Publications

@article{nokey,

title = {Large Tolerance of Lasing Properties to Impurity Defects in GaAs(Sb)-AlGaAs Core-Shell Nanowire Lasers},

author = {T Schreitm\"{u}ller and H W Jeong and H Esmaielpour and C E Mead and M Ramsteiner and P Schmiedeke and A Thurn and A Ajay and S Matich and M D\"{o}blinger and L J Lauhon and J J Finley and G Koblm\"{u}ller},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202311210},

doi = {https://doi.org/10.1002/adfm.202311210},

issn = {1616-301X},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2311210},

abstract = {Abstract GaAs-AlGaAs based nanowire (NW) lasers hold great potential for on-chip photonic applications, where lasing metrics have steadily improved over the years by optimizing resonator design and surface passivation methods. The factor that will ultimately limit the performance will depend on material properties, such as native- or impurity-induced point defects and their impact on non-radiative recombination. Here, the role of impurity-induced point defects on the lasing performance of low-threshold GaAs(Sb)-AlGaAs NW-lasers is evaluated, particularly by exploring Si-dopants and their associated vacancy complexes. Si-induced point defects and their self-compensating nature are identified using correlated atom probe tomography, resonant Raman scattering, and photoluminescence experiments. Under pulsed optical excitation the lasing threshold is remarkably low (\<10 µJ cm−2) and insensitive to impurity defects over a wide range of Si doping densities, while excess doping ([Si]\>1019 cm−3) imposes increased threshold at low temperature. These characteristics coincide with increased Shockley-Read-Hall recombination, reflected by shorter carrier lifetimes, and reduced internal quantum efficiencies (IQE) . Remarkably, despite the lower IQE the presence of self-compensating Si-vacancy defects provides an improved temperature stability in lasing threshold with higher characteristic temperature and room-temperature lasing. These findings highlight an overall large tolerance of lasing metrics to impurity defects in GaAs-AlGaAs based NW-lasers.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Accessible hotspots for single-protein SERS in DNA-origami assembled gold nanorod dimers with tip-to-tip alignment},

author = {F Schuknecht and K Ko\l\k{a}taj and M Steinberger and T Liedl and T Lohmueller},

url = {https://doi.org/10.1038/s41467-023-42943-7},

doi = {10.1038/s41467-023-42943-7},

issn = {2041-1723},

journal = {Nature Communications},

volume = {14},

number = {1},

pages = {7192},

abstract = {The label-free identification of individual proteins from liquid samples by surface-enhanced Raman scattering (SERS) spectroscopy is a highly desirable goal in biomedical diagnostics. However, the small Raman scattering cross-section of most (bio-)molecules requires a means to strongly amplify their Raman signal for successful measurement, especially for single molecules. This amplification can be achieved in a plasmonic hotspot that forms between two adjacent gold nanospheres. However, the small (≈1−2 nm) gaps typically required for single-molecule measurements are not accessible for most proteins. A useful strategy would thus involve dimer structures with gaps large enough to accommodate single proteins, whilst providing sufficient field enhancement for single-molecule SERS. Here, we report on using a DNA origami scaffold for tip-to-tip alignment of gold nanorods with an average gap size of 8 nm. The gaps are accessible to streptavidin and thrombin, which are captured at the plasmonic hotspot by specific anchoring sites on the origami template. The field enhancement achieved for the nanorod dimers is sufficient for single-protein SERS spectroscopy with sub-second integration times. This design for SERS probes composed of DNA origami with accessible hotspots promotes future use for single-molecule biodiagnostics in the near-infrared range.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {In-situ study of degradation in PTB7:PCBM films prepared with the binary solvent additive DPE:DIO},

author = {D M Schwaiger and W Lohstroh and M Wolf and C J Garvey and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pol.20230072},

doi = {https://doi.org/10.1002/pol.20230072},

issn = {2642-4150},

journal = {Journal of Polymer Science},

volume = {61},

number = {15},

pages = {1660-1674},

abstract = {Abstract Blend films of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) in combination with 6,6-phenyl-C61-butyric-acid-methyl-ester (PCBM) are a model system for low bandgap organic photovoltaics. Typically, solvent additives are used to improve the power conversion efficiencies of the resulting devices but possibly also decrease the device stability. In this study, we use the binary solvent additive 1,8-diiodooctane:diphenylether (DIO:DPE) for PTB7:PCBM blend films and study how different film drying procedures influence the physical and chemical stability of the polymer blend. The strong influence of the drying procedure on the stability against photoinduced degradation of the PTB7:PCBM films, produced with solvent additives, is shown with data from UV\textendashvisible (UV\textendashvis), Fourier transform infrared (FTIR) and Raman spectroscopy. The addition of solvent additive molecules DIO:DPE to the PTB7:PCBM blend accelerates the degradation compared with the pristine blend. At higher annealing temperature a removal of the additives is bringing degradation back to the level of the pristine blend films, which is promising for photovoltaic applications.},

