing the critical role of conductivity in ensuring efficient charge carrier transport to active sites. This study not only deepens the understanding of iridium-based catalysts but also identifies practical strategies to enhance cost-effectiveness and efficiency in PEM electrolysis technologies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Highly Crystalline and Oriented Thin Films of Fully Conjugated 3D-Covalent Organic Frameworks},

author = {I Munoz-Alonso and D Bessinger and S Reuter and M Righetto and L Fuchs and M D\"{o}blinger and D D Medina and F Ortmann and L M Herz and T Bein},

url = {\<Go to ISI\>://WOS:001525541100001},

doi = {10.1002/anie.202505799},

year  = {2025},

date = {2025-06-15},

journal = {Angewandte Chemie-International Edition},

abstract = {Fully conjugated 3D covalent organic frameworks (COFs) are a newly emerged class of materials that expands reticular chemistry to extended electron delocalization for optoelectronic applications. To overcome the limitations of sp3-connected 3D frameworks, the pseudo-tetrahedral motif cyclooctatetrathiophene (COTh) has gained attention for forming fully conjugated 3D COFs. We report on a novel COTh building block, featuring functional formyl groups directly attached to the core's conjugated thiophenes. The modulation synthesis approach with mono-functionalized inhibitors enables the formation of COTh-1P COF, which exhibited remarkable crystallinity and permanent porosity. By following this approach and by optimizing the synthesis conditions for the solvothermal growth of thin films, we fabricated the first preferentially oriented conjugated 3D COF films on various substrates without pre-functionalization. With these thin films, optical pump terahertz probe studies allowed us, for the first time with 3D-fully conjugated COFs, to provide insights into the excited state and charge-carrier dynamics of these unique organic frameworks. Low effective masses are discovered for valence and conduction bands by density functional theory simulations. The ability to create crystalline and oriented films of fully pi-conjugated 3D COTh-based COFs on non-modified substrates is expected to open the way for integration of such frameworks into diverse optoelectronic applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {MnI-Functionalized Covalent Organic Framework as Efficient Electrocatalyst for CO2 Reduction in a Catholyte-Free Zero-Gap Electrolyzer},

author = {L Spies and M E G Carmo and G J Marrenjo and S Reuther and P Ganswindt and A O T Patrocinio and T Bein and O F Lopes and J Schneider},

url = {\<Go to ISI\>://WOS:001509037200001},

doi = {10.1002/adfm.202502953},

issn = {1616-301X},

year  = {2025},

date = {2025-06-11},

journal = {Advanced Functional Materials},

abstract = {Covalent Organic Frameworks (COFs) have emerged as versatile platforms for the rational design of heterogeneous CO2 electrocatalysts, offering molecular-level precision due to their well-ordered, porous structures. While COF-based hybrid electrocatalysts have demonstrated potential in lab-scale electrochemical cells with liquid electrolytes, their application in industry-relevant architectures remains largely unexplored. Here, the first successful integration of a phenanthroline-based 2D COF, modified with Mn-I single catalytic sites, into a catholyte-free membrane-electrode-assembly (MEA) cell for CO2 electroreduction is presented. The crystalline COF catalyst achieves an outstanding turnover frequency of 617 h(-1) (quantified per total concentration of catalytic sites) and a CO evolution of 222 mu mol cm(-2) (at a full-cell potential of 2.8 V) within 30 min. Moreover, the COF structure actively suppresses Mn-0-Mn-0 dimer formation and supports stable operation at high potentials with a partial current density of 23 mA cm(-2). The synergy between the crystalline nature of the COF and the MEA cell architecture, facilitating direct interactions between the modified electrode and the CO2 gas, enhances both the catalytic activity and stability. This work paves the way for broader adoption of COF-based hybrid materials in advanced electrocatalytic CO2 reduction technologies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Oriented Naphthalene-O-propylammonium-Based (NOP)4AuBIIII8 (B = Au, Bi, Sb) Ruddlesden\textendashPopper Two-Dimensional Gold Double Perovskite Thin Films Featuring High Charge-Carrier Mobility},

author = {F Wolf and T Chau and D Han and K B Spooner and M Righetto and P D\"{o}rflinger and S Wang and R Guntermann and R Hooijer and D O Scanlon and H Ebert and V Dyakonov and L M Herz and T Bein},

url = {https://doi.org/10.1021/jacs.5c01102},

doi = {10.1021/jacs.5c01102},

issn = {0002-7863},

year  = {2025},

date = {2025-05-21},

journal = {Journal of the American Chemical Society},

volume = {147},

number = {20},

pages = {16992-17001},

abstract = {Two-dimensional perovskites show intriguing optoelectronic properties due to their anisotropic structure and multiple quantum well structure. Here, we report the first three gold-based Ruddlesden\textendashPopper type two-dimensional double perovskites with a general formula (NOP)4AuIBIIII8 (B = Au, Bi, Sb) employing naphthalene-O-propylammonium (NOP) as an organic cation. They were found to form highly crystalline thin films on various substrates, predominantly oriented in the [001] direction featuring continuous, crack-free film areas on the μm2 scale. The thin films show strong optical absorption in the visible region, with band gap energies between 1.48 and 2.32 eV. Density functional theory calculations support the experimentally obtained band gap energies and predict high charge-carrier mobilities and effective charge separation. A comprehensive study with time-resolved microwave conductivity (TRMC) and optical-pump-THz-probe (OPTP) spectroscopy revealed high charge-carrier mobilities for lead-free two-dimensional perovskites of 4.0 ± 0.2 cm2(V s)−1 and charge-carrier lifetimes in the range of μs. Photoconductivity measurements under 1 sun illumination demonstrated the material’s application as a photodetector, showing a 2-fold increase in conductivity when exposed to light.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Surface Charge Modulation in Covalent Organic Frameworks for Controlled Pt-Photodeposition and Enhanced Photocatalytic Hydrogen Evolution},

author = {K Paliusyte and L L Nascimento and H Illner and M Wiedmaier and R Guntermann and M D\"{o}blinger and T Bein and A O T Patrocinio and J Schneider},

doi = {10.1002/smll.202500870},

issn = {1613-6810 

1613-6829},

year  = {2025},

date = {2025-05-19},

journal = {SMALL},

abstract = {Covalent organic frameworks (COFs) represent a new class of organic photocatalysts for the hydrogen evolution reaction (HER). While the influence of COF structural and optoelectronic properties on HER is well-studied, the role of surface charge in optimizing interfacial interactions with reactants remains underexplored. In this study, it is demonstrated that converting imine to amide linkages in a thiophene-based COF allows for altering surface charge through different protonation behaviors of the linkages. Zeta potential measurements reveal that the amide-linked COF, due to its lower basicity, is deprotonated and negatively charged in the presence of ascorbic acid, while the imine-linked COF is protonated and positively charged. This electrostatic contrast drives the photoreduction of [PtCl6]2(-) to Pt, with the imine-linked COF yielding uniformly distributed small Pt particles (1-2 nm), whereas the amide-linked COF forms larger Pt particles (up to 100 nm). The amide-linked COF, acting as an antenna that facilitates interdomain electron transport along COF agglomerates, promotes both Pt growth and subsequent proton reduction demonstrating a 300% increase in photocatalytic HER rate compared to its imine form. This work introduces surface charge modulation as a novel tool for controlling photocatalytic processes in COF-based systems expanding the COF functionality in photocatalysis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Effects of Tail States in Cs2AgBiBr6 Double Perovskites on Solar Cell Performance: A Temperature-Dependent Study of Photovoltaic External Quantum Efficiency, Open-Circuit Voltage, and Luminescence},

author = {F Ebadi and K Meraji and M A Torre Cachafeiro and F Wolf and M T Sirtl and T Bein and W Tress},

url = {https://doi.org/10.1002/aenm.202500758},

doi = {https://doi.org/10.1002/aenm.202500758},

issn = {1614-6832},

year  = {2025},

date = {2025-05-03},

journal = {Advanced Energy Materials},

volume = {n/a},

number = {n/a},

pages = {2500758},

abstract = {Cs2AgBiBr6 double perovskites have been investigated as a lead-free alternatives to lead-based perovskites. However, despite promising features such as high luminescence lifetimes, solar-cell efficiencies and the open-circuit voltage still remain too low. Various spectroscopic studies suggested multiple reasons such as a fast relaxation into localized self-trapped excitonic and polaronic states. However, it remains unclear to what extent the suggested processes are the culprit for the low device performance. In this study, full devices are characterized as a function of temperature, focusing on highly sensitive measurements of tail states. In the spectral response, a strongly-temperature-dependent Urbach energy is identified, indicative of high dynamic disorder. The current generated from the excitonic absorption becomes only limiting at lower temperatures with an activation energy of 0.15 eV. Analysis of light-, temperature- and voltage-dependent photoluminescence (PL) indicates that charge extraction correlates with PL quenching and PL does not originate from geminate pairs. The bandgap deduced from temperature-dependent open-circuit voltage is found at 2.0 eV, coinciding with the PL peak. In contrast, tail-state excitation leads to lower open-circuit voltage and luminescence that cannot be quenched with voltage. Having identified the importance of tail-state features, the methodology might assist in optimizing materials and devices for enhanced efficiency.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Defect Imide Double Antiperovskites AE5AsPn(NH)2 (AE=Ca, Sr; Pn=Sb, Bi) as Potential Solar Cell Absorber Materials},

author = {T G Chau and D Han and F Wolf and S S Rudel and Y Yao and H Oberhofer and T Bein and H Ebert and W Schnick},

url = {https://doi.org/10.1002/anie.202500768},

doi = {https://doi.org/10.1002/anie.202500768},

issn = {1433-7851},

year  = {2025},

date = {2025-04-17},

journal = {Angewandte Chemie International Edition},

volume = {64},

number = {17},

pages = {e202500768},

abstract = {Abstract An abundance of oxide, halide and chalcogenide perovskites have been explored, demonstrating outstanding properties, while the emerging nitride perovskites are extremely rare due to their challenging synthesis requirements. By inverting the ion type in the perovskite structure, the corresponding antiperovskite structure is obtained. Among them, ternary antiperovskite nitrides X3AN (X=Ba, Sr, Ca, Mg; A=As, Sb) have recently been identified as exhibiting excellent optoelectronic properties. To explore the unrealized composition space of nitride perovskites, the ammonothermal method was applied, yielding three new layered quaternary imide-based defect-antiperovskites, namely AE5AsPn(NH)2 (AE=Ca, Sr; Pn=Sb, Bi). These new compounds feature distorted square-pyramidal coordination around the imide-group (Ca5NH). Layers with Ca2+ vacancies are found with an alternating As3? and Pn3? (Pn3?=Sb3?, Bi3?) coordination along the A-site, forming a two-dimensional (2D) structure. All three AE5AsPn(NH)2 compounds show suitable direct band gaps within the visible light spectrum. Density functional theory calculations reveal favorable band dispersion, as well as transport and optical properties, especially along the out-of-plane direction, demonstrating their 3D character of electronic transport. The narrow tunable direct band gaps and favorable charge carrier properties make AE5AsPn(NH)2 promising candidates for solar cell absorber materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Redox-Active Microporous Covalent Organic Frameworks for Additive-Free Supercapacitors},

author = {R Guntermann and J M Rotter and A Singh and D D Medina and T Bein},

url = {https://doi.org/10.1002/smsc.202400585},

doi = {https://doi.org/10.1002/smsc.202400585},

year  = {2025},

date = {2025-03-21},

journal = {Small Science},

volume = {n/a},

number = {n/a},

pages = {2400585},

abstract = {2D covalent organic frameworks (COFs) have garnered significant attention by virtue of their porous nature, structural tunability, and ability to incorporate highly reversible redox-active groups. These characteristics qualify them for a range of energy storage devices, including supercapacitors, which can assume a pivotal role towards attaining a more sustainable future amid escalating energy needs. Herein, two 2D COFs are reported containing wurster (W) and pyrene (PY) units, WW COF and WPy-I COF, which demonstrate reversible redox behavior and characteristic pseudocapacitance. Both COFs exhibit high crystallinity demonstrated with X-ray diffraction analysis, exhibiting a thermal dependence of the intralayer bonding and interlayer stacking arrangement from WPy-I toward WPy-II COFs. Additionally, the WW and WPy-I COFs were grown on glass and stainless-steel meshes (SSMs) featuring different surface coatings. These coated SSMs proved suitable as current collectors for testing the COFs regarding their specific capacitance, without the need to add any conducting additives, revealing a promising capacitance of 48.9?F?g?1 for the WW COF. Moreover, these electrodes can be applied in symmetrical supercapacitor devices with an ionic liquid serving as electrolyte. The remarkable performance of the redox-active Wurster unit identifies it as a promising building motif for COFs with high specific capacitance, even in devices devoid of carbon additives.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Designing Atomically Precise and Robust COF Hybrids for Efficient Photocatalytic CO₂ Reduction},

author = {L Spies and M E G Carmo and M D\"{o}blinger and Z Xu and T Xue and A Hartschuh and T Bein and J Schneider and A O T Patrocinio},

url = {https://doi.org/10.1002/smll.202500550},

doi = {https://doi.org/10.1002/smll.202500550},

issn = {1613-6810},

year  = {2025},

date = {2025-03-03},

journal = {Small},

volume = {n/a},

number = {n/a},

pages = {2500550},

abstract = {Abstract Hybrid photocatalysts based on molecular species and solid substrates are elegant solutions for improving the performance and stability of molecular catalytic systems aiming at solar-driven CO2 conversion. In this work, a new dibenzochrysene-based covalent organic framework (COF) is developed to accept ReI centers, keeping its high crystallinity and allowing for atomistic control of the position of the catalytic centers. The rigid structure of the COF leads to long-term stability under illumination, whereas the efficient light-harvesting capability and the strong electronic interactions between the COF and the ReI centers lead to CO evolution rates of up to 1.16 mmol g?1 h?1. The favorable photocatalytic performance of this novel ReI-COF offers new insights regarding the development of efficient photocatalytic hybrid systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Printed CsMg\textendashZnO ETLs achieve over 9 % efficiency in PbS quantum dot solar cells},

author = {R Holfeuer and C Maheu and H Illner and R Hoojier and H Balakrishnan and B M\"{a}rz and S Lotfi and H Sezen and K M\"{u}ller-Caspary and T Bein and J P Hofmann and T Ameri and A Hartschuh and A Yousefiamin},

