Publications

@article{nokey,

title = {Selective anode catalyst for the mitigation of start-up/shut-down induced cathode degradation in proton exchange membrane fuel cells},

author = {B M St\"{u}hmeier and A M Damjanovi\'{c} and K Rodewald and H A Gasteiger},

url = {https://www.sciencedirect.com/science/article/pii/S037877532201549X},

doi = {https://doi.org/10.1016/j.jpowsour.2022.232572},

issn = {0378-7753},

year  = {2023},

date = {2023-02-28},

journal = {Journal of Power Sources},

volume = {558},

pages = {232572},

abstract = {Reducing cathode degradation during start-up and shut-down (SUSD) events is one of the remaining challenges for the widespread application of proton exchange membrane fuel cells (PEMFC). An anode catalyst that is selective for the hydrogen oxidation reaction (HOR) while its activity for the oxygen reduction reaction (ORR) is severely reduced, could substantially prolong the SUSD lifetime of the cathode. Herein, we report on single-cell measurements with a Pt/TiOx/C (x ≤ 2) catalyst that has been shown to be HOR selective by rotating disk electrode (RDE) measurements. The HOR activity of the catalyst was compared to conventional Pt/C by H2-pump measurements at ultra-low loadings. The ORR activity of Pt/TiOx/C was compared to Pt/C anodes with high and low Pt loadings, showing a diminished selectivity in MEA compared to RDE measurements. Unfortunately, the PEMFC performance with the Pt/TiOx/C catalyst was compromised by TiOx dissolution, deduced from voltage loss analysis of the H2/O2 performance curves and by ex-situ SEM/EDX of the MEAs. Finally, the successful mitigation of cathode carbon corrosion was shown over the course of 3200 SUSD cycles, whereby the retention of Pt surface area when using a Pt/TiOx/C anode by far exceeded the improvements expected from the reduced ORR kinetics.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ligand Chemistry of Inorganic Lead Halide Perovskite Nanocrystals},

author = {N Fiuza-Maneiro and K Sun and I L\'{o}pez-Fern\'{a}ndez and S G\'{o}mez-Gra\~{n}a and P M\"{u}ller-Buschbaum and L Polavarapu},

url = {https://doi.org/10.1021/acsenergylett.2c02363},

doi = {10.1021/acsenergylett.2c02363},

year  = {2023},

date = {2023-01-26},

journal = {ACS Energy Letters},

pages = {1152-1191},

abstract = {Lead halide perovskite nanocrystals (LHP NCs) have emerged as next-generation semiconductor materials with outstanding optical and optoelectronic properties. Because of the high surface-to-volume ratio, the optical and optoelectronic performance and the colloidal stability of LHP NCs largely depend on their surface chemistry, especially the ligands and surface termination. On one hand, the capping ligands improve the colloidal stability and luminescence; on the other hand the highly dynamic binding nature of ligands is detrimental to the colloidal stability and photoluminescence of LHP NCs. In addition, the surface functionalization with desired molecules induces new functionalities such as chirality, light harvesting, and triplet sensitization through energy/electron transfer or use as X-ray detectors. In this review, we present the current understanding of an atomic view of the surface chemistry of colloidal LHP NCs, including crystal termination, vacancies, and different types of capping ligands. Furthermore, we discuss the ligand-induced functionalities, including photocatalysis and chirality.},

keywords = {Foundry Inorganic, Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Does cluster encapsulation inhibit sintering? Stabilization of size-selected Pt clusters on Fe $ _3 $ O $ _4 $(001) by SMSI},

author = {S Kaiser and J Plansky and M Krinninger and A Shavorskiy and S Zhu and U Heiz and F Esch and B A Lechner},

url = {https://arxiv.org/abs/2301.10845},

doi = {https://doi.org/10.48550/arXiv.2301.10845},

year  = {2023},

date = {2023-01-25},

journal = {arXiv preprint arXiv:2301.10845},

abstract = {The metastability of supported metal nanoparticles limits their application in heterogeneous catalysis at elevated temperatures due to their tendency to sinter. One strategy to overcome these thermodynamic limits on reducible oxide supports is encapsulation via strong metal-support interaction (SMSI). While annealing-induced encapsulation is a well-explored phenomenon for extended nanoparticles, it is as yet unknown whether the same mechanisms hold for sub-nanometer clusters, where concomitant sintering and alloying might play a significant role. In this article, we explore the encapsulation and stability of size-selected Pt5, Pt10 and Pt19 clusters deposited on Fe3O4(001). In a multimodal approach using temperature-programmed desorption (TPD), x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), we demonstrate that SMSI indeed leads to the formation of a defective, FeO-like conglomerate encapsulating the clusters. By stepwise annealing up to 1023 K, we observe the succession of encapsulation, cluster coalescence and Ostwald ripening, resulting in square-shaped crystalline Pt particles, independent of the initial cluster sizes. The respective sintering onset temperatures scale with the cluster footprint and thus size. Remarkably, while small encapsulated clusters can still diffuse as a whole, atom detachment and thus Ostwald ripening are successfully suppressed up to 823 K, i.e. 200 K above the H\"{u}ttig temperature that indicates the thermodynamic stability limit.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Lead-free, luminescent perovskite nanocrystals obtained through ambient condition synthesis},