keywords = {Foundry Organic, Molecularly-Functionalized},

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},

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 = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Theoretical spectroscopy for unraveling the intensity mechanism of the optical and photoluminescent spectra of chiral Re(I) transition metal complexes},

author = {R Shafei and A Hamano and C Gourlaouen and D Maganas and K Takano and C Daniel and F Neese},

url = {https://doi.org/10.1063/5.0153742},

doi = {10.1063/5.0153742},

issn = {0021-9606},

journal = {The Journal of Chemical Physics},

volume = {159},

number = {8},

abstract = {In this work, we present a computational study that is able to predict the optical absorption and photoluminescent properties of the chiral Re(I) family of complexes [fac-ReX(CO)3L], where X is either Cl or I and L is N-heterocyclic carbene extended with π-conjugated [5]-helicenic unit. The computational strategy is based on carefully calibrated time dependent density functional theory calculations and operates in conjunction with an excited state dynamics approach to treat in addition to absorption (ABS) and photoluminescence (PL), electronic circular dichroism (ECD), and circularly polarized luminescence (CPL) spectroscopies, respectively. The employed computational approach provides, an addition, access to the computation of phosphorescence rates in terms of radiative and non-radiative relaxation processes. The chosen molecules consist of representative examples of non-helicenic (NHC) and helicenic diastereomers. The agreement between theoretical and experimental spectra, including absorption (ABS, ECD) and emission (PL, CPL), is excellent, validating a quantitative interpretation of the spectral features on the basis of natural transition orbitals and TheoDore analyses. It is demonstrated that across the set of studied Re(I) diastereomers, the emission process in the case of NHC diastereomers is metal to ligand charge transfer in nature and is dominated by the easy-axis anisotropy of the emissive excited multiplet. On the contrary, in the cases of the helicenic diastereomers, the emission process is intra ligand charge transfer in nature and is dominated by the respective easy-plane anisotropy of the emissive excited multiplet. This affects remarkably the photoluminescent properties of the molecules in terms of PL and CPL spectral band shapes, spin-vibronic coupling, relaxation times, and the respective quantum yields. Spin-vibronic coupling effects are investigated at the level of the state-average complete active space self-consistent field in conjunction with quasi-degenerate second order perturbation theory. It is in fact demonstrated that a spin-vibronic coupling mechanism controls the observed photophysics of this class of Re(I) complexes.},

keywords = {Foundry Organic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optically addressable spin defects coupled to bound states in the continuum metasurfaces},

author = {L Sortino and A Gale and L K\"{u}hner and C Li and J Biechteler and F J Wendisch and M Kianinia and H Ren and M Toth and S A Maier},

url = {https://arxiv.org/abs/2306.05735},

doi = {https://doi.org/10.48550/arXiv.2306.05735},

journal = {arXiv preprint arXiv:2306.05735},

abstract = {Van der Waals (vdW) materials, including hexagonal boron nitride (hBN), are layered crystalline solids with appealing properties for investigating light-matter interactions at the nanoscale. hBN has emerged as a versatile building block for nanophotonic structures, and the recent identification of native optically addressable spin defects has opened up exciting possibilities in quantum technologies. However, these defects exhibit relatively low quantum efficiencies and a broad emission spectrum, limiting potential applications. Optical metasurfaces present a novel approach to boost light emission efficiency, offering remarkable control over light-matter coupling at the sub-wavelength regime. Here, we propose and realise a monolithic scalable integration between intrinsic spin defects in hBN metasurfaces and high quality (Q) factor resonances leveraging quasi-bound states in the continuum (qBICs). Coupling between spin defect ensembles and qBIC resonances delivers a 25-fold increase in photoluminescence intensity, accompanied by spectral narrowing to below 4 nm linewidth facilitated by Q factors exceeding 10 ^2. Our findings demonstrate a new class of spin based metasurfaces and pave the way towards vdW-based nanophotonic devices with enhanced efficiency and sensitivity for quantum applications in imaging, sensing, and light emission.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Photoexcitation Control of Excitation Relaxation in Mixed-Phase Ruddlesden-Popper Hybrid Organic-Inorganic Lead-Iodide Perovskites},

author = {A Stadlbauer and L Eyre and A Biewald and F Rauh and M W Heindl and S Liu and J Zerhoch and S Feldmann and A Hartschuh and F Deschler},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202301331},

doi = {https://doi.org/10.1002/adom.202301331},

issn = {2195-1071},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2301331},