url = {https://www.sciencedirect.com/science/article/pii/S2468606925000218},

doi = {https://doi.org/10.1016/j.mtener.2025.101813},

issn = {2468-6069},

year  = {2025},

date = {2025-03-01},

journal = {Materials Today Energy},

volume = {48},

pages = {101813},

abstract = {Zinc oxide (ZnO) is a key electron transport layer (ETL) material in next-generation lead sulfide (PbS) colloidal quantum dot solar cells (CQDSCs) due to its high transparency, strong exciton binding energy, and good electron mobility. Here, we demonstrate a scalable doctor-blading printing protocol for ZnO ETLs that integrates dual defect passivation with magnesium (Mg2⁺) and caesium (Cs⁺) and employs solvent engineering to achieve uniform, defect-minimized films. Using a ternary solvent blend (methanol, chloroform, and 2-methoxyethanol) optimizes the ink's viscosity and boiling point, preventing particle migration and ensuring full substrate coverage. Our modified ZnO ink leads to improved crystallinity, smoother surfaces, and reduced trap states, boosting the fill factor (FF) and short-circuit current (Jsc). Consequently, we achieve a power conversion efficiency increase from 5.98 % to 9.53 % using a printed CsMg-ZnO film. Notably, 80 % of dual-doped devices exceeded 7.5 % efficiency, demonstrating high reproducibility and reliability. This performance enhancement underscores the effectiveness of dual metal ion treatment and solvent engineering strategies in overcoming printability challenges. Moreover, the compatibility of our approach with low-temperature processing and established coating techniques paves the way for seamless integration into large-scale manufacturing, bringing PbS CQDSCs closer to commercial viability.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Spatiotemporal Spectroscopy of Fast Excited-State Diffusion in 2D Covalent Organic Framework Thin Films},

author = {L Spies and A Biewald and L Fuchs and K Merkel and M Righetto and Z Xu and R Guntermann and R Hooijer and L M Herz and F Ortmann and J Schneider and T Bein and A Hartschuh},

url = {https://doi.org/10.1021/jacs.4c13129},

doi = {10.1021/jacs.4c13129},

issn = {0002-7863},

year  = {2025},

date = {2025-01-02},

journal = {Journal of the American Chemical Society},

abstract = {Covalent organic frameworks (COFs), crystalline and porous conjugated structures, are of great interest for sustainable energy applications. Organic building blocks in COFs with suitable electronic properties can feature strong optical absorption, whereas the extended crystalline network can establish a band structure enabling long-range coherent transport. This peculiar combination of both molecular and solid-state materials properties makes COFs an interesting platform to study and ultimately utilize photoexcited charge carrier diffusion. Herein, we investigated the charge carrier diffusion in a two-dimensional COF thin film generated through condensation of the building blocks benzodithiophene-dialdehyde (BDT) and N,N,N′,N′-tetra(4-aminophenyl)benzene-1,4-diamine (W). We visualized the spatiotemporal evolution of photogenerated excited states in the 2D WBDT COF thin film using remote-detected time-resolved PL measurements (RDTR PL). Combined with optical pump terahertz probe (OPTP) studies, we identified two diffusive species dominating the process at different time scales. Initially, short-lived free charge carriers diffuse almost temperature-independently before relaxing into bound states at a rate of 0.7 ps\textendash1. Supported by theoretical simulations, these long-lived bound states were identified as excitons. We directly accessed the lateral exciton diffusion within the oriented and crystalline film, revealing remarkably high diffusion coefficients of up to 4 cm2 s\textendash1 (200 K) and diffusion lengths of several hundreds of nanometers and across grain boundaries. Temperature-dependent exciton transport analysis showed contributions from both incoherent hopping and coherent band-like transport. In the transport model developed based on these findings, we discuss the complex impact of order and disorder on charge carrier diffusion within the WBDT COF thin film.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Photons, Excitons, and Electrons in Covalent Organic Frameworks},

author = {D Bl\"{a}tte and F Ortmann and T Bein},

url = {https://doi.org/10.1021/jacs.3c14833},

doi = {10.1021/jacs.3c14833},

issn = {0002-7863},

year  = {2024},

date = {2024-11-27},

journal = {Journal of the American Chemical Society},

volume = {146},

number = {47},

pages = {32161-32205},

abstract = {Covalent organic frameworks (COFs) are created by the condensation of molecular building blocks and nodes to form two-dimensional (2D) or three-dimensional (3D) crystalline frameworks. The diversity of molecular building blocks with different properties and functionalities and the large number of possible framework topologies open a vast space of possible well-defined porous architectures. Besides more classical applications of porous materials such as molecular absorption, separation, and catalytic conversions, interest in the optoelectronic properties of COFs has recently increased considerably. The electronic properties of both the molecular building blocks and their linkage chemistry can be controlled to tune photon absorption and emission, to create excitons and charge carriers, and to use these charge carriers in different applications such as photocatalysis, luminescence, chemical sensing, and photovoltaics. In this Perspective, we will discuss the relationship between the structural features of COFs and their optoelectronic properties, starting with the building blocks and their chemical connectivity, layer stacking in 2D COFs, control over defects and morphology including thin film synthesis, exploring the theoretical modeling of structural, electronic, and dynamic features of COFs, and discussing recent intriguing applications with a focus on photocatalysis and photoelectrochemistry. We conclude with some remarks about present challenges and future prospects of this powerful architectural paradigm.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Fabrication of functional 3D nanoarchitectures via atomic layer deposition on DNA origami crystals},

author = {A Ermatov and M Kost and X Yin and P Butler and M Dass and I D Sharp and T Liedl and T Bein and G Posnjak},

year  = {2024},

date = {2024-10-17},

journal = {arXiv preprint arXiv:2410.13393},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Overcoming Intrinsic Quantum Confinement and Ultrafast Self-Trapping in Ag\textendashBi\textendashI- and Cu\textendashBi\textendashI-Based 2D Double Perovskites through Electroactive Cations},

author = {R Hooijer and S Wang and A Biewald and C Eckel and M Righetto and M Chen and Z Xu and D Bl\"{a}tte and D Han and H Ebert and L M Herz and R T Weitz and A Hartschuh and T Bein},

url = {https://doi.org/10.1021/jacs.4c04616},

doi = {10.1021/jacs.4c04616},

issn = {0002-7863},

year  = {2024},

date = {2024-10-02},

journal = {Journal of the American Chemical Society},

volume = {146},

number = {39},

pages = {26694-26706},

abstract = {The possibility to combine organic semiconducting materials with inorganic halide perovskites opens exciting pathways toward tuning optoelectronic properties. Exploring stable and nontoxic, double perovskites as a host for electroactive organic cations to form two-dimensional (2D) hybrid materials is an emerging opportunity to create both functional and lead-free materials for optoelectronic applications. By introducing naphthalene and pyrene moieties into Ag\textendashBi\textendashI and Cu\textendashBi\textendashI double perovskite lattices, intrinsic electronic challenges of double perovskites are addressed and the electronic anisotropy of 2D perovskites can be modulated. (POE)4AgBiI8 containing pyrene moieties in the 2D layers was selected from a total of eight new 2D double perovskites, exhibiting a favorable electronic band structure with a type IIb multiple quantum well system based on a layer architecture suitable for out-of-plane conductivity and leading to a photocurrent response ratio of almost 3 orders of magnitude under AM1.5G illumination. Finally, an exclusively parallelly oriented thin film of (POE)4AgBiI8 was integrated into a device to construct the first pure n = 1 Ruddlesden\textendashPopper 2D double perovskite solar cell.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Interpenetrated Donor\textendashAcceptor Heterojunctions in 2D Conjugated Dibenzo[g,p]chrysene-Based Kagome Covalent Organic Frameworks},

author = {T Xue and R Guntermann and A Biewald and D Bl\"{a}tte and D D Medina and A Hartschuh and T Bein},

url = {https://doi.org/10.1021/acsami.4c09286},

doi = {10.1021/acsami.4c09286},

issn = {1944-8244},

year  = {2024},

date = {2024-09-11},

journal = {ACS Applied Materials \& Interfaces},

volume = {16},

number = {36},

pages = {48085-48093},

abstract = {Dibenzo[g,p]chrysene can be viewed as a constrained propeller-shaped tetraphenylethylene with reduced curvature and has been utilized to construct dual-pore kagome covalent organic frameworks (COFs) with tightly packed two-dimensional (2D) layers owing to its rigid and more planar structural characteristics. Here, we introduce 2D COFs based on the node 4,4′,4″,4‴-(dibenzo[g,p]chrysene-2,7,10,15-tetraphenyl)tetraamine (DBCTPTA) featuring extended conjugation compared to the dibenzo[g,p]chrysene-3,6,11,14-tetraamine (DBCTA) node. We establish two exceptionally crystalline imine-linked 2D COFs with a hexagonal dual-pore kagome structure based on the DBCTPTA core. The newly synthesized thienothiophene (TT) and benzodithiophene (BDT)-based DBCTPTA COFs show a tight stacking behavior between adjacent layers. Furthermore, we obtained an unprecedented, interpenetrated electron-donor/acceptor host\textendashguest system with an electron-donating BDT DBCTPTA COF synthesized in situ with the soluble fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) serving as molecular acceptor. The BDT DBCTPTA COF@PCBM film shows a much shorter amplitude-averaged PL lifetime of 7 ± 2 ps compared to 30 ± 4 ps of the BDT DBCTPTA COF film, indicating the light-induced charge transfer process. The successful in situ formation of interpenetrated donor\textendashacceptor heterojunctions within 2D COFs offers a promising strategy for establishing D\textendashA heterojunctions in diverse framework materials with open channel systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Chemical Epitaxy of Iridium Oxide on Tin Oxide Enhances Stability of Supported OER Catalyst},

author = {M Kost and M Kornherr and P Zehetmaier and H Illner and D S Jeon and H A Gasteiger and M D\"{o}blinger and D Fattakhova-Rohlfing and T Bein},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202404118},

doi = {https://doi.org/10.1002/smll.202404118},

issn = {1613-6810},

year  = {2024},

date = {2024-08-21},

urldate = {2024-08-21},

journal = {Small},

volume = {20},

number = {42},

pages = {2404118},

abstract = {Abstract Significantly reducing the iridium content in oxygen evolution reaction (OER) catalysts while maintaining high electrocatalytic activity and stability is a key priority in the development of large-scale proton exchange membrane (PEM) electrolyzers. In practical catalysts, this is usually achieved by depositing thin layers of iridium oxide on a dimensionally stable metal oxide support material that reduces the volumetric packing density of iridium in the electrode assembly. By comparing two support materials with different structure types, it is shown that the chemical nature of the metal oxide support can have a strong influence on the crystallization of the iridium oxide phase and the direction of crystal growth. Epitaxial growth of crystalline IrO2 is achieved on the isostructural support material SnO2, both of which have a rutile structure with very similar lattice constants. Crystallization of amorphous IrOx on an SnO2 substrate results in interconnected, ultrasmall IrO2 crystallites that grow along the surface and are firmly anchored to the substrate. Thereby, the IrO2 phase enables excellent conductivity and remarkable stability of the catalyst at higher overpotentials and current densities at a very low Ir content of only 14 at%. The chemical epitaxy described here opens new horizons for the optimization of conductivity, activity and stability of electrocatalysts and the development of other epitaxial materials systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tunable Isometric Donor-Acceptor Wurster-Type Covalent Organic Framework Photocathodes},

author = {R Guntermann and D Helminger and L Frey and P M Zehetmaier and C Wangnick and A Singh and T Xue and D D Medina and T Bein},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202407166},

doi = {https://doi.org/10.1002/anie.202407166},

issn = {1433-7851},

year  = {2024},

date = {2024-08-13},

journal = {Angewandte Chemie International Edition},

volume = {63},

number = {51},

pages = {e202407166},

abstract = {Abstract Covalent organic frameworks (COFs) offer remarkable versatility, combining ordered structures, high porosity, and tailorable functionalities in nanoscale reaction spaces. Herein, we report the synthesis of a series of isostructural, photoactive Wurster-type COFs achieved by manipulating the chemical and electronic nature of the Wurster aromatic amine building blocks. A series of donor-acceptor-donor (D-A-D) Wurster building block molecules was synthesized by incorporating heteroaromatic acceptors with varying strengths between triphenylamine donor groups. These tailored building blocks were integrated into a 2D COF scaffold, resulting in highly crystalline structures and similar morphologies across all COFs. Remarkably, this structural uniformity was also achieved in the synthesis of homogeneous and oriented thin films. Steady-state photoluminescence revealed a tunable red-shift in film emission exceeding 100 nm, demonstrating effective manipulation of their optical properties. Furthermore, photoelectrochemical (PEC) water splitting studies exhibited a doubled current density (8.1 μA cm−2 at 0.2 VRHE) for the COF with the strongest acceptor unit. These findings highlight the potential of Wurster D-A-D COFs in photoelectrochemical water splitting devices and pave the way for further exploration of chemical functionality-reactivity-property relationships in this promising class of photoactive materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tetrathiafulvalene-based covalent organic frameworks as high-voltage organic cathodes for lithium batteries},

author = {G Valente and R Dantas and P Ferreira and R Grieco and N Patil and A Guillem-Navajas and D Rodr\'{i}guez-San Miguel and F Zamora and R Guntermann and T Bein and J Rocha and M H Braga and K Struty\'{n}ski and M Melle-Franco and R Marcilla and M Souto},

url = {http://dx.doi.org/10.1039/D4TA04576A},

doi = {10.1039/D4TA04576A},

issn = {2050-7488},

year  = {2024},

date = {2024-08-09},

journal = {Journal of Materials Chemistry A},

volume = {12},

number = {36},

pages = {24156-24164},

abstract = {Redox-active covalent organic frameworks (COFs) are promising electrode materials for metal-ion batteries owing to their tunable electrochemical properties, adjustable structure, and resource availability. Herein, we report a series of two-dimensional tetrathiafulvalene (TTF)-based COFs incorporating different organic linkers between the electroactive moieties. These COFs were investigated as p-type organic cathode materials for lithium-organic batteries. The electrical conductivity of both neutral and doped TTF-COFs was measured using a van der Pauw setup, and their electronic structures were investigated through quantum-chemical calculations. Binder-free buckypaper TTF-based electrodes were prepared and systematically tested as organic cathodes in lithium half-cells. The results revealed high average discharge potentials (∼3.6 V vs. Li/Li+) and consistent cycling stability (80% capacity retention after 400 cycles at 2C) for the three TTF-COF electrodes. In addition, the specific capacity, rate capability, and kinetics varied depending on the structure of the framework. Our results highlight the potential of TTF-COFs as high-voltage organic cathodes for metal-ion batteries and emphasize the importance of molecular design in optimizing their electrochemical performance.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dynamic two-dimensional covalent organic frameworks},