author = {F Treber and K Frank and B Nickel and C Lampe and A S Urban},

url = {https://arxiv.org/abs/2301.08936},

doi = {https://doi.org/10.48550/arXiv.2301.08936},

year  = {2023},

date = {2023-01-21},

journal = {arXiv preprint arXiv:2301.08936},

abstract = {Heterovalent substitution of toxic lead is an increasingly popular design strategy to obtain environmentally sustainable variants of the exciting material class of halide perovskites. Perovskite nanocrystals (NCs) obtained through solution-based methods exhibit exceedingly high optical quality. Unfortunately, most of these synthesis routes still require reaction under inert gas and at very high temperatures. Herein we present a novel synthesis routine for lead-free double perovskite NCs. We combine hot injection and ligand-assisted reprecipitation (LARP) methods to achieve a low-temperature and ambient atmosphere-based synthesis for manganese-doped Cs_2NaBiCl_6 NCs. Mn incorporation is critical for the otherwise non-emissive material, with a 9:1 Bi:Mn precursor ratio maximizing the bright orange photoluminescence (PL) and quantum yield (QY). Higher temperatures slightly increased the material's performance, yet NCs synthesized at room temperature were still emissive, highlighting the versatility of the synthetic approach. Furthermore, the NCs show excellent long-term stability in ambient conditions, facilitating additional investigations and energy-related applications.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Rapid Data-Efficient Optimization of Perovskite Nanocrystal Syntheses through Machine Learning Algorithm Fusion},

author = {C Lampe and I Kouroudis and M Harth and S Martin and A Gagliardi and A S Urban},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202208772},

doi = {https://doi.org/10.1002/adma.202208772},

issn = {0935-9648},

year  = {2023},

date = {2023-01-21},

journal = {Advanced Materials},

volume = {n/a},

number = {n/a},

pages = {2208772},

abstract = {Abstract With the demand for renewable energy and efficient devices rapidly increasing, a need arises to find and optimize novel (nano)materials. With sheer limitless possibilities for material combinations and synthetic procedures, obtaining novel, highly functional materials has been a tedious trial and error process. Recently, machine learning has emerged as a powerful tool to help optimize syntheses; however, most approaches require a substantial amount of input data, limiting their pertinence. Here, we merge three well-known machine-learning models with Bayesian Optimization into one to optimize the synthesis of CsPbBr3 nanoplatelets with limited data demand. The algorithm can accurately predict the photoluminescence emission maxima of nanoplatelet dispersions using only the three precursor ratios as input parameters. This allowed us to fabricate previously unobtainable 7 and 8 monolayer-thick nanoplatelets. Moreover, the algorithm dramatically improved the homogeneity of 2-6 monolayer-thick nanoplatelet dispersions, as evidenced by narrower and more symmetric photoluminescence spectra. Decisively, only 200 total syntheses were required to achieve this vast improvement, highlighting how rapidly material properties can be optimized. The algorithm is highly versatile and can incorporate additional synthetic parameters. Accordingly, it is readily applicable to other less-explored nanocrystal syntheses and can help rapidly identify and improve exciting compositions' quality. This article is protected by copyright. All rights reserved},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Shrinking gate fluorescence correlation spectroscopy yields equilibrium constants and separates photophysics from structural dynamics},

author = {T Schr\"{o}der and J Bohlen and S E Ochmann and P Sch\"{u}ler and S Krause and D C Lamb and P Tinnefeld},

url = {https://www.pnas.org/doi/abs/10.1073/pnas.2211896120},

doi = {doi:10.1073/pnas.2211896120},

year  = {2023},

date = {2023-01-18},

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

volume = {120},

number = {4},

pages = {e2211896120},

abstract = {Fluorescence correlation spectroscopy is a versatile tool for studying fast conformational changes of biomolecules especially when combined with F\"{o}rster resonance energy transfer (FRET). Despite the many methods available for identifying structural dynamics in FRET experiments, the determination of the forward and backward transition rate constants and thereby also the equilibrium constant is difficult when two intensity levels are involved. Here, we combine intensity correlation analysis with fluorescence lifetime information by including only a subset of photons in the autocorrelation analysis based on their arrival time with respect to the excitation pulse (microtime). By fitting the correlation amplitude as a function of microtime gate, the transition rate constants from two fluorescence-intensity level systems and the corresponding equilibrium constants are obtained. This shrinking-gate fluorescence correlation spectroscopy (sg-FCS) approach is demonstrated using simulations and with a DNA origami-based model system in experiments on immobilized and freely diffusing molecules. We further show that sg-FCS can distinguish photophysics from dynamic intensity changes even if a dark quencher, in this case graphene, is involved. Finally, we unravel the mechanism of a FRET-based membrane charge sensor indicating the broad potential of the method. With sg-FCS, we present an algorithm that does not require prior knowledge and is therefore easily implemented when an autocorrelation analysis is carried out on time-correlated single-photon data.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {All-optical controlled-NOT logic gate achieving directional asymmetric transmission based on metasurface doublet},

author = {Y Huang and T Xiao and S Chen and Z Xie and J Zheng and J Zhu and Y Su and W Chen and K Liu and M Tang and P M\"{u}ller-Buschbaum and L Li},