abstract = {Abstract The electronic states and exciton binding energies of layered Ruddlesden-Popper (RP) metal-halide perovskites can be tailored through changes of their chemical composition, yielding multi-phase systems with complex energy cascades. Ultrafast photoexcitation relaxation with transfer dynamics into domains of increasing layer number has been reported for these materials. Here, ultrafast optical spectroscopy is used to report an unexpected excitation energy dependence of photoexcitation relaxation dynamics in mixed-dimensional benzylammonium cesium lead iodide RP perovskite (BeA2CsPb2I7) thin films, which gives rise to spectrally broadband luminescence over the visible region. Using transient absorption and photoluminescence spectroscopy it is found that excitations, which are formed in the n = 2 RP-phase after photoexcitation with ≈0.2 electron volt excess energy, transfer to higher layer number RP-phases on unexpectedly slow timescales of tens of picoseconds. Further, it is observed that such excitations are initially optically passive. Notably, luminescence occurs under these conditions from multiple RP-phases with optical bandgaps across the visible range, yielding broadband luminescence. The results hold potential for realization of broadband white-light emitters and other light-emitting devices.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Nonlinear potentiodynamic battery charging protocols for fun, education, and application},

author = {H S Stein},

url = {https://chemrxiv.org/engage/chemrxiv/article-details/650ef57ab927619fe7acea3e},

doi = {10.26434/chemrxiv-2023-vj5n0},

abstract = {Most secondary batteries in academia are (dis)charged by applying a constant current (CC) followed by a constant voltage (CV) i.e. a CCCV procedure. The usual concept is then to condense data for interpretation into representations such as differential capacity, or dQ/dV, graphs. This is done to extract information related to phenomena such as the growth of the solid electrolyte interphase (SEI) or, more broadly, degradation. Typically, these measurements take several months because measurements for differential capacity analysis need to be performed at relatively low C-rates. An alternate charging schedule to CCCV is pulsed charging, where CC sections are interrupted by an open-circuit measurement on the second time scale. These and similar partially constant current strategies primarily target diffusive effects during charging and broadly fall into a linear charging category, where the time derivative for the actuated property is mostly zero. Herein, I explore nonlinear charging i.e., the process of actively applying a potential with a nontrivial time derivate and a resulting non-trivial current time derivative to engineer (dis)charge cycles with enhanced information density. This method of nonlinear charging is then used to charge a cell such that some potential ranges in the differential capacity diagram are omitted. This study is purely a simulative endeavor and not backed by experimentation, owing mainly to the lack of facile implementation of arbitrary function inputs for battery cyclers and might point to limitations of the underlying theory. If found to be confirmed through an experiment, this technique would, however motivate a new roadmap to better understand secondary battery degradation inspired by electrocatalyst degradation.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Morphological Insights into the Degradation of Perovskite Solar Cells under Light and Humidity},

author = {K Sun and R Guo and Y Liang and J E Heger and S Liu and S Yin and M A Reus and L V Spanier and F Deschler and S Bernstorff and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsami.3c05671},

doi = {10.1021/acsami.3c05671},

issn = {1944-8244},

journal = {ACS Applied Materials \& Interfaces},

volume = {15},

number = {25},

pages = {30342-30349},

abstract = {Perovskite solar cells (PSCs) have achieved competitive power conversion efficiencies compared with established solar cell technologies. However, their operational stability under different external stimuli is limited, and the underlying mechanisms are not fully understood. In particular, an understanding of degradation mechanisms from a morphology perspective during device operation is missing. Herein, we investigate the operational stability of PSCs with CsI bulk modification and a CsI-modified buried interface under AM 1.5G illumination and 75 ± 5% relative humidity, respectively, and concomitantly probe the morphology evolution with grazing-incidence small-angle X-ray scattering. We find that volume expansion within perovskite grains, induced by water incorporation, initiates the degradation of PSCs under light and humidity and leads to the degradation of device performance, in particular, the fill factor and short-circuit current. However, PSCs with modified buried interface degrade faster, which is ascribed to grain fragmentation and increased grain boundaries. In addition, we reveal a slight lattice expansion and PL redshifts in both PSCs after exposure to light and humidity. Our detailed insights from a buried microstructure perspective on the degradation mechanisms under light and humidity are essential for extending the operational stability of PSCs.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Unraveling the Morphology-Function Correlation of Mesoporous ZnO Films upon Water Exposure},

author = {T Tian and S Tu and A Xu and S Yin and A L Oechsle and T Xiao and A Vagias and J Eichhorn and J Suo and Z Yang and S Bernstorff and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202311793},

doi = {https://doi.org/10.1002/adfm.202311793},

issn = {1616-301X},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2311793},