author = {F Auras and L Ascherl and V Bon and S M Vornholt and S Krause and M D\"{o}blinger and D Bessinger and S Reuter and K W Chapman and S Kaskel and R H Friend and T Bein},

url = {https://doi.org/10.1038/s41557-024-01527-8},

doi = {10.1038/s41557-024-01527-8},

issn = {1755-4349},

year  = {2024},

date = {2024-08-01},

journal = {Nature Chemistry},

volume = {16},

number = {8},

pages = {1373-1380},

abstract = {Porous covalent organic frameworks (COFs) enable the realization of functional materials with molecular precision. Past research has typically focused on generating rigid frameworks where structural and optoelectronic properties are static. Here we report dynamic two-dimensional (2D) COFs that can open and close their pores upon uptake or removal of guests while retaining their crystalline long-range order. Constructing dynamic, yet crystalline and robust frameworks requires a well-controlled degree of flexibility. We have achieved this through a ‘wine rack’ design where rigid π-stacked columns of perylene diimides are interconnected by non-stacked, flexible bridges. The resulting COFs show stepwise phase transformations between their respective contracted-pore and open-pore conformations with up to 40% increase in unit-cell volume. This variable geometry provides a handle for introducing stimuli-responsive optoelectronic properties. We illustrate this by demonstrating switchable optical absorption and emission characteristics, which approximate ‘null-aggregates’ with monomer-like behaviour in the contracted COFs. This work provides a design strategy for dynamic 2D COFs that are potentially useful for realizing stimuli-responsive materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Contrasting Ultra-Low Frequency Raman and Infrared Modes in Emerging Metal Halides for Photovoltaics},

author = {V J Y Lim and M Righetto and S Yan and J B Patel and T Siday and B Putland and K M Mccall and M T Sirtl and Y Kominko and J Peng and Q Lin and T Bein and M Kovalenko and H J Snaith and M B Johnston and L M Herz},

url = {https://doi.org/10.1021/acsenergylett.4c01473},

doi = {10.1021/acsenergylett.4c01473},

year  = {2024},

date = {2024-07-29},

journal = {ACS Energy Letters},

volume = {9},

number = {8},

pages = {4127-4135},

abstract = {Lattice dynamics are critical to photovoltaic material performance, governing dynamic disorder, hot-carrier cooling, charge-carrier recombination, and transport. Soft metal-halide perovskites exhibit particularly intriguing dynamics, with Raman spectra exhibiting an unusually broad low-frequency response whose origin is still much debated. Here, we utilize ultra-low frequency Raman and infrared terahertz time-domain spectroscopies to provide a systematic examination of the vibrational response for a wide range of metal-halide semiconductors: FAPbI3, MAPbIxBr3\textendashx, CsPbBr3, PbI2, Cs2AgBiBr6, Cu2AgBiI6, and AgI. We rule out extrinsic defects, octahedral tilting, cation lone pairs, and “liquid-like” Boson peaks as causes of the debated central Raman peak. Instead, we propose that the central Raman response results from an interplay of the significant broadening of Raman-active, low-energy phonon modes that are strongly amplified by a population component from Bose\textendashEinstein statistics toward low frequency. These findings elucidate the complexities of light interactions with low-energy lattice vibrations in soft metal-halide semiconductors emerging for photovoltaic applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Regioisomerism in Thienothiophene-Based Covalent Organic Frameworks─A Tool for Band-Gap Engineering},

author = {R Guntermann and L Frey and A Biewald and A Hartschuh and T Clark and T Bein and D D Medina},

url = {https://doi.org/10.1021/jacs.4c02365},

doi = {10.1021/jacs.4c02365},

issn = {0002-7863},

year  = {2024},

date = {2024-06-12},

journal = {Journal of the American Chemical Society},

volume = {146},

number = {23},

pages = {15869-15878},

abstract = {The craft of tuning optical properties is well-established for crystalline inorganic and hybrid solids. However, a far greater challenge is to tune the optical properties of organic materials systematically by design. We now introduce a synthesis concept that enables us to alter the optical properties of crystalline covalent organic frameworks (COFs) systematically using isomeric structures of thienothiophene-based building blocks (T23/32T) combined with a variety of tetratopic aromatic amines, e.g., the Wurster moiety (W\textendashNH2). This concept is demonstrated for the synthesis of COFs in bulk and film forms and provides highly crystalline and porous isomeric COFs featuring predesigned photophysical properties. The band gap of the framework can be tuned continuously and precisely by chemically doping the pristine W23TT COF with its related constitutional isomer building block. Density-functional theory investigations of COF model compounds indicate that the extent of π-conjugation is among the key characteristics enabling the band-gap engineering.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {An electrically conducting 3D coronene-based metal\textendashorganic framework},

author = {M I Sch\"{o}nherr and P I Scheurle and L Frey and M Mart\'{i}nez-Abad\'{i}a and M D\"{o}blinger and A M\"{a}hringer and D Fehn and L Gerhards and I Santourian and A Schirmacher and T Quast and G Wittstock and T Bein and K Meyer and A Mateo-Alonso and D D Medina},

url = {http://dx.doi.org/10.1039/D3TA07120K},

doi = {10.1039/D3TA07120K},

issn = {2050-7488},

year  = {2024},

date = {2024-04-19},

journal = {Journal of Materials Chemistry A},

volume = {12},

number = {17},

pages = {10044-10049},

abstract = {A novel cubic mesoporous metal\textendashorganic framework (MOF), consisting of hexahydroxy-cata-hexabenzocoronene (c-HBC) and FeIII ions is presented. The highly crystalline and porous MOF features broad optical absorption over the whole visible and near infrared spectral regions. An electrical conductivity of 10−4 S cm−1 was measured on a pressed pellet.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Imaging built-in electric fields and light matter by Fourier-precession TEM},

author = {T Lorenzen and B M\"{a}rz and T Xue and A Beyer and K Volz and T Bein and K M\"{u}ller-Caspary},

url = {https://doi.org/10.1038/s41598-024-51423-x},

doi = {10.1038/s41598-024-51423-x},

issn = {2045-2322},

year  = {2024},

date = {2024-01-15},

journal = {Scientific Reports},

volume = {14},

number = {1},

pages = {1320},

abstract = {We report the precise measurement of electric fields in nanostructures, and high-contrast imaging of soft matter at ultralow electron doses by transmission electron microscopy (TEM). In particular, a versatile method based on the theorem of reciprocity is introduced to enable differential phase contrast imaging and ptychography in conventional, plane-wave illumination TEM. This is realised by a series of TEM images acquired under different tilts, thereby introducing the sampling rate in reciprocal space as a tuneable parameter, in contrast to momentum-resolved scanning techniques. First, the electric field of a p\textendashn junction in GaAs is imaged. Second, low-dose, in-focus ptychographic and DPC characterisation of Kagome pores in weakly scattering covalent organic frameworks is demonstrated by using a precessing electron beam in combination with a direct electron detector. The approach offers utmost flexibility to record relevant spatial frequencies selectively, while acquisition times and dose requirements are significantly reduced compared to the 4D-STEM counterpart.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Discovery of multi-anion antiperovskites X6NFSn2 (X = Ca, Sr) as promising thermoelectric materials by computational screening},

author = {D Han and B Zhu and Z Cai and K B Spooner and S S Rudel and W Schnick and T Bein and D O Scanlon and H Ebert},

url = {https://www.sciencedirect.com/science/article/pii/S2590238523005234},

doi = {https://doi.org/10.1016/j.matt.2023.10.022},

issn = {2590-2385},

year  = {2024},

date = {2024-01-03},

urldate = {2024-01-03},

journal = {Matter},

volume = {7},

issue = {1},

pages = {158-174},

abstract = {Summary The thermoelectric performance of existing perovskites lags far behind that of state-of-the-art thermoelectric materials such as SnSe. Despite halide perovskites showing promising thermoelectric properties, namely, high Seebeck coefficients and ultralow thermal conductivities, their thermoelectric performance is significantly restricted by low electrical conductivities. Here, we explore new multi-anion antiperovskites X6NFSn2 (X = Ca, Sr, and Ba) via B-site anion mutation in antiperovskite and global structure searches and demonstrate their phase stability by first-principles calculations. Ca6NFSn2 and Sr6NFSn2 exhibit decent Seebeck coefficients and ultralow lattice thermal conductivities (\<1 W m−1 K−1). Notably, Ca6NFSn2 and Sr6NFSn2 show remarkably larger electrical conductivities compared to the halide perovskite CsSnI3. The combined superior electrical and thermal properties of Ca6NFSn2 and Sr6NFSn2 lead to high thermoelectric figures of merit (ZTs) of ∼1.9 and ∼2.3 at high temperatures. Our exploration of multi-anion antiperovskites X6NFSn2 (X = Ca, Sr) realizes the “phonon-glass, electron-crystal” concept within the antiperovskite structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Cu/Ag\textendashSb\textendashI Rudorffite Thin Films for Photovoltaic Applications},

author = {R Hooijer and A Weis and W Kaiser and A Biewald and P D\"{o}rflinger and C Maheu and O Arsatiants and D Helminger and V Dyakonov and A Hartschuh and E Mosconi and F De Angelis and T Bein},

url = {https://doi.org/10.1021/acs.chemmater.3c01837},

doi = {10.1021/acs.chemmater.3c01837},

issn = {0897-4756},

year  = {2023},

date = {2023-11-16},

journal = {Chemistry of Materials},

volume = {35},

number = {23},

pages = {9988-10000},

abstract = {In the search for lead-free perovskites, silver pnictohalides recently gained attention as novel perovskite-inspired materials for photovoltaics due to their high stability, low toxicity, and promising early efficiencies, especially for indoor applications. Recent research on such “rudorffites” mainly addresses silver bismuth iodides (Ag\textendashBi\textendashI), while their antimony analogues are hardly investigated due to intrinsic challenges in the synthesis of Sb-based thin films. Here, we establish a synthetic route to prepare Ag\textendashSb\textendashI thin films by employing thiourea as a Lewis-base additive. Thin film morphologies were further optimized by alloying them with Cu, resulting in solar cells with an improved power conversion efficiency of 0.7% by reducing undesired side phases. Density functional theory calculations and optical characterization methods support the incorporation of Cu into a Cu1\textendashxAgxSbI4 phase, keeping the overall stoichiometry and band gap virtually unchanged upon alloying. Our results further reveal the detrimental role of Ag point defects representing trap states in the band gap, being responsible for low open-circuit voltages and subgap absorption and emission features. Moreover, additional minor amounts of Bi are shown to boost the efficiency and stabilize the performance over a wider compositional range. Despite the remaining challenges regarding device performance, we demonstrate a strong increase in external quantum efficiency when reducing the light intensity, highlighting the potential of Ag\textendashSb\textendashI rudorffites for indoor photovoltaics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Alloying Effects on Charge-Carrier Transport in Silver\textendashBismuth Double Perovskites},

author = {M Righetto and S Caicedo-D\'{a}vila and M T Sirtl and V J Y Lim and J B Patel and D A Egger and T Bein and L M Herz},

url = {https://doi.org/10.1021/acs.jpclett.3c02750},

doi = {10.1021/acs.jpclett.3c02750},

year  = {2023},

date = {2023-11-10},

journal = {The Journal of Physical Chemistry Letters},

volume = {14},

number = {46},

pages = {10340-10347},

abstract = {Alloying is widely adopted for tuning the properties of emergent semiconductors for optoelectronic and photovoltaic applications. So far, alloying strategies have primarily focused on engineering bandgaps rather than optimizing charge-carrier transport. Here, we demonstrate that alloying may severely limit charge-carrier transport in the presence of localized charge carriers (e.g., small polarons). By combining reflection\textendashtransmission and optical pump\textendashterahertz probe spectroscopy with first-principles calculations, we investigate the interplay between alloying and charge-carrier localization in Cs2AgSbxBi1\textendashxBr6 double perovskite thin films. We show that the charge-carrier transport regime strongly determines the impact of alloying on the transport properties. While initially delocalized charge carriers probe electronic bands formed upon alloying, subsequently self-localized charge carriers probe the energetic landscape more locally, thus turning an alloy’s low-energy sites (e.g., Sb sites) into traps, which dramatically deteriorates transport properties. These findings highlight the inherent limitations of alloying strategies and provide design tools for newly emerging and highly efficient semiconductors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Study on the properties of wafer-scale grown MoS2 deposited via thermally induced chemical vapor deposition with Mo(CO)6 and H2S precursors},

author = {A Klumpp and R Hooijer and N Kr\"{u}ger and J Boudaden and F Wolf and M D\"{o}blinger and T Bein},

url = {https://dx.doi.org/10.1088/2053-1591/acf7ae},

doi = {10.1088/2053-1591/acf7ae},

issn = {2053-1591},

year  = {2023},

date = {2023-09-22},

journal = {Materials Research Express},

volume = {10},

number = {9},

pages = {095903},

abstract = {To realize profitable applications with 2D-materials the transition from research scale to microelectronic fabrication methods is needed. This means the use of equipment for larger substrates and assessment of the process flows. In this study we demonstrate an effective way to assess MoS2 as semiconducting material, deposited with the lower priced precursors Mo(CO)6 and H2S on 200 mm silicon wafers. We could show how the evolution of layer quality develops depending on temperature and interface pretreatment. It is not possible to achieve mono-layers of 0.6 nm with high quality due to seeding kinetics and mechanism. In contrast, layers with thicknesses above 3 nm have suitable electrical and optical qualities to proceed with the design of active devices on 200 mm wafers.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Novel Multi-Functional Thiophene-Based Organic Cation as Passivation, Crystalline Orientation, and Organic Spacer Agent for Low-Dimensional 3D/1D Perovskite Solar Cells},

author = {A Semerci and A Buyruk and S Emin and R Hooijer and D Kovacheva and P Mayer and M A Reus and D Bl\"{a}tte and M G\"{u}nther and N F Hartmann and S Lotfi and J P Hofmann and P M\"{u}ller-Buschbaum and T Bein and T Ameri},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202300267},