url = {http://www.oejournal.org//article/doi/10.29026/oea.2023.220073},

doi = {10.29026/oea.2023.220073},

issn = {2096-4579},

year  = {2023},

date = {2023-01-18},

journal = {Opto-Electronic Advances},

pages = {220073-1-220073-9},

abstract = {Optical logic gates play important roles in all-optical logic circuits, which lie at the heart of the next-generation optical computing technology. However, the intrinsic contradiction between compactness and robustness hinders the development in this field. Here, we propose a simple design principle that can possess multiple-input-output states according to the incident circular polarization and direction based on the metasurface doublet, which enables controlled-NOT logic gates in infrared region. Therefore, the directional asymmetric electromagnetic transmission can be achieved. As a proof of concept, a spin-dependent Janus metasurface is designed and experimentally verified that four distinct images corresponding to four input states can be captured in the far-field. In addition, since the design method is derived from geometric optics, it can be easily applied to other spectra. We believe that the proposed metasurface doublet may empower many potential applications in chiral imaging, chiroptical spectroscopy and optical computing.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Sensing Diamagnetic Electrolytes with Spin Defects in Diamond},

author = {F A Freire-Moschovitis and R Rizzato and A Pershin and M R Schepp and R D Allert and L M Todenhagen and M S Brandt and \'{A} Gali and D B Bucher},

url = {https://arxiv.org/abs/2301.04952v1},

doi = {https://doi.org/10.48550/arXiv.2301.04952},

year  = {2023},

date = {2023-01-12},

journal = {arXiv preprint arXiv:2301.04952},

abstract = {Quantum sensing with spin defects in diamond, such as the nitrogen vacancy (NV) center, enables the detection of various chemical species on the nanoscale. Molecules or ions with unpaired electronic spins are typically probed by their influence on the NV-center's spin relaxation. Whereas it is well-known that paramagnetic ions reduce the NV-center's relaxation time T1, here we report on the opposite effect for diamagnetic ions. We demonstrate that millimolar concentrations of aqueous diamagnetic electrolyte solutions increase the T1 time of near-surface NV-center ensembles compared to pure water. To elucidate the underlying mechanism of this surprising effect, single and double quantum NV experiments are performed, which indicate a reduction of magnetic and electric noise in the presence of diamagnetic electrolytes. In combination with ab initio simulations, we propose that a change in the interfacial band bending due to the formation of an electric double layer leads to a stabilization of fluctuating charges at the interface of an oxygen-terminated diamond. This work not only helps to understand noise sources in quantum systems but also broadens the application space of quantum sensors towards electrolyte sensing in cell biology, neuroscience and electrochemistry.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Highly selective monomethylation of amines with CO2/H2 via Ag/Al2O3 as catalyst},

author = {Y Long and J He and H Zhang and Y Chen and K Liu and J Fu and H Li and L Zhu and Z Lin and A Stefancu and E Cortes and M Zhu and M Liu},

url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202203152},

doi = {https://doi.org/10.1002/chem.202203152},

issn = {0947-6539},

year  = {2023},

date = {2023-01-10},

journal = {Chemistry \textendash A European Journal},

volume = {n/a},

number = {n/a},

abstract = {The selective synthesis of monomethylated amines with CO2 is particularly challenging because the formation of tertiary amines is thermodynamically more favorable. Here we explore a new strategy for the controllable synthesis of N-monomethylated amines from primary amines and CO2/H2. Our first-principle calculations reveal that the dissociation of H2 via an heterolytic route reduces the reactivity of methylated amines and thus inhibit successive methylation. In-situ DRIFTS prove the process of formation and decomposition of ammonium salt by secondary amine reversible binding with H+ on the Ag/Al2O3 catalyst, thereby reducing its reactivity. Meanwhile, the energy barrier for rate-determining step of monomehylation was much lower than that of over methylation (0.34 eV vs 0.58 eV) means amines monomethylation in preference to successive methylation. Under optimal reaction conditions, a variety of amines conversion to corresponding monomethylated amines in good to excellent yields, and more than 90% yield of product obtained.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Surface Oxygen Depletion of Layered Transition Metal Oxides in Li-Ion Batteries Studied by Operando Ambient Pressure X-ray Photoelectron Spectroscopy},

author = {A T S Freiberg and S Qian and J Wandt and H A Gasteiger and E J Crumlin},

url = {https://doi.org/10.1021/acsami.2c19008},

doi = {10.1021/acsami.2c19008},

issn = {1944-8244},

year  = {2023},

date = {2023-01-09},

journal = {ACS Applied Materials \& Interfaces},

volume = {15},

number = {3},

pages = {4743-4754},

abstract = {A new operando spectro-electrochemical setup was developed to study oxygen depletion from the surface of layered transition metal oxide particles at high degrees of delithiation. An NCM111 working electrode was paired with a chemically delithiated LiFePO4 counter electrode in a fuel cell-inspired membrane electrode assembly (MEA). A propylene carbonate-soaked Li-ion conducting ionomer served as an electrolyte, providing both good electrochemical performance and direct probing of the NCM111 particles during cycling by ambient pressure X-ray photoelectron spectroscopy. The irreversible emergence of an oxygen-depleted phase in the O 1s spectra of the layered oxide particles was observed upon the first delithiation to high state-of-charge, which is in excellent agreement with oxygen release analysis via mass spectrometry analysis of such MEAs. By comparing the metal oxide-based O 1s spectral features to the Ni 2p3/2 intensity, we can calculate the transition metal-to-oxygen ratio of the metal oxide close to the particle surface, which shows good agreement with the formation of a spinel-like stoichiometry as an oxygen-depleted phase. This new setup enables a deeper understanding of interfacial changes of layered oxide-based cathode active materials for Li-ion batteries upon cycling.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