abstract = {Abstract Ubiquitous moisture in synthetic conditions and ambient environments can strongly influence the conductivity of ZnO semiconductors via the chemisorption and physisorption of water molecules on the ZnO surface. Such an intrinsically water-sensitive nature will become more evident in mesoporous ZnO films where a large surface area and active sites are created simultaneously. However, fundamental insights underlying water-mediated ZnO surface chemistry and electrical conductivity and the factors affecting them remain ambiguous due to the complexity of ZnO surfaces and the difficulties of in situ characterizations at multi-dimensions. Here, self-assembling diblock copolymers are exploited as structure-directing agents to achieve mesoporous ZnO thin films with highly tailorable structural characteristics ranging from nanomorphologies, over crystalline levels, to defect contents. As verified by theoretical calculations, the presence of oxygen vacancy will facilitate favorable water adsorption and subsequent dissociation on the polar ZnO surfaces. Upon humidity exposure with progressively increased levels, mesoporous ZnO films are revealed to follow an almost positive relationship between adsorption and electrical conductivity but show superior morphological stability. This work not only elucidates the water-governed ZnO surface chemistry but may also promote a comprehensive understanding of the morphology-function relationship on ZnO-based electronics.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Comparison of Harmonic Generation from Crystalline and Amorphous Gallium Phosphide Nanofilms},

author = {B Tilmann and T Huq and T Possmayer and J Dranczewski and B Nickel and H Zhang and L Krivitsky and A I Kuznetsov and L De S. Menezes and S Vezzoli and R Sapienza and S A Maier},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202300269},

doi = {https://doi.org/10.1002/adom.202300269},

issn = {2195-1071},

journal = {Advanced Optical Materials},

volume = {11},

number = {16},

pages = {2300269},

abstract = {Abstract Gallium phosphide (GaP) is a promising material for nanophotonics, given its large refractive index and a transparency over most of the visible spectrum. However, since easy phase-matching is not possible with bulk GaP, a comprehensive study of its nonlinear optical properties for harmonic generation, especially when grown as thin films, is still missing. Here, second harmonic generation is studied from epitaxially grown GaP thin films, demonstrating that the absolute conversion efficiencies are comparable to a bulk wafer over the pump wavelength range from 1060 to 1370 nm. Furthermore, the results are compared to nonlinear simulations, and the second order nonlinear susceptibility is extracted, showing a similar dispersion and magnitude to that of the bulk material. Furthermore, the third order nonlinear susceptibility of amorphous GaP thin films is extracted from third harmonic generation to be more than one order of magnitude larger than that of the crystalline material, and generation of up to the fifth harmonic is reported. The results show the potential of crystalline and amorphous thin films for nonlinear optics with nanoantennas and metasurfaces, particularly in the visible to near infrared part of the spectrum.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Understanding the Electrolyte Chemistry Induced Enhanced Stability of Si Anodes in Li-Ion Batteries based on Physico-Chemical Changes, Impedance, and Stress Evolution during SEI Formation},

author = {R Tripathi and G Yesilbas and X Lamprecht and P Gandharapu and A S Bandarenka and R O Dusane and A Mukhopadhyay},

url = {https://dx.doi.org/10.1149/1945-7111/acfb3f},

doi = {10.1149/1945-7111/acfb3f},

issn = {1945-7111 

0013-4651},

journal = {Journal of The Electrochemical Society},

volume = {170},

number = {9},

pages = {090544},

abstract = {The volume expansion/contraction of Si-based anodes during electrochemical lithiation/delithiation cycles causes a loss in mechanical integrity and accrued instability of the solid electrolyte interphase (SEI) layer, culminating into capacity fade. Electrolyte additives like fluoroethylene carbonate (FEC) improve SEI stability, but the associated causes still under debate. This work reveals some of the roles of FEC via post-mortem observations/analyses, operando stress measurements and a comprehensive study of the impedance associated with the formation/evolution of SEI during lithiation/delithiation. Usage of 10 vol.% FEC as electrolyte additive leads to significant improvements in cyclic stability, Coulombic efficiency and facilitates smoother/compact/crack-free surface/SEI, in contrast to the cracked/pitted/uneven surface upon non-usage of FEC. Operando stress measurements during SEI formation reveal compressive stress development, followed by loss in mechanical integrity, upon non-usage of electrolyte additive, in contrast to insignificant stress development associated with SEI formation upon usage of FEC. The EIS model proposed here facilitates good fit with the impedance data at all states-of-charges, with the SEI resistance and capacitance exhibiting expected variations with cycling and the SEI resistance progressively decreasing with cycle number in the presence of FEC. By contrast, in the absence of FEC, severe fluctuations observed with the SEI resistance and capacitance indicate instability.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Modulation of electronic and ionic conduction in mixed polymer conductors via additive engineering: Towards targeted applications under varying humidity},

author = {S Tu and T Tian and A Vagias and L F Huber and L Liu and S Liang and R A Fischer and S Bernstorff and P M\"{u}ller-Buschbaum},

