Publications

@article{nokey,

title = {Photophysics and Electronic Structure of Lateral Graphene/MoS2 and Metal/MoS2 Junctions},

author = {S Subramanian and Q T Campbell and S K Moser and J Kiemle and P Zimmermann and P Seifert and F Sigger and D Sharma and H Al-Sadeg and M Labella and D Waters and R M Feenstra and R J Koch and C Jozwiak and A Bostwick and E Rotenberg and I Dabo and A W Holleitner and T E Beechem and U Wurstbauer and J A Robinson},

url = {https://doi.org/10.1021/acsnano.0c02527},

doi = {10.1021/acsnano.0c02527},

issn = {1936-0851},

year  = {2020},

date = {2020-11-16},

journal = {ACS Nano},

volume = {14},

number = {12},

pages = {16663-16671},

abstract = {Integration of semiconducting transition metal dichalcogenides (TMDs) into functional optoelectronic circuitries requires an understanding of the charge transfer across the interface between the TMD and the contacting material. Here, we use spatially resolved photocurrent microscopy to demonstrate electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2) interface. A 10× larger photocurrent is extracted at the EG/MoS2 interface when compared to the metal (Ti/Au)/MoS2 interface. This is supported by semi-local density functional theory (DFT), which predicts the Schottky barrier at the EG/MoS2 interface to be ∼2× lower than that at Ti/MoS2. We provide a direct visualization of a 2D material Schottky barrier through combination of angle-resolved photoemission spectroscopy with spatial resolution selected to be ∼300 nm (nano-ARPES) and DFT calculations. A bending of ∼500 meV over a length scale of ∼2\textendash3 μm in the valence band maximum of MoS2 is observed via nano-ARPES. We explicate a correlation between experimental demonstration and theoretical predictions of barriers at graphene/TMD interfaces. Spatially resolved photocurrent mapping allows for directly visualizing the uniformity of built-in electric fields at heterostructure interfaces, providing a guide for microscopic engineering of charge transport across heterointerfaces. This simple probe-based technique also speaks directly to the 2D synthesis community to elucidate electronic uniformity at domain boundaries alongside morphological uniformity over large areas.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Photophysics and Electronic Structure of Lateral Graphene/MoS2 and Metal/MoS2 Junctions},

author = {S Subramanian and Q T Campbell and S K Moser and J Kiemle and P Zimmermann and P Seifert and F Sigger and D Sharma and H Al-Sadeg and M Labella and D Waters and R M Feenstra and R J Koch and C Jozwiak and A Bostwick and E Rotenberg and I Dabo and A W Holleitner and T E Beechem and U Wurstbauer and J A Robinson},

url = {https://doi.org/10.1021/acsnano.0c02527},

doi = {10.1021/acsnano.0c02527},

issn = {1936-0851},

year  = {2020},

date = {2020-11-16},

journal = {ACS Nano},

abstract = {Integration of semiconducting transition metal dichalcogenides (TMDs) into functional optoelectronic circuitries requires an understanding of the charge transfer across the interface between the TMD and the contacting material. Here, we use spatially resolved photocurrent microscopy to demonstrate electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2) interface. A 10× larger photocurrent is extracted at the EG/MoS2 interface when compared to the metal (Ti/Au)/MoS2 interface. This is supported by semi-local density functional theory (DFT), which predicts the Schottky barrier at the EG/MoS2 interface to be ∼2× lower than that at Ti/MoS2. We provide a direct visualization of a 2D material Schottky barrier through combination of angle-resolved photoemission spectroscopy with spatial resolution selected to be ∼300 nm (nano-ARPES) and DFT calculations. A bending of ∼500 meV over a length scale of ∼2\textendash3 μm in the valence band maximum of MoS2 is observed via nano-ARPES. We explicate a correlation between experimental demonstration and theoretical predictions of barriers at graphene/TMD interfaces. Spatially resolved photocurrent mapping allows for directly visualizing the uniformity of built-in electric fields at heterostructure interfaces, providing a guide for microscopic engineering of charge transport across heterointerfaces. This simple probe-based technique also speaks directly to the 2D synthesis community to elucidate electronic uniformity at domain boundaries alongside morphological uniformity over large areas.},

keywords = {Solid-Solid},

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 = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Sodium Dodecylbenzene Sulfonate Interface Modification of Methylammonium Lead Iodide for Surface Passivation of Perovskite Solar Cells},

author = {Y Zou and R Guo and A Buyruk and W Chen and T Xiao and S Yin and X Jiang and L P Kreuzer and C Mu and T Ameri and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsami.0c14732},

doi = {10.1021/acsami.0c14732},

issn = {1944-8244},

year  = {2020},

date = {2020-11-15},

journal = {ACS Applied Materials \& Interfaces},

volume = {12},

number = {47},

pages = {52643-52651},

abstract = {Perovskite solar cells (PSCs) have been developed as a promising photovoltaic technology because of their excellent photovoltaic performance. However, interfacial recombination and charge carrier transport losses at the surface greatly limit the performance and stability of PSCs. In this work, the fabrication of high-quality PSCs based on methylammonium lead iodide with excellent ambient stability is reported. An anionic surfactant, sodium dodecylbenzene sulfonate (SDBS), is introduced to simultaneously passivate the defect states and stabilize the cubic phase of the perovskite film. The SDBS located at grain boundaries and the surface of the active layer can effectively passivate under-coordinated lead ions and protect the perovskite components from water-induced degradation. As a result, a champion power conversion efficiency (PCE) of 19.42% is achieved with an open-circuit voltage (VOC) of 1.12 V, a short-circuit current (JSC) of 23.23 mA cm\textendash2, and a fill factor (FF) of 74% in combination with superior moisture stability. The SDBS-passivated devices retain 80% of their initial average PCE after 2112 h of storage under ambient conditions.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Room-Temperature Synthesis of 2D Janus Crystals and their Heterostructures},

author = {D B Trivedi and G Turgut and Y Qin and M Y Sayyad and D Hajra and M Howell and L Liu and S Yang and N H Patoary and H Li and M M Petri\'{c} and M Meyer and M Kremser and M Barbone and G Soavi and A V Stier and K M\"{u}ller and S Yang and I S Esqueda and H Zhuang and J J Finley and S Tongay},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202006320},

doi = {https://doi.org/10.1002/adma.202006320},

issn = {0935-9648},

year  = {2020},

date = {2020-11-11},

journal = {Advanced Materials},

volume = {32},

number = {50},

pages = {2006320},

abstract = {Abstract Janus crystals represent an exciting class of 2D materials with different atomic species on their upper and lower facets. Theories have predicted that this symmetry breaking induces an electric field and leads to a wealth of novel properties, such as large Rashba spin\textendashorbit coupling and formation of strongly correlated electronic states. Monolayer MoSSe Janus crystals have been synthesized by two methods, via controlled sulfurization of monolayer MoSe2 and via plasma stripping followed thermal annealing of MoS2. However, the high processing temperatures prevent growth of other Janus materials and their heterostructures. Here, a room-temperature technique for the synthesis of a variety of Janus monolayers with high structural and optical quality is reported. This process involves low-energy reactive radical precursors, which enables selective removal and replacement of the uppermost chalcogen layer, thus transforming classical transition metal dichalcogenides into a Janus structure. The resulting materials show clear mixed character for their excitonic transitions, and more importantly, the presented room-temperature method enables the demonstration of first vertical and lateral heterojunctions of 2D Janus TMDs. The results present significant and pioneering advances in the synthesis of new classes of 2D materials, and pave the way for the creation of heterostructures from 2D Janus layers.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Improved Projection-Operator Diabatization Schemes for the Calculation of Electronic Coupling Values},

author = {S Ghan and C Kunkel and K Reuter and H Oberhofer},

url = {https://doi.org/10.1021/acs.jctc.0c00887},

doi = {10.1021/acs.jctc.0c00887},

issn = {1549-9618},

year  = {2020},

date = {2020-11-10},

urldate = {2020-11-10},

journal = {Journal of Chemical Theory and Computation},

volume = {16},

number = {12},

pages = {7431-7443},

abstract = {We address a long-standing ambiguity in the DFT-based projection-operator diabatization method for charge transfer couplings in donor\textendashacceptor systems. It has long been known that the original method yields diabats which are not strictly fragment-localized due to mixing arising from basis-set orthogonalization. We demonstrate that this can contribute to a severe underestimation of coupling strengths and a spurious dependence on the choice of the basis set. As a remedy, we reformulate the method within a simple tight-binding model to generate diabats with increased localization, yielding a proper basis set convergence and improved performance for the general Hab11 benchmark set. Orthogonality of diabats is ensured either through symmetric L\"{o}wdin or asymmetric Gram-Schmid procedures, the latter of which offers to extend these improvements to asymmetric systems such as adsorbates on surfaces.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks},

