Publications

@article{,

title = {Coupled Dynamics of Anode and Cathode in Proton-Exchange Membrane Fuel Cells},

author = {J A Nogueira and K Krischer and H Varela},

url = {\<Go to ISI\>://WOS:000478934200001},

doi = {10.1002/cphc.201900531},

issn = {1439-4235},

year  = {2019},

date = {2019-07-19},

journal = {Chemphyschem},

volume = {20},

number = {22},

pages = {3081-3088},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The fast and the furious: Ultrafast hot electrons in plasmonic metastructures. Size and structure matter},

author = {L V Besteiro and P Yu and Z M Wang and A W Holleitner and G V Hartland and G P Wiederrecht and A O Govorov},

url = {\<Go to ISI\>://WOS:000482526300011},

doi = {10.1016/j.nantod.2019.05.006},

issn = {1748-0132},

year  = {2019},

date = {2019-07-18},

journal = {Nano Today},

volume = {27},

pages = {120-145},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Influence of Local Defects on the Dynamics of O-H Bond Breaking and Formation on a Magnetite Surface},

author = {A Bourgund and B A J Lechner and M Meier and C Franchini and G S Parkinson and U Heiz and F Esch},

url = {\<Go to ISI\>://WOS:000481568900054},

doi = {10.1021/acs.jpcc.9b05547},

issn = {1932-7447},

year  = {2019},

date = {2019-07-17},

urldate = {2019-07-17},

journal = {Journal of Physical Chemistry C},

volume = {123},

number = {32},

pages = {19742-19747},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {In-situ visualization of hydrogen evolution sites on helium ion treated molybdenum dichalcogenides under reaction conditions},

author = {E Mitterreiter and Y Liang and M Golibrzuch and D Mclaughlin and C Csoklich and J D Bartl and A W Holleitner and U Wurstbauer and A S Bandarenka},

url = {https://doi.org/10.1038/s41699-019-0107-5},

doi = {10.1038/s41699-019-0107-5},

issn = {2397-7132},

year  = {2019},

date = {2019-07-15},

journal = {npj 2D Materials and Applications},

volume = {3},

number = {1},

pages = {25},

abstract = {Nanostructured 2D transition metal dichalcogenides play an increasingly important role in heterogeneous catalysis. These materials are abundant (co-)catalysts with tunable properties to catalyze a number of key reactions related to energy provision, for instance the hydrogen evolution reaction (HER). It is vital to understand which surface sites are active in order to maximize their number and to improve the overall (photo-)catalytic behavior of those materials. Here, we visualize these active sites under HER conditions at the surface of molybdenum dichalcogenides (MoX2, X = Se, S) with lateral resolution on the nanometer scale by means of electrochemical scanning tunneling microscopy. The edges of single MoX2 flakes show high catalytic activity, whereas their terraces are inactive. We demonstrate how the inert basal planes of these materials can be activated towards the HER with the help of a focused beam of a He-ion microscope. Our findings demonstrate that the He-ion induced defects contribute at lower overpotentials to the HER, while the activity of the edges exceeds the activity of the basal defects for sufficiently high overpotentials. Given the lithographic resolution of the helium ion microscope, our results show the possibility to generate active sites in transition metal dichalcogenides with a spatial resolution below a few nanometers.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Using Polar Alcohols for the Direct Synthesis of Cesium Lead Halide Perovskite Nanorods with Anisotropic Emission},

author = {Y X Li and H Huang and Y Xiong and A F Richter and S V Kershaw and J Feldmann and A L Rogach},

url = {\<Go to ISI\>://WOS:000477786400088},

doi = {10.1021/acsnano.9b03508},

issn = {1936-0851},

year  = {2019},

date = {2019-07-11},

journal = {Acs Nano},

volume = {13},

number = {7},

pages = {8237-8245},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Distance Dependence of Single-Molecule Energy Transfer to Graphene Measured with DNA Origami Nanopositioners},

author = {I Kaminska and J Bohlen and S Rocchetti and F Selbach and G P Acuna and P Tinnefeld},

url = {https://doi.org/10.1021/acs.nanolett.9b00172},

doi = {10.1021/acs.nanolett.9b00172},

issn = {1530-6984},

year  = {2019},

date = {2019-07-10},

journal = {Nano Letters},

volume = {19},

number = {7},

pages = {4257-4262},

abstract = {Despite the thorough investigation of graphene since 2004, altering its surface chemistry and reproducible functionalization remain challenging. This hinders fabrication of more complex hybrid materials with controlled architectures, and as a consequence the development of sensitive and reliable sensors and biological assays. In this contribution, we introduce DNA origami structures as nanopositioners for placing single dye molecules at controlled distances from graphene. The measurements of fluorescence intensity and lifetime of single emitters carried out for distances ranging from 3 to 58 nm confirmed the d\textendash4 dependence of the excitation energy transfer to graphene. Moreover, we determined the characteristic distance for 50% efficiency of the energy transfer from single dyes to graphene to be 17.7 nm. Using pyrene molecules as a glue to immobilize DNA origami nanostructures of various shape on graphene opens new possibilities to develop graphene-based biophysics and biosensing.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Degradation mechanisms in polymer electrolyte membrane fuel cells caused by freeze-cycles: Investigation using electrochemical impedance spectroscopy},

author = {J P Sabawa and A S Bandarenka},

url = {http://www.sciencedirect.com/science/article/pii/S0013468619307881},

doi = {https://doi.org/10.1016/j.electacta.2019.04.102},

issn = {0013-4686},

year  = {2019},

date = {2019-07-10},

journal = {Electrochimica Acta},

volume = {311},

pages = {21-29},

abstract = {The performance of the polymer electrolyte membrane (PEM) fuel cells is sensitive to the exposure of these devices to subzero temperatures. In general, it is important to precondition the fuel cells prior to the shut-down preventing degradation after the start-up. Standard tests with conventional climatic chambers are nowadays costly and very time consuming. In this work, we introduce a method, which uses a simplified process with a PEM single-cell. The new design uses a Peltier-Element-Tempered (PET) single-cell with an active area size of 43.56 cm2. Now it is possible to achieve efficient and temperature controlled cold starts without a climate chamber or chiller plant. With the PET-controlled single cell, it was possible to do a series of complex accelerated freeze stress tests within the shortest time. To classify the performance change, polarization curves, cyclic voltammetry with the CV-CO-stripping method and Electrochemical Impedance Spectroscopy (EIS) at different current densities were performed. The measured impedance spectra were analyzed with a physical impedance model consisting of only 6 equivalent circuit elements. The charge-transfer resistance and the parameters of the Warburg diffusion element clearly reveal irreversible changes of the cathode during repeated freeze-cycles.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Aspects of semiconductivity in soft, porous metal-organic framework crystals},

author = {C Muschielok and H Oberhofer},

url = {\<Go to ISI\>://WOS:000474214600025},

doi = {10.1063/1.5108995},

issn = {0021-9606},

year  = {2019},

date = {2019-07-03},

journal = {Journal of Chemical Physics},

volume = {151},

number = {1},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Site-selectively generated photon emitters in monolayer MoS2 via local helium ion irradiation},

author = {J Klein and M Lorke and M Florian and F Sigger and L Sigl and S Rey and J Wierzbowski and J Cerne and K M\"{u}ller and E Mitterreiter and P Zimmermann and T Taniguchi and K Watanabe and U Wurstbauer and M Kaniber and M Knap and R Schmidt and J J Finley and A W Holleitner},