url = {https://www.sciencedirect.com/science/article/pii/S1385894723057650},

doi = {https://doi.org/10.1016/j.cej.2023.147034},

issn = {1385-8947},

journal = {Chemical Engineering Journal},

volume = {477},

pages = {147034},

abstract = {Polymer solids with mixed ion and electron transport hold great promise for next-generation organic electronics, and rational regulation of ionic/electronic contribution within these materials can enable a broadened spectrum of practical applications. However, a fundamental understanding of the conduction mechanisms and their correlations with morphological characteristics remains limited, especially under varying environmental humidity conditions. In the present work, simple additive engineering enables the effective regulation of electronic and ionic contribution in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) based conductors, giving rising to ion- and/or electron-dominant conductions. As a demonstration, PEDOT:PSS films with different electrical characteristics are successfully applied for thermal energy harvesting, healthcare monitoring and human motion detection upon humidity exposure. Combining operando alternating current (AC) impedance spectroscopy and grazing incidence small-angle X-ray scattering at low and high humidity levels, additive-dependent charge transport mechanisms are elucidated, and correlations between morphological alterations and conductivity evolutions are revealed. This work achieves highly tailorable PEDOT:PSS conduction utilizing Zonyl, dimethyl sulfoxide (DMSO) and carbon nanotubes (CNTs) as additives with distinct humidity responses and gains an in-depth comprehension of underlying mechanisms, which are expected to pave the way for next-generation organic electronics.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Fluorescence enhancement in topologically optimized gallium phosphide all-dielectric nanoantennas},

author = {C Vidal and B Tilmann and S Tiwari and T Raziman and S A Maier and J Wenger and R Sapienza},

url = {https://arxiv.org/abs/2310.07309},

doi = {https://doi.org/10.48550/arXiv.2310.07309},

journal = {arXiv preprint arXiv:2310.07309},

abstract = {Nanoantennas capable of large fluorescence enhancement with minimal absorption are crucial for future optical technologies from single-photon sources to biosensing. Efficient dielectric nanoantennas have been designed, however, evaluating their performance at the individual emitter level is challenging due to the complexity of combining high-resolution nanofabrication, spectroscopy and nanoscale positioning of the emitter. Here, we study the fluorescence enhancement in infinity-shaped gallium phosphide (GaP) nanoantennas based on a topologically optimized design. Using fluorescence correlation spectroscopy (FCS), we probe the nanoantennas enhancement factor and observed an average of 63-fold fluorescence brightness enhancement with a maximum of 93-fold for dye molecules in nanogaps between 20 nm and 50 nm. The experimentally determined fluorescence enhancement of the nanoantennas was confirmed by numerical simulations of the local density of optical states (LDOS). Furthermore, we show that beyond design optimisation of dielectric nanoantennas, increased performances can be achieved via tailoring of nanoantenna fabrication.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Direct Bottom-Up In Situ Growth: A Paradigm Shift for Studies in Wet-Chemical Synthesis of Gold Nanoparticles},

author = {G A Vinnacombe-Willson and Y Conti and A Stefancu and P S Weiss and E Cort\'{e}s and L Scarabelli},

url = {https://doi.org/10.1021/acs.chemrev.2c00914},

doi = {10.1021/acs.chemrev.2c00914},

issn = {0009-2665},

journal = {Chemical Reviews},

volume = {123},

number = {13},

pages = {8488-8529},

abstract = {Plasmonic gold nanoparticles have been used increasingly in solid-state systems because of their applicability in fabricating novel sensors, heterogeneous catalysts, metamaterials, and thermoplasmonic substrates. While bottom-up colloidal syntheses take advantage of the chemical environment to control size, shape, composition, surface chemistry, and crystallography of the nanostructures precisely, it can be challenging to assemble nanoparticles rationally from suspension onto solid supports or within devices. In this Review, we discuss a powerful recent synthetic methodology, bottom-up in situ substrate growth, which circumvents time-consuming batch presynthesis, ligand exchange, and self-assembly steps by applying wet-chemical synthesis to form morphologically controlled nanostructures on supporting materials. First, we briefly introduce the properties of plasmonic nanostructures. Then we comprehensively summarize recent work that adds to the synthetic understanding of in situ geometrical and spatial control (patterning). Next, we briefly discuss applications of plasmonic hybrid materials prepared by in situ growth. Overall, despite the vast potential advantages of in situ growth, the mechanistic understanding of these methodologies remains far from established, providing opportunities and challenges for future research.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Defect Engineering of Ta3N5 Photoanodes: Enhancing Charge Transport and Photoconversion Efficiencies via Ti Doping},

author = {L I Wagner and E Sirotti and O Brune and G Gr\"{o}tzner and J Eichhorn and S Santra and F Munnik and L Olivi and S Pollastri and V Streibel and I D Sharp},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202306539},

doi = {https://doi.org/10.1002/adfm.202306539},

issn = {1616-301X},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2306539},