author = {F Haase and B V Lotsch},

url = {http://dx.doi.org/10.1039/D0CS01027H},

doi = {10.1039/D0CS01027H},

issn = {0306-0012},

year  = {2020},

date = {2020-11-06},

journal = {Chemical Society Reviews},

abstract = {Covalent organic frameworks (COFs) have entered the stage as a new generation of porous polymers which stand out by virtue of their crystallinity, diverse framework topologies and accessible pore systems. An important \textendash but still underdeveloped \textendash feature of COFs is their potentially superior stability in comparison to other porous materials. Achieving COFs which are simultaneously crystalline, stable, and functional is still challenging as reversible bond formation is one of the prime prerequisites for the crystallization of COFs. However, as the COF field matures new strategies have surfaced that bypass this crystallinity \textendash stability dichotomy. Three major approaches for obtaining both stable and crystalline COFs have taken form in recent years: Tweaking the reaction conditions for reversible linkages, separating the order inducing step and the stability inducing step, and controlling the structural degrees of freedom during assembly and in the final COF. This review discusses rational approaches to stability and crystallinity engineering in COFs, which are apt at overcoming current challenges in COF design and open up new avenues to new real-world applications of COFs.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Polymer photocatalysts for solar-to-chemical energy conversion},

author = {T Banerjee and F Podjaski and J Kr\"{o}ger and B P Biswal and B V Lotsch},

url = {https://doi.org/10.1038/s41578-020-00254-z},

doi = {10.1038/s41578-020-00254-z},

issn = {2058-8437},

year  = {2020},

date = {2020-11-05},

journal = {Nature Reviews Materials},

abstract = {Solar-to-chemical energy conversion for the generation of high-energy chemicals is one of the most viable solutions to the quest for sustainable energy resources. Although long dominated by inorganic semiconductors, organic polymeric photocatalysts offer the advantage of a broad, molecular-level design space of their optoelectronic and surface catalytic properties, owing to their molecularly precise backbone. In this Review, we discuss the fundamental concepts of polymeric photocatalysis and examine different polymeric photocatalysts, including carbon nitrides, conjugated polymers, covalent triazine frameworks and covalent organic frameworks. We analyse the photophysical and physico-chemical concepts that govern the photocatalytic performance of these materials, and derive design principles and possible future research directions in this emerging field of ‘soft photocatalysis’.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {DNA origami nanorulers and emerging reference structures},

author = {M Scheckenbach and J Bauer and J Z\"{a}hringer and F Selbach and P Tinnefeld},

url = {https://doi.org/10.1063/5.0022885},

doi = {10.1063/5.0022885},

year  = {2020},

date = {2020-11-01},

journal = {APL Materials},

volume = {8},

number = {11},

pages = {110902},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Band structure engineering and defect control of Ta3N5 for efficient photoelectrochemical water oxidation},

author = {Y Xiao and C Feng and J Fu and F Wang and C Li and V F Kunzelmann and C-M Jiang and M Nakabayashi and N Shibata and I D Sharp and K Domen and Y Li},

url = {https://doi.org/10.1038/s41929-020-00522-9},

doi = {10.1038/s41929-020-00522-9},

issn = {2520-1158},

year  = {2020},

date = {2020-11-01},

urldate = {2020-11-01},

journal = {Nature Catalysis},

volume = {3},

number = {11},

pages = {932-940},

abstract = {Ta3N5 is a promising photoanode material with a theoretical maximum solar conversion efficiency of 15.9% for photoelectrochemical water splitting. However, the highest applied bias photon-to-current efficiency achieved so far is only 2.72%. To bridge the efficiency gap, effective carrier management strategies for Ta3N5 photoanodes should be developed. Here, we propose to use gradient Mg doping for band structure engineering and defect control of Ta3N5. The gradient Mg doping profile in Ta3N5 induces a gradient of the band edge energetics, which greatly enhances the charge separation efficiency. Furthermore, defect-related recombination is significantly suppressed due to the passivation effect of Mg dopants on deep-level defects and, more importantly, the matching of the gradient Mg doping profile with the distribution of defects within Ta3N5. As a result, a photoanode based on the gradient Mg-doped Ta3N5 delivers a low onset potential of 0.4 V versus that of a reversible hydrogen electrode and a high applied bias photon-to-current efficiency of 3.25 ± 0.05%.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Electron tunneling at the molecularly thin 2D perovskite and graphene van der Waals interface},

author = {K Leng and L Wang and Y Shao and I Abdelwahab and G Grinblat and I Verzhbitskiy and R Li and Y Cai and X Chi and W Fu and P Song and A Rusydi and G Eda and S A Maier and K P Loh},

url = {https://doi.org/10.1038/s41467-020-19331-6},

doi = {10.1038/s41467-020-19331-6},

issn = {2041-1723},

year  = {2020},

date = {2020-10-30},

journal = {Nature Communications},

volume = {11},

number = {1},

pages = {5483},

abstract = {Quasi-two-dimensional perovskites have emerged as a new material platform for optoelectronics on account of its intrinsic stability. A major bottleneck to device performance is the high charge injection barrier caused by organic molecular layers on its basal plane, thus the best performing device currently relies on edge contact. Herein, by leveraging on van der Waals coupling and energy level matching between two-dimensional Ruddlesden-Popper perovskite and graphene, we show that the plane-contacted perovskite and graphene interface presents a lower barrier than gold for charge injection. Electron tunneling across the interface occurs via a gate-tunable, direct tunneling-to-field emission mechanism with increasing bias, and photoinduced charge transfer occurs at femtosecond timescale (~50 fs). Field effect transistors fabricated on molecularly thin Ruddlesden-Popper perovskite using graphene contact exhibit electron mobilities ranging from 0.1 to 0.018 cm2V−1s−1 between 1.7 to 200 K. Scanning tunneling spectroscopy studies reveal layer-dependent tunneling barrier and domain size on few-layered Ruddlesden-Popper perovskite.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Metal Halide Perovskite@Metal-Organic Framework Hybrids: Synthesis, Design, Properties, and Applications},

author = {S K Yadav and G K Grandhi and D P Dubal and J C De Mello and M Otyepka and R Zbo\v{r}il and R A Fischer and K Jayaramulu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202004891},

doi = {https://doi.org/10.1002/smll.202004891},

issn = {1613-6810},

year  = {2020},

date = {2020-10-30},

journal = {Small},

volume = {16},

number = {47},

pages = {2004891},

abstract = {Abstract Metal halide perovskites (MHPs) have excellent optoelectronic and photovoltaic applications because of their cost-effectiveness, tunable emission, high photoluminescence quantum yields, and excellent charge carrier properties. However, the potential applications of the entire MHP family are facing a major challenge arising from its weak resistance to moisture, polar solvents, temperature, and light exposure. A viable strategy to enhance the stability of MHPs could lie in their incorporation into a porous template. Metal-organic frameworks (MOFs) have outstanding properties, with a unique network of ordered/functional pores, which render them promising for functioning as such a template, accommodating a wide range of MHPs to the nanosized region, alongside minimizing particle aggregation and enhancing the stability of the entrapped species. This review highlights recent advances in design strategies, synthesis, characterization, and properties of various hybrids of MOFs with MHPs. Particular attention is paid to a critical review of the emergence of MHP@MOF for comprehensive studies of next-generation materials for various technological applications including sensors, photocatalysis, encryption/decryption, light-emitting diodes, and solar cells. Finally, by summarizing the state-of-the-art, some promising future applications of reported hybrids are proposed. Considering the inherent correlation and synergic functionalities of MHPs and MOFs, further advancement; new functional materials; and applications can be achieved through designing MHP@MOF hybrids.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Electron tunneling at the molecularly thin 2D perovskite and graphene van der Waals interface},

author = {K Leng and L Wang and Y Shao and I Abdelwahab and G Grinblat and I Verzhbitskiy and R Li and Y Cai and X Chi and W Fu and P Song and A Rusydi and G Eda and S A Maier and K P Loh},