url = {https://doi.org/10.1038/s41467-019-10632-z},

doi = {10.1038/s41467-019-10632-z},

issn = {2041-1723},

year  = {2019},

date = {2019-06-21},

journal = {Nature Communications},

volume = {10},

number = {1},

pages = {2755},

abstract = {Quantum light sources in solid-state systems are of major interest as a basic ingredient for integrated quantum photonic technologies. The ability to tailor quantum emitters via site-selective defect engineering is essential for realizing scalable architectures. However, a major difficulty is that defects need to be controllably positioned within the material. Here, we overcome this challenge by controllably irradiating monolayer MoS2 using a sub-nm focused helium ion beam to deterministically create defects. Subsequent encapsulation of the ion exposed MoS2 flake with high-quality hBN reveals spectrally narrow emission lines that produce photons in the visible spectral range. Based on ab-initio calculations we interpret these emission lines as stemming from the recombination of highly localized electron\textendashhole complexes at defect states generated by the local helium ion exposure. Our approach to deterministically write optically active defect states in a single transition metal dichalcogenide layer provides a platform for realizing exotic many-body systems, including coupled single-photon sources and interacting exciton lattices that may allow the exploration of Hubbard physics.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Sustained Solar H-2 Evolution from a Thiazolo 5,4-d thiazole-Bridged Covalent Organic Framework and Nickel-Thiolate Cluster in Water},

author = {B P Biswal and H A Vignolo-Gonzalez and T Banerjee and L Grunenberg and G Savasci and K Gottschling and J Nuss and C Ochsenfeld and B V Lotsch},

url = {\<Go to ISI\>://WOS:000476684700023},

doi = {10.1021/jacs.9b03243},

issn = {0002-7863},

year  = {2019},

date = {2019-06-20},

journal = {Journal of the American Chemical Society},

volume = {141},

number = {28},

pages = {11082-11092},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Sub-stoichiometric 2D covalent organic frameworks from tri- and tetratopic linkers},

author = {T Banerjee and F Haase and S Trenker and B P Biswal and G Savasci and V Duppel and I Moudrakovski and C Ochsenfeld and B V Lotsch},

url = {\<Go to ISI\>://WOS:000472032300004},

doi = {10.1038/s41467-019-10574-6},

issn = {2041-1723},

year  = {2019},

date = {2019-06-19},

journal = {Nature Communications},

volume = {10},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{,

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

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

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

doi = {10.1021/acsami.9b04592},

issn = {1944-8244},

year  = {2019},

date = {2019-06-12},

journal = {ACS Applied Materials \& Interfaces},

volume = {11},

number = {23},

pages = {20838-20844},

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

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Hydrophobic Metal\textendashOrganic Frameworks},

author = {K Jayaramulu and F Geyer and A Schneemann and \v{S} Kment and M Otyepka and R Zboril and D Vollmer and R A Fischer},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201900820},

doi = {https://doi.org/10.1002/adma.201900820},

issn = {0935-9648},

year  = {2019},

date = {2019-06-03},

journal = {Advanced Materials},

volume = {31},

number = {32},

pages = {1900820},

abstract = {Abstract Metal\textendashorganic frameworks (MOFs) have diverse potential applications in catalysis, gas storage, separation, and drug delivery because of their nanoscale periodicity, permanent porosity, channel functionalization, and structural diversity. Despite these promising properties, the inherent structural features of even some of the best-performing MOFs make them moisture-sensitive and unstable in aqueous media, limiting their practical usefulness. This problem could be overcome by developing stable hydrophobic MOFs whose chemical composition is tuned to ensure that their metal\textendashligand bonds persist even in the presence of moisture and water. However, the design and fabrication of such hydrophobic MOFs pose a significant challenge. Reported syntheses of hydrophobic MOFs are critically summarized, highlighting issues relating to their design, characterization, and practical use. First, wetting of hydrophobic materials is introduced and the four main strategies for synthesizing hydrophobic MOFs are discussed. Afterward, critical challenges in quantifying the wettability of these hydrophobic porous surfaces and solutions to these challenges are discussed. Finally, the reported uses of hydrophobic MOFs in practical applications such as hydrocarbon storage/separation and their use in separating oil spills from water are summarized. Finally, the state of the art is summarized and promising future developments of hydrophobic MOFs are highlighted.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Short-Range Structural Correlations in Amorphous 2D Polymers},

author = {P Alexa and C Oligschleger and P Gr\"{o}ger and C Morchutt and V Vyas and B V Lotsch and J C Sch\"{o}n and R Gutzler and K Kern},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/cphc.201900326},

doi = {10.1002/cphc.201900326},

issn = {1439-4235},

year  = {2019},

date = {2019-05-21},

journal = {ChemPhysChem},

volume = {20},

number = {18},

pages = {2340-2347},

abstract = {Abstract Many 2D covalent polymers synthesized as single layers on surfaces show inherent disorder, expressed for example in their ring-size distribution. Systems which are expected to form the thermodynamically favored hexagonal lattice usually deviate from crystallinity and include high numbers of pentagons, heptagons, and rings of other sizes. The amorphous structure of two different covalent polymers in real space using scanning tunneling microscopy is investigated. Molecular dynamics simulations are employed to extract additional information. We show that short-range correlations exist in the structure of one polymer, i. e. that polygons are not tessellating the surface randomly but that ring neighborhoods have preferential compositions. The correlation is dictated by the energy of formation of the ring neighborhoods.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Cu9.1Te4Cl3: A Thermoelectric Compound with Low Thermal and High Electrical Conductivity},

author = {A Vogel and T Miller and C Hoch and M Jakob and O Oeckler and T Nilges},

url = {https://doi.org/10.1021/acs.inorgchem.9b00453},

doi = {10.1021/acs.inorgchem.9b00453},

issn = {0020-1669},

year  = {2019},

date = {2019-05-06},

journal = {Inorganic Chemistry},

volume = {58},

number = {9},

pages = {6222-6230},

abstract = {Cu9.1Te4Cl3 is a new polymorphic compound in the class of coinage metal polytelluride halides. Copper is highly mobile, which results in multiple order\textendashdisorder phase transitions in a limited temperature interval from 240 to 370 K. Mainly as a consequence of thermal transport properties, the compound’s thermoelectric figure of merit reaches values up to ZT = 0.15 in the temperature range between room temperature and 523 K. Its structure is closely related to that of Ag10Te4Br3, another coinage metal polytelluride halide, which represents the first p\textendashn\textendashp-switchable semiconductor approachable by a simple temperature change. The title compound outperforms Ag10Te4Br3 in terms of thermoelectric properties by 1 order of magnitude and therefore acts as a link between the class of p\textendashn\textendashp compounds and thermoelectric materials.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Excited State Conformations of Bridged and Unbridged Pyrene Excimers},

author = {S Reiter and M K Roos and R De Vivie-Riedle},

url = {\<Go to ISI\>://WOS:000487014600024},

doi = {10.1002/cptc.201900096},

issn = {2367-0932},

year  = {2019},

date = {2019-05-06},

journal = {Chemphotochem},

volume = {3},

number = {9},

pages = {881-888},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Optimizing the Size of Platinum Nanoparticles for Enhanced Mass Activity in the Electrochemical Oxygen Reduction Reaction},