abstract = {Abstract While Ta3N5 shows excellent potential as a semiconductor photoanode for solar water splitting, its performance is hindered by poor charge carrier transport and trapping due to native defects that introduce electronic states deep within its bandgap. Here, it is demonstrated that controlled Ti doping of Ta3N5 can dramatically reduce the concentration of deep-level defects and enhance its photoelectrochemical performance, yielding a sevenfold increase in photocurrent density and a 300 mV cathodic shift in photocurrent onset potential compared to undoped material. Comprehensive characterization reveals that Ti4+ ions substitute Ta5+ lattice sites, thereby introducing compensating acceptor states, reducing the concentrations of deleterious nitrogen vacancies and reducing Ta3+ states, and thereby suppressing trapping and recombination. Owing to the similar ionic radii of Ti4+ and Ta5+, substitutional doping does not introduce lattice strain or significantly affect the underlying electronic structure of the host semiconductor. Furthermore, Ti can be incorporated without increasing the oxygen donor content, thereby enabling the electrical conductivity to be tuned by over seven orders of magnitude. Thus, Ti doping of Ta3N5 provides a powerful basis for precisely engineering its optoelectronic characteristics and to substantially improve its functional characteristics as an advanced photoelectrode for solar fuels applications.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Probing Charge-Transfer Processes in a Covalently Linked [Ge9]-Cluster Imine Dyad},

author = {C Wallach and Y Selic and F S Geitner and A Kumar and E Thyrhaug and J Hauer and A J Karttunen and T F F\"{a}ssler},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202304088},

doi = {https://doi.org/10.1002/anie.202304088},

issn = {1433-7851},

journal = {Angewandte Chemie International Edition},

volume = {62},

number = {29},

pages = {e202304088},

abstract = {Abstract C60 donor dyads in which the carbon cage is covalently linked to an electron-donating unit have been discussed as one possibility for an electron-transfer system, and it has been shown that spherical [Ge9] cluster anions show a close relation to fullerenes with respect to their electronic structure. However, the optical properties of these clusters and of functionalized cluster derivatives are almost unknown. We now report on the synthesis of the intensely red [Ge9] cluster linked to an extended π-electron system. [Ge9Si(TMS)32CH3C=N-DAB(II)Dipp]− (1−) is formed upon the reaction of [Ge9Si(TMS)32]2− with bromo-diazaborole DAB(II)Dipp-Br in CH3CN (TMS=trimethylsilyl; DAB(II)=1,3,2-diazaborole with an unsaturated backbone; Dipp=2,6-di-iso-propylphenyl). Reversible protonation of the imine entity in 1− yields the deep green, zwitterionic cluster [Ge9Si(TMS)32CH3C=N(H)-DAB(II)Dipp] (1-H) and vice versa. Optical spectroscopy combined with time-dependent density functional theory suggests a charge-transfer excitation between the cluster and the antibonding π* orbital of the imine moiety as the cause of the intense coloration. An absorption maximum of 1-H in the red region of the electromagnetic spectrum and the corresponding lowest-energy excited state at λ=669 nm make the compound an interesting starting point for further investigations targeting the design of photo-active cluster compounds.},

keywords = {Foundry Organic, Molecularly-Functionalized},

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},

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 = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Isolating Pure Donor and Acceptor Signals by Polarization-Controlled Transient Absorption Spectroscopy},

author = {Y Xu and L Mewes and E Thyrhaug and V Sl\'{a}ma and F \v{S}anda and H Langhals and J Hauer},

url = {https://doi.org/10.1021/acs.jpclett.3c01451},

doi = {10.1021/acs.jpclett.3c01451},

journal = {The Journal of Physical Chemistry Letters},

volume = {14},

number = {23},

pages = {5390-5396},

abstract = {The optical spectra of molecules are often highly congested, inhibiting definite assignment of features and dynamics. In this work, we demonstrate and apply a polarization-based strategy for the decomposition of time-resolved optical spectra to analyze the electronic structure and energy transfer in a molecular donor\textendashacceptor (D\textendashA) dyad. We choose a dyad with orthogonal transition dipole moments for D and A and high fluorescence quantum yield to show that polarization-controlled ultrafast transient absorption spectra can isolate the pure D and A parts of the total signal. This provides a strategy to greatly reduce spectral congestion in complex systems and thus allows for detailed studies of electronic structure and electronic energy transfer.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tailoring Low-Dimensional Perovskites Passivation for Efficient Two-Step-Processed FAPbI3 Solar Cells and Modules},

author = {F Ye and T Tian and J Su and R Jiang and J Li and C Jin and J Tong and S Bai and F Huang and P M\"{u}ller-Buschbaum and Y-B Cheng and T Bu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202302775},