doi = {https://doi.org/10.1002/adom.202300267},

issn = {2195-1071},

year  = {2023},

date = {2023-05-25},

journal = {Advanced Optical Materials},

volume = {11},

number = {16},

pages = {2300267},

abstract = {Abstract Recently, the mixed-dimensional (3D/2D or 3D/1D) perovskite solar cells using small organic spacers have attracted interest due to their outstanding long-term stability. Here, a new type of thiophene-based organic cation 2-(thiophene-2yl-)pyridine-1-ium iodide (ThPyI), which is used to fabricate mixed-dimensional 3D/1D perovskite solar cells, is presented. The ThPyI-based 1D perovskitoid is applied as a passivator on top of a 3D methyl ammonium lead iodide (MAPI) to fabricate surface-passivated 3D/1D perovskite films or added alone into the 3D perovskite precursor to generate bulk-passivated 3D MAPI. The 1D perovskitoid acts as a passivating agent at the grain boundaries of surface-passivated 3D/1D, which improves the power conversion efficiency (PCE) of the solar cells. Grazing incidence wide-angle X-ray scattering (GIWAXS) studies confirm that ThPyI triggers the preferential orientation of the bulk MAPI slabs, which is essential to enhance charge transport. Champion bulk-passivated 3D and surface-passivated 3D/1D devices yield 14.10% and 19.60% PCE, respectively. The bulk-passivated 3D offers favorable stability, with 84% PCE retained after 2000 h without encapsulation. This study brings a new perspective to the design of organic spacers having a different binding motif and a passivation strategy to mitigate the impact of defects in hybrid 3D/1D perovskite solar cells.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {From conventional inorganic semiconductors to covalent organic frameworks: advances and opportunities in heterogeneous photocatalytic CO2 reduction},

author = {M E G Carmo and L Spies and G N Silva and O F Lopes and T Bein and J Schneider and A O T Patrocinio},

url = {http://dx.doi.org/10.1039/D3TA01470C},

doi = {10.1039/D3TA01470C},

issn = {2050-7488},

year  = {2023},

date = {2023-05-18},

journal = {Journal of Materials Chemistry A},

volume = {11},

number = {26},

pages = {13815-13843},

abstract = {Solar-driven photochemical CO2 reduction over semiconducting materials is a strategic technology towards sustainable development as it represents a source of renewable liquid and gaseous fuels, and simultaneously provides a solution for current environmental problems caused substantially by the accumulation of this greenhouse gas in the atmosphere. However, the unfavorable thermodynamics and the sluggish kinetics of the multi-electron CO2 reduction reactions pose several challenges in terms of selectivity, conversion efficiencies, and long-term stability. Continuous advances have been made by different research groups on the fundamental understanding of the relationship between the CO2 conversion efficiency and the physicochemical properties of the photocatalyst. This review aims to present the main findings in this field to a broad audience, starting with the application of conventional inorganic semiconductors as photocatalysts for CO2 reduction, followed by the introduction of covalent organic frameworks as a new generation of photocatalytic materials. The rational design of organic\textendashinorganic hybrids to enhance the activity and selectivity of the CO2 reduction is also summarized along with the remaining challenges regarding both fundamental understanding and potential upscaling.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Behind the scenes: insights into the structural properties of amide-based hole-transporting materials for lead-free perovskite solar cells},

author = {F Wolf and M T Sirtl and S Klenk and M H H Wurzenberger and M Armer and P D\"{o}rflinger and P Ganswindt and R Guntermann and V Dyakonov and T Bein},

url = {http://dx.doi.org/10.1039/D2CE01512A},

doi = {10.1039/D2CE01512A},

year  = {2023},

date = {2023-05-17},

journal = {CrystEngComm},

volume = {25},

number = {21},

pages = {3142-3149},

abstract = {State-of-the-art perovskite solar cells often employ expensive organic hole transporting materials (HTM) such as spiro-OMeTAD, motivating the search for potential alternatives. Here we report single-crystal data of EDOT-amide-TPA as well as the first utilization of EDOT-amide-TPA as HTM for Cs2AgBiBr6 perovskite solar cells, outperforming spiro-OMeTAD. The dense packing of the EDOT-amide-TPA film improves the charge carrier extraction, increasing the JSC and PCE.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Room-temperature synthesis of lead-free copper(I)-antimony(III)-based double perovskite nanocrystals},

author = {S Wang and D Han and C Maheu and Z Xu and A Biewald and H Illner and R Hooijer and T Mayer and A Hartschuh and H Ebert and T Bein},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0144708},

doi = {10.1063/5.0144708},

year  = {2023},

date = {2023-04-05},

journal = {APL Materials},

volume = {11},

number = {4},

pages = {041110},

abstract = {In the field of perovskite solar cells, explorations of new lead-free all-inorganic perovskite materials are of great interest to address the instability and toxicity issues of lead-based hybrid perovskites. Recently, copper-antimony-based double perovskite materials have been reported with ideal band gaps, which possess great potential as absorbers for photovoltaic applications. Here, we synthesize Cs2CuSbCl6 double perovskite nanocrystals (DPNCs) at ambient conditions by a facile and fast synthesis method, namely, a modified ligand-assisted reprecipitation method. We choose methanol as a solvent for precursor salts as it is less toxic and easily removed in contrast to widely used dimethylformamide. Our computational structure search shows that the Cs2CuSbCl6 structure containing alternating [CuCl6]5− and [SbCl6]3− octahedral units is a metastable phase that is 30 meV/atom higher in energy compared to the ground state structure with [CuCl3]2− and [SbCl6]3− polyhedra. However, this metastable Cs2CuSbCl6 double perovskite structure can be stabilized through solution-based nanocrystal synthesis. Using an anion-exchange method, Cs2CuSbBr6 DPNCs are obtained for the first time, featuring a narrow bandgap of 0.9 eV. Finally, taking advantage of the solution processability of DPNCs, smooth and dense Cs2CuSbCl6 and Cs2CuSbBr6 DPNC films are successfully fabricated.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Low Temperature Optical Properties of Novel Lead-Free Cs2NaFeCl6 Perovskite Single Crystals},

author = {M Armer and P D\"{o}rflinger and A Weis and C B\"{u}chner and A Gottscholl and J H\"{o}cker and K Frank and L Nusser and M T Sirtl and B Nickel and T Bein and V Dyakonov},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adpr.202300017},

doi = {https://doi.org/10.1002/adpr.202300017},

issn = {2699-9293},

year  = {2023},

date = {2023-04-02},

journal = {Advanced Photonics Research},

volume = {n/a},

number = {n/a},

pages = {2300017},

abstract = {Lead-free double perovskites have attracted much attention as possible alternatives to lead halide based perovskites in photovoltaic applications. However, to date only few double perovskites have been successfully employed in optoelectronic device prototypes. Therefore, the search for stable and lead-free materials is ongoing. Here, we present the successful growth of high-quality Cs2NaFeCl6 single crystals and their temperature-dependent structural and optical properties. By combining electron paramagnetic resonance (EPR), crystal structure analysis and density functional theory (DFT) we could determine a cubic crystal structure with a spin of 5/2 for this material, showing strongly spin polarized character. Furthermore, combining photoluminescence (PL) and optical absorption measurements we find a bandgap of approximately 2.1 eV at room temperature as well as the presence of excitonic states. Using Elliot's formula, we are able to extract the temperature-dependent behavior of the bandgap as well as an estimated exciton binding energy of only 20 meV at 80 K.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electrically Conductive Carbazole and Thienoisoindigo-Based COFs Showing Fast and Stable Electrochromism},

author = {K Muggli and L Spies and D Bessinger and F Auras and T Bein},

url = {https://doi.org/10.1021/acsnanoscienceau.2c00049},

doi = {10.1021/acsnanoscienceau.2c00049},

year  = {2023},

date = {2023-02-17},

journal = {ACS Nanoscience Au},

abstract = {Thienothiophene thienoisoindigo (ttTII)-based covalent organic frameworks (COFs) have been shown to offer low band gaps and intriguing optical and electrochromic properties. So far, only one tetragonal thienothiophene thienoisoindigo-based COF has been reported showing stable and fast electrochromism and good coloration efficiencies. We have developed two novel COFs using this versatile and nearly linear ttTII building block in a tetragonal and a hexagonal framework geometry to demonstrate their attractive features for optoelectronic applications of thienoisoindigo-based COFs. Both COFs exhibit good electrical conductivities, show promising optical absorption features, are redox-active, and exhibit a strong electrochromic behavior when applying an external electrical stimulus, shifting the optical absorption even farther into the NIR region of the electromagnetic spectrum and achieving absorbance changes of up to 2.5 OD. Cycle-stable cyclic voltammograms with distinct oxidation and reduction waves reveal excellent reversibility and electrochromic switching over 200 cycles and confirm the high stability of the frameworks. Furthermore, high coloration efficiencies in the NIR region and fast switching speeds for coloration/decoloration as fast as 0.75 s/0.37 s for the Cz-ttTII COF and 0.61 s/0.29 s for the TAPB-ttTII COF at 550 nm excitation were observed, outperforming many known electrochromic materials, and offering options for a great variety of applications, such as stimuli-responsive coatings, optical information processing, or thermal control.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {The neglected influence of zinc oxide light-soaking on stability measurements of inverted organic solar cells},

author = {M G\"{u}nther and S Lotfi and S S Rivas and D Bl\"{a}tte and J P Hofmann and T Bein and T Ameri},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202209768},

doi = {https://doi.org/10.1002/adfm.202209768},

issn = {1616-301X},

year  = {2023},

date = {2023-01-15},

journal = {Advanced Functional Materials},

volume = {33},

number = {13},

pages = {2209768},

abstract = {Abstract Although zinc oxide (ZnO) is one of the most commonly used materials for electron transport layers in organic solar cells (OSCs), it also comes with disadvantages such as the so-called light-soaking issues, i.e., its need for exposure to UV light to reach its full potential in OSCs. Here, the impact of ZnO light-soaking issues on stability measurements of OSCs is investigated. It is found that in the absence of UV light a reversible degradation occurs, which is independent of the used active layer material and accelerates at higher temperatures but can be undone with a short UV exposure. This reversible aging is attributed to the re-adsorption of oxygen, which for manufacturing reasons is trapped at the interface of ZnO, even in an oxygen-free environment. This oxygen can be removed with a UV pretreatment of the ZnO but at the expense of device efficiency and production that has to take place in an oxygen-free environment. This study establishes that stability measurements of ZnO-containing OSCs must be performed exclusively with a light source including a UV part since the usage of a simple white light source \textendash as often reported in the literature \textendash can lead to erroneous results.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Covalent Organic Framework Thin-Film Photodetectors from Solution-Processable Porous Nanospheres},

author = {S Bag and H S Sasmal and S P Chaudhary and K Dey and D Bl\"{a}tte and R Guntermann and Y Zhang and M Polo\v{z}ij and A Kuc and A Shelke and R K Vijayaraghavan and T G Ajithkumar and S Bhattacharyya and T Heine and T Bein and R Banerjee},

url = {https://doi.org/10.1021/jacs.2c09838},

doi = {10.1021/jacs.2c09838},

issn = {0002-7863},

year  = {2023},

date = {2023-01-09},

journal = {Journal of the American Chemical Society},

volume = {145},

number = {3},

pages = {1649-1659},

abstract = {The synthesis of homogeneous covalent organic framework (COF) thin films on a desired substrate with decent crystallinity, porosity, and uniform thickness has great potential for optoelectronic applications. We have used a solution-processable sphere transmutation process to synthesize 300 ± 20 nm uniform COF thin films on a 2 × 2 cm2 TiO2-coated fluorine-doped tin oxide (FTO) surface. This process controls the nucleation of COF crystallites and molecular morphology that helps the nanospheres to arrange periodically to form homogeneous COF thin films. We have synthesized four COF thin films (TpDPP, TpEtBt, TpTab, and TpTta) with different functional backbones. In a close agreement between the experiment and density functional theory, the TpEtBr COF film showed the lowest optical band gap (2.26 eV) and highest excited-state lifetime (8.52 ns) among all four COF films. Hence, the TpEtBr COF film can participate in efficient charge generation and separation. We constructed optoelectronic devices having a glass/FTO/TiO2/COF-film/Au architecture, which serves as a model system to study the optoelectronic charge transport properties of COF thin films under dark and illuminated conditions. Visible light with a calibrated intensity of 100 mW cm\textendash2 was used for the excitation of COF thin films. All of the COF thin films exhibit significant photocurrent after illumination with visible light in comparison to the dark. Hence, all of the COF films behave as good photoactive substrates with minimal pinhole defects. The fabricated out-of-plane photodetector device based on the TpEtBr COF thin film exhibits high photocurrent density (2.65 ± 0.24 mA cm\textendash2 at 0.5 V) and hole mobility (8.15 ± 0.64 ×10\textendash3 cm2 V\textendash1 S\textendash1) compared to other as-synthesized films, indicating the best photoactive characteristics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Heterovalent Tin Alloying in Layered MA3Sb2I9 Thin Films: Assessing the Origin of Enhanced Absorption and Self-Stabilizing Charge States},

author = {A Weis and P Ganswindt and W Kaiser and H Illner and C Maheu and N Gl\"{u}ck and P D\"{o}rflinger and M Armer and V Dyakonov and J P Hofmann and E Mosconi and F De Angelis and T Bein},

url = {https://doi.org/10.1021/acs.jpcc.2c06106},

doi = {10.1021/acs.jpcc.2c06106},

issn = {1932-7447},

year  = {2022},

date = {2022-11-30},

journal = {The Journal of Physical Chemistry C},

volume = {126},

number = {49},

pages = {21040-21049},

abstract = {Heteroatom alloying of lead-free perovskite derivatives is a highly promising route to tailor their optoelectronic properties and stability for multiple applications. Here, we demonstrate the facile solution-based synthesis of Sn-alloyed layered MA3Sb2I9 thin films by precursor engineering, combining acetate and halide salts. An increasing concentration of tin halides in different oxidation states leads to a strong boost in absorption over the whole visible spectrum. We demonstrate phase-pure synthesis and elucidate the heterovalent incorporation of Sn into the MA3Sb2I9 lattice, proving the formation of additional electronic states in the bandgap by theoretical calculations. On this basis, we dissect the strong absorption increase into three components that we attribute to intervalence and heteroatom-induced interband absorption. Finally, we show the charge-stabilizing effect of the system through robustness toward precursors in mixed oxidation states and trace the improved ambient stability of this material back to this feature.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ground-state structures, electronic structure, transport properties and optical properties of Ca-based anti-Ruddlesden-Popper phase oxide perovskites},