url = {https://doi.org/10.1038/s41467-020-19331-6},

doi = {10.1038/s41467-020-19331-6},

issn = {2041-1723},

year  = {2020},

date = {2020-10-30},

journal = {Nature Communications},

volume = {11},

number = {1},

pages = {5483},

abstract = {Quasi-two-dimensional perovskites have emerged as a new material platform for optoelectronics on account of its intrinsic stability. A major bottleneck to device performance is the high charge injection barrier caused by organic molecular layers on its basal plane, thus the best performing device currently relies on edge contact. Herein, by leveraging on van der Waals coupling and energy level matching between two-dimensional Ruddlesden-Popper perovskite and graphene, we show that the plane-contacted perovskite and graphene interface presents a lower barrier than gold for charge injection. Electron tunneling across the interface occurs via a gate-tunable, direct tunneling-to-field emission mechanism with increasing bias, and photoinduced charge transfer occurs at femtosecond timescale (~50 fs). Field effect transistors fabricated on molecularly thin Ruddlesden-Popper perovskite using graphene contact exhibit electron mobilities ranging from 0.1 to 0.018 cm2V−1s−1 between 1.7 to 200 K. Scanning tunneling spectroscopy studies reveal layer-dependent tunneling barrier and domain size on few-layered Ruddlesden-Popper perovskite.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Deep Learning Total Energies and Orbital Energies of Large Organic Molecules Using Hybridization of Molecular Fingerprints},

author = {O Rahaman and A Gagliardi},

url = {https://doi.org/10.1021/acs.jcim.0c00687},

doi = {10.1021/acs.jcim.0c00687},

issn = {1549-9596},

year  = {2020},

date = {2020-10-29},

journal = {Journal of Chemical Information and Modeling},

volume = {60},

number = {12},

pages = {5971-5983},

abstract = {The ability to predict material properties without the need for resource-consuming experimental efforts can immensely accelerate material and drug discovery. Although ab initio methods can be reliable and accurate in making such predictions, they are computationally too expensive on a large scale. The recent advancements in artificial intelligence and machine learning as well as the availability of large quantum mechanics derived datasets enable us to train models on these datasets as a benchmark and to make fast predictions on much larger datasets. The success of these machine learning models highly depends on the machine-readable fingerprints of the molecules that capture their chemical properties as well as topological information. In this work, we propose a common deep learning-based framework to combine different types of molecular fingerprints to enhance prediction accuracy. A graph neural network (GNN), many-body tensor representation (MBTR), and a set of simple molecular descriptors (MD) were used to predict the total energies, highest occupied molecular orbital (HOMO) energies, and lowest unoccupied molecular orbital (LUMO) energies of a dataset containing ∼62k large organic molecules with complex aromatic rings and remarkably diverse functional groups. The results demonstrate that a combination of best performing molecular fingerprints can produce better results than the individual ones. The simple and flexible deep learning framework developed in this work can be easily adapted to incorporate other types of molecular fingerprints.},

keywords = {Foundry Organic, Molecularly-Functionalized},

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 = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Collective oscillations of globally coupled bistable, nonresonant components},

author = {M Salman and C Bick and K Krischer},

url = {https://link.aps.org/doi/10.1103/PhysRevResearch.2.043125},

doi = {10.1103/PhysRevResearch.2.043125},

year  = {2020},

date = {2020-10-23},

journal = {Physical Review Research},

volume = {2},

number = {4},

pages = {043125},

abstract = {Bistable microelectrodes with an S-shaped current-voltage characteristic have recently been shown to oscillate under current control, when connected in parallel. In other systems with equivalently coupled bistable components, such oscillatory instabilities have not been reported. In this paper, we derive a general criterion for when an ensemble of coupled bistable components may become oscillatorily unstable. Using a general model, we perform a stability analysis of the ensemble equilibria, in which the components always group in three or fewer clusters. Based thereon, we give a necessary condition for the occurrence of collective oscillations. Moreover, we demonstrate that stable oscillations may persist for an arbitrarily large number of components, even though, as we show, any equilibrium with two or more components on the middle, autocatalytic branch is unstable.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Multiscale Conformational Sampling Reveals Excited-State Locality in DNA Self-Repair Mechanism},

author = {V Piccinni and S Reiter and D Keefer and R De Vivie-Riedle},

url = {https://doi.org/10.1021/acs.jpca.0c07207},

doi = {10.1021/acs.jpca.0c07207},

issn = {1089-5639},

year  = {2020},

date = {2020-10-22},

urldate = {2020-10-22},

journal = {The Journal of Physical Chemistry A},

volume = {124},

number = {44},

pages = {9133-9140},

abstract = {Ultraviolet (UV) irradiation is known to be responsible for DNA damage. However, experimental studies in DNA oligonucleotides have shown that UV light can also induce sequence-specific self-repair. Following charge transfer from a guanine adenine sequence adjacent to a cyclobutane pyrimidine dimer (CPD), the covalent bond between the two thymines could be cleaved, recovering the intact base sequence. Mechanistic details promoting the self-repair remained unclear, however. In our theoretical study, we investigated whether optical excitation could directly lead to a charge-transfer state, thereby initiating the repair, or whether the initial excited state remains localized on a single nucleobase. We performed conformational sampling of 200 geometries of the damaged DNA double strand solvated in water and used a hybrid quantum and molecular mechanics approach to compute excited states at the complete active space perturbation level of theory. Analysis of the conformational data set clearly revealed that the excited-state properties are uniformly distributed across the fluctuations of the nucleotide in its natural environment. From the electronic wavefunction, we learned that the electronic transitions remained predominantly local on either adenine or guanine, and no direct charge transfer occurred in the experimentally accessed energy range. The investigated base sequence is not only specific to the CPD repair mechanism but ubiquitously occurs in nucleic acids. Our results therefore give a very general insight into the charge locality of UV-excited DNA, a property that is regarded to have determining relevance in the structural consequences following absorption of UV photons.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Hydrogel-supported graphitic carbon nitride nanosheets loaded with Pt atoms as a novel self-water-storage photocatalyst for H2 evolution},

author = {L Lei and W Wang and C Wang and H Fan and A K Yadav and N Hu and Q Zhong and P M\"{u}ller-Buschbaum},

url = {http://dx.doi.org/10.1039/D0TA07805K},

doi = {10.1039/D0TA07805K},

issn = {2050-7488},

year  = {2020},

date = {2020-10-21},

urldate = {2020-10-21},

journal = {Journal of Materials Chemistry A},

volume = {8},

number = {45},

pages = {23812-23819},

abstract = {Graphitic carbon nitride (g-C3N4) exhibits an excellent photocatalytic performance as a powder, especially under visible light irradiation. However, it encounters great challenges for practical applications. For instance, to avoid aggregation and precipitation, a continuous stirring process is required for the bare g-C3N4 powder during the photocatalytic reaction. In addition, recycling of the powder photocatalyst is complicated and usually not environment friendly. To overcome these drawbacks, we present a hybrid materials. This material combines g-C3N4 nanosheets loaded with cocatalyst Pt atoms (CN) with a polymer hydrogel. In the ready-to-use photocatalyst, CN is well distributed in the hydrogel matrix. Water stored in the hydrogel can serve as a water reservoir for the photocatalytic water splitting. Due to the intermolecular interactions between CN and the hydrogel, a 3D network with a small-sized nanostructure is formed, which enhances the light absorption and the charge carrier separation. As a result, the H2 evolution rate is 7437 μmol h−1 g−1, which is 130% higher than that of the bare CN powder in water. Furthermore, the hydrogel-supported CN is able to function under ambient environment conditions without any significant reduction of the photocatalytic performance, as compared to the bare CN powder. In the hybrid material, the combination of hydrogel and CN provides a possibility for the photocatalyst to work without a water environment and accomplish an efficient H2 evolution.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Internal nanoscale architecture and charge carrier dynamics of wide bandgap non-fullerene bulk heterojunction active layers in organic solar cells},

author = {X Jiang and H Kim and P S Deimel and W Chen and W Cao and D Yang and S Yin and R Schaffrinna and F Allegretti and J V Barth and M Schwager and H Tang and K Wang and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {http://dx.doi.org/10.1039/D0TA09671G},

doi = {10.1039/D0TA09671G},

issn = {2050-7488},

year  = {2020},

date = {2020-10-19},

journal = {Journal of Materials Chemistry A},

volume = {8},

number = {44},

pages = {23628-23636},

abstract = {Bulk heterojunction (BHJ) organic solar cells have gained increasing attention in the past few years. In this work, active layers of a wide-bandgap polymer donor with benzodithiophene units PBDB-T-2F and a non-fullerene small molecule acceptor IT-M are assembled into photovoltaic devices with different amounts of solvent additive 1,8-diiodooctane (DIO). The influence of DIO on the nanoscale film morphology and crystalline structure as well as the charge carrier dynamics of the active layers are investigated by combining grazing-incidence small-angle X-ray scattering (GISAXS), grazing-incidence wide-angle X-ray scattering (GIWAXS), X-ray reflectivity (XRR), UV-visible (UV-vis) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), time-resolved photoluminescence (TRPL) and space charge limited current measurements, which are correlated with the corresponding performance of the solar cells. At 0.5 vol% DIO addition, the wide-bandgap non-fullerene organic solar cells show the best performance due to high open-circuit voltage and short-circuit current resulting from an improved charge carrier management due to the optimal inner nanoscale morphology of the active layers in terms of surface enrichment, crystallinity and crystalline orientation.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Light\textendashMatter Interaction in Quantum Confined 2D Polar Metals},