doi = {https://doi.org/10.1002/aenm.202302775},

issn = {1614-6832},

journal = {Advanced Energy Materials},

volume = {n/a},

number = {n/a},

pages = {2302775},

abstract = {Abstract Converting PbI2 residues into low-dimensional perovskites through post-treatment with ammonium-based large cations can passivate 3D perovskites, thus has emerged as an effective strategy to improve the performance of perovskite solar cells (PSCs). Herein, a dramatically improved efficiency is demonstrated for PSCs based on a two-step-processed FAPbI3 perovskite via post-treatment with formamidinium (FA)-based benzamidine hydrochloride (PFACl), outperforming the commonly used methylamine (MA)-based benzylamine hydrochloride (PMACl). With an in-depth exploration of the crystal structures and morphology changes of the FAPbI3 perovskite upon the PFACl post-treatment, the preferential formation of 1D rather than 2D structures on the 3D perovskite film is identified. In contrast to the 2D counterpart, the more energetically favorable 1D structure enables a more effective elimination of PbI2 residues. As a consequence, the PFACl-induced 1D/3D perovskite film is endowed with smoother morphology, more uniform surface potential distribution, lower trap density, faster charge transfer, and better film stability than the PMACl-induced 2D/3D perovskite and control films, demonstrating champion efficiencies of 24.9% for a small-size PSC, 23.6% for a 1 cm2 large-size PSC, and 21.2% for a 5 × 5 cm2 mini-module, which is the highest among the perovskite solar mini-modules using the two-step deposition method.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Physical Impedance Model of Lithium Intercalation into Graphite Electrodes for a Coin-Cell Assembly},

author = {G Yesilbas and C-Y Chou and A S Bandarenka},

url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/celc.202300270},

doi = {https://doi.org/10.1002/celc.202300270},

issn = {2196-0216},

journal = {ChemElectroChem},

volume = {10},

number = {21},

pages = {e202300270},

abstract = {Abstract Graphite electrodes are widely used in commercial metal-ion batteries as anodes. Electrochemical impedance spectroscopy serves as one of the primary non-destructive techniques to obtain key information about various batteries during their operation. However, interpretation of the impedance response of graphite electrodes in contact with common organic electrolytes can be complicated. It is especially challenging, particularly when utilizing the 2-electrode configuration that is common in battery research. In this work, we elaborate on a physical impedance model capable of accurately describing the impedance spectra of a graphite|electrolyte|metallic Li system in a coin-cell assembly during two initial charge/discharge cycles. We analyze the dependencies of the model parameters for graphite and metallic lithium as a function of the state of charge to verify the model. Additionally, we suggest that the double layer capacitance values obtained during specific intercalation stages could help to determine if the area-normalized values align with the expected range. The data and the procedure necessary for calibration are provided.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Highly Efficient Decomposition of Perfluorocarbons for over 1000 Hours via Active Site Regeneration},

author = {H Zhang and T Luo and Y Chen and K Liu and H Li and E Pensa and J Fu and Z Lin and L Chai and E Cort\'{e}s and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202305651},

doi = {https://doi.org/10.1002/anie.202305651},

issn = {1433-7851},

journal = {Angewandte Chemie International Edition},

volume = {62},

number = {46},

pages = {e202305651},

abstract = {Abstract Tetrafluoromethane (CF4), the simplest perfluorocarbon (PFC), has the potential to exacerbate global warming. Catalytic hydrolysis is a viable method to degrade CF4, but fluorine poisoning severely restricts both the catalytic performance and catalyst lifetime. In this study, Ga is introduced to effectively assists the defluorination of poisoned Al active sites, leading to highly efficient CF4 decomposition at 600 °C with a catalytic lifetime exceeding 1,000 hours. 27Al and 71Ga magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) showed that the introduced Ga exists as tetracoordinated Ga sites (GaIV), which readily dissociate water to form Ga−OH. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density function theory (DFT) calculations confirmed that Ga−OH assists the defluorination of poisoned Al active sites via a dehydration-like process. As a result, the Ga/Al2O3 catalyst achieved 100 % CF4 decomposition keeping an ultra-long catalytic lifetime and outperforming reported results. This work proposes a new approach for efficient and long-term CF4 decomposition by promoting the regeneration of active sites.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {All-Dielectric Structural Coloration Empowered by Bound States in the Continuum},

author = {H Zheng and H Hu and T Weber and J Wang and L Nan and B Zou and S A Maier and A Tittl},

url = {https://arxiv.org/abs/2311.13315},

doi = {https://doi.org/10.48550/arXiv.2311.13315},

journal = {arXiv preprint arXiv:2311.13315},

abstract = {The technological requirements of low-power and high-fidelity color displays have been instrumental in driving research into advanced coloration technologies. At the forefront of these developments is the implementation of dye-free coloration techniques, which overcome previous constraints related to insufficient resolution and color fading. In this context, resonant dielectric nanostructures have emerged as a promising paradigm, showing great potential for high efficiency, remarkably high color saturation, wide gamut palette, and realistic image reproduction. However, they still face limitations related to color accuracy, purity, and simultaneous brightness tunability. Here, we demonstrate an all-dielectric metasurface empowered by photonic bound states in the continuum (BICs), which supports sharp resonances throughout the visible spectral range, ideally suited for producing a wide range of structural colors. The metasurface design consists of titanium dioxide (TiO2) ellipses with carefully controlled sizes and geometrical asymmetry, allowing versatile and on-demand variation of the brightness and hue of the output colors, respectively.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Breaking K+ Concentration Limit on Cu Nanoneedles for Acidic Electrocatalytic CO2 Reduction to Multi-Carbon Products},