author = {B Garlyyev and K Kratzl and M R\"{u}ck and J Michali\v{c}ka and J Fichtner and J M Macak and T Kratky and S G\"{u}nther and M Cokoja and A S Bandarenka and A Gagliardi and R A Fischer},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201904492},

doi = {10.1002/anie.201904492},

issn = {1433-7851},

year  = {2019},

date = {2019-05-03},

journal = {Angewandte Chemie International Edition},

volume = {58},

number = {28},

pages = {9596-9600},

abstract = {Abstract High oxygen reduction (ORR) activity has been for many years considered as the key to many energy applications. Herein, by combining theory and experiment we prepare Pt nanoparticles with optimal size for the efficient ORR in proton-exchange-membrane fuel cells. Optimal nanoparticle sizes are predicted near 1, 2, and 3 nm by computational screening. To corroborate our computational results, we have addressed the challenge of approximately 1 nm sized Pt nanoparticle synthesis with a metal\textendashorganic framework (MOF) template approach. The electrocatalyst was characterized by HR-TEM, XPS, and its ORR activity was measured using a rotating disk electrode setup. The observed mass activities (0.87±0.14 A mgPt−1) are close to the computational prediction (0.99 A mgPt−1). We report the highest to date mass activity among pure Pt catalysts for the ORR within similar size range. The specific and mass activities are twice as high as the Tanaka commercial Pt/C catalysis.},

keywords = {Foundry Organic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

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

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

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

doi = {10.1021/acsnano.9b01137},

issn = {1936-0851},

year  = {2019},

date = {2019-05-02},

journal = {ACS Nano},

volume = {13},

number = {6},

pages = {6711-6719},

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

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Monitoring the morphological evolution in mixed-dimensional lead bromide perovskite films with lamellar-stacked perovskite nanoplatelets},

author = {R Wang and Y Tong and K Wang and S Xia and E Kentzinger and O Soltwedel and P M\"{u}ller-Buschbaum and H Frielinghaus},

url = {http://dx.doi.org/10.1039/C9NH00156E},

doi = {10.1039/C9NH00156E},

issn = {2055-6756},

year  = {2019},

date = {2019-04-23},

journal = {Nanoscale Horizons},

volume = {4},

number = {5},

pages = {1139-1144},

abstract = {Mixed-dimensional lead bromide perovskite films combine the properties of both three-dimensional (3D) and two-dimensional (2D) perovskite crystals, and due to their good humidity tolerance, they emerge as promising candidates for long-term stable optoelectronic applications. In order to further tailor the film morphology aiming for a better device performance, it is important to unravel the structural formation mechanism in these perovskite thin films. In the present study, the formation of 3D lead bromide perovskite crystals and the self-assembly of lamellar-stacked 2D perovskite nanoplatelets are comprehensively studied. Samples are prepared through a two-step vapor assisted route with different vapor exposure times in order to monitor the detailed morphology at the specific reaction stage. With grazing incidence X-ray scattering techniques, the preferential orientation of the 3D crystals is found to decrease upon increasing the reaction time. Also, it is evidenced that well-ordered in-plane lamellar-stacked 2D nanoplatelets form aggregates in the bulk structure only. The obtained hierarchical morphology shows excellent structural stability in a humid atmosphere even at a relative humidity level of 80%. Our findings statistically offer a morphological understanding, which is important for the optimization of the sample preparation route and thus the resulting performance of moisture-tolerant perovskite based optoelectronic devices.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Identifying and Reducing Interfacial Losses to Enhance Color-Pure Electroluminescence in Blue-Emitting Perovskite Nanoplatelet Light-Emitting Diodes},

author = {R L Z Hoye and M L Lai and M Anaya and Y Tong and K Galkowski and T Doherty and W W Li and T N Huq and S Mackowski and L Polavarapu and J Feldmann and J L Macmanus-Driscoll and R H Friend and A S Urban and S D Stranks},

url = {\<Go to ISI\>://WOS:000468015600025},

doi = {10.1021/acsenergylett.9b00571},

issn = {2380-8195},

year  = {2019},

date = {2019-04-17},

journal = {Acs Energy Letters},

volume = {4},

number = {5},

pages = {1181-1188},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Tuning the optical bandgap in layered hybrid perovskites through variation of alkyl chain length},

author = {J A Sichert and A Hemmerling and C Cardenas-Daw and A S Urban and J Feldmann},

url = {\<Go to ISI\>://WOS:000466615300017},

doi = {10.1063/1.5087296},

issn = {2166-532X},

year  = {2019},

date = {2019-04-16},

journal = {Apl Materials},

volume = {7},

number = {4},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Structure and Charge Carrier Dynamics in Colloidal PbS Quantum Dot Solids},

author = {W Chen and J L Zhong and J Z Li and N Saxena and L P Kreuzer and H C Liu and L Song and B Su and D Yang and K Wang and J Schlipf and V Korstgens and T C He and K Wang and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000466991300006},

doi = {10.1021/acs.jpclett.9b00869},

issn = {1948-7185},

year  = {2019},

date = {2019-04-09},

urldate = {2019-04-09},

journal = {Journal of Physical Chemistry Letters},

volume = {10},

number = {9},

pages = {2058-2065},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Unprecedented High Oxygen Evolution Activity of Electrocatalysts Derived from Surface-Mounted Metal\textendashOrganic Frameworks},

author = {W Li and S Watzele and H A El-Sayed and Y Liang and G Kieslich and A S Bandarenka and K Rodewald and B Rieger and R A Fischer},

url = {https://doi.org/10.1021/jacs.9b00549},

doi = {10.1021/jacs.9b00549},

issn = {0002-7863},

year  = {2019},

date = {2019-03-19},

journal = {Journal of the American Chemical Society},

volume = {141},

number = {14},

pages = {5926-5933},

abstract = {The oxygen evolution reaction (OER) is a key process for renewable energy storage. However, developing non-noble metal OER electrocatalysts with high activity, long durability and scalability remains a major challenge. Herein, high OER activity and stability in alkaline solution were discovered for mixed nickel/cobalt hydroxide electrocatalysts, which were derived in one-step procedure from oriented surface-mounted metal\textendashorganic framework (SURMOF) thin films that had been directly grown layer-by-layer on macro- and microelectrode substrates. The obtained mass activity of ∼2.5 mA·μg\textendash1 at the defined overpotential of 300 mV is 1 order of magnitude higher than that of the benchmarked IrO2 electrocatalyst and at least 3.5 times higher than the mass activity of any state-of-the-art NiFe-, FeCoW-, or NiCo-based electrocatalysts reported in the literature. The excellent morphology of the SURMOF-derived ultrathin electrocatalyst coating led to a high exposure of the most active Ni- and Co-based sites.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems Based on SnIP},

author = {C Ott and F Reiter and M Baumgartner and M Pielmeier and A Vogel and P Walke and S Burger and M Ehrenreich and G Kieslich and D Daisenberger and J Armstrong and U K Thakur and P Kumar and S Chen and D Donadio and L S Walter and R T Weitz and K Shankar and T Nilges},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201900233},