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

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

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

doi = {10.1021/jacs.2c09838},

issn = {0002-7863},

year  = {2023},

date = {2023-01-09},

journal = {Journal of the American Chemical Society},

volume = {145},

number = {3},

pages = {1649-1659},

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

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Improved in-situ characterization of electrochemical interfaces using metasurface-driven surface-enhanced infrared absorption spectroscopy},

author = {L M Berger and M Duportal and L D S Menezes and E Cortes and S A Maier and A Tittl and K Krischer},

url = {https://arxiv.org/abs/2301.01993},

doi = {arXiv:2301.01993v1},

year  = {2023},

date = {2023-01-05},

journal = {arXiv preprint arXiv:2301.01993},

abstract = {Electrocatalysis plays a crucial role in realizing the transition towards green energy, driving research directions from hydrogen generation to carbon dioxide reduction. Understanding electrochemical reactions is crucial to improve their efficiency and to bridge the gap toward a sustainable zero-carbon future. Surface-enhanced infrared absorption spectroscopy (SEIRAS) is a suitable method for investigating these processes because it can monitor with chemical specificity the mechanisms of the reactions. However, it remains difficult to detect many relevant aspects of electrochemical reactions such as short-lived intermediates. Here, we develop and experimentally realize an integrated nanophotonic-electrochemical SEIRAS platform for the in situ investigation of molecular signal traces emerging during electrochemical experiments. Specifically, we implement a platinum nano-slot metasurface featuring strongly enhanced electromagnetic near fields and spectrally target it at the weak vibrational bending mode of adsorbed CO at ~2033 cm-1. Crucially, our platinum nano-slot metasurface provides high molecular sensitivity. The resonances can be tuned over a broad range in the mid-infrared spectrum. Compared to conventional unstructured platinum layers, our nanophotonic-electrochemical platform delivers a substantial improvement of the experimentally detected characteristic absorption signals by a factor of 27, enabling the detection of new species with weak signals, fast conversions, or low surface concentrations. By providing a deeper understanding of catalytic reactions, we anticipate our nanophotonic-electrochemical platform to open exciting perspectives for electrochemical SEIRAS, surface-enhanced Raman spectroscopy, and the study of reactions in other fields of chemistry such as photoelectrocatalysis.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Gold Nanorod DNA Origami Antennas for 3 Orders of Magnitude Fluorescence Enhancement in NIR},

author = {K Trofymchuk and K Ko\l\k{a}taj and V Glembockyte and F Zhu and G P Acuna and T Liedl and P Tinnefeld},

url = {https://doi.org/10.1021/acsnano.2c09577},

doi = {10.1021/acsnano.2c09577},

issn = {1936-0851},

year  = {2023},

date = {2023-01-03},

journal = {ACS Nano},

volume = {17},

number = {2},

pages = {1327-1334},

abstract = {DNA origami has taken a leading position in organizing materials at the nanoscale for various applications such as manipulation of light by exploiting plasmonic nanoparticles. We here present the arrangement of gold nanorods in a plasmonic nanoantenna dimer enabling up to 1600-fold fluorescence enhancement of a conventional near-infrared (NIR) dye positioned at the plasmonic hotspot between the nanorods. Transmission electron microscopy, dark-field spectroscopy, and fluorescence analysis together with numerical simulations give us insights on the heterogeneity of the observed enhancement values. The size of our hotspot region is ∼12 nm, granted by using the recently introduced design of NAnoantenna with Cleared HotSpot (NACHOS), which provides enough space for placing of tailored bioassays. Additionally, the possibility to synthesize nanoantennas in solution might allow for production upscaling.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Control of the Crystallization and Phase Separation Kinetics in Sequential Blade-Coated Organic Solar Cells by Optimizing the Upper Layer Processing Solvent},

author = {Y Wang and J Xue and H Zhong and C R Everett and X Jiang and M A Reus and A Chumakov and S V Roth and M A Adedeji and N Jili and K Zhou and G Lu and Z Tang and G T Mola and P M\"{u}ller-Buschbaum and W Ma},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202203496},

doi = {https://doi.org/10.1002/aenm.202203496},

issn = {1614-6832},

year  = {2023},

date = {2023-01-01},

journal = {Advanced Energy Materials},

volume = {n/a},

number = {n/a},

pages = {2203496},

abstract = {Abstract Sequential deposition of the active layer in organic solar cells (OSCs) is favorable to circumvent the existing drawbacks associated with controlling the microstructure in bulk-heterojunction (BHJ) device fabrication. However, how the processing solvents impact on the morphology during sequential deposition processes is still poorly understood. Herein, high-efficiency OSCs are fabricated by a sequential blade coating (SBC) through optimization of the morphology evolution process induced by processing solvents. It is demonstrated that the device performance is highly dependent on the processing solvent of the upper layer. In situ morphology characterizations reveal that an obvious liquid\textendashsolid phase separation can be identified during the chlorobenzene processing of the D18 layer, corresponding to larger phase separation. During chloroform (CF) processing of the D18 layer, a proper aggregation rate of Y6 and favorable intermixing of lower and upper layers results in the enhanced crystallinity of the acceptor. This facilitates efficient exciton dissociation and charge transport with an inhibited charge recombination in the D18/CF-based devices, contributing to a superior performance of 17.23%. These results highlight the importance of the processing solvent for the upper layer in the SBC strategy and suggest the great potential of achieving optimized morphology and high-efficiency OSCs using the SBC strategy.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Subsurface Engineering Induced Fermi Level De-pinning in Metal Oxide Semiconductors for Photoelectrochemical Water Splitting},