author = {K Nisi and S Subramanian and W He and K A Ulman and H El-Sherif and F Sigger and M Lassauni\`{e}re and M T Wetherington and N Briggs and J Gray and A W Holleitner and N Bassim and S Y Quek and J A Robinson and U Wurstbauer},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202005977},

doi = {https://doi.org/10.1002/adfm.202005977},

issn = {1616-301X},

year  = {2020},

date = {2020-10-15},

urldate = {2020-10-15},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2005977},

abstract = {Abstract This work is a systematic experimental and theoretical study of the in-plane dielectric functions of 2D gallium and indium films consisting of two or three atomic metal layers confined between silicon carbide and graphene with a corresponding bonding gradient from covalent to metallic to van der Waals type. k-space resolved free electron and bound electron contributions to the optical response are identified, with the latter pointing towards the existence of thickness dependent quantum confinement phenomena. The resonance energies in the dielectric functions and the observed epsilon near-zero behavior in the near infrared to visible spectral range, are dependent on the number of atomic metal layers and properties of the metal involved. A model-based spectroscopic ellipsometry approach is used to estimate the number of atomic metal layers, providing a convenient route over expensive invasive characterization techniques. A strong thickness and metal choice dependence of the light\textendashmatter interaction makes these half van der Waals 2D polar metals attractive for quantum engineered metal films, tunable (quantum-)plasmonics and nano-photonics.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Formation and stability of small polarons at the lithium-terminated Li4Ti5O12 (LTO) (111) surface},

author = {M Kick and C Scheurer and H Oberhofer},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0021443},

doi = {10.1063/5.0021443},

year  = {2020},

date = {2020-10-08},

journal = {The Journal of Chemical Physics},

volume = {153},

number = {14},

pages = {144701},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Nanoscale patterning at the Si/SiO2/graphene interface by focused He+ beam},

author = {A B\"{o}ttcher and R Schwaiger and T M Pazdera and D Exner and J Hauns and D Strelnikov and S Lebedkin and R Gr\"{o}ger and F Esch and B A J Lechner},

url = {https://iopscience.iop.org/article/10.1088/1361-6528/abb5cf/meta?casa_token=0ch84-BOwLoAAAAA:0ibNutoV58k0ONYDhRhhBtMaAbaDMOWEDghZKBvbCABbhx1dGH2gGSD1baUoc-Zosx5xyOGgxg},

doi = {10.1088/1361-6528/abb5cf},

issn = {0957-4484},

year  = {2020},

date = {2020-10-06},

urldate = {2020-10-06},

journal = {Nanotechnology},

volume = {31},

number = {50},

pages = {505302},

abstract = {We have studied the capability of He+ focused ion beam (He+-FIB) patterning to fabricate defect arrays on the Si/SiO2/Graphene interface using a combination of atomic force microscopy (AFM) and Raman imaging to probe damage zones. In general, an amorphized 'blister' region of cylindrical symmetry results upon exposing the surface to the stationary focused He+ beam. The topography of the amorphized region depends strongly on the ion dose, DS, (ranging from 103 to 107ions/spot) with craters and holes observed at higher doses. Furthermore, the surface morphology depends on the distance between adjacent irradiated spots, LS. Increasing the dose leads to (enhanced) subsurface amorphization and a local height increase relative to the unexposed regions. At the highest areal ion dose, the average height of a patterned area also increases as ∼1/LS. Correspondingly, in optical micrographs, the µm2-sized patterned surface regions change appearance. These phenomena can be explained by implantation of the He+ ions into the subsurface layers, formation of helium nanobubbles, expansion and modification of the dielectric constant of the patterned material. The corresponding modifications of the terminating graphene monolayer have been monitored by micro Raman imaging. At low ion doses, DS, the graphene becomes modified by carbon atom defects which perturb the 2D lattice (as indicated by increasing D/G Raman mode ratio). Additional x-ray photoionization spectroscopy (XPS) measurements allow us to infer that for moderate ion doses, scattering of He+ ions by the subsurface results in the oxidation of the graphene network. For largest doses and smallest LS values, the He+ beam activates extensive Si/SiO2/C bond rearrangement and a multicomponent material possibly comprising SiC and silicon oxycarbides, SiOC, is observed. We also infer parameter ranges for He+-FIB patterning defect arrays of potential use for pinning transition metal nanoparticles in model studies of heterogeneous catalysis.},

keywords = {Foundry Inorganic, Molecularly-Functionalized, Solid-Solid},

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 = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ultrathin catalyst-free InAs nanowires on silicon with distinct 1D sub-band transport properties},

author = {F Del Giudice and J Becker and C De Rose and M D\"{o}blinger and D Ruhstorfer and L Suomenniemi and J Treu and H Riedl and J J Finley and G Koblm\"{u}ller},

url = {http://dx.doi.org/10.1039/D0NR05666A},

doi = {10.1039/D0NR05666A},

issn = {2040-3364},

year  = {2020},

date = {2020-10-01},

journal = {Nanoscale},

volume = {12},

number = {42},

pages = {21857-21868},

abstract = {Ultrathin InAs nanowires (NW) with a one-dimensional (1D) sub-band structure are promising materials for advanced quantum-electronic devices, where dimensions in the sub-30 nm diameter limit together with post-CMOS integration scenarios on Si are much desired. Here, we demonstrate two site-selective synthesis methods that achieve epitaxial, high aspect ratio InAs NWs on Si with ultrathin diameters below 20 nm. The first approach exploits direct vapor\textendashsolid growth to tune the NW diameter by interwire spacing, mask opening size and growth time. The second scheme explores a unique reverse-reaction growth by which the sidewalls of InAs NWs are thermally decomposed under controlled arsenic flux and annealing time. Interesting kinetically limited dependencies between interwire spacing and thinning dynamics are found, yielding diameters as low as 12 nm for sparse NW arrays. We clearly verify the 1D sub-band structure in ultrathin NWs by pronounced conductance steps in low-temperature transport measurements using back-gated NW-field effect transistors. Correlated simulations reveal single- and double degenerate conductance steps, which highlight the rotational hexagonal symmetry and reproduce the experimental traces in the diffusive 1D transport limit. Modelling under the realistic back-gate configuration further evidences regimes that lead to asymmetric carrier distribution and breakdown of the degeneracy depending on the gate bias.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Ultrathin catalyst-free InAs nanowires on silicon with distinct 1D sub-band transport properties},

author = {Del F Giudice and J Becker and De C Rose and M D\"{o}blinger and D Ruhstorfer and L Suomenniemi and J Treu and H Riedl and J J Finley and G Koblm\"{u}ller},

url = {http://dx.doi.org/10.1039/D0NR05666A},

doi = {10.1039/D0NR05666A},

issn = {2040-3364},

year  = {2020},

date = {2020-10-01},

journal = {Nanoscale},

volume = {12},

number = {42},

pages = {21857-21868},

abstract = {Ultrathin InAs nanowires (NW) with a one-dimensional (1D) sub-band structure are promising materials for advanced quantum-electronic devices, where dimensions in the sub-30 nm diameter limit together with post-CMOS integration scenarios on Si are much desired. Here, we demonstrate two site-selective synthesis methods that achieve epitaxial, high aspect ratio InAs NWs on Si with ultrathin diameters below 20 nm. The first approach exploits direct vapor\textendashsolid growth to tune the NW diameter by interwire spacing, mask opening size and growth time. The second scheme explores a unique reverse-reaction growth by which the sidewalls of InAs NWs are thermally decomposed under controlled arsenic flux and annealing time. Interesting kinetically limited dependencies between interwire spacing and thinning dynamics are found, yielding diameters as low as 12 nm for sparse NW arrays. We clearly verify the 1D sub-band structure in ultrathin NWs by pronounced conductance steps in low-temperature transport measurements using back-gated NW-field effect transistors. Correlated simulations reveal single- and double degenerate conductance steps, which highlight the rotational hexagonal symmetry and reproduce the experimental traces in the diffusive 1D transport limit. Modelling under the realistic back-gate configuration further evidences regimes that lead to asymmetric carrier distribution and breakdown of the degeneracy depending on the gate bias.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Nanostructured amorphous gallium phosphide on silica for nonlinear and ultrafast nanophotonics},