doi = {10.1002/adfm.201900233},

issn = {1616-301X},

year  = {2019},

date = {2019-03-13},

journal = {Advanced Functional Materials},

volume = {29},

number = {18},

pages = {1900233},

abstract = {Abstract Low dimensionality and high flexibility are key demands for flexible electronic semiconductor devices. SnIP, the first atomic-scale double helical semiconductor combines structural anisotropy and robustness with exceptional electronic properties. The benefit of the double helix, combined with a diverse structure on the nanoscale, ranging from strong covalent bonding to weak van der Waals interactions, and the large structure and property anisotropy offer substantial potential for applications in energy conversion and water splitting. It represents the next logical step in downscaling the inorganic semiconductors from classical 3D systems, via 2D semiconductors like MXenes or transition metal dichalcogenides, to the first downsizeable, polymer-like atomic-scale 1D semiconductor SnIP. SnIP shows intriguing mechanical properties featuring a bulk modulus three times lower than any IV, III-V, or II-VI semiconductor. In situ bending tests substantiate that pure SnIP fibers can be bent without an effect on their bonding properties. Organic and inorganic hybrids are prepared illustrating that SnIP is a candidate to fabricate flexible 1D composites for energy conversion and water splitting applications. SnIP@C3N4 hybrid forms an unusual soft material core\textendashshell topology with graphenic carbon nitride wrapping around SnIP. A 1D van der Waals heterostructure is formed capable of performing effective water splitting.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Spectral Screening of the Energy of Hot Holes over a Particle Plasmon Resonance},

author = {E Pensa and J Gargiulo and A Lauri and S Schl\"{u}cker and E Cort\'{e}s and S A Maier},

url = {https://doi.org/10.1021/acs.nanolett.8b04950},

doi = {10.1021/acs.nanolett.8b04950},

issn = {1530-6984},

year  = {2019},

date = {2019-03-13},

journal = {Nano Letters},

volume = {19},

number = {3},

pages = {1867-1874},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Ruthenium Oxide Nanosheets for Enhanced Oxygen Evolution Catalysis in Acidic Medium},

author = {S Laha and Y Lee and F Podjaski and D Weber and V Duppel and L M Schoop and F Pielnhofer and C Scheurer and K Muller and U Starke and K Reuter and B V Lotsch},

url = {\<Go to ISI\>://WOS:000465464500007},

doi = {10.1002/aenm.201803795},

issn = {1614-6832},

year  = {2019},

date = {2019-02-21},

journal = {Advanced Energy Materials},

volume = {9},

number = {15},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Quantifying Figures of Merit for Localized Surface Plasmon Resonance Applications: A Materials Survey},

author = {B Doiron and M Mota and M P Wells and R Bower and A Mihai and Y Li and L F Cohen and N M Alford and P K Petrov and R F Oulton and S A Maier},

url = {https://doi.org/10.1021/acsphotonics.8b01369},

doi = {10.1021/acsphotonics.8b01369},

year  = {2019},

date = {2019-02-20},

journal = {ACS Photonics},

volume = {6},

number = {2},

pages = {240-259},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Tuning the Fr\"{o}hlich exciton-phonon scattering in monolayer MoS2},

author = {B Miller and J Lindlau and M Bommert and A Neumann and H Yamaguchi and A W Holleitner and A H\"{o}gele and U Wurstbauer},

url = {https://doi.org/10.1038/s41467-019-08764-3},

doi = {10.1038/s41467-019-08764-3},

issn = {2041-1723},

year  = {2019},

date = {2019-02-18},

journal = {Nature Communications},

volume = {10},

number = {1},

pages = {807},

abstract = {Charge carriers in semiconducting transition metal dichalcogenides possess a valley degree of freedom that allows for optoelectronic applications based on the momentum of excitons. At elevated temperatures, scattering by phonons limits valley polarization, making a detailed knowledge about strength and nature of the interaction of excitons with phonons essential. In this work, we directly access exciton-phonon coupling in charge tunable single layer MoS2 devices by polarization resolved Raman spectroscopy. We observe a strong defect mediated coupling between the long-range oscillating electric field induced by the longitudinal optical phonon in the dipolar medium and the exciton. This so-called Fr\"{o}hlich exciton phonon interaction is suppressed by doping. The suppression correlates with a distinct increase of the degree of valley polarization up to 20% even at elevated temperatures of 220 K. Our result demonstrates a promising strategy to increase the degree of valley polarization towards room temperature valleytronic applications.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Exciton Diffusion Lengths and Dissociation Rates in CsPbBr3 Nanocrystal\textendashFullerene Composites: Layer-by-Layer versus Blend Structures},

author = {E-P Yao and B J Bohn and Y Tong and H Huang and L Polavarapu and J Feldmann},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.201801776},

doi = {10.1002/adom.201801776},

issn = {2195-1071},

year  = {2019},

date = {2019-02-18},

journal = {Advanced Optical Materials},

volume = {7},

number = {8},

pages = {1801776},

abstract = {Abstract Solution-processable perovskite nanocrystals (NCs) are gaining increasing interest in the field of photovoltaics because of their enhanced stability compared to their thin-film counterparts. However, the charge transfer dynamics in perovskite NC based light-harvesting systems are not well understood. By applying femtosecond differential transmission (DT) spectroscopy the photoinduced charge transfer from inorganic perovskite CsPbBr3 NCs to the fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) is investigated for two fundamentally different architectures, namely layer-by-layer heterostructures and blend structures. By varying the thickness of the NC layer on top of the PCBM in the layer-by-layer heterostructure, an exciton diffusion length of 290 ± 28 nm for CsPbBr3 NC is extracted. The diffusion process is followed by an ultrafast exciton dissociation (within 200 fs) at the CsPbBr3 NC/PCBM interface. In blend structures an overall faster charge transfer process is observed. Furthermore, photoconductivity measurements on a blend structure-based photodetector reveal an effective charge extraction from the active layer resulting in a high photosensitivity. DT measurements on this blend structure including adjacent electron- or hole-transport layers give insight into the extraction process and suggest a certain degree of phase segregation, which assists the charge collection.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Toward Plasmonic Tunnel Gaps for Nanoscale Photoemission Currents by On-Chip Laser Ablation},

author = {P Zimmermann and A H\"{o}tger and N Fernandez and A Nolinder and K M\"{u}ller and J J Finley and A W Holleitner},

url = {https://doi.org/10.1021/acs.nanolett.8b04612},

doi = {10.1021/acs.nanolett.8b04612},

issn = {1530-6984},

year  = {2019},

date = {2019-02-13},

journal = {Nano Letters},

volume = {19},

number = {2},

pages = {1172-1178},

abstract = {We demonstrate that prestructured metal nanogaps can be shaped on-chip to below 10 nm by femtosecond laser ablation. We explore the plasmonic properties and the nonlinear photocurrent characteristics of the formed tunnel junctions. The photocurrent can be tuned from multiphoton absorption toward the laser-induced strong-field tunneling regime in the nanogaps. We demonstrate that a unipolar ballistic electron current is achieved by designing the plasmonic junctions to be asymmetric, which allows ultrafast electronics on the nanometer scale.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Toward Plasmonic Tunnel Gaps for Nanoscale Photoemission Currents by On-Chip Laser Ablation},

author = {P Zimmermann and A H\"{o}tger and N Fernandez and A Nolinder and K M\"{u}ller and J J Finley and A W Holleitner},