author = {D Han and M-H Du and M Huang and S Wang and G Tang and T Bein and H Ebert},

url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.6.114601},

doi = {10.1103/PhysRevMaterials.6.114601},

year  = {2022},

date = {2022-11-07},

journal = {Physical Review Materials},

volume = {6},

number = {11},

pages = {114601},

abstract = {Anti-Ruddlesden-Popper (ARP) phase oxide perovskites Ca4OA2 (A=P, As, Sb, Bi) have recently attracted great interest in the field of ferroelectrics and thermoelectrics, whereas their optoelectronic application is limited by their indirect band gaps. In this work, we introduce A-site anion ordering in Ca4OA2 (A=P, As, Sb, Bi), and find that it induces an indirect-to-direct band gap transition. Using first-principles calculations, we study the ground-state structures, electronic structure, transport properties and optical properties of anion-ordered ARP phase oxide perovskites Ca4OAA′. Based on analyses of the lattice dynamics, the ground-state structures of Ca4OAsSb and Ca4OAsBi are identified in P4/nmm symmetry and those of Ca4OPSb and Ca4OPBi are in the I222 symmetry. In contrast to the Ruddlesden-Popper (RP) phase oxide and halide counterparts, Ca4OAA′ (AA′=PSb, PBi, AsSb, AsBi) show larger band dispersion along the out-of-plane direction, smaller band gaps and highly enhanced out-of-plane mobilities, which results from the short interlayer distances and the enhanced covalency of the pnictides. Although the out-of-plane mobilities of these n=1 ARP phase perovskites highly increase, the comparatively strong polar optical phonon scattering limits the further enhancement of their mobilities. Furthermore, compared to RP phase halide Cs2PbI2Cl2, Ca4OAA′ show strong optical absorption around the band edges, and their optical absorption coefficients can reach 10^5 cm−1 within the visible light region due to small band gaps. This study reveals that these ARP phase oxide perovskites exhibit the potential for optoelectronic applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Silver-Bismuth Based 2D Double Perovskites (4FPEA)4AgBiX8 (X = Cl, Br, I): Highly Oriented Thin Films with Large Domain Sizes and Ultrafast Charge-Carrier Localization},

author = {R Hooijer and A Weis and A Biewald and M T Sirtl and J Malburg and R Holfeuer and S Thamm and A Y Amin and M Righetto and A Hartschuh and L M Herz and T Bein},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202200354},

doi = {https://doi.org/10.1002/adom.202200354},

issn = {2195-1071},

year  = {2022},

date = {2022-07-03},

urldate = {2022-07-03},

journal = {Advanced Optical Materials},

volume = {10},

issue = {14},

pages = {2200354},

abstract = {Abstract Two-dimensional (2D) hybrid double perovskites are a promising emerging class of materials featuring superior intrinsic and extrinsic stability over their 3D parent structures, while enabling additional structural diversity and tunability. Here, we expand the Ag\textendashBi-based double perovskite system, comparing structures obtained with the halides chloride, bromide, and iodide and the organic spacer cation 4-fluorophenethylammonium (4FPEA) to form the n = 1 Ruddlesden\textendashPopper (RP) phases (4FPEA)4AgBiX8 (X = Cl, Br, I). We demonstrate access to the iodide RP-phase through a simple organic spacer, analyze the different properties as a result of halide substitution and incorporate the materials into photodetectors. Highly oriented thin films with very large domain sizes are fabricated and investigated with grazing incidence wide angle X-ray scattering, revealing a strong dependence of morphology on substrate choice and synthesis parameters. First-principles calculations confirm a direct band gap and show type Ib and IIb band alignment between organic and inorganic quantum wells. Optical characterization, temperature-dependent photoluminescence, and optical-pump terahertz-probe spectroscopy give insights into the absorption and emissive behavior of the materials as well as their charge-carrier dynamics. Overall, we further elucidate the possible reasons for the electronic and emissive properties of these intriguing materials, dominated by phonon-coupled and defect-mediated polaronic states.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Covalent Organic Framework Nanoplates Enable Solution-Processed Crystalline Nanofilms for Photoelectrochemical Hydrogen Evolution},

author = {L Yao and A Rodr\'{i}guez-Camargo and M Xia and D M\"{u}cke and R Guntermann and Y Liu and L Grunenberg and A Jim\'{e}nez-Solano and S T Emmerling and V Duppel and K Sivula and T Bein and H Qi and U Kaiser and M Gr\"{a}tzel and B V Lotsch},

url = {https://doi.org/10.1021/jacs.2c01433},

doi = {10.1021/jacs.2c01433},

issn = {0002-7863},

year  = {2022},

date = {2022-06-15},

journal = {Journal of the American Chemical Society},

volume = {144},

number = {23},

pages = {10291-10300},

abstract = {As covalent organic frameworks (COFs) are coming of age, the lack of effective approaches to achieve crystalline and centimeter-scale-homogeneous COF films remains a significant bottleneck toward advancing the application of COFs in optoelectronic devices. Here, we present the synthesis of colloidal COF nanoplates, with lateral sizes of ∼200 nm and average heights of 35 nm, and their utilization as photocathodes for solar hydrogen evolution. The resulting COF nanoplate colloid exhibits a unimodal particle-size distribution and an exceptional colloidal stability without showing agglomeration after storage for 10 months and enables smooth, homogeneous, and thickness-tunable COF nanofilms via spin coating. Photoelectrodes comprising COF nanofilms were fabricated for photoelectrochemical (PEC) solar-to-hydrogen conversion. By rationally designing multicomponent photoelectrode architectures including a polymer donor/COF heterojunction and a hole-transport layer, charge recombination in COFs is mitigated, resulting in a significantly increased photocurrent density and an extremely positive onset potential for PEC hydrogen evolution (over +1 V against the reversible hydrogen electrode), among the best of classical semiconductor-based photocathodes. This work thus paves the way toward fabricating solution-processed large-scale COF nanofilms and heterojunction architectures and their use in solar-energy-conversion devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Helical Anthracene\textendashEthyne-Based MOF-74 Analogue},

author = {P I Scheurle and A M\"{a}hringer and T Haug and A Biewald and D Axthammer and A Hartschuh and L Harms and G Wittstock and D D Medina and T Bein},

url = {https://doi.org/10.1021/acs.cgd.1c01145},

doi = {10.1021/acs.cgd.1c01145},

issn = {1528-7483},

year  = {2022},

date = {2022-05-04},

journal = {Crystal Growth \& Design},

volume = {22},

number = {5},

pages = {2849-2853},

abstract = {A flexible, electron-rich building block was integrated into the backbone of a metal\textendashorganic framework with a MOF-74 topology. The building block comprises a central anthracene core connected to acetylene groups. Solvothermal synthesis with Mn2+ yields a highly crystalline anthracene\textendashethyne-based MOF-74 structure. It shows an unusual helical rod-like morphology, exhibiting visible light absorption and photoluminescence.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A novel electrically conductive perylene diimide-based MOF-74 series featuring luminescence and redox activity},

author = {P I Scheurle and A Biewald and A M\"{a}hringer and A Hartschuh and D D Medina and T Bein},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/sstr.202100195},

doi = {https://doi.org/10.1002/sstr.202100195},

issn = {2688-4062},

year  = {2022},

date = {2022-01-11},

journal = {Small Structures},

volume = {n/a},

number = {n/a},

abstract = {Metal-organic frameworks (MOFs) featuring significant electrical conductivity constitute a growing class of materials, with intriguing possible applications as porous semiconductors or supercapacitors. If such features are combined with photoluminescence, additional functionalities such as selective chemical sensing become accessible. Here, we incorporate perylene diimide (PDI) based linear building blocks into the MOF-74 topology with the three metal ions Zn2+, Mg2+ and Ni2+, resulting in a new series of MOFs, namely PDI-MOF-74(M). PDI derivatives are dye molecules exhibiting remarkable optical properties, high electron mobilities, as well as interesting redox behavior. However, PDI-based 3D MOFs are very rare and to date were only reported once. The frameworks of the PDI-MOF-74(M) series exhibit high crystallinity, electrical conductivity and show well-defined redox activity. In addition, the frameworks of the series feature photoluminescence in the orange and red spectral regions. With this work we expand the series of electroactive MOF-74 structures as well as the group of 3D PDI-based MOFs, hence opening up the development of novel MOFs with promising optoelectronic properties comprising PDI building blocks. This article is protected by copyright. All rights reserved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {2D/3D Hybrid Cs2AgBiBr6 Double Perovskite Solar Cells: Improved Energy Level Alignment for Higher Contact-Selectivity and Large Open Circuit Voltage},

author = {M T Sirtl and R Hooijer and M Armer and F G Ebadi and M Mohammadi and C Maheu and A Weis and B T Van Gorkom and S H\"{a}ringer and R J Janssen and T Mayer and V Dyakonov and W Tress and T Bein},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202103215},

doi = {https://doi.org/10.1002/aenm.202103215},

issn = {1614-6832},

year  = {2022},

date = {2022-01-09},

journal = {Advanced Energy Materials},

volume = {n/a},

number = {n/a},

pages = {2103215},

abstract = {Abstract Since their introduction in 2017, the efficiency of lead-free halide perovskite solar cells based on Cs2AgBiBr6 has not exceeded 3%. The limiting bottlenecks are attributed to a low electron diffusion length, self-trapping events and poor selectivity of the contacts, leading to large non-radiative VOC losses. Here, 2D/3D hybrid double perovskites are introduced for the first time, using phenethyl ammonium as the constituting cation. The resulting solar cells show an increased efficiency of up to 2.5% for the champion cells and 2.03% on average, marking an improvement by 10% compared to the 3D reference on mesoporous TiO2. The effect is mainly due to a VOC improvement by up to 70 mV on average, yielding a maximum VOC of 1.18 V using different concentrations of phenethylammonium bromide. While these are among the highest reported VOC values for Cs2AgBiBr6 solar cells, the effect is attributed to a change in recombination behavior within the full device and a better selectivity at the interface toward the hole transporting material (HTM). This explanation is supported by voltage-dependent external quantum efficiency, as well as photoelectron spectroscopy, revealing a better energy level alignment and thus a better hole-extraction and improved electron blocking at the HTM interface.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Highly conductive titania supported iridium oxide nanoparticles with low overall iridium density as OER catalyst for large-scale PEM electrolysis},

author = {D B\"{o}hm and M Beetz and C Gebauer and M Bernt and J Schr\"{o}ter and M Kornherr and F Zoller and T Bein and D Fattakhova-Rohlfing},

url = {https://www.sciencedirect.com/science/article/pii/S2352940721001980},

doi = {https://doi.org/10.1016/j.apmt.2021.101134},

issn = {2352-9407},

year  = {2021},

date = {2021-09-01},

journal = {Applied Materials Today},

volume = {24},

pages = {101134},

abstract = {To enable future large-scale generation of hydrogen via proton exchange membrane (PEM) electrolysis, utilization of scarce iridium-based catalysts required for the oxygen evolution reaction (OER) has to be significantly lowered. To address this question, the facile synthesis of a highly active TiO2 supported iridium oxide based OER catalyst with reduced noble metal content and an Ir-density of the catalyst powder as low as 0.05\textendash0.08 gIr cm-3 is described in this work. A high surface area corrosion-resistant titania catalyst support homogeneously coated with a 1-2 nm thin layer of amorphous IrOOHx is oxidized in molten NaNO3 between 350-375°C. This procedure allows for a controllable phase transformation and crystallization to form a layer of interconnected IrO2 nanoparticles of ≈2 nm on the surface of the TiO2 support. The increase in crystallinity is thereby accompanied by a significant increase in conductivity of up to 11 S cm-1 for a 30 wt% Ir loaded catalyst. Oxidized samples further display a significantly increased stability with less detectable Ir dissolution under OER conditions. With a mass-based activity of 59 A g-1 at an overpotential of 300 mV, the electrocatalytic activity is maintained at the level of the highly active amorphous IrOOHx phase used as precursor and outperforms it at higher current densities through the increased conductivity. MEA measurements with catalyst loadings of 0.2-0.3 mg cm-2 further confirm the high catalytic activity and initial stability at industrially relevant current densities. The introduced synthesis approach therefore shows a path for the fabrication of novel highly active and atom-efficient oxide supported catalysts with complex nanostructures and thin homogenous nanoparticle coatings that allows a future large-scale application of PEM electrolysis technology without restrictions by the natural abundance of iridium.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Selective functionalization of the 1H-imidazo[1,2-b]pyrazole scaffold. A new potential non-classical isostere of indole and a precursor of push\textendashpull dyes},

author = {K Schw\"{a}rzer and S K Rout and D Bessinger and F Lima and C E Brocklehurst and K Karaghiosoff and T Bein and P Knochel},

url = {http://dx.doi.org/10.1039/D1SC04155J},

doi = {10.1039/D1SC04155J},

issn = {2041-6520},

year  = {2021},

date = {2021-08-30},

urldate = {2021-08-30},

journal = {Chemical Science},

volume = {12},

number = {39},

pages = {12993-13000},

abstract = {We report the selective functionalization of the 1H-imidazo[1,2-b]pyrazole scaffold using a Br/Mg-exchange, as well as regioselective magnesiations and zincations with TMP-bases (TMP = 2,2,6,6-tetramethylpiperidyl), followed by trapping reactions with various electrophiles. In addition, we report a fragmentation of the pyrazole ring, giving access to push\textendashpull dyes with a proaromatic (1,3-dihydro-2H-imidazol-2-ylidene)malononitrile core. These functionalization methods were used in the synthesis of an isostere of the indolyl drug pruvanserin. Comparative assays between the original drug and the isostere showed that a substitution of the indole ring with a 1H-imidazo[1,2-b]pyrazole results in a significantly improved solubility in aqueous media.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Overcoming the Challenges of Freestanding Tin Oxide-Based Composite Anodes to Achieve High Capacity and Increased Cycling Stability},

author = {F Zoller and S H\"{a}ringer and D B\"{o}hm and H Illner and M D\"{o}blinger and Z K Sofer and M Finsterbusch and T Bein and D Fattakhova-Rohlfing},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202106373},