author = {B Tilmann and G Grinblat and R Bert\'{e} and M \"{O}zcan and V F Kunzelmann and B Nickel and I D Sharp and E Cort\'{e}s and S A Maier and Y Li},

url = {http://dx.doi.org/10.1039/D0NH00461H},

doi = {10.1039/D0NH00461H},

issn = {2055-6756},

year  = {2020},

date = {2020-09-30},

journal = {Nanoscale Horizons},

volume = {5},

number = {11},

pages = {1500-1508},

abstract = {Nanophotonics based on high refractive index dielectrics relies on appreciable contrast between the indices of designed nanostructures and their immediate surrounding, which can be achieved by the growth of thin films on low-index substrates. Here we propose the use of high index amorphous gallium phosphide (a-GaP), fabricated by radio-frequency sputter deposition, on top of a low refractive index glass substrate and thoroughly examine its nanophotonic properties. Spectral ellipsometry of the amorphous material demonstrates the optical properties to be considerably close to crystalline gallium phosphide (c-GaP), with low-loss transparency for wavelengths longer than 650 nm. When nanostructured into nanopatches, the second harmonic (SH) response of an individual a-GaP patch is characterized to be more than two orders of magnitude larger than the as-deposited unstructured film, with an anapole-like resonant behavior. Numerical simulations are in good agreement with the experimental results over a large spectral and geometrical range. Furthermore, by studying individual a-GaP nanopatches through non-degenerate pump\textendashprobe spectroscopy with sub-10 fs pulses, we find a more than 5% ultrafast modulation of the reflectivity that is accompanied by a slower decaying free carrier contribution, caused by absorption. Our investigations reveal a potential for a-GaP as an adequate inexpensive and CMOS-compatible material for nonlinear nanophotonic applications as well as for photocatalysis.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {In Situ Quantification of the Local Electrocatalytic Activity via Electrochemical Scanning Tunneling Microscopy},

author = {R W Haid and R M Kluge and Y Liang and A S Bandarenka},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smtd.202000710},

doi = {https://doi.org/10.1002/smtd.202000710},

issn = {2366-9608},

year  = {2020},

date = {2020-09-29},

journal = {Small Methods},

volume = {5},

number = {2},

pages = {2000710},

abstract = {Abstract Identification of catalytically active sites at solid/liquid interfaces under reaction conditions is an essential task to improve the catalyst design for sustainable energy devices. Electrochemical scanning tunneling microscopy (EC-STM) combines the control of the surface reactions with imaging on a nanoscale. When performing EC-STM under reaction conditions, the recorded analytical signal shows higher fluctuations (noise) at active sites compared to non-active sites (noise-EC-STM or n-EC-STM). In the past, this approach has been proven as a valid tool to identify the location of active sites. In this work, the authors show that this method can be extended to obtain quantitative information of the local activity. For the platinum(111) surface under oxygen reduction reaction conditions, a linear relationship between the STM noise level and a measure of reactivity, the turn-over frequency is found. Since it is known that the most active sites for this system are located at concave sites, the method has been applied to quantify the activity at steps. The obtained activity enhancement factors appeared to be in good agreement with the literature. Thus, n-EC-STM is a powerful method not only to in situ identify the location of active sites but also to determine and compare local reactivity.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Magnetic proximity effect on excitonic spin states in Mn-doped layered hybrid perovskites},

author = {T Neumann and S Feldmann and P Moser and J Zerhoch and T Van De Goor and A Delhomme and T Winkler and J J Finley and C Faugeras and M S Brandt},

url = {https://arxiv.org/abs/2009.13867},

doi = {arXiv:2009.13867v1},

year  = {2020},

date = {2020-09-29},

journal = {arXiv preprint arXiv:2009.13867},

abstract = {Materials combining the optoelectronic functionalities of semiconductors with control of the spin degree of freedom are highly sought after for the advancement of quantum technology devices. Here, we report the paramagnetic Ruddlesden-Popper hybrid perovskite Mn:(PEA)2PbI4 (PEA = phenethylammonium) in which the interaction of isolated Mn2+ ions with magnetically brightened excitons leads to circularly polarized photoluminescence. Using a combination of superconducting quantum interference device (SQUID) magnetometry and magneto-optical experiments, we find that the Brillouin-shaped polarization curve of the photoluminescence follows the magnetization of the material. This indicates coupling between localized manganese magnetic moments and exciton spins via a magnetic proximity effect. The saturation polarization of 15% at 4 K and 6 T indicates a highly imbalanced spin population and demonstrates that manganese doping enables efficient control of excitonic spin states in Ruddlesden-Popper perovskites. Our finding constitutes the first example of polarization control in magnetically doped hybrid perovskites and will stimulate research on this highly tuneable material platform that promises tailored interactions between magnetic moments and electronic states.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Alternative electron pathways in photosynthesis: strength in numbers},

author = {D Leister},

url = {https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.16911},

doi = {https://doi.org/10.1111/nph.16911},

issn = {0028-646X},

year  = {2020},

date = {2020-09-26},

urldate = {2020-09-26},

journal = {New Phytologist},

volume = {228},

number = {4},

pages = {1166-1168},

abstract = {This article is a Commentary on Storti et al. (2020), 228: 1316\textendash1326.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Mesoporous GeOx/Ge/C as a Highly Reversible Anode Material with High Specific Capacity for Lithium-Ion Batteries},

author = {N Hohn and X Wang and M A Giebel and S Yin and D M\"{u}ller and A E Hetzenecker and L Bie\ssmann and L P Kreuzer and G E M\"{o}hl and H Yu and J G C Veinot and T F F\"{a}ssler and Y-J Cheng and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsami.0c13560},

doi = {10.1021/acsami.0c13560},

issn = {1944-8244},

year  = {2020},

date = {2020-09-21},

journal = {ACS Applied Materials \& Interfaces},

volume = {12},

number = {41},

pages = {47002-47009},

abstract = {Nanostructured Ge is considered a highly promising material for Li-ion battery applications as Ge offers high specific capacity and Li-ion diffusivity, while inherent mesoporous nanostructures can contribute resistance against capacity fading as typically induced by high volume expansion in bulk Ge films. Mesoporous GeOx/Ge/C films are synthesized using K4Ge9 Zintl clusters as a Ge precursor and the amphiphilic diblock copolymer polystyrene-block-polyethylene oxide as a templating tool. As compared to a reference sample without post-treatment, enhanced surface-to-volume ratios are achieved through post-treatment with a poor-good azeotrope solvent mixture. High capacities of over 2000 mA h g\textendash1 are obtained with good stability over 300 cycles. Information from morphological and compositional characterization for both reference and post-treated sample suggests that the good electrochemical performance originates from reversible GeO2 conversion reactions.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Carbon nitride-based light-driven microswimmers with intrinsic photocharging ability},

author = {V Sridhar and F Podjaski and J Kr\"{o}ger and A Jim\'{e}nez-Solano and B-W Park and B V Lotsch and M Sitti},

url = {http://www.pnas.org/content/117/40/24748.abstract},

doi = {10.1073/pnas.2007362117},

year  = {2020},

date = {2020-09-21},

journal = {Proceedings of the National Academy of Sciences},

volume = {117},

number = {40},

pages = {24748},

abstract = {Light-driven microswimmers offer prospects for autonomous microsystems. Understanding their surface catalytic processes responsible for propulsion is essential in tailoring them for specific applications. So far, photocatalytic microswimmers have been limited by the requirement of continuous illumination. Here, we report light-driven 2D carbon nitride-based Janus microswimmers, which show efficient propulsion in aqueous media not only during but also after illumination for about 30 min after 30 s prior illumination, due to so-called solar battery swimming. Contrary to the mainstream reports, we reveal oxygen reduction rather than hydrogen evolution being responsible for propulsion with alcohol fuels. Balancing reaction conditions, we report the realization of light-induced intrinsic charging of a microswimmer, enabling sustained ballistic propulsion in the dark through discharge of accumulated energy.Controlling autonomous propulsion of microswimmers is essential for targeted drug delivery and applications of micro/nanomachines in environmental remediation and beyond. Herein, we report two-dimensional (2D) carbon nitride-based Janus particles as highly efficient, light-driven microswimmers in aqueous media. Due to the superior photocatalytic properties of poly(heptazine imide) (PHI), the microswimmers are activated by both visible and ultraviolet (UV) light in conjunction with different capping materials (Au, Pt, and SiO2) and fuels (H2O2 and alcohols). Assisted by photoelectrochemical analysis of the PHI surface photoreactions, we elucidate the dominantly diffusiophoretic propulsion mechanism and establish the oxygen reduction reaction (ORR) as the major surface reaction in ambient conditions on metal-capped PHI and even with TiO2-based systems, rather than the hydrogen evolution reaction (HER), which is generally invoked as the source of propulsion under ambient conditions with alcohols as fuels. Making use of the intrinsic solar energy storage ability of PHI, we establish the concept of photocapacitive Janus microswimmers that can be charged by solar energy, thus enabling persistent light-induced propulsion even in the absence of illumination\textemdasha process we call “solar battery swimming”\textemdashlasting half an hour and possibly beyond. We anticipate that this propulsion scheme significantly extends the capabilities in targeted cargo/drug delivery, environmental remediation, and other potential applications of micro/nanomachines, where the use of versatile earth-abundant materials is a key prerequisite.All data, materials, and associated protocols that support the findings of this study are shown in Materials and Methods and SI Appendix.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electrical control of single-photon emission in highly charged individual colloidal quantum dots},