url = {https://doi.org/10.1021/acs.nanolett.8b04612},

doi = {10.1021/acs.nanolett.8b04612},

issn = {1530-6984},

year  = {2019},

date = {2019-02-13},

journal = {Nano Letters},

volume = {19},

number = {2},

pages = {1172-1178},

abstract = {We demonstrate that prestructured metal nanogaps can be shaped on-chip to below 10 nm by femtosecond laser ablation. We explore the plasmonic properties and the nonlinear photocurrent characteristics of the formed tunnel junctions. The photocurrent can be tuned from multiphoton absorption toward the laser-induced strong-field tunneling regime in the nanogaps. We demonstrate that a unipolar ballistic electron current is achieved by designing the plasmonic junctions to be asymmetric, which allows ultrafast electronics on the nanometer scale.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Interchromophoric Interactions Determine the Maximum Brightness Density in DNA Origami Structures},

author = {T Schr\"{o}der and M B Scheible and F Steiner and J Vogelsang and P Tinnefeld},

url = {https://doi.org/10.1021/acs.nanolett.8b04845},

doi = {10.1021/acs.nanolett.8b04845},

issn = {1530-6984},

year  = {2019},

date = {2019-02-13},

urldate = {2019-02-13},

journal = {Nano Letters},

volume = {19},

number = {2},

pages = {1275-1281},

abstract = {An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye\textendashdye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye\textendashdye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Top-Down Synthesis of Nanostructured Platinum\textendashLanthanide Alloy Oxygen Reduction Reaction Catalysts: PtxPr/C as an Example},

author = {J Fichtner and B Garlyyev and S Watzele and H A El-Sayed and J N Schw\"{a}mmlein and W-J Li and F M Maillard and L Dubau and J Michali\v{c}ka and J M Macak and A W Holleitner and A S Bandarenka},

url = {https://doi.org/10.1021/acsami.8b20174},

doi = {10.1021/acsami.8b20174},

issn = {1944-8244},

year  = {2019},

date = {2019-02-06},

journal = {ACS Applied Materials \& Interfaces},

volume = {11},

number = {5},

pages = {5129-5135},

abstract = {The oxygen reduction reaction (ORR) is of great interest for future sustainable energy conversion and storage, especially concerning fuel cell applications. The preparation of active, affordable, and scalable electrocatalysts and their application in fuel cell engines of hydrogen cars is a prominent step toward the reduction of air pollution, especially in urban areas. Alloying nanostructured Pt with lanthanides is a promising approach to enhance its catalytic ORR activity, whereby the development of a simple synthetic route turned out to be a nontrivial endeavor. Herein, for the first time, we present a successful single-step, scalable top-down synthetic route for Pt\textendashlanthanide alloy nanoparticles, as witnessed by the example of Pr-alloyed Pt nanoparticles. The catalyst was characterized by high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and photoelectron spectroscopy, and its electrocatalytic oxygen reduction activity was investigated using a rotating disk electrode technique. PtxPr/C showed ∼3.5 times higher [1.96 mA/cm2Pt, 0.9 V vs reversible hydrogen electrode (RHE)] specific activity and ∼1.7 times higher (0.7 A/mgPt, 0.9 V vs RHE) mass activity compared to commercial Pt/C catalysts. On the basis of previous findings and characterization of the PtxPr/C catalyst, the activity improvement over commercial Pt/C originates from a lattice strain introduced by the alloying process.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Phase-matching and Peak Nonlinearity Enhanced Third-Harmonic Generation in Graphene Plasmonic Coupler},

author = {T Wu and Y Luo and S A Maier and L Wei},

url = {https://link.aps.org/doi/10.1103/PhysRevApplied.11.014049},

doi = {10.1103/PhysRevApplied.11.014049},

year  = {2019},

date = {2019-01-24},

journal = {Physical Review Applied},

volume = {11},

number = {1},

pages = {014049},

abstract = {Strong nonlinear optical effects generally require giant optical fields interacting with the nonlinear media. Doped graphene hosts electrically tunable plasmons with long lifetimes that interact strongly with light. We investigate a graphene plasmonic coupler and explore two mechanisms to pursue highly efficient third-harmonic generation (THG): (1) phase matching of graphene plasmons at fundamental- and third-harmonic frequencies and (2) peak third-order nonlinear susceptibility of doped graphene. The third-harmonic wave is mainly converted from the evanescent mode of the incident light and the THG efficiency is found to be enhanced by over 10 orders of magnitude compared with a bare monolayer graphene. The significantly enhanced nonlinear optical responses in the graphene plasmonic coupler make this configuration an ideal platform for the development of alternative frequency generators and for signal processing at midinfrared and terahertz frequencies.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

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

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

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

doi = {10.1021/jacs.8b11466},

issn = {0002-7863},

year  = {2019},

date = {2019-01-09},

journal = {Journal of the American Chemical Society},

volume = {141},

number = {1},

pages = {98-103},

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

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Enhancing photosynthesis at high light levels by adaptive laboratory evolution},

author = {M Dann and E M Ortiz and M Thomas and A Guljamow and M Lehmann and H Schaefer and D Leister},

url = {\<Go to ISI\>://WOS:000646516500001},

doi = {10.1038/s41477-021-00904-2},

issn = {2055-026X},

journal = {Nature Plants},

volume = {7},

number = {5},

pages = {681-+},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Probing the micro- and nanoscopic properties of dental materials using infrared spectroscopy: A proof-of-principle study},

author = {M Beddoe and T G\"{o}lz and M Barkey and E Bau and M Godejohann and S A Maier and F Keilmann and M Moldovan and D Prodan and N Ilie and A Tittl},

url = {https://www.sciencedirect.com/science/article/pii/S1742706123004026},

doi = {https://doi.org/10.1016/j.actbio.2023.07.017},

issn = {1742-7061},

journal = {Acta Biomaterialia},

volume = {168},

pages = {309-322},

abstract = {The preservation of oral health over a person's lifespan is a key factor for a high quality of life. Sustaining oral health requires high-end dental materials with a plethora of attributes such as durability, non-toxicity and ease of application. The combination of different requirements leads to increasing miniaturization and complexity of the material components such as the composite and adhesives, which makes the precise characterization of the material blend challenging. Here, we demonstrate how modern IR spectroscopy and imaging from the micro- to the nanoscale can provide insights on the chemical composition of the different material sections of a dental filling. We show how the recorded IR-images can be used for a fast and non-destructive porosity determination of the studied adhesive. Furthermore, the nanoscale study allows precise assessment of glass cluster structures and distribution within their characteristic organically modified ceramic (ORMOCER) matrix and an assessment of the interface between the composite and adhesive material. For the study we used a Fourier-Transform-IR (FTIR) microscope and a quantum cascade laser-based IR-microscope (QCL-IR) for the microscale analysis and a scattering-type scanning near-field optical microscopy (s-SNOM) for the nanoscale analysis. The paper ends with an in-depth discussion of the strengths and weaknesses of the different imaging methods to give the reader a clear picture for which scientific question the microscopes are best suited for. Statement of significance Modern resin-based composites for dental restoration are complex multi-compound materials. In order to improve these high-end materials, it is important to investigate the molecular composition and morphology of the different parts. An emergent method to characterize these materials is infrared spectroscopic imaging, which combines the strength of infrared spectroscopy and an imaging approach known from optical microscopy. In this work, three state of the art methods are compared for investigating a dental filling including FTIR- and quantum cascade laser IR-imaging microscopy for the microscale and scattering-type scanning near-field optical microscopy for the nanoscale.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Sprayed Hybrid Cellulose Nanofibril\textendashSilver Nanowire Transparent Electrodes for Organic Electronic Applications},