doi = {https://doi.org/10.1002/adfm.202106373},

issn = {1616-301X},

year  = {2021},

date = {2021-08-27},

journal = {Advanced Functional Materials},

volume = {31},

number = {43},

pages = {2106373},

abstract = {Abstract Freestanding electrodes are a promising way to increase the energy density of the batteries by decreasing the overall amount of electrochemically inactive materials. Freestanding antimony doped tin oxide (ATO)-based hybrid materials have not been reported so far, although this material has demonstrated excellent performance in conventionally designed electrodes. Two different strategies, namely electrospinning and freeze-casting, are explored for the fabrication of ATO-based hybrid materials. It is shown that the electrospinning of ATO/carbon based electrodes from polyvinyl pyrrolidone polymer (PVP) solutions was not successful, as the resulting electrode material suffers from rapid degradation. However, freestanding reduced graphene oxide (rGO) containing ATO/C/rGO nanocomposites prepared via a freeze-casting route demonstrates an impressive rate and cycling performance reaching 697 mAh g−1 at a high current density of 4 A g−1, which is 40 times higher as compared to SnO2/rGO and also exceeds the freestanding SnO2-based composites reported so far. Antimony doping of the nanosized tin oxide phase and carbon coating are thereby shown to be essential factors for appealing electrochemical performance. Finally, the freestanding ATO/C/rGO anodes are combined with freestanding LiFe0.2Mn0.8PO4/rGO cathodes to obtain a full freestanding cell operating without metal current collector foils showing nonetheless an excellent cycling stability.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ultra‐Thin Protective Coatings for Sustained Photoelectrochemical Water Oxidation with Mo: BiVO4},

author = {M Beetz and S H\"{a}ringer and P Els\"{a}sser and J Kampmann and L Sauerland and F Wolf and M G\"{u}nther and A Fischer and T Bein},

url = {https://doi.org/10.1002/adfm.202011210},

issn = {1616-301X},

year  = {2021},

date = {2021-08-12},

urldate = {2021-08-12},

journal = {Advanced Functional Materials},

pages = {2011210},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Design of High-Performance Lead-Free Quaternary Antiperovskites for Photovoltaics via Ion Type Inversion and Anion Ordering},

author = {D Han and C Feng and M-H Du and T Zhang and S Wang and G Tang and T Bein and H Ebert},

url = {https://doi.org/10.1021/jacs.1c06403},

doi = {10.1021/jacs.1c06403},

issn = {0002-7863},

year  = {2021},

date = {2021-08-02},

urldate = {2021-08-02},

journal = {Journal of the American Chemical Society},

volume = {143},

number = {31},

pages = {12369-12379},

abstract = {The emergence of halide double perovskites significantly increases the compositional space for lead-free and air-stable photovoltaic absorbers compared to halide perovskites. Nevertheless, most halide double perovskites exhibit oversized band gaps (\>1.9 eV) or dipole-forbidden optical transition, which are unfavorable for efficient single-junction solar cell applications. The current device performance of halide double perovskite is still inferior to that of lead-based halide perovskites, such as CH3NH3PbI3 (MAPbI3). Here, by ion type inversion and anion ordering on perovskite lattice sites, two new classes of pnictogen-based quaternary antiperovskites with the formula of X6B2AA′ and X6BB′A2 are designed. Phase stability and tunable band gaps in these quaternary antiperovskites are demonstrated based on first-principles calculations. Further photovoltaic-functionality-directed screening of these materials leads to the discovery of 5 stable compounds (Ca6N2AsSb, Ca6N2PSb, Sr6N2AsSb, Sr6N2PSb, and Ca6NPSb2) with suitable direct band gaps, small carrier effective masses and low exciton binding energies, and dipole-allowed strong optical absorption, which are favorable properties for a photovoltaic absorber material. The calculated theoretical maximum solar cell efficiencies based on these five compounds are all larger than 29%, comparable to or even higher than that of the MAPbI3 based solar cell. Our work reveals the huge potential of quaternary antiperovskites in the optoelectronic field and provides a new strategy to design lead-free and air-stable perovskite-based photovoltaic absorber materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {MOF-74(M) Films Obtained through Vapor-Assisted Conversion\textemdashImpact on Crystal Orientation and Optical Properties},

author = {P I Scheurle and A M\"{a}hringer and A Biewald and A Hartschuh and T Bein and D D Medina},

url = {https://doi.org/10.1021/acs.chemmater.1c00743},

doi = {10.1021/acs.chemmater.1c00743},

issn = {0897-4756},

year  = {2021},

date = {2021-07-28},

journal = {Chemistry of Materials},

volume = {33},

number = {15},

pages = {5896-5904},

abstract = {In recent years, metal\textendashorganic frameworks (MOFs) with the structure MOF-74 have attracted much interest owing to their tunable pore aperture, high surface area, and electrical conductivity. The synthesis of well-defined, highly crystalline thin films of MOF-74 is of paramount importance for their implementation into device-based applications such as in chemical sensing, optoelectronics, gas storage, and separations. Here, we present the synthesis of highly crystalline MOF-74 (M = Zn2+, Mg2+, Ni2+, and Co2+) films by vapor-assisted conversion. MOF-74(M) thin films were grown on bare glass, quartz, gold, and silicon surfaces, showing high crystallinity, crystal orientation, and average thicknesses of 500 nm. By including a benzoic acid modulator, oriented MOF-74(Zn) films, with the crystallographic c-axis of the MOF crystallites oriented horizontally to the surface, were obtained on all substrates. In addition, highly crystalline MOF-74(Mg) was grown on glass and gold substrates with the crystallographic c-axis aligned orthogonally to the surface. Moreover, randomly oriented highly crystalline MOF-74(Co) and MOF-74(Ni) films were synthesized on glass, quartz, gold, and silicon. The pore accessibility of the obtained films was examined by means of krypton sorption measurements, revealing permanent and accessible porosity, reaching a BET surface area of 975 cm2/cm2 for MOF-74(Mg). Steady-state and time-resolved photoluminescence studies show emission in the blue spectral region of MOF-74(Zn and Mg) on quartz with a biexponential decay. In addition, confocal photoluminescence mapping confirmed a homogeneous MOF film surface with a similar emission profile over the whole examined area of 70 μm × 70 μm.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {1,10-Phenanthroline as an Efficient Bifunctional Passivating Agent for MAPbI3 Perovskite Solar Cells},

author = {A Buyruk and D Bl\"{a}tte and M G\"{u}nther and M A Scheel and N F Hartmann and M D\"{o}blinger and A Weis and A Hartschuh and P M\"{u}ller-Buschbaum and T Bein and T Ameri},

url = {https://doi.org/10.1021/acsami.1c05055},

doi = {10.1021/acsami.1c05055},

issn = {1944-8244},

year  = {2021},

date = {2021-07-09},

urldate = {2021-07-09},

journal = {ACS Applied Materials \& Interfaces},

abstract = {Passivation is one of the most promising concepts to heal defects created at the surface and grain boundaries of polycrystalline perovskite thin films, which significantly deteriorate the photovoltaic performance and stability of corresponding devices. Here, 1,10-phenanthroline, known as a bidentate chelating ligand, is implemented between the methylammonium lead iodide (MAPbI3) film and the hole-transport layer for both passivating the lead-based surface defects (undercoordinated lead ions) and converting the excess/unreacted lead iodide (PbI2) buried at interfaces, which is problematic for the long-term stability, into “neutralized” and beneficial species (PbI2(1,10-phen)x},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The Bottlenecks of Cs2AgBiBr6 Solar Cells: How Contacts and Slow Transients Limit the Performance},

author = {M T Sirtl and F Ebadi and Van B T Gorkom and P Ganswindt and R J a Janssen and T Bein and W Tress},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202100202},

doi = {https://doi.org/10.1002/adom.202100202},

issn = {2195-1071},

year  = {2021},

date = {2021-06-21},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2100202},

abstract = {Abstract Cs2AgBiBr6 has attracted much interest as a potential lead-free alternative for perovskite solar cells. Although this material offers encouraging optoelectronic features, severe bottlenecks limit the performance of the resulting solar cells to a power conversion efficiency of below 3%. Here, the performance-limiting factors of this material are investigated in full solar cells featuring various architectures. It is found that the photovoltaic parameters of Cs2AgBiBr6-based solar cells strongly depend on the scan speed of the J/V measurements, suggesting a strong impact of ionic conductivity in the material. Moreover, a sign change of the photocurrent for bias voltages above 0.9 V during the measurement of the external quantum efficiency (EQE) is revealed, which can be explained by non-selective contacts. The radiative loss of the VOC from sensitive subgap-EQE measurements is calculated and it is revealed that the loss is caused by a low external luminescence yield and therefore a high non-radiative recombination, supported by the first report of a strongly red shifted electroluminescence signal between 800 and 1000 nm. Altogether, these results point to a poor selectivity of the contacts and charge transport layers, caused by poor energy level alignment that can be overcome by optimizing the architecture of the solar cell.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dehydrogenative 6π heterocyclization under visible light irradiation and mechanistic insights},

author = {Z Zhang and H Chen and N Keller and Q Xiong and L Liu and Y Lan and T Bein and J Li},

url = {http://dx.doi.org/10.1039/D1QO00356A},

doi = {10.1039/D1QO00356A},

year  = {2021},

date = {2021-05-07},

journal = {Organic Chemistry Frontiers},

volume = {8},

number = {14},

pages = {3788-3795},

abstract = {A visible-light-driven oxidative 6π heterocyclization for the synthesis of structurally diverse π-conjugated polycyclic 1-aminoisoquinolines has been developed. The reaction proceeds under visible-light or sunlight, obviates the need for photocatalysts and transition-metals, and features an unusually broad substrate scope and high efficacy. This synthetic pathway provided an easy access to highly fluorescent small molecules with high photoluminescence quantum yields. The N-heterocycles exhibit suitable optical properties for application as fluorescence quantum yield standards. DFT calculations were employed to gain insight into the mechanism and the results show that deprotonation is the rate-determining step, which can be promoted by a TFA additive.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Increasing Photostability of Inverted Nonfullerene Organic Solar Cells by Using Fullerene Derivative Additives},

author = {M G\"{u}nther and D Bl\"{a}tte and A L Oechsle and S S Rivas and Yousefi A A Amin and P M\"{u}ller-Buschbaum and T Bein and T Ameri},

url = {https://doi.org/10.1021/acsami.1c00700},

doi = {10.1021/acsami.1c00700},

issn = {1944-8244},

year  = {2021},

date = {2021-04-16},

urldate = {2021-04-16},

journal = {ACS Applied Materials \& Interfaces},

abstract = {Organic solar cells (OSCs) recently achieved efficiencies of over 18% and are well on their way to practical applications, but still considerable stability issues need to be overcome. One major problem emerges from the electron transport material zinc oxide (ZnO), which is mainly used in the inverted device architecture and decomposes many high-performance nonfullerene acceptors due to its photocatalytic activity. In this work, we add three different fullerene derivatives\textemdashPC71BM, ICMA, and BisPCBM\textemdashto an inverted binary PBDB-TF:IT-4F system in order to suppress the photocatalytic degradation of IT-4F on ZnO via the radical scavenging abilities of the fullerenes. We demonstrate that the addition of 5% fullerene not only increases the performance of the binary PBDB-TF:IT-4F system but also significantly improves the device lifetime under UV illumination in an inert atmosphere. While the binary devices lose 20% of their initial efficiency after only 3 h, this time is increased fivefold for the most promising ternary devices with ICMA. We attribute this improvement to a reduced photocatalytic decomposition of IT-4F in the ternary system, which results in a decreased recombination. We propose that the added fullerenes protect the IT-4F by acting as a sacrificial reagent, thereby suppressing the trap state formation. Furthermore, we show that the protective effect of the most promising fullerene ICMA is transferable to two other binary systems PBDB-TF:BTP-4F and PTB7-Th:IT-4F. Importantly, this effect can also increase the air stability of PBDB-TF:IT-4F. This work demonstrates that the addition of fullerene derivatives is a transferable and straightforward strategy to improve the stability of OSCs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {An electrically conducting three-dimensional iron-catecholate porous framework},

author = {A M\"{a}hringer and M D\"{o}blinger and M Hennemann and C Gruber and D Fehn and P I Scheurle and P Hosseini and I Santourian and A Schirmacher and J M Rotter and G Wittstock and K Meyer and T Clark and T Bein and D D Medina},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202102670},

doi = {https://doi.org/10.1002/anie.202102670},

issn = {1433-7851},

year  = {2021},

date = {2021-03-29},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

abstract = {Here, we report the synthesis of a unique cubic metal-organic framework (MOF), the Fe-HHTP-MOF, comprising hexahydroxytriphenylene (HHTP) supertetrahedral units and FeIII ions, arranged in a diamond topology. The MOF is synthesized under solvothermal conditions, yielding a highly crystalline, deep black powder, with crystallites of 300-500 nm size and tetrahedral morphology. Nitrogen sorption analysis indicates a highly porous material with a surface area exceeding 1400 m2 g−1. Furthermore, Fe-HHTP-MOF shows broadband absorption from 475 nm up to 1900 nm with excellent absorption capability of 98.5% of the incoming light over the visible spectral region. Electrical conductivity measurements of pressed pellets reveal a high intrinsic electrical conductivity of up to 10−3 S cm−1. Quantum mechanical calculations predict Fe-HHTP-MOF to be an efficient electron conductor, exhibiting continuous charge-carrier pathways throughout the structure. This report expands the paradigm of intrinsically electroactive MOFs, serving as a solid basis for the development of highly porous, ordered frameworks with enhanced electrical conductivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Fast-Switching Vis\textendashIR Electrochromic Covalent Organic Frameworks},