author = {S Morozov and E L Pensa and A H Khan and A Polovitsyn and E Cort\'{e}s and S A Maier and S Vezzoli and I Moreels and R Sapienza},

url = {https://pubmed.ncbi.nlm.nih.gov/32948584/},

doi = {10.1126/sciadv.abb1821},

issn = {2375-2548},

year  = {2020},

date = {2020-09-18},

urldate = {2020-09-18},

journal = {Sci Adv},

volume = {6},

number = {38},

abstract = {Electron transfer to an individual quantum dot promotes the formation of charged excitons with enhanced recombination pathways and reduced lifetimes. Excitons with only one or two extra charges have been observed and exploited for very efficient lasing or single-quantum dot light-emitting diodes. Here, by room-temperature time-resolved experiments on individual giant-shell CdSe/CdS quantum dots, we show the electrochemical formation of highly charged excitons containing more than 12 electrons and 1 hole. We report the control over intensity blinking, along with a deterministic manipulation of quantum dot photodynamics, with an observed 210-fold increase in the decay rate, accompanied by 12-fold decrease in the emission intensity, while preserving single-photon emission characteristics. These results pave the way for deterministic control over the charge state, and room-temperature decay rate engineering for colloidal quantum dot-based classical and quantum communication technologies.},

keywords = {Solid-Liquid, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Identifying Performance-Limiting Deep Traps in Ta3N5 for Solar Water Splitting},

author = {J Fu and F Wang and Y Xiao and Y Yao and C Feng and L Chang and C-M Jiang and V F Kunzelmann and Z M Wang and A O Govorov and I D Sharp and Y Li},

url = {https://doi.org/10.1021/acscatal.0c02648},

doi = {10.1021/acscatal.0c02648},

year  = {2020},

date = {2020-09-18},

journal = {ACS Catalysis},

volume = {10},

number = {18},

pages = {10316-10324},

abstract = {Ta3N5 is a promising semiconductor for solar-driven photocatalytic or photoelectrochemical (PEC) water splitting. However, the lack of an in-depth understanding of its intrinsic defect properties limits further improvement of its performance. In this study, comprehensive spectroscopic characterizations are combined with theoretical calculations to investigate the defect properties of Ta3N5. The obtained electronic structure of Ta3N5 reveals that oxygen impurities are shallow donors, while nitrogen vacancies and reduced Ta centers (Ta3+) are deep traps. The Ta3+ defects are identified to be most detrimental to the water splitting performance because their energetic position lies below the water reduction potential. Based on these findings, a simple H2O2 pretreatment method is employed to improve the PEC performance of the Ta3N5 photoanode by reducing the concentration of Ta3+ defects, resulting in a high solar-to-hydrogen conversion efficiency of 2.25%. The fundamental knowledge about the defect properties of Ta3N5 could serve as a guideline for developing more efficient photoanodes and photocatalysts.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {In Situ Photothermal Response of Single Gold Nanoparticles through Hyperspectral Imaging Anti-Stokes Thermometry},

author = {M Barella and I L Violi and J Gargiulo and L P Martinez and F Goschin and V Guglielmotti and D Pallarola and S Schl\"{u}cker and M Pilo-Pais and G P Acuna and S A Maier and E Cort\'{e}s and F D Stefani},

url = {https://doi.org/10.1021/acsnano.0c06185},

doi = {10.1021/acsnano.0c06185},

issn = {1936-0851},

year  = {2020},

date = {2020-09-17},

journal = {ACS Nano},

volume = {15},

number = {2},

pages = {2458-2467},

abstract = {Several fields of applications require a reliable characterization of the photothermal response and heat dissipation of nanoscopic systems, which remains a challenging task for both modeling and experimental measurements. Here, we present an implementation of anti-Stokes thermometry that enables the in situ photothermal characterization of individual nanoparticles (NPs) from a single hyperspectral photoluminescence confocal image. The method is label-free, potentially applicable to any NP with detectable anti-Stokes emission, and does not require any prior information about the NP itself or the surrounding media. With it, we first studied the photothermal response of spherical gold NPs of different sizes on glass substrates, immersed in water, and found that heat dissipation is mainly dominated by the water for NPs larger than 50 nm. Then, the role of the substrate was studied by comparing the photothermal response of 80 nm gold NPs on glass with sapphire and graphene, two materials with high thermal conductivity. For a given irradiance level, the NPs reach temperatures 18% lower on sapphire and 24% higher on graphene than on bare glass. The fact that the presence of a highly conductive material such as graphene leads to a poorer thermal dissipation demonstrates that interfacial thermal resistances play a very significant role in nanoscopic systems and emphasize the need for in situ experimental thermometry techniques. The developed method will allow addressing several open questions about the role of temperature in plasmon-assisted applications, especially ones where NPs of arbitrary shapes are present in complex matrixes and environments.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {In situ Grazing-Incidence Small-Angle X-ray Scattering Observation of Gold Sputter Deposition on a PbS Quantum Dot Solid},

author = {W Chen and S Liang and F C L\"{o}hrer and S J Schaper and N Li and W Cao and L P Kreuzer and H Liu and H Tang and V K\"{o}rstgens and M Schwartzkopf and K Wang and X W Sun and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsami.0c12732},

doi = {10.1021/acsami.0c12732},

issn = {1944-8244},

year  = {2020},

date = {2020-09-17},

urldate = {2020-09-17},

journal = {ACS Applied Materials \& Interfaces},

volume = {12},

number = {41},

pages = {46942-46952},

abstract = {For PbS quantum dot (QD)-based optoelectronic devices, gold is the most frequently used electrode material. In most device architectures, gold is in direct contact with the QD solid. To better understand the formation of the interface between gold and a close-packed QD layer at an early stage, in situ grazing-incidence small-angle X-ray scattering is used to observe the gold sputter deposition on a 1,2-ethanedithiol (EDT)-treated PbS QD solid. In the kinetics of gold layer growth, the forming and merging of small gold clusters (radius less than 1.6 nm) are observed at the early stages. The thereby formed medium gold clusters (radius between 1.9\textendash2.4 nm) are influenced by the QDs’ templating effect. Furthermore, simulations suggest that the medium gold clusters grow preferably along the QDs’ boundaries rather than as a top coating of the QDs. When the thickness of the sputtered gold layer reaches 6.25 nm, larger gold clusters with a radius of 5.3 nm form. Simultaneously, a percolation layer with a thickness of 2.5 nm is established underneath the gold clusters. This fundamental understanding of the QD\textendashgold interface formation will help to control the implementation of sputtered gold electrodes on close-packed QD solids in device manufacturing processes.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Annihilation Dynamics of Molecular Excitons Measured at a Single Perturbative Excitation Energy},

author = {C Heshmatpour and P Malevich and F Plasser and M Menger and C Lambert and F \v{S}anda and J Hauer},

url = {https://doi.org/10.1021/acs.jpclett.0c02141},

doi = {10.1021/acs.jpclett.0c02141},

year  = {2020},

date = {2020-09-17},

journal = {The Journal of Physical Chemistry Letters},

volume = {11},

number = {18},

pages = {7776-7781},

abstract = {Exciton\textendashexciton annihilation (EEA) is a ubiquitous phenomenon, which may limit the efficiency of photovoltaic devices. Conventional methods of determining EEA time scales rely on measuring the intensity dependence of third-order signals. In this work, we directly extract the annihilation rate of molecular excitons in a covalently joined molecular trimer without the need to perform and analyze intensity dependent data by employing fifth-order coherent optical spectroscopy signals emitted into ±2k⃗1 ∓ 2k⃗2 + k⃗3 phase matching directions. Measured two-dimensional line shapes and their time traces are analyzed in the framework of the many-body version of the Frenkel exciton model, extended to incorporate annihilation dynamics. Combining double-sided Feynman diagrams with explicit simulations of the fifth-order response, we identify a single peak as a direct reporter of EEA. We retrieve an annihilation time of 30 fs for the investigated squaraine trimer.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Direct Detection of Optical Forces of Magnetic Nature in Dielectric Nanoantennas},