author = {J Wang and G Ni and W Liao and K Liu and J Chen and F Liu and Z Zhang and M Jia and J Li and J Fu and E Pensa and L Jiang and Z Bian and E Cortes and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202217026},

doi = {https://doi.org/10.1002/anie.202217026},

issn = {1433-7851},

year  = {2022},

date = {2022-12-28},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

abstract = {Photoelectrochemical (PEC) water splitting is a promising approach for renewable solar light conversion. However, surface Fermi level pinning (FLP), caused by surface trap states, severely restricts the PEC activities. Theoretical calculations indicate subsurface oxygen vacancy (sub-Ov) could release the FLP and retain the active structure. A series of metal oxide semiconductors with sub-Ov were prepared through precisely regulated spin-coating and calcination. Etching X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and electron energy loss spectra (EELS) demonstrated Ov located at sub ~2-5 nm region. Mott-Schottky and open circuit photovoltage results confirmed the surface trap states elimination and Fermi level de-pinning. Thus, superior PEC performances of 5.1, 3.4, and 2.1 mA cm-2 at 1.23 V vs. RHE were achieved on BiVO4, Bi2O3, TiO2 with outstanding stability for 72 h, outperforming most reported works under the identical conditions.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Morphology Matters: 0D/2D WO3 Nanoparticle-Ruthenium Oxide Nanosheet Composites for Enhanced Photocatalytic Oxygen Evolution Reaction Rates},

author = {H A Vignolo-Gonz\'{a}lez and A Gouder and S Laha and V Duppel and S Carretero-Palacios and A Jim\'{e}nez-Solano and T Oshima and P Sch\"{u}tzend\"{u}be and B V Lotsch},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202203315},

doi = {https://doi.org/10.1002/aenm.202203315},

issn = {1614-6832},

year  = {2022},

date = {2022-12-22},

journal = {Advanced Energy Materials},

volume = {n/a},

number = {n/a},

pages = {2203315},

abstract = {Abstract In the field of artificial photosynthesis with semiconductor light harvesters, the default cocatalyst morphologies are isotropic, 0D nanoparticles. Herein, the use of highly anisotropic 2D ruthenium oxide nanosheet (RONS) cocatalysts as an approach to enhance photocatalytic oxygen evolution (OER) rates on commercial WO3 nanoparticles (0D light harvester) is presented. At optimal cocatalyst loadings and identical photocatalysis conditions, WO3 impregnated with RONS (RONS/WO3) shows a fivefold increase in normalized photonic efficiency compared to when it is impregnated with conventional ruthenium oxide (rutile) nanoparticles (RONP/WO3). The superior RONS/WO3 performance is attributed to two special properties of the RONS: i) lower electrochemical water oxidation overpotential for RONS featuring highly active edge sites, and ii) decreased parasitic light absorption on RONS. Evidence is presented that OER photocatalytic performance can be doubled with control of RONS edges and it is shown that compared to WO3 impregnated with RONP, the advantageous optical properties and geometry of RONS decrease the fraction of light absorbed by the cocatalyst, thus reducing the parasitic light absorption on the RONS/WO3 composite. Therefore, the results presented in the current study are expected to promote engineering of cocatalyst morphology as a complementary concept to optimize light harvester-cocatalyst composites for enhanced photocatalytic efficiency.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Waterborne conductive carbon paste with an eco-friendly binder},

author = {M Shadabfar and M Ehsani and H A Khonakdar and M Abdouss and T Ameri},

url = {https://doi.org/10.1007/s10570-022-04998-5},

doi = {10.1007/s10570-022-04998-5},

issn = {1572-882X},

year  = {2022},

date = {2022-12-22},

journal = {Cellulose},

abstract = {Conductive carbon pastes are widely used in flexible and printed electronic devices such as wearable electronics and optoelectronics. The use of conductive pastes comes with some challenges, such as replacing toxic synthetic materials with environmentally-friendly and sustainable ones, achieving an appropriate level of electrical conductivity, and controlling the thickness of the coated film. Waterborne conductive carbon pastes have been used to tackle the mentioned problems. In this study, carboxymethyl cellulose (CMC) was introduced as an eco-friendly binder combined with Graphene Nanoplatelets (GNPs) and Carbon Nanotubes (CNTs) to synthesize a conductive carbon paste without any metallic elements. The double-coated GNP/CNT/CMC paste films were coated on a paper surface using the doctor blade method. Morphological and thermal characteristics, sheet resistance, and optoelectrical properties of the paste films were comprehensively investigated. It was found that the conductive carbon paste containing 35 wt% CNTs exhibits higher conductivity (80.4 S/m) than the other combinations. Moreover, Field Emission Scanning Electron Microscopy (FE-SEM) showed that GNPs and CNTs are distributed within cellulosic matrix very homogeneously. Great flexibility and high electrical conductivity are achieved in the paste film. EIS results implied that the double-coated paste could act as a highly conductive surface in fabricating electrochemical sensors with high performance. In conclusion, this study represents a novel and environmentally-friendly method to produce low-cost, highly-efficient, and large-scale conductive carbon paste.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Boosting Nitrogen Activation via Ag Nanoneedle Arrays for Efficient Ammonia Synthesis},