author = {M Betker and C Harder and E Erbes and J E Heger and A E Alexakis and B Sochor and Q Chen and M Schwartzkopf and V K\"{o}rstgens and P M\"{u}ller-Buschbaum and K Schneider and S A Techert and L D S\"{o}derberg and S V Roth},

url = {https://doi.org/10.1021/acsanm.3c02496},

doi = {10.1021/acsanm.3c02496},

journal = {ACS Applied Nano Materials},

volume = {6},

number = {14},

pages = {13677-13688},

abstract = {In times of climate change and resource scarcity, researchers are aiming to find sustainable alternatives to synthetic polymers for the fabrication of biodegradable, eco-friendly, and, at the same time, high-performance materials. Nanocomposites have the ability to combine several favorable properties of different materials in a single device. Here, we evaluate the suitability of two kinds of inks containing silver nanowires for the fast, facile, and industrial-relevant fabrication of two different types of cellulose-based silver nanowire electrodes via layer-by-layer spray deposition only. The Type I electrode has a layered structure, which is composed of a network of silver nanowires sprayed on top of a cellulose nanofibrils layer, while the Type II electrode consists of a homogeneous mixture of silver nanowires and cellulose nanofibrils. A correlation between the surface structure, conductivity, and transparency of both types of electrodes is established. We use the Haacke figure of merit for transparent electrode materials to demonstrate the favorable influence of cellulose nanofibrils in the spray ink by identifying Type II as the electrode with the lowest sheet resistance (minimum 5 ± 0.04 Ω/sq), while at the same time having a lower surface roughness and shorter fabrication time than Type I. Finally, we prove the mechanical stability of the Type II electrode by bending tests and its long-time stability under ambient conditions. The results demonstrate that the mixed spray ink of silver nanowires and cellulose nanofibrils is perfectly suitable for the fast fabrication of highly conductive organic nanoelectronics on an industrial scale.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Quantitative electric field mapping between electrically biased needles by scanning transmission electron microscopy and electron holography},

author = {J F Dushimineza and J Jo and R E Dunin-Borkowski and K M\"{u}ller-Caspary},

url = {https://www.sciencedirect.com/science/article/pii/S0304399123001250},

doi = {https://doi.org/10.1016/j.ultramic.2023.113808},

issn = {0304-3991},

journal = {Ultramicroscopy},

volume = {253},

pages = {113808},

abstract = {Stray electric fields in free space generated by two biased gold needles have been quantified in comprehensive finite-element (FE) simulations, accompanied by first moment (FM) scanning TEM (STEM) and electron holography (EH) experiments. The projected electrostatic potential and electric field have been derived numerically under geometrical variations of the needle setup. In contrast to the FE simulation, application of an analytical model based on line charges yields a qualitative understanding. By experimentally probing the electric field employing FM STEM and EH under alike conditions, a discrepancy of about 60% became apparent initially. However, the EH setup suggests the reconstructed phase to be significantly affected by the perturbed reference wave effect, opposite to STEM where the field-free reference was recorded subsequently with unbiased needles in which possibly remaining electrostatic influences are regarded as being minor. In that respect, the observed discrepancy between FM imaging and EH is resolved after including the long-range potential landscape from FE simulations into the phase of the reference wave in EH.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optoelectronic perovskite film characterization via machine vision},

author = {M Harth and L Vesce and I Kouroudis and M Stefanelli and A Di Carlo and A Gagliardi},

url = {https://www.sciencedirect.com/science/article/pii/S0038092X23004656},

doi = {https://doi.org/10.1016/j.solener.2023.111840},

issn = {0038-092X},

journal = {Solar Energy},

volume = {262},

pages = {111840},

abstract = {We present our research for fast and reliable extraction of bandgap and absorption quality values for triple-cation perovskite thin films from sample scans. Our approach leverages machine learning methods, namely convolutional neural networks, to perform regression tasks aimed at predicting the properties of interest. To this end, thin film samples were synthesized via blade-coating and their photoluminescence and ultraviolet\textendashvisible spectra collected, along with the film thickness. We propose a method of computing a dimensionless figure of merit we called the Area Under Absorption Coefficient (AUAC), its purpose being to qualitatively evaluate the absorption quality of perovskite films for use in photovoltaic modules. This work demonstrates the usability of simple imaging techniques to analyze experimental samples while requiring only a feasibly acquirable initial amount of data. Our reported method can help speed up time consuming material optimizations by reducing lab time spent on recurrent characterization, nicely synergizes with high throughput production lines and could be adapted for quick extraction of other optoelectrical quantities.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Mechanistic Insights into ZIF-8 Encapsulation of Atom-Precise Pt(M) Carbonyl Clusters},

author = {K L Kollmannsberger and Poonam and C Cesari and R Khare and T Kratky and M Boniface and O Tomanec and J Michali\v{c}ka and E Mosconi and A Gagliardi and S G\"{u}nther and W Kaiser and T Lunkenbein and S Zacchini and J Warnan and R A Fischer},

url = {https://doi.org/10.1021/acs.chemmater.3c00807},

doi = {10.1021/acs.chemmater.3c00807},

issn = {0897-4756},

journal = {Chemistry of Materials},

volume = {35},

number = {14},

pages = {5475-5486},

abstract = {Precisely designing metal nanoparticles (NPs) is the cornerstone for maximizing their efficiency in applications like catalysis or sensor technology. Metal\textendashorganic frameworks (MOFs) with their defined and tunable pore systems provide a confined space to host and stabilize small metal NPs. In this work, the MOF encapsulation of various atom-precise clusters following the bottle-around-ship approach is investigated, providing general insights into the scaffolding mechanism. Eleven carbonyl-stabilized Pt(M) (M = Co, Ni, Fe, and Sn) clusters are employed for the encapsulation in the zeolitic imidazolate framework (ZIF)-8. Infrared and UV/Vis spectroscopy, density functional theory, and ab initio molecular dynamics revealed structure\textendashencapsulation relationship guidelines. Thereby, cluster polarization, size, and composition were found to condition the scaffolding behavior. Encaging of [NBnMe3]2[Co8Pt4C2(CO)24] (Co8Pt4) is thus achieved as the first MOF-encapsulated bimetallic carbonyl cluster, Co8Pt4@ZIF-8, and is fully characterized including X-ray absorption near edge and extended X-ray absorption spectroscopy. ZIF-8 confinement not only promotes property changes, like the T-dependent magnetism, but it also further allows heat-induced ligand-stripping without altering the cluster size, enabling the synthesis of naked, heterometallic, close to atom-precise clusters.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Utilizing Data-Driven Optimization to Automate the Parametrization of Kinetic Monte Carlo Models},