author = {D Bessinger and K Muggli and M Beetz and F Auras and T Bein},

url = {https://doi.org/10.1021/jacs.0c12392},

doi = {10.1021/jacs.0c12392},

issn = {0002-7863},

year  = {2021},

date = {2021-03-16},

journal = {Journal of the American Chemical Society},

abstract = {Electrochromic coatings are promising for applications in smart windows or energy-efficient optical displays. However, classical inorganic electrochromic materials such as WO3 suffer from low coloration efficiency and slow switching speed. We have developed highly efficient and fast-switching electrochromic thin films based on fully organic, porous covalent organic frameworks (COFs). The low band gap COFs have strong vis\textendashNIR absorption bands in the neutral state, which shift significantly upon electrochemical oxidation. Fully reversible absorption changes by close to 3 OD can be triggered at low operating voltages and low charge per unit area. Our champion material reaches an electrochromic coloration efficiency of 858 cm2 C\textendash1 at 880 nm and retains \>95% of its electrochromic response over 100 oxidation/reduction cycles. Furthermore, the electrochromic switching is extremely fast with response times below 0.4 s for the oxidation and around 0.2 s for the reduction, outperforming previous COFs by at least an order of magnitude and rendering these materials some of the fastest-switching frameworks to date. This combination of high coloration efficiency and very fast switching reveals intriguing opportunities for applications of porous organic electrochromic materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Transition-Metal-Free Synthesis of Polyfunctional Triarylmethanes and 1,1-Diarylalkanes by Sequential Cross-Coupling of Benzal Diacetates with Organozinc Reagents},

author = {B Wei and Q Ren and T Bein and P Knochel},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202101682},

doi = {https://doi.org/10.1002/anie.202101682},

issn = {1433-7851},

year  = {2021},

date = {2021-02-24},

journal = {Angewandte Chemie International Edition},

volume = {60},

number = {18},

pages = {10409-10414},

abstract = {Abstract A variety of functionalized triarylmethane and 1,1-diarylalkane derivatives were prepared via a transition-metal-free, one-pot and two-step procedure, involving the reaction of various benzal diacetates with organozinc reagents. A sequential cross-coupling is enabled by changing the solvent from THF to toluene, and a two-step SN1-type mechanism was proposed and evidenced by experimental studies. The synthetic utility of the method is further demonstrated by the synthesis of several biologically relevant molecules, such as an anti-tuberculosis agent, an anti-breast cancer agent, a precursor of a sphingosine-1-phosphate (S1P) receptor modulator, and a FLAP inhibitor.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Optoelectronic processes in covalent organic frameworks},

author = {N Keller and T Bein},

url = {http://dx.doi.org/10.1039/D0CS00793E},

doi = {10.1039/D0CS00793E},

issn = {0306-0012},

year  = {2020},

date = {2020-12-17},

journal = {Chemical Society Reviews},

abstract = {Covalent organic frameworks (COFs) are crystalline porous materials constructed from molecular building blocks using diverse linkage chemistries. Their modular construction system allows not only for tailor-made design but also for an immense variety of building blocks, opening the door to numerous different functionalities and potential applications. As a consequence, a large number of building blocks that can act as light-harvesters, semiconductors, ligands, binding sites or redox centers have recently been integrated into the scaffolds of COFs. This unique combination of reticular chemistry with the molecular control of intrinsic properties paves the way towards the design of new semiconducting materials for (opto-)electronic applications such as sensors, photocatalysts or -electrodes, supercapacitor and battery materials, solar-harvesting devices or light emitting diodes. With new developments regarding the linkage motif, highly stable but still tunable COFs have been developed for applications even under harsh conditions. Further, the molecular stacking modes and distances in the COFs have been investigated as a powerful means to control optical and electrical characteristics of these self-assembled frameworks. Advanced understanding of optoelectronic processes in COFs has enabled their implementation in optoelectronic devices with promising potential for real-world applications. This review highlights the key developments of design concepts for the synthesis of electro- and photoactive COFs as well as our understanding of optoelectronic processes in these frameworks, hence establishing a new paradigm for the rational construction of well-defined novel optoelectronic materials and devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Optoelectronic Properties of Cs2AgBiBr6 Thin Films: The Influence of Precursor Stoichiometry},

author = {M T Sirtl and M Armer and L K Reb and R Hooijer and P D\"{o}rflinger and M A Scheel and K Tvingstedt and P Rieder and N Gl\"{u}ck and P Pandit and S V Roth and P M\"{u}ller-Buschbaum and V Dyakonov and T Bein},

url = {https://doi.org/10.1021/acsaem.0c01308},

doi = {10.1021/acsaem.0c01308},

year  = {2020},

date = {2020-11-25},

journal = {ACS Applied Energy Materials},

abstract = {Lead-free double perovskites have recently attracted growing attention as possible alternatives to lead-based halide perovskites in photovoltaics and other optoelectronic applications. The most prominent compound Cs2AgBiBr6, however, presents issues such as a rather large and indirect band gap, high exciton binding energies, and poor charge carrier transport, especially in thin films. In order to address some of these challenges, we systematically modified the stoichiometry of the precursors used for the synthesis of thin films toward a BiBr3-deficient system. In combination with a stoichiometric excess of AgBr, we obtained highly oriented double perovskite thin films. These modifications directly boost the lifetime of the charge carriers up to 500 ns as observed by time-resolved photoluminescence spectroscopy. Moreover, time-resolved microwave conductivity studies revealed an increase of the charge carrier mobility from 3.5 to around ∼5 cm2/(V s). Solar cells comprising the modified films as planar active layers reached power conversion efficiency (PCE) values up to 1.11%, exceeding the stoichiometric reference film (∼0.97%), both on average and with champion cells. The results in this work underline the importance of controlling the nanomorphology of the bulk film. We anticipate that control of precursor stoichiometry will also offer a promising approach for enhancing the efficiency of other perovskite photovoltaic absorber materials and thin films.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {V(III)-Doped Nickel Oxide-Based Nanocatalysts for Electrochemical Water Splitting: Influence of Phase, Composition, and Doping on the Electrocatalytic Activity},

author = {D B\"{o}hm and M Beetz and C Kutz and S Zhang and C Scheu and T Bein and D Fattakhova-Rohlfing},

url = {https://doi.org/10.1021/acs.chemmater.0c02851},

doi = {10.1021/acs.chemmater.0c02851},

issn = {0897-4756},

year  = {2020},

date = {2020-11-16},

journal = {Chemistry of Materials},

volume = {32},

number = {24},

pages = {10394-10406},

abstract = {Doped nickel oxide-based compounds are attracting great interest as very efficient and abundant catalysts and were thoroughly investigated as battery materials in the past. However, there is still no clear understanding of the influence of dopants on the complex dynamic character of their chemically and potentially driven transformations. We have developed a synthesis procedure enabling the controlled formation of nanosized nickel hydroxide and nickel oxide polymorphs substituted with vanadium(III) [V(III)] ions and further investigated their structure\textendashactivity correlation for electrochemical water oxidation. This work therefore primarily focuses on an in-depth structural characterization of the homogeneously doped nanosized α- and β-Ni(OH)2 polymorphs. It could be shown that concentrations of 10 at. % V(III) and higher can effectively inhibit a spontaneous phase transformation known as chemical aging of the turbostratic α-phase to the more crystalline β-Ni(OH)2 phase in neutral aqueous media. The Fe-impurity-biased electrocatalytic activity determined for α-/β-Ni1\textendashxVx(OH)2 showed only a minor increase of 10% oxygen evolution reaction (OER) activity for an 1 at. % doped nonaged sample resembling the α-phase, while a 5 at. % V(III)-doped sample chemically aged over 24 h led to a doubled OER activity versus the undoped reference which transformed into β-Ni(OH)2 over that period of time.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Highly conducting Wurster-type twisted covalent organic frameworks},

author = {J M Rotter and R Guntermann and M Auth and A M\"{a}hringer and A Sperlich and V Dyakonov and D D Medina and T Bein},

url = {http://dx.doi.org/10.1039/D0SC03909H},

doi = {10.1039/D0SC03909H},

issn = {2041-6520},

year  = {2020},

date = {2020-10-27},

urldate = {2020-10-27},

journal = {Chemical Science},

volume = {11},

number = {47},

pages = {12843-12853},

abstract = {Covalent organic frameworks (COFs) define a versatile structural paradigm combining attractive properties such as crystallinity, porosity, and chemical and structural modularity which are valuable for various applications. For the incorporation of COFs into optoelectronic devices, efficient charge carrier transport and intrinsic conductivity are often essential. Here, we report the synthesis of two imine-linked two-dimensional COFs, WTA and WBDT, featuring a redox-active Wurster-type motif based on the twisted tetragonal N,N,N′,N′-tetraphenyl-1,4-phenylenediamine node. By condensing this unit with either terephthalaldehyde (TA) or benzodithiophene dialdehyde (BDT), COFs featuring a dual-pore kagome-type structure were obtained as highly crystalline materials with large specific surface areas and mesoporosity. In addition, the experimentally determined high conduction band energies of both COFs render them suitable candidates for oxidative doping. The incorporation of a benzodithiophene linear building block into the COF allows for high intrinsic macroscopic conductivity. Both anisotropic and average isotropic electrical conductivities were determined with van der Pauw measurements using oriented films and pressed pellets, respectively. Furthermore, the impact of different dopants such as F4TCNQ, antimony pentachloride and iodine on the conductivities of the resulting doped COFs was studied. By using the strong organic acceptor F4TCNQ, a massive increase of the radical cation density (up to 0.5 radicals per unit cell) and long-term stable electrical conductivity as high as 3.67 S m−1 were achieved for the anisotropic transport in an oriented film, one of the highest for any doped COF to date. Interestingly, no significant differences between isotropic and anisotropic charge transport were found in films and pressed pellets. This work expands the list of possible building nodes for electrically conducting COFs from planar systems to twisted geometries. The achievement of high and stable electrical conductivity paves the way for possible applications of new COFs in organic (opto)electronics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Energy Efficient Ultrahigh Flux Separation of Oily Pollutants from Water with Superhydrophilic Nanoscale Metal\textendashOrganic Framework Architectures},

author = {A M\"{a}hringer and M Hennemann and T Clark and T Bein and D D Medina},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202012428},

doi = {https://doi.org/10.1002/anie.202012428},

issn = {1433-7851},

year  = {2020},

date = {2020-10-05},

journal = {Angewandte Chemie International Edition},

volume = {60},

number = {10},

pages = {5519-5526},

abstract = {Abstract The rising demand for clean water for a growing and increasingly urban global population is one of the most urgent issues of our time. Here, we introduce the synthesis of a unique nanoscale architecture of pillar-like Co-CAT-1 metal\textendashorganic framework (MOF) crystallites on gold-coated woven stainless steel meshes with large, 50 μm apertures. These nanostructured mesh surfaces feature superhydrophilic and underwater superoleophobic wetting properties, allowing for gravity-driven, highly efficient oil\textendashwater separation featuring water fluxes of up to nearly one million L m−2 h−1. Water physisorption experiments reveal the hydrophilic nature of Co-CAT-1 with a total water vapor uptake at room temperature of 470 cm3 g−1. Semiempirical molecular orbital calculations shed light on water affinity of the inner and outer pore surfaces. The MOF-based membranes enable high separation efficiencies for a number of liquids tested, including the notorious water pollutant, crude oil, affording chemical oxygen demand (COD) concentrations below 25 mg L−1 of the effluent. Our results demonstrate the great impact of suitable nanoscale surface architectures as a means of encoding on-surface extreme wetting properties, yielding energy-efficient water-selective large-aperture membranes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Prospects of lead-free perovskite-inspired materials for photovoltaic applications},

author = {N Gl\"{u}ck and T Bein},

url = {http://dx.doi.org/10.1039/D0EE01651A},

doi = {10.1039/D0EE01651A},

issn = {1754-5692},

year  = {2020},

date = {2020-09-14},

journal = {Energy \& Environmental Science},

volume = {13},

number = {12},

pages = {4691-4716},

abstract = {With hybrid lead halide perovskites, a new class of materials for photovoltaics emerged, approaching GaAs in their optoelectronic properties. However, issues concerning toxicity and instability of lead-based perovskites impede their commercialization. Therefore, alternative lead-free solution-processable semiconductors have attracted increasing attention. The focus is mainly on compounds with structural similarities to the three-dimensional network of the lead halide octahedra in the perovskite structure. Furthermore, additional metal halides or chalcogenides have emerged with non-perovskite-related crystal structures but promising physical properties. This review will discuss recent progress on lead-free perovskite-inspired materials suitable for optoelectronics, considering their structure as well as their physical properties and resulting implications for device applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Local Disorder at the Phase Transition Interrupts Ambipolar Charge Carrier Transport in Large Crystal Methylammonium Lead Iodide Thin Films},

author = {A Biewald and N Giesbrecht and T Bein and P Docampo and A Hartschuh and R Ciesielski},

url = {https://doi.org/10.1021/acs.jpcc.0c06240},

doi = {10.1021/acs.jpcc.0c06240},

issn = {1932-7447},

year  = {2020},

date = {2020-08-25},

journal = {The Journal of Physical Chemistry C},

volume = {124},

number = {38},

pages = {20757-20764},

abstract = {The low-temperature transition from a tetragonal to an orthorhombic crystal phase in methylammonium lead iodide (MAPI) is accompanied by drastic changes in the charge carrier mobility around a critical temperature of approximately 164 K. This transition is studied here using photoluminescence (PL) microscopy on large crystal MAPI thin films, which is extremely sensitive to modifications of the charge carrier dynamics and can resolve physical properties on a single-grain level. The key observation is that ambipolar charge carrier diffusion suddenly stops when the temperature falls below the phase transition temperature. From coexisting PL bands and their spatial distribution, it is concluded that the temperature range from just below the phase transition until about 150 K is determined by a mixed phase where small orthorhombic and tetragonal domains coexist. This results in local disorder, which hinders ambipolar charge carrier diffusion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Freestanding LiFe0.2Mn0.8PO4/rGO nanocomposites as high energy density fast charging cathodes for lithium-ion batteries},

author = {F Zoller and D B\"{o}hm and J Luxa and M D\"{o}blinger and Z Sofer and D Semenenko and T Bein and D Fattakhova-Rohlfing},