author = {W Liao and K Liu and J Wang and A Stefancu and Q Chen and K Wu and Y Zhou and H Li and L Mei and M Li and J Fu and M Miyauchi and E Cort\'{e}s and M Liu},

url = {https://doi.org/10.1021/acsnano.2c08853},

doi = {10.1021/acsnano.2c08853},

issn = {1936-0851},

year  = {2022},

date = {2022-12-16},

journal = {ACS Nano},

abstract = {Electrocatalytic N2 reduction reaction (eNRR) provides a promising carbon-neutral and sustainable ammonia-synthesizing alternative to the Haber-Bosch process. However, the nonpolar N2 has significant thermodynamic stability and requires ultrahigh energy to break down the N≡N bond. Here, we report the construction of local enhanced electric fields (LEEFs) by Ag nanoneedle arrays to promote N≡N fracture thus assisting the eNRR. The LEEFs could induce charge polarization on nitrogen atoms and reduce the energy barrier in the N2 first-protonation step. The detected N─N and N─H intermediates prove the cleavage of the N≡N bond and the hydrogenation of N2 by LEEFs. The increased LEEFs lead to logarithmic growth rates for the targeted eNRR and exponential growth rates for the unavoidable competitive hydrogen evolution reaction. Thus, regulation and tuning of LEEFs to ∼4 × 104 kV m\textendash1 endows the raise of eNRR to the summit, achieving high ammonia selectivity with a Faradaic efficiency of 72.3 ± 4.0%.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Spatially-Modulated Silicon Interface Energetics Via Hydrogen Plasma-Assisted Atomic Layer Deposition of Ultrathin Alumina},

author = {A Henning and J D Bartl and L Wolz and M Christis and F Rauh and M Bissolo and T Gr\"{u}nleitner and J Eichhorn and P Zeller and M Amati and L Gregoratti and J J Finley and B Rieger and M Stutzmann and I D Sharp},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/admi.202202166},

doi = {https://doi.org/10.1002/admi.202202166},

issn = {2196-7350},

year  = {2022},

date = {2022-12-16},

journal = {Advanced Materials Interfaces},

volume = {n/a},

number = {n/a},

pages = {2202166},

abstract = {Abstract Atomic layer deposition (ALD) is a key technique for the continued scaling of semiconductor devices, which increasingly relies on scalable processes for interface manipulation of structured surfaces on the atomic level. While ALD allows the synthesis of conformal films with utmost control over the thickness, atomically-defined closed coatings and surface modifications are challenging to achieve because of 3D growth during nucleation. Here, a route is presented toward the sub-nanometer thin and continuous aluminum oxide (AlOx) coatings on silicon substrates for the spatial control of the surface charge density and interface energetics. Trimethylaluminum in combination with remote hydrogen plasma is used instead of a gas-phase oxidant for the transformation of silicon dioxide (SiO2) into alumina. Depending on the number of ALD cycles, the SiO2 can be partially or fully transformed, which is exploited to deposit ultrathin AlOx layers in selected regions defined by lithographic patterning. The resulting patterned surfaces are characterized by lateral AlOx/SiO2 interfaces possessing 0.3 nm step heights and surface potential steps exceeding 0.4 V. In addition, the introduction of fixed negative charges of 9 × 1012 cm−2 enables modulation of the surface band bending, which is relevant to the field-effect passivation of silicon and low-impedance charge transfer across contact interfaces.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Combining impedance and hydrodynamic methods in electrocatalysis. Characterization of Pt(pc), Pt5Gd, and nanostructured Pd for the hydrogen evolution reaction},

author = {K-T Song and C M Schott and P M Schneider and S A Watzele and R M Kluge and E L Gubanova and A S Bandarenka},

url = {http://iopscience.iop.org/article/10.1088/2515-7655/acabe5},

issn = {2515-7655},

year  = {2022},

date = {2022-12-15},

journal = {Journal of Physics: Energy},

abstract = {Electrochemical hydrodynamic techniques typically involve electrodes that move relative to the solution. Historically, approaches involving rotating disc electrode (RDE) configurations have become very popular, as one can easily control the electroactive species' mass transport in those cases. The combination of cyclic voltammetry and RDE is nowadays one of the standard characterization protocols in electrocatalysis. On the other hand, impedance spectroscopy is one of the most informative electrochemistry techniques, enabling the acquisition of information on the processes taking place simultaneously at the electrode/electrolyte interface. In this work, we investigated the hydrogen evolution reaction (HER) catalyzed by polycrystalline Pt (Pt(pc)) and Pt5Gd disc electrodes and characterized them using RDE and EIS techniques simultaneously. Pt5Gd shows higher HER activities than Pt in acidic and alkaline media due to strain and ligand effects. The mechanistic study of the reaction showed that the rotation rates in acidic media have no effect on the contribution of the Volmer-Heyrovsky and Volmer-Tafel pathways. However, the Volmer-Heyrovsky pathway dominates at lower rotation rates in alkaline media. Besides, the HER in acidic solutions depends more strongly on mass diffusion than in alkaline media. In addition to simple and clearly defined systems, the combined method of both techniques is applicable for systems with greater complexity, such as Pd/C nanostructured catalysts. Applying the above-presented approach, we found that the Volmer-Tafel pathway is the dominating mechanism of the HER for this catalytic system.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Gold\textendashRhodium Nanoflowers for the Plasmon-Enhanced CO2 Electroreduction Reaction upon Visible Light},