author = {X Zi and Y Zhou and L Zhu and Q Chen and Y Tan and X Wang and M Sayed and E Pensa and R A Geioushy and K Liu and J Fu and E Cort\'{e}s and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202309351},

doi = {https://doi.org/10.1002/anie.202309351},

issn = {1433-7851},

journal = {Angewandte Chemie International Edition},

volume = {62},

number = {42},

pages = {e202309351},

abstract = {Abstract Electrocatalytic CO2 reduction reaction (CO2RR) to multi-carbon products (C2+) in acidic electrolyte is one of the most advanced routes for tackling our current climate and energy crisis. However, the competing hydrogen evolution reaction (HER) and the poor selectivity towards the valuable C2+ products are the major obstacles for the upscaling of these technologies. High local potassium ions (K+) concentration at the cathode's surface can inhibit proton-diffusion and accelerate the desirable carbon-carbon (C−C) coupling process. However, the solubility limit of potassium salts in bulk solution constrains the maximum achievable K+ concentration at the reaction sites and thus the overall acidic CO2RR performance of most electrocatalysts. In this work, we demonstrate that Cu nanoneedles induce ultrahigh local K+ concentrations (4.22 M) \textendash thus breaking the K+ solubility limit (3.5 M) \textendash which enables a highly efficient CO2RR in 3 M KCl at pH=1. As a result, a Faradaic efficiency of 90.69±2.15 % for C2+ (FEC2+) can be achieved at 1400 mA.cm−2, simultaneous with a single pass carbon efficiency (SPCE) of 25.49±0.82 % at a CO2 flow rate of 7 sccm.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ionic liquids tailoring crystal orientation and electronic properties for stable perovskite solar cells},

author = {Y Zou and J Eichhorn and S Rieger and Y Zheng and S Yuan and L Wolz and L V Spanier and J E Heger and S Yin and C R Everett and L Dai and M Schwartzkopf and C Mu and S V Roth and I D Sharp and C-C Chen and J Feldmann and S D Stranks and P M\"{u}ller-Buschbaum},

url = {https://www.sciencedirect.com/science/article/pii/S2211285523002860},

doi = {https://doi.org/10.1016/j.nanoen.2023.108449},

issn = {2211-2855},

journal = {Nano Energy},

volume = {112},

pages = {108449},

abstract = {The crystallization behavior of perovskite films has a profound influence on the resulting defect densities, charge carrier dynamics and photovoltaic performance. Herein, we introduce ionic liquids into the perovskite component to tailor the crystal growth of perovskite films from a disordered to a preferential corner-up orientation and accordingly increase the charge carrier mobility to accelerate electron transport and extraction. Using time-resolved measurements, we probe the charge carrier generation, transport and recombination behavior in these films and related devices. We find the ionic liquid-containing samples exhibit lower defects, faster charge carrier transport and suppressed non-radiative recombination, contributing to higher efficiency and fill factor. Via operando grazing-incidence small- and wide-angle X-ray scattering measurements, we observe a light-induced lattice compression and grain fragmentation in the control devices, whereas the ionic liquid-containing devices exhibit a slight light-induced crystal reconstitution and stronger tolerance against illumination. Under ambient conditions, the non-encapsulated device with the pyrrolidinium-based ionic compound (Pyr14BF4) maintains 97% of its initial efficiency after 4368 h.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Advanced processing of differential phase contrast data: Distinction between different causes of electron phase shifts},

author = {J Zweck and F Schwarzhuber and S P\"{o}llath and K M\"{u}ller-Caspary},

url = {https://www.sciencedirect.com/science/article/pii/S0304399123000694},

doi = {https://doi.org/10.1016/j.ultramic.2023.113752},

issn = {0304-3991},

journal = {Ultramicroscopy},

volume = {250},

pages = {113752},

abstract = {Differential phase contrast, in its high resolution modification also known as first moment microscopy or momentum resolved STEM [1], [2], [3], [4], [5], [6], [7] , basically measures the lateral momentum transfer to the electron probe due to the beam interaction with either electrostatic and/or magnetic fields, when the probe transmits the specimen. In other words, the result of the measurement is a vector field p→(x,y) which describes the lateral momentum transfer to the probe electrons. In the case of electric fields, this momentum transfer is easily converted to the electric field E→(x,y) causing the deflection, and from ϱ=ɛ0∇⋅E→ the local charge density can be calculated from the divergence of the electric field. However, from experimental data it is known that also the calculation of the vector field’s curl ∇→×p→ in general yields non-zero results. In this paper, we use the Helmholtz decomposition (Wikipedia contributors, 2022), also known as the fundamental theorem of vector calculus, to split the measured vector fields into their curl-free and divergence-free components and to interpret the physical meaning of these components in detail. It will be shown, that non-zero curl components may be used to measure geometric phases occurring from irregularities in crystal structure such as a screw dislocation.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}