author = {M Poblet and Y Li and E Cort\'{e}s and S A Maier and G Grinblat and A V Bragas},

url = {https://doi.org/10.1021/acs.nanolett.0c03157},

doi = {10.1021/acs.nanolett.0c03157},

issn = {1530-6984},

year  = {2020},

date = {2020-09-16},

urldate = {2020-09-16},

journal = {Nano Letters},

volume = {20},

number = {10},

pages = {7627-7634},

abstract = {Optical forces on nanostructures are usually characterized by their interaction with the electric field component of the light wave, given that most materials present negligible magnetic response at optical frequencies. This is not the case however of a high-refractive-index dielectric nanoantenna, which has been recently shown to efficiently support both electric and magnetic optical modes. In this work, we use a photoinduced force microscopy configuration to measure optically induced forces produced by a germanium nanoantenna on a surrounding silicon near-field probe. We reveal the spatial distribution, character, and magnitude of the generated forces when exciting the nanoantenna at its anapole state condition. We retrieve optical force maps showing values of up to 20 pN, which are found to be mainly magnetic in nature, according to our numerical simulations. The results of this investigation open new pathways for the study, detection, and generation of magnetic light forces at the nanometer scale.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Perovskite and Organic Solar Cells on a Rocket Flight},

author = {L K Reb and M B\"{o}hmer and B Predeschly and S Grott and C L Weindl and G I Ivandekic and R Guo and C Drei\ssigacker and R Gernh\"{a}user and A Meyer and P M\"{u}ller-Buschbaum},

url = {https://www.sciencedirect.com/science/article/pii/S2542435120303226},

doi = {https://doi.org/10.1016/j.joule.2020.07.004},

issn = {2542-4351},

year  = {2020},

date = {2020-09-16},

urldate = {2020-09-16},

journal = {Joule},

volume = {4},

number = {9},

pages = {1880-1892},

abstract = {Summary Perovskite and organic solar cells possess a revolutionary potential for space applications. The thin-film solar cells can be processed onto thin polymer foils that enable an exceptional specific power, i.e., obtainable electric power per mass, being superior to their inorganic counterparts. However, research toward space applications was mainly restricted to terrestrial conditions so far. Here, we report the launch of perovskite and organic solar cells of different architectures on a suborbital rocket flight. This is an in situ demonstration of their functionality and power generation under space conditions. We measured solar cell current-voltage characteristics in variable illumination states due to different rocket orientations during flight. Under strong solar irradiance, the solar cells perform efficiently, and they even produce power with weak diffuse light reflected from Earth’s surface. These results highlight both the suitability for near-Earth applications as well as the potential for deep-space missions for these innovative technologies.},

keywords = {Foundry Inorganic, Solid-Solid},

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 = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Stepping Out of Equilibrium: The Quest for Understanding the Role of Non-Equilibrium (Thermo-)Dynamics in Electronic and Electrochemical Processes},

author = {W Kaiser and A Gagliardi},

url = {https://www.mdpi.com/1099-4300/22/9/1013},

issn = {1099-4300},

year  = {2020},

date = {2020-09-10},

journal = {Entropy},

volume = {22},

number = {9},

pages = {1013},

abstract = {This editorial aims to interest researchers and inspire novel research on the topic of non-equilibrium Thermodynamics and Monte Carlo for Electronic and Electrochemical Processes. We present a brief outline on recent progress and challenges in the study of non-equilibrium dynamics and thermodynamics using numerical Monte Carlo simulations. The aim of this special issue is to collect recent advances and novel techniques of Monte Carlo methods to study non-equilibrium electronic and electrochemical processes at the nanoscale.},

keywords = {Solid-Liquid, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Nickel clusters on TiO2(110): thermal chemistry and photocatalytic hydrogen evolution of methanol},

author = {M Eder and C Courtois and T Kratky and S G\"{u}nther and M Tschurl and U Heiz},

url = {http://dx.doi.org/10.1039/D0CY01465F},

doi = {10.1039/D0CY01465F},

issn = {2044-4753},

year  = {2020},

date = {2020-09-09},

journal = {Catalysis Science \& Technology},

volume = {10},

number = {22},

pages = {7630-7639},

abstract = {In heterogeneous photocatalysis, noble metals such as Au, Pt, or Pd are most commonly used as co-catalysts to facilitate H2 evolution, yet their costs are problematic for applications on a large scale. In this work, we show that the cheaper, more abundant transition metal nickel as co-catalyst material reacts accordingly, when being deposited as small clusters onto rutile TiO2. Different to noble metal systems the photocatalysts undergo photocorrosion, depicted in a declining activity during the photoreforming of methanol. The reaction being performed in an ultra-high vacuum environment allows for a more detailed elucidation of the deactivation processes. Supported by reactivity studies under different conditions, Auger electron spectroscopy reveals that coking of the clusters occurs, while nickel oxide formation is not observed. The study thus shows that nickel co-catalysts are indeed prospective systems for the photocatalytic hydrogen evolution reaction, similar to platinum clusters, but instead may also feature unexpected photon-driven deactivation pathways.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electrosorption at metal surfaces from first principles},

author = {N G H\"{o}rmann and N Marzari and K Reuter},

url = {https://doi.org/10.1038/s41524-020-00394-4},

doi = {10.1038/s41524-020-00394-4},

issn = {2057-3960},

year  = {2020},

date = {2020-09-08},

urldate = {2020-09-08},

journal = {npj Computational Materials},

volume = {6},

number = {1},

pages = {136},

abstract = {Electrosorption of solvated species at metal electrodes is a most fundamental class of processes in interfacial electrochemistry. Here, we use its sensitive dependence on the electric double layer to assess the performance of ab initio thermodynamics approaches increasingly used for the first-principles description of electrocatalysis. We show analytically that computational hydrogen electrode calculations at zero net-charge can be understood as a first-order approximation to a fully grand canonical approach. Notably, higher-order terms in the applied potential caused by the charging of the double layer include contributions from adsorbate-induced changes in the work function and in the interfacial capacitance. These contributions are essential to yield prominent electrochemical phenomena such as non-Nernstian shifts of electrosorption peaks and non-integer electrosorption valencies. We illustrate this by calculating peak shifts for H on Pt electrodes and electrosorption valencies of halide ions on Ag electrodes, obtaining qualitative agreement with experimental data already when considering only second order terms. The results demonstrate the agreement between classical electrochemistry concepts and a first-principles fully grand canonical description of electrified interfaces and shed new light on the widespread computational hydrogen electrode approach.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Self-activation of copper electrodes during CO electro-oxidation in alkaline electrolyte},

author = {A Auer and M Andersen and E-M Wernig and N G H\"{o}rmann and N Buller and K Reuter and J Kunze-Liebh\"{a}user},

url = {https://doi.org/10.1038/s41929-020-00505-w},

doi = {10.1038/s41929-020-00505-w},

issn = {2520-1158},

year  = {2020},

date = {2020-09-07},

journal = {Nature Catalysis},

abstract = {The development of low-temperature fuel cells for clean energy production is an appealing alternative to fossil-fuel technologies. CO is a key intermediate in the electro-oxidation of energy carrying fuels and, due to its strong interaction with state-of-the-art Pt electrodes, it is known to act as a poison. Here we demonstrate the ability of Earth-abundant Cu to electro-oxidize CO efficiently in alkaline media, reaching high current densities of ≥0.35 mA cm−2 on single-crystal Cu(111) model catalysts. Strong and continuous surface structural changes are observed under reaction conditions. Supported by first-principles microkinetic modelling, we show that the concomitant presence of high-energy undercoordinated Cu structures at the surface is a prerequisite for the high activity. Similar CO-induced self-activation has been reported for gas\textendashsurface reactions at coinage metals, demonstrating the strong parallels between heterogeneous thermal catalysis and heterogeneous electrocatalysis.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optically Active Perovskite CsPbBr3 Nanocrystals Helically Arranged on Inorganic Silica Nanohelices},

author = {P Liu and W Chen and Y Okazaki and Y Battie and L Brocard and M Decossas and E Pouget and P M\"{u}ller-Buschbaum and B Kauffmann and S Pathan and T Sagawa and R Oda},