author = {M P S Rodrigues and A H B Dourado and A G Sampaio De Oliveira-Filho and A P De Lima Batista and M Feil and K Krischer and S I C\'{o}rdoba De Torresi},

url = {https://doi.org/10.1021/acscatal.2c04207},

doi = {10.1021/acscatal.2c04207},

year  = {2022},

date = {2022-12-15},

journal = {ACS Catalysis},

pages = {267-279},

abstract = {Bimetallic nanostructures combining catalytic and plasmonic properties are a class of materials that might possess improved efficiency and/or selectivity in electrocatalytic reactions. In this paper, we described the application of gold\textendashrhodium core\textendashshell nanoflowers (Au@Rh NFs) as a model system for the electrochemical CO2 reduction reaction. The nanoparticles consist of a gold nucleus surrounded by rhodium branches, combining Au localized surface plasmon resonance (LSPR) in the visible range of the spectrum and Rh catalytic properties. The influence of LSPR excitation on the catalytic properties was evaluated for different excitation wavelengths and various Au@Rh NF metallic ratios. Our catalysts showed enhanced activity upon LSPR excitation, demonstrating that LSPR excitation may lead to improved performance even with a low content of metallic NFs (2% Au + Rh in Carbon Vulcan). Electrochemical impedance spectroscopy (EIS) experiments performed under LSPR excitation suggest that the superior activity under illumination is related to lower energetic barriers that facilitate the desorption of adsorbed species compared to dark conditions.L},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Charge transport in single polymer fiber transistors in the sub 100 nm regime: temperature dependence and Coulomb blockade},

author = {J Lenz and M Statz and K Watanabe and T Taniguchi and F Ortmann and R T Weitz},

url = {https://iopscience.iop.org/article/10.1088/2515-7639/aca82f/meta},

doi = {10.1088/2515-7639/aca82f},

issn = {2515-7639},

year  = {2022},

date = {2022-12-15},

journal = {Journal of Physics: Materials},

abstract = {Even though charge transport in semiconducting polymers is of relevance for a number of potential applications in (opto-)electronic devices, the fundamental mechanism of how charges are transported through organic polymers that are typically characterized by a complex nanostructure is still open. One of the challenges which we address here, is how to gain controllable experimental access to charge transport at the sub-100 nm lengthscale. To this end charge transport in single poly(diketopyrrolopyrrole-terthiophene) fiber transistors, employing two different solid gate dielectrics, a hybrid Al2O3/self-assembled monolayer and hexagonal boron nitride, is investigated in the sub-50 nm regime using electron-beam contact patterning. The electrical characteristics exhibit near ideal behavior at room temperature which demonstrates the general feasibility of the nanoscale contacting approach, even though the channels are only a few nanometers in width. At low temperatures, we observe nonlinear behavior in the current\textendashvoltage characteristics in the form of Coulomb diamonds which can be explained by the formation of an array of multiple quantum dots at cryogenic temperatures.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Real-Time Investigation of Sulfur Vacancy Generation and Passivation in Monolayer Molybdenum Disulfide via in situ X-ray Photoelectron Spectromicroscopy},

author = {T Gr\"{u}nleitner and A Henning and M Bissolo and M Zengerle and L Gregoratti and M Amati and P Zeller and J Eichhorn and A V Stier and A W Holleitner and J J Finley and I D Sharp},

url = {https://doi.org/10.1021/acsnano.2c06317},

doi = {10.1021/acsnano.2c06317},

issn = {1936-0851},

year  = {2022},

date = {2022-12-14},

journal = {ACS Nano},

abstract = {Understanding the chemical and electronic properties of point defects in two-dimensional materials, as well as their generation and passivation, is essential for the development of functional systems, spanning from next-generation optoelectronic devices to advanced catalysis. Here, we use synchrotron-based X-ray photoelectron spectroscopy (XPS) with submicron spatial resolution to create sulfur vacancies (SVs) in monolayer MoS2 and monitor their chemical and electronic properties in situ during the defect creation process. X-ray irradiation leads to the emergence of a distinct Mo 3d spectral feature associated with undercoordinated Mo atoms. Real-time analysis of the evolution of this feature, along with the decrease of S content, reveals predominant monosulfur vacancy generation at low doses and preferential disulfur vacancy generation at high doses. Formation of these defects leads to a shift of the Fermi level toward the valence band (VB) edge, introduction of electronic states within the VB, and formation of lateral pn junctions. These findings are consistent with theoretical predictions that SVs serve as deep acceptors and are not responsible for the ubiquitous n-type conductivity of MoS2. In addition, we find that these defects are metastable upon short-term exposure to ambient air. By contrast, in situ oxygen exposure during XPS measurements enables passivation of SVs, resulting in partial elimination of undercoordinated Mo sites and reduction of SV-related states near the VB edge. Correlative Raman spectroscopy and photoluminescence measurements confirm our findings of localized SV generation and passivation, thereby demonstrating the connection between chemical, structural, and optoelectronic properties of SVs in MoS2.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Using Metal\textendashOrganic Frameworks to Confine Liquid Samples for Nanoscale NV-NMR},