url = {https://www.sciencedirect.com/science/article/pii/S2468606920300356},

doi = {https://doi.org/10.1016/j.mtener.2020.100416},

issn = {2468-6069},

year  = {2020},

date = {2020-06-01},

journal = {Materials Today Energy},

volume = {16},

pages = {100416},

abstract = {Freestanding electrodes for lithium ion batteries are considered as a promising option to increase the total gravimetric energy density of the cells due to a decreased weight of electrochemically inactive materials. We report a simple procedure for the fabrication of freestanding LiFe0.2Mn0.8PO4 (LFMP)/rGO electrodes with a very high loading of active material of 83 wt%, high total loading of up to 8 mg cm−2, high energy density, excellent cycling stability and at the same time very fast charging rate, with a total performance significantly exceeding the values reported in the literature. The keys to the improved electrode performance are optimization of LFMP nanoparticles via nanoscaling and doping; the use of graphene oxide (GO) with its high concentration of surface functional groups favoring the adhesion of high amounts of LFMP nanoparticles, and freeze-casting of the GO-based nanocomposites to prevent the morphology collapse and provide a unique fluffy open microstructure of the freestanding electrodes. The rate and the cycling performance of the obtained freestanding electrodes are superior compared to their Al-foil coated equivalents, especially when calculated for the entire weight of the electrode, due to the extremely reduced content of electrochemically inactive material (17 wt% of electrochemically inactive material in case of the freestanding compared to 90 wt% for the Al-foil based electrode), resulting in 120 mAh g−1electrode in contrast to 10 mAh g−1electrode at 0.2 C. The electrochemical performance of the freestanding LFMP/rGO electrodes is also considerably better than the values reported in literature for freestanding LFMP and LMP composites, and can even keep up with those of LFP-based analogues. The freestanding LFMP/rGO reported in this work is additionally attractive due to its high gravimetric energy density (604 Wh kg−1LFMP at 0.2C). The obtained results demonstrate the advantage of freestanding LiFe0.2Mn0.8PO4/rGO electrodes and their great potential for applications in lithium ion batteries.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Formation of stable 2D methylammonium antimony iodide phase for lead-free perovskite-like solar cells*},

author = {N Giesbrecht and A Weis and T Bein},

url = {http://dx.doi.org/10.1088/2515-7655/ab78ef},

doi = {10.1088/2515-7655/ab78ef},

issn = {2515-7655},

year  = {2020},

date = {2020-03-20},

journal = {Journal of Physics: Energy},

volume = {2},

number = {2},

pages = {024007},

abstract = {The presence of lead in novel hybrid perovskite-based solar cells remains a significant issue regarding commercial applications. Therefore, antimony-based perovskite-like A3M2X9 structures are promising new candidates for low toxicity photovoltaic applications. So far, MA3Sb2I9 was reported to only crystallize in the ‘zero-dimensional’ (0D) dimer structure with wide indirect bandgap properties. However, the formation of the 2D layered polymorph is more suitable for solar cell applications due to its expected direct and narrow bandgap. Here, we demonstrate the first synthesis of phase pure 2D layered MA3Sb2I9, based on antimony acetate dissolved in alcoholic solvents. Using in situ XRD methods, we confirm the stability of the layered phase towards high temperature, but the exposure to 75% relative humidity for several hours leads to a rearrangement of the phase with partial formation of the 0D structure. We investigated the electronic band structure and confirmed experimentally the presence of a semi-direct bandgap at around 2.1 eV. Our work shows that careful control of nucleation via processing conditions can provide access to promising perovskite-like phases for photovoltaic applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dibenzochrysene enables tightly controlled docking and stabilizes photoexcited states in dual-pore covalent organic frameworks},

author = {N Keller and T Sick and N N Bach and A Koszalkowski and J M Rotter and D D Medina and T Bein},

url = {http://dx.doi.org/10.1039/C9NR08007D},

doi = {10.1039/C9NR08007D},

issn = {2040-3364},

year  = {2019},

date = {2019-11-08},

urldate = {2019-11-08},

journal = {Nanoscale},

volume = {11},

number = {48},

pages = {23338-23345},

abstract = {Covalent organic frameworks (COFs), consisting of covalently connected organic building units, combine attractive features such as crystallinity, open porosity and widely tunable physical properties. For optoelectronic applications, the incorporation of heteroatoms into a 2D COF has the potential to yield desired photophysical properties such as lower band gaps, but can also cause lateral offsets of adjacent layers. Here, we introduce dibenzo[g,p]chrysene (DBC) as a novel building block for the synthesis of highly crystalline and porous 2D dual-pore COFs showing interesting properties for optoelectronic applications. The newly synthesized terephthalaldehyde (TA), biphenyl (Biph), and thienothiophene (TT) DBC-COFs combine conjugation in the a,b-plane with a tight packing of adjacent layers guided through the molecular DBC node serving as specific docking site for successive layers. The resulting DBC-COFs exhibit a hexagonal dual-pore kagome geometry, which is comparable to COFs containing another molecular docking site, namely 4,4′,4′′,4′′′-(ethylene-1,1,2,2-tetrayl)-tetraaniline (ETTA). In this context, the respective interlayer distances decrease from about 4.6 r{A} in ETTA-COFs to about 3.6 r{A} in DBC-COFs, leading to well-defined hexagonally faceted single crystals sized about 50\textendash100 nm. The TT DBC-COF features broad light absorption covering large parts of the visible spectrum, while Biph DBC-COF shows extraordinary excited state lifetimes exceeding 10 ns. In combination with the large number of recently developed linear conjugated building blocks, the new DBC tetra-connected node is expected to enable the synthesis of a large family of highly correlated and ordered 2D COFs with promising optoelectronic properties.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Efficient OER Catalyst with Low Ir Volume Density Obtained by Homogeneous Deposition of Iridium Oxide Nanoparticles on Macroporous Antimony-Doped Tin Oxide Support},

author = {D Bohm and M Beetz and M Schuster and K Peters and A G Hufnagel and M Doblinger and B Boller and T Bein and D Fattakhova-Rohlfing},

url = {\<Go to ISI\>://WOS:000492384200001},

doi = {10.1002/adfm.201906670},

issn = {1616-301X},

year  = {2019},

date = {2019-10-25},

journal = {Advanced Functional Materials},

volume = {30},

number = {1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Covalent Organic Framework Films through Electrophoretic Deposition\textemdashCreating Efficient Morphologies for Catalysis},

author = {J M Rotter and S Weinberger and J Kampmann and T Sick and M Shalom and T Bein and D D Medina},

url = {https://doi.org/10.1021/acs.chemmater.9b02286},

doi = {10.1021/acs.chemmater.9b02286},

issn = {0897-4756},

year  = {2019},

date = {2019-10-03},

urldate = {2019-10-03},

journal = {Chemistry of Materials},

volume = {31},

number = {24},

pages = {10008-10016},

abstract = {The ability to grow covalent organic framework (COF) films allows for studying their properties as solid layers and enables the incorporation of these materials into a variety of functional devices. Here, we report on the fabrication of COF films and coatings by electrophoretic deposition (EPD). We demonstrate that the EPD technique is suitable for depositing COFs featuring two- and three-dimensional structures linked by imine or boronate ester bonds, namely, BDT-ETTA COF, COF-300, and COF-5. For the deposition, COF nanoparticle suspensions are prepared by dispersing the as-synthesized bulk materials in solvents with low dielectric constants. Subsequently, two electrodes are immersed into the COF particle suspensions, and upon inducing electric fields ranging from 100 to 900 V cm\textendash1, COFs are deposited as films on the positively charged electrode. Through EPD, within 2 min, large-area films of up to 25 cm2 are obtained on smooth or corrugated surfaces. COF films prepared by EPD feature an inherent textural porosity and tunable thickness, demonstrated from 400 nm to 24 μm. By controlling the deposition parameters such as duration, particle concentration, and applied potential, deposits of precise thickness can be produced. Furthermore, codepositions of different COFs as well as COF/Pt nanoparticles from mixed suspensions are demonstrated. The film morphologies obtained by EPD are shown to be advantageous for catalysis, as demonstrated for sacrificial agent-free photoelectrochemical water reduction. Here, BDT-ETTA COF photocathodes show a strongly increased photocurrent density compared to the respective dense and oriented films. Typical BDT-ETTA COF/Pt nanoparticle hybrid films exhibit photocurrent densities of over 100 μA cm\textendash2. The rapid and scalable deposition of COF particles as films and coatings through EPD is a versatile addition to the toolbox of COF film fabrication techniques, allowing for tailoring COF film architectures for desired functionalities.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A highly crystalline anthracene-based MOF-74 series featuring electrical conductivity and luminescence},

author = {P I Scheurle and A M\"{a}hringer and A C Jakowetz and P Hosseini and A F Richter and G Wittstock and D D Medina and T Bein},

url = {http://dx.doi.org/10.1039/C9NR05431F},

doi = {10.1039/C9NR05431F},

issn = {2040-3364},

year  = {2019},

date = {2019-09-10},

journal = {Nanoscale},

volume = {11},

number = {43},

pages = {20949-20955},

abstract = {Recently, a small group of metal\textendashorganic frameworks (MOFs) has been discovered featuring substantial charge transport properties and electrical conductivity, hence promising to broaden the scope of potential MOF applications in fields such as batteries, fuel cells and supercapacitors. In combination with light emission, electroactive MOFs are intriguing candidates for chemical sensing and optoelectronic applications. Here, we incorporated anthracene-based building blocks into the MOF-74 topology with five different divalent metal ions, that is, Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, resulting in a series of highly crystalline MOFs, coined ANMOF-74(M). This series of MOFs features substantial photoluminescence, with ANMOF-74(Zn) emitting across the whole visible spectrum. The materials moreover combine this photoluminescence with high surface areas and electrical conductivity. Compared to the original MOF-74 materials constructed from 2,5-dihydroxy terephthalic acid and the same metal ions Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, we observed a conductivity enhancement of up to six orders of magnitude. Our results point towards the importance of building block design and the careful choice of the embedded MOF topology for obtaining materials with desired properties such as photoluminescence and electrical conductivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Temperature-Dependent Ambipolar Charge Carrier Mobility in Large-Crystal Hybrid Halide Perovskite Thin Films},

author = {A Biewald and N Giesbrecht and T Bein and P Docampo and A Hartschuh and R Ciesielski},

url = {https://doi.org/10.1021/acsami.9b04592},

doi = {10.1021/acsami.9b04592},

issn = {1944-8244},

year  = {2019},

date = {2019-06-12},

journal = {ACS Applied Materials \& Interfaces},

volume = {11},

number = {23},

pages = {20838-20844},

abstract = {Perovskite-based thin-film solar cells today reach power conversion efficiencies of more than 22%. Methylammonium lead iodide (MAPI) is prototypical for this material class of hybrid halide perovskite semiconductors and at the focal point of interest for a growing community in research and engineering. Here, a detailed understanding of the charge carrier transport and its limitations by underlying scattering mechanisms is of great interest to the material’s optimization and development. In this article, we present an all-optical study of the charge carrier diffusion properties in large-crystal MAPI thin films in the tetragonal crystal phase from 170 K to room temperature. We probe the local material properties of individual crystal grains within a MAPI thin film and find a steady decrease of the charge carrier diffusion constant with increasing temperature. From the resulting charge carrier mobility, we find a power law dependence of μ ∝ Tm with m = −(1.8 ± 0.1). We further study the temperature-dependent mobility of the orthorhombic crystal phase from 50 to 140 K and observe a distinctly different exponent of m = −(1.2 ± 0.1).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Oriented Thin Films of Electroactive Triphenylene Catecholate-Based Two-Dimensional Metal\textendashOrganic Frameworks},

author = {A M\"{a}hringer and A C Jakowetz and J M Rotter and B J Bohn and J K Stolarczyk and J Feldmann and T Bein and D D Medina},

url = {https://doi.org/10.1021/acsnano.9b01137},

doi = {10.1021/acsnano.9b01137},

issn = {1936-0851},

year  = {2019},

date = {2019-05-02},

journal = {ACS Nano},

volume = {13},

number = {6},

pages = {6711-6719},

abstract = {Two-dimensional triphenylene-based metal\textendashorganic frameworks (TP-MOFs) attract significant scientific interest due to their long-range order combined with significant electrical conductivity. The deposition of these structures as oriented films is expected to promote their incorporation into diverse optoelectronic devices. However, to date, a controlled deposition strategy applicable for the different members of this MOF family has not been reported yet. Herein, we present the synthesis of highly oriented thin films of TP-MOFs by vapor-assisted conversion (VAC). We targeted the M-CAT-1 series comprising hexahydroxytriphenylene organic ligands and metal-ions such as Ni2+, Co2+, and Cu2+. These planar organic building blocks are connected in-plane to the metal-ions through a square planar node forming extended sheets which undergo self-organization into defined stacks. Highly oriented thin Ni- and Co-CAT-1 films grown on gold substrates feature a high surface coverage with a uniform film topography and thickness ranging from 180 to 200 nm. The inclusion of acid modulators in the synthesis enabled the growth of films with a preferred orientation on quartz and on conductive substrates such as indium-doped tin oxide (ITO). The van der Pauw measurements performed across the M-CAT-1 films revealed high electrical conductivity values of up to 10\textendash3 S cm\textendash1 for both the Ni- and Co-CAT-1 films. Films grown on quartz allowed for a detailed photophysical characterization by means of UV\textendashvis, photoluminescence, and transient absorption spectroscopy. The latter revealed the existence of excited states on a nanosecond time scale, sufficiently long to demonstrate a photoinduced charge generation and extraction in Ni-CAT-1 films. This was achieved by fabricating a basic photovoltaic device with an ITO/Ni-CAT-1/Al architecture, thus establishing this MOF as a photoactive material. Our results point to the intriguing capabilities of these conductive M-CAT-1 materials and an additional scope of applications as photoabsorbers enabled through VAC thin-film synthesis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Cobalt-Catalyzed Electrophilic Aminations with Anthranils: An Expedient Route to Condensed Quinolines},

author = {J Li and E Tan and N Keller and Y-H Chen and P M Zehetmaier and A C Jakowetz and T Bein and P Knochel},

url = {https://doi.org/10.1021/jacs.8b11466},

doi = {10.1021/jacs.8b11466},

issn = {0002-7863},

year  = {2019},

date = {2019-01-09},

journal = {Journal of the American Chemical Society},

volume = {141},

number = {1},

pages = {98-103},

abstract = {The reaction of various organozinc pivalates with anthranils provides anilines derivatives, which cyclize under acidic conditions providing condensed quinolines. Using alkenylzinc pivalates, electron-rich arylzinc pivalates or heterocyclic zinc pivalates produces directly the condensed quinolines of which several structures belong to new heterocyclic scaffolds. These N-heterocycles are of particular interest for organic light emitting diodes with their high photoluminescence quantum yields and long exciton lifetimes as well as for hole-transporting materials in methylammonium lead iodide perovskites solar cells due to an optimal band alignment for holes and a large bandgap.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}