url = {https://doi.org/10.1021/acs.nanolett.0c02013},

doi = {10.1021/acs.nanolett.0c02013},

issn = {1530-6984},

year  = {2020},

date = {2020-09-03},

urldate = {2020-09-03},

journal = {Nano Letters},

volume = {20},

number = {12},

pages = {8453-8460},

abstract = {Perovskite nanocrystals (PNCs) exhibit excellent absorption and luminescent properties. Inorganic silica right (or left) handed nanohelices are used as chiral templates to induce optically active properties to CsPbBr3 PNCs grafted on their surfaces. In suspension, PNCs grafted on the nanohelices do not show any detectable chiroptical properties. In contrast, in a dried film state, they show large circular dichroism (CD) and circularly polarized luminescence (CPL) signals with dissymmetric factor up to 6 × 10\textendash3. Grazing incidence X-ray scattering, tomography, and cryo-electron microscopy (EM) have shown closely and helically packed PNCs on the dried helices and much more loosely organized PNCs on helices in suspension. Simulations based on the coupled dipole method (CDM) demonstrate that the CD comes from the dipolar interaction between PNC assembled into a chiral structure and the CD decreases with the interparticle distance.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Growth of Perovskite CsPbBr3 Nanocrystals and Their Formed Superstructures Revealed by In Situ Spectroscopy},

author = {H Huang and M W Feil and S Fuchs and T Debnath and A F Richter and Y Tong and L Wu and Y Wang and M D\"{o}blinger and B Nickel},

url = {https://doi.org/10.1021/acs.chemmater.0c02467},

doi = {10.1021/acs.chemmater.0c02467},

issn = {0897-4756},

year  = {2020},

date = {2020-09-02},

journal = {Chemistry of Materials},

volume = {32},

number = {20},

pages = {8877-8884},

abstract = {Metal halide perovskites have attracted substantial interest because of their promising properties for optoelectronic applications. Despite much progress made in the field, the exact growth mechanism of perovskite nanocrystals (e.g., CsPbBr3) remains elusive and further improvement of their controllable synthesis is challenging. Herein, we point out different phenomena during the processes of growth, cooling, and purification of high-quality CsPbBr3 nanocrystals using in situ photoluminescence spectroscopy. The as-synthesized materials have been further characterized by time-resolved transient differential transmission and photoluminescence spectroscopies. Using X-ray scattering, we confirm that nanocrystals form superstructures during the process of cooling already in dispersion, which is frequently ignored. The purification process is explained using a proposed model based on the self-size-selection. On the one hand, such superstructures pave a potential pathway to the fabrication of high-quality devices such as light-emitting devices. On the other hand, the approach to reveal their formation process benefits the comparison and understanding of the difference between nanocrystals and supercrystals. The fact that superstructures form already during synthesis may also apply to the different perovskite systems and thus help to improve the quality of the as-prepared nanocrystals.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Fermi smearing variant of the Tamm\textendashDancoff approximation for nonadiabatic dynamics involving S1\textendashS0 transitions: Validation and application to azobenzene},

author = {L D M Peters and J Kussmann and C Ochsenfeld},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0016487},

doi = {10.1063/5.0016487},

year  = {2020},

date = {2020-09-02},

journal = {The Journal of Chemical Physics},

volume = {153},

number = {9},

pages = {094104},

abstract = {The main shortcoming of time-dependent density functional theory (TDDFT) regarding its use for nonadiabatic molecular dynamics (NAMD) is its incapability to describe conical intersections involving the ground state. To overcome this problem, we combine Fermi smearing (FS) DFT with a fractional-occupation variant of the Tamm\textendashDancoff approximation (TDA) of TDDFT in the generalized gradient approximation. The resulting method (which we denote as FS-TDA) gives access to ground- and excited-state energies, gradients, and nonadiabatic coupling vectors, which are physically correct even in the vicinity of S1\textendashS0 conical intersections. This is shown for azobenzene, a widely used photoswitch, via single point calculations and NAMD simulations of its cis\textendashtrans photoisomerization. We conclude that FS-TDA may be used as an efficient alternative to investigate these processes.},

keywords = {Molecularly-Functionalized, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Ionothermal Synthesis of Imide-Linked Covalent Organic Frameworks},

author = {J Maschita and T Banerjee and G Savasci and F Haase and C Ochsenfeld and B V Lotsch},

url = {https://doi.org/10.1002/anie.202007372},

doi = {https://doi.org/10.1002/anie.202007372},

issn = {1433-7851},

year  = {2020},

date = {2020-09-01},

journal = {Angewandte Chemie International Edition},

volume = {59},

number = {36},

pages = {15750-15758},

abstract = {Abstract Covalent organic frameworks (COFs) are an extensively studied class of porous materials, which distinguish themselves from other porous polymers in their crystallinity and high degree of modularity, enabling a wide range of applications. COFs are most commonly synthesized solvothermally, which is often a time-consuming process and restricted to well-soluble precursor molecules. Synthesis of polyimide-linked COFs (PI-COFs) is further complicated by the poor reversibility of the ring-closing reaction under solvothermal conditions. Herein, we report the ionothermal synthesis of crystalline and porous PI-COFs in zinc chloride and eutectic salt mixtures. This synthesis does not require soluble precursors and the reaction time is significantly reduced as compared to standard solvothermal synthesis methods. In addition to applying the synthesis to previously reported imide COFs, a new perylene-based COF was also synthesized, which could not be obtained by the classical solvothermal route. In situ high-temperature XRPD analysis hints to the formation of precursor?salt adducts as crystalline intermediates, which then react with each other to form the COF.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Disorder and Linker Deficiency in Porphyrinic Zr-MOFs: Resolving the Zr8O6 Cluster Conundrum in PCN-221},

author = {C Koschnick and R St\"{a}glich and T Scholz and M Terban and A V Mankowski and G Savasci and F Binder and A Sch\"{o}kel and M Etter and J Nuss and R Siegel and L Germann and C Ochsenfeld and R Dinnebier and J Senker and B V Lotsch},

url = {http://europepmc.org/abstract/PPR/PPR210987 

https://doi.org/10.26434/chemrxiv.12918968.v1},

doi = {10.26434/chemrxiv.12918968.v1},

year  = {2020},

date = {2020-09-01},

urldate = {2020-09-01},

publisher = {ChemRxiv},

abstract = {Porphyrin-based metal-organic frameworks (MOFs), exemplified by the prototypical representatives MOF-525, PCN-221, and PCN-224 are among the most promising MOF systems for catalysis, optoelectronics, and solar energy conversion. However, subtle differences between synthetic protocols for these three MOFs give rise to vast discrepancies in purported product outcomes and description of framework topologies. Here, we reveal the type and disorder of the Zr-clusters based on a comprehensive synthetic and structural analysis spanning local and long-range length scales. Our analysis on PCN-221 reveals Zr6O4(OH)4 clusters in four distinct orientations within the unit cell, rather than Zr8O6 clusters as originally published, accompanied by random linker vacancies around 50%. We propose disordered PCN-224 (dPCN-224) as a unified model to understand PCN-221, MOF-525, and PCN-224 by varying the degree of orientational cluster disorder, linker conformation and vacancies, and cluster\textemdashlinker binding. Our work thus introduces a new perspective on network topology and disorder in Zr-MOFs and pinpoints the structural variables that direct their functional properties.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Light-Induced and Oxygen-Mediated Degradation Processes in Photoactive Layers Based on PTB7-Th},

author = {F C L\"{o}hrer and C Senfter and C J Schaffer and J Schlipf and D Mosegu\'{i} Gonz\'{a}lez and P Zhang and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adpr.202000047},

doi = {https://doi.org/10.1002/adpr.202000047},

issn = {2699-9293},

year  = {2020},

date = {2020-08-26},

urldate = {2020-08-26},

journal = {Advanced Photonics Research},

volume = {1},

number = {1},

pages = {2000047},

abstract = {Low-bandgap polymers are sensitive to various degradation processes, which strongly decrease their lifetime. The chemical and physical changes occurring in the low-bandgap polymer with benzodithiophene units poly[4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-2-carboxylate] (PTB7-Th) and its blend with the fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) are followed during irradiation-induced aging by combination of various characterization methods. The active layer morphology is investigated using atomic force microscopy (AFM) as well as in-operando grazing incidence small angle X-ray scattering (GISAXS), indicating morphological alterations and material loss due to chemical modifications. Optical spectroscopy gives insights into these chemical processes which lead to significant absorption losses under ambient conditions. Independent of the energy of the absorbed photons, but only in combination with oxygen, the excitation of the polymer leads to a fatal increase in oxidation probability. Fourier transform infrared (FTIR) data highlight the sensitivity of the conjugated polymer backbone to oxidation, a result of lost conjugation and therefore absorption capability. With combined AFM height and infrared (IR) mapping, the chemical degradation and material loss is confirmed on a nanoscale. Although the chemical structure is seriously damaged, the blend morphology is not undergoing major changes.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}