author = {I Kouroudis and M G\"{o}\sswein and A Gagliardi},

url = {https://doi.org/10.1021/acs.jpca.3c02482},

doi = {10.1021/acs.jpca.3c02482},

issn = {1089-5639},

journal = {The Journal of Physical Chemistry A},

volume = {127},

number = {28},

pages = {5967-5978},

abstract = {Kinetic Monte Carlo (kMC) simulations are a popular tool to investigate the dynamic behavior of stochastic systems. However, one major limitation is their relatively high computational costs. In the last three decades, significant effort has been put into developing methodologies to make kMC more efficient, resulting in an enhanced runtime efficiency. Nevertheless, kMC models remain computationally expensive. This is in particular an issue in complex systems with several unknown input parameters where often most of the simulation time is required for finding a suitable parametrization. A potential route for automating the parametrization of kinetic Monte Carlo models arises from coupling kMC with a data-driven approach. In this work, we equip kinetic Monte Carlo simulations with a feedback loop consisting of Gaussian Processes (GPs) and Bayesian optimization (BO) to enable a systematic and data-efficient input parametrization. We utilize the results from fast-converging kMC simulations to construct a database for training a cheap-to-evaluate surrogate model based on Gaussian processes. Combining the surrogate model with a system-specific acquisition function enables us to apply Bayesian optimization for the guided prediction of suitable input parameters. Thus, the amount of trial simulation runs can be considerably reduced facilitating an efficient utilization of arbitrary kMC models. We showcase the effectiveness of our methodology for a physical process of growing industrial relevance: the space-charge layer formation in solid-state electrolytes as it occurs in all-solid-state batteries. Our data-driven approach requires only 1\textendash2 iterations to reconstruct the input parameters from different baseline simulations within the training data set. Moreover, we show that the methodology is even capable of accurately extrapolating into regions outside the training data set which are computationally expensive for direct kMC simulation. Concluding, we demonstrate the high accuracy of the underlying surrogate model via a full parameter space investigation eventually making the original kMC simulation obsolete.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optoelectronics Meets Optoionics: Light Storing Carbon Nitrides and Beyond},

author = {F Podjaski and B V Lotsch},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202003049},

doi = {https://doi.org/10.1002/aenm.202003049},

issn = {1614-6832},

journal = {Advanced Energy Materials},

volume = {11},

number = {4},

pages = {2003049},

abstract = {Abstract Known for decades, Liebig's carbon nitrides have evolved into a burgeoning class of macromolecular semiconductors over the past 10+ years, front and center of many efforts revolving around the discovery of resource-efficient and high-performance photocatalysts for solar fuel generation. The recent discovery of a new class of “ionic” 2D carbon nitrides\textemdashpoly(heptazine imide) (PHI)\textemdashhas given new momentum to this field, driven both by unconventional properties and the prospect of new applications at the intersection between solar energy conversion and electrochemical energy storage. In this essay, key concepts of the emerging field of optoionics are delineated and the “light storing” ability of PHI-type carbon nitrides is rationalized by an intricate interplay between their optoelectronic and optoionic properties. Based on these insights, key characteristics and general principles for the de novo design of optoionic materials across the periodic table are derived, opening up new research avenues such as “dark photocatalysis”, direct solar batteries, light-driven autonomous systems, and photomemristive devices.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dynamical scattering in ice-embedded proteins in conventional and scanning transmission electron microscopy},

author = {M L Leidl and C Sachse and K Muller-Caspary},

url = {https://doi.org/10.1107/S2052252523004505},

doi = {doi:10.1107/S2052252523004505},

issn = {2052-2525},

journal = {IUCrJ},

volume = {10},

number = {4},

pages = {475-486},

abstract = {Structure determination of biological macromolecules using cryogenic electron microscopy is based on applying the phase object (PO) assumption and the weak phase object (WPO) approximation to reconstruct the 3D potential density of the molecule. To enhance the understanding of image formation of protein complexes embedded in glass-like ice in a transmission electron microscope, this study addresses multiple scattering in tobacco mosaic virus (TMV) specimens. This includes the propagation inside the molecule while also accounting for the effect of structural noise. The atoms in biological macromolecules are light but are distributed over several nanometres. Commonly, PO and WPO approximations are used in most simulations and reconstruction models. Therefore, dynamical multislice simulations of TMV specimens embedded in glass-like ice were performed based on fully atomistic molecular-dynamics simulations. In the first part, the impact of multiple scattering is studied using different numbers of slices. In the second part, different sample thicknesses of the ice-embedded TMV are considered in terms of additional ice layers. It is found that single-slice models yield full frequency transfer up to a resolution of 2.5 A, followed by attenuation up to 1.4 A. Three slices are sufficient to reach an information transfer up to 1.0 A. In the third part, ptychographic reconstructions based on scanning transmission electron microscopy (STEM) and single-slice models are compared with conventional TEM simulations. The ptychographic reconstructions do not need the deliberate introduction of aberrations, are capable of post-acquisition aberration correction and promise benefits for information transfer, especially at resolutions beyond 1.8 A.},

keywords = {Foundry Inorganic, Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optimization of p-Type Cu2O Nanocube Photocatalysts Based on Electronic Effects},

author = {R Lin and H Chen and T Cui and Z Zhang and Q Zhou and L Nan and W-C Cheong and L Schr\"{o}ck and V Ramm and Q Ding and X Liang and S Saris and F J Wendisch and S A Maier and R A Fischer and Y Zhu and D Wang and E Cortes},

url = {https://doi.org/10.1021/acscatal.3c02710},

doi = {10.1021/acscatal.3c02710},

journal = {ACS Catalysis},

pages = {11352-11361},

abstract = {The size effect in semiconductor photocatalysis has been widely investigated but still remains elusive. Herein, employing p-type Cu2O nanocubes as the heterogeneous photocatalysts, we propose a feasible size optimization strategy to enhance the photocatalytic performance of semiconductors. With the size of Cu2O increasing from 2.5 nm (exciton Bohr radius) to 5 nm (twice the exciton Bohr radius), the corresponding calculated band gap of Cu2O decreases from 3.39 to 2.41 eV, indicating that controlling the size to above twice the exciton Bohr radius is vital for retaining the visible-light response of Cu2O. Based on the theoretical calculations and experimental measurements of the charge carrier dynamics, we found that the synthesized 30 nm Cu2O nanocubes have an electron diffusion length of 191 nm, while 229 nm Cu2O nanocubes show an electron diffusion length of 45 nm. An electron diffusion length larger than the semiconductor particle size lowers the electron\textendashhole recombination, resulting in a visible-light CO generation rate 23.4 times higher for the smaller Cu2O nanocubes than that for the larger ones. These results verify that confining Cu2O size to within the minority carrier diffusion length and above twice the exciton Bohr radius is a promising way to enhance Cu2O photocatalytic activity.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Fine-Tuning Blue-Emitting Halide Perovskite Nanocrystals},

author = {S Martin and N A Henke and C Lampe and M D\"{o}blinger and K Frank and P Ganswindt and B Nickel and A S Urban},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202301009},

doi = {https://doi.org/10.1002/adom.202301009},

issn = {2195-1071},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2301009},

abstract = {Abstract Lead halide perovskite nanocrystals (NCs) with narrow, bright emission in the visible range are promising candidates for light-emitting applications. Near-unity quantum yields have been realized for green and red-emitting perovskites, but efficient, stable blue-emitting perovskite materials are scarce. Current methods to synthesize quantum-confined CsPbBr3 NCs with blue emission are limited to specific wavelength ranges and still suffer from inhomogeneously broadened emission profiles. Herein, anisotropic blue-green emitting CsPbBr3 NCs are synthesized in ambient atmosphere using a spontaneous crystallization method. Optical spectroscopy reveals a gradual, asymptotic photoluminescence (PL) redshift of pristine colloidal NCs after synthesis. During this process, the emission quality improves notably as the PL spectra become narrower and more symmetric, accompanied by a PL intensity increase. Electron microscopy indicates that the gradual redshift stems from an isotropic growth of the CsPbBr3 NCs in at least two dimensions, likely due to residual precursor ions in the dispersion. Most importantly, the growth process can be halted at any point by injecting an enhancement solution containing PbBr2 and organic capping ligands. Thus, excellent control over NC size is achieved, allowing for nanometer-precise tunability of the respective emission wavelength in the range between 475 and 500 nm, enhancing the functionality of these already impressive NCs.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Intrinsic strong light-matter coupling with self-hybridized bound states in the continuum in van der Waals metasurfaces},

author = {T Weber and L K\"{u}hner and L Sortino and A Ben Mhenni and N P Wilson and J K\"{u}hne and J J Finley and S A Maier and A Tittl},

url = {https://doi.org/10.1038/s41563-023-01580-7},

doi = {10.1038/s41563-023-01580-7},

issn = {1476-4660},

journal = {Nature Materials},

volume = {22},

number = {8},

pages = {970-976},

abstract = {Photonic bound states in the continuum (BICs) provide a standout platform for strong light-matter coupling with transition metal dichalcogenides (TMDCs) but have so far mostly been implemented as traditional all-dielectric metasurfaces with adjacent TMDC layers, incurring limitations related to strain, mode overlap and material integration. Here, we demonstrate intrinsic strong coupling in BIC-driven metasurfaces composed of nanostructured bulk tungsten disulfide (WS2) and exhibiting resonances with sharp, tailored linewidths and selective enhancement of light-matter interactions. Tuning of the BIC resonances across the exciton resonance in bulk WS2 is achieved by varying the metasurface unit cells, enabling strong coupling with an anticrossing pattern and a Rabi splitting of 116 meV. Crucially, the coupling strength itself can be controlled and is shown to be independent of material-intrinsic losses. Our self-hybridized metasurface platform can readily incorporate other TMDCs or excitonic materials to deliver fundamental insights and practical device concepts for polaritonic applications.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Active Loss Engineering in Vanadium Dioxide Based BIC Metasurfaces},

author = {A Aigner and F Ligmajer and K Rovensk\'{a} and J Holobr\'{a}dek and B Idesov\'{a} and S A Maier and A Tittl and L D S Menezes},

url = {https://arxiv.org/abs/2312.00547},

doi = {https://doi.org/10.48550/arXiv.2312.00547},

journal = {arXiv preprint arXiv:2312.00547},

abstract = {Metasurfaces have unlocked significant advancements across photonics, yet their efficient active control remains challenging. The active materials required often lack continuous tunability, exhibit inadequate refractive index (RI) changes, or suffer from high losses. These aspects pose an inherent limitation for resonance-shifting based switching: when RI changes are small, the resulting shift is also minor. Conversely, high RI changes typically come with high intrinsic losses necessitating broad modes because narrow ones cannot tolerate such losses. Therefore, larger spectral shifts are required to effectively detune the modes. This paper introduces a novel active metasurface approach that converts the constraint of high intrinsic losses into a beneficial feature. This is achieved by controlling the losses in a hybrid vanadium dioxide (VO2) - silicon metasurface, supporting symmetry-protected bound states in the continuum (BICs) within the infrared spectrum. By leveraging the temperature-controlled losses in VO2 and combining them with the inherent far-field-coupling tunability of BICs, we gain unprecedented precision in independently controlling both the radiative and nonradiative losses of the resonant system. Our dual-control mechanism allows us to optimize our metasurfaces and we experimentally demonstrate quality factors above 200, a maximum reflectance amplitude of 90%, a relative switching contrast of 78%, and continuous tuning from under- to over-coupling within the infrared spectral range. This study provides a foundation for experimentally and technologically simple, fine-tunable, active metasurfaces for applications ranging from molecular sensors to filters and optical modulators.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Continuous spectral and coupling-strength encoding with dual-gradient metasurfaces},

author = {A Aigner and T Weber and A Wester and S A Maier and A Tittl},

url = {https://arxiv.org/abs/2312.05600},

doi = {https://doi.org/10.48550/arXiv.2312.05600},

journal = {arXiv preprint arXiv:2312.05600},

abstract = {Optical metasurfaces excel at enhancing and controlling light-matter interactions, which are primarily dictated by two factors: the spectral overlap of the resonances with target excitations in the material and the coupling-strength between them, where resonance linewidth and localized field enhancement are the governing influences. Current metasurface designs are limited to sampling a few discrete points within this vast 2D interaction parameter space or have varied only a single parameter. Symmetry-protected bound states in the continuum (BICs) allow precise control over the wavelength and linewidth of individual resonances, but rely on large arrangements of identical unit cells, limiting the continuous mapping of the parameter space. Therefore, optical platforms that concurrently probe the spectral and coupling parameters, so far, remained elusive. Here, we introduce the concept of dual-gradient metasurfaces for the continuous and simultaneous encoding of the spectral and coupling-strength of light-matter interactions, enabled by smooth local variations of the unit cell parameters. Contrary to conventional understanding, we demonstrate that BICs can be excited in such non-periodic systems provided the parameter variations are sufficiently small. Our dual-gradient metasurface exhibits an extraordinary resonance density, with each unit cell supporting a unique mode. This results in up to 27,500 distinct modes, all contained within a compact footprint. We apply this technology to surface-enhanced molecular sensing, capturing not only the spectral fingerprint of molecules but also unveiling an additional coupling-based dimension of spectroscopic data. This advancement in metasurface design paves the way for generalized light-matter coupling with metasurfaces, with applications ranging from on-chip spectrometer, to chirality encoding and AI-driven biochemical spectroscopy.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Thermally-Induced Degradation in PM6:Y6-Based Bulk Heterojunction Organic Solar Cells},

author = {S Alam and H Aldosari and C E Petoukhoff and T V\'{a}ry and W Althobaiti and M Alqurashi and H Tang and J I Khan and V N\'{a}da\v{z}dy and P M\"{u}ller-Buschbaum and G C Welch and F Laquai},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202308076},

doi = {https://doi.org/10.1002/adfm.202308076},

issn = {1616-301X},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2308076},

abstract = {Abstract Thermally induced degradation of organic photovoltaic devices hinders the commercialization of this emerging PV technology. Thus, a precise understanding of the origin of thermal device instability, as well as identifying strategies to circumvent degradation is of utmost importance. Here, it investigates thermally-induced degradation of state-of-the-art PBDB-T-2F (PM6):BTP (Y6) bulk heterojunction solar cells at different temperatures and reveal changes of their optical properties, photophysics, and morphology. The open-circuit voltage and fill factor of thermally degraded devices are limited by dissociation and charge collection efficiency differences, while the short-circuit current density is only slightly affected. Energy-resolved electrochemical impedance spectroscopy measurements reveal that thermally degraded samples exhibit a higher energy barrier for the charge-transfer state to charge-separated state conversion. Furthermore, the field dependence of charge generation, recombination, and extraction are studied by time-delayed collection field and transient photocurrent and photovoltage experiments, indicating significant bimolecular recombination limits device performance. Finally, coupled optical-electrical device simulations are conducted to fit the devices’ current-voltage characteristics, enabling us to find useful correlations between optical and electrical properties of the active layers and device performance parameters.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}