author = {K S Liu and X Ma and R Rizzato and A L Semrau and A Henning and I D Sharp and R A Fischer and D B Bucher},

url = {https://doi.org/10.1021/acs.nanolett.2c03069},

doi = {10.1021/acs.nanolett.2c03069},

issn = {1530-6984},

year  = {2022},

date = {2022-12-08},

journal = {Nano Letters},

abstract = {Atomic-scale magnetic field sensors based on nitrogen vacancy (NV) defects in diamonds are an exciting platform for nanoscale nuclear magnetic resonance (NMR) spectroscopy. The detection of NMR signals from a few zeptoliters to single molecules or even single nuclear spins has been demonstrated using NV centers close to the diamond surface. However, fast molecular diffusion of sample molecules in and out of the nanoscale detection volumes impedes their detection and limits current experiments to solid-state or highly viscous samples. Here, we show that restricting diffusion by confinement enables nanoscale NMR spectroscopy of liquid samples. Our approach uses metal\textendashorganic frameworks (MOF) with angstrom-sized pores on a diamond chip to trap sample molecules near the NV centers. This enables the detection of NMR signals from a liquid sample, which would not be detectable without confinement. These results set the route for nanoscale liquid-phase NMR with high spectral resolution.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

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

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

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

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

issn = {1932-7447},

year  = {2022},

date = {2022-11-30},

journal = {The Journal of Physical Chemistry C},

volume = {126},

number = {49},

pages = {21040-21049},

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

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Antisolvent Additive Engineering for Boosting Performance and Stability of Graded Heterojunction Perovskite Solar Cells Using Amide-Functionalized Graphene Quantum Dots},

author = {E Khorshidi and B Rezaei and A Kavousighahfarokhi and J Hanisch and M A Reus and P M\"{u}ller-Buschbaum and T Ameri},

url = {https://doi.org/10.1021/acsami.2c12944},

doi = {10.1021/acsami.2c12944},

issn = {1944-8244},

year  = {2022},

date = {2022-11-29},

journal = {ACS Applied Materials \& Interfaces},

volume = {14},

number = {49},

pages = {54623-54634},

abstract = {Additive and antisolvent engineering strategies are outstandingly efficient in enhancing perovskite quality, photovoltaic performance, and stability of perovskite solar cells (PSCs). In this work, an effective approach is applied by coupling the antisolvent mixture and multi-functional additive procedures, which is recognized as antisolvent additive engineering (AAE). The graphene quantum dots functionalized with amide (AGQDs), which consists of carbonyl, amine, and long hydrophobic alkyl chain functional groups, are added to the antisolvent mixture of toluene (T) and hexane (H) as an efficient additive to form the CH3NH3PbI3 (MAPI):AGQDs graded heterojunction structure. A broad range of analytical techniques, including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, space charge limited current, UV\textendashvisible spectroscopy, external quantum efficiency, and time-of-flight secondary ion mass spectrometry, are used to investigate the effect of AAE treatment with AGQDs on the quality of perovskite film and performance of the PSCs. Importantly, not only a uniform and dense perovskite film with hydrophobic property is obtained but also defects on the perovskite surface are significantly passivated by the interaction between AGQDs and uncoordinated Pb2+. As a result, an enhanced power conversion efficiency (PCE) of 19.10% is achieved for the champion PSCs treated with AGQD additive, compared to the PCE of 16.00% for untreated reference PSCs. In addition, the high-efficiency PSCs based on AGQDs show high stability and maintain 89% of their initial PCE after 960 h in ambient conditions.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tailored fabrication of quasi-isoporous and double layered α-Fe2O3 thin films and their application in photovoltaic devices},

author = {S Yin and Y Zou and M A Reus and X Jiang and S Tu and T Tian and R Qi and Z Xu and S Liang and Y Cheng and J E Heger and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://www.sciencedirect.com/science/article/pii/S1385894722056157},

doi = {https://doi.org/10.1016/j.cej.2022.140135},

issn = {1385-8947},

year  = {2022},

date = {2022-11-21},

journal = {Chemical Engineering Journal},

pages = {140135},

abstract = {A series of α-Fe2O3 thin films with distinct morphologies are prepared via a facile polystyrene-block-polyethylene oxide templated sol\textendashgel method. By tailoring the poor solvent contents and FeCl3-to-polymer weight ratio in the sol\textendashgel solutions, quasi-isoporous α-Fe2O3 thin films with different substructures and thicknesses are obtained. Via a thermal annealing post-treatment, double layered structures are induced by a synergistic dewetting and Oswald ripening effect. Special focus is set on the α-Fe2O3 thin films prepared with no annealing/annealing-medium FeCl3 concentration, as they possess uniform periodic structures, which is suitable to be used as hole blocking modification layer of perovskite solar cells (PSCs). An improved power conversion efficiency (PCE) is obtained when the double layered α-Fe2O3 thin film is applied as the hole blocking modification layer for PSCs. The improved PCE primarily originates from the increased VOC, which probably benefits from the synergistic effect of the suppressed charge carrier recombination at the interfaces, the enhanced light transmittance as well as the superior electron extraction capacity.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Direct Coupling of Methane and Carbon Dioxide on Tantalum Cluster Cations},

author = {J Lengyel and N Levin and M On\v{c}\'{a}k and K Jakob and M Tschurl and U Heiz},

url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202203259},

doi = {https://doi.org/10.1002/chem.202203259},

issn = {0947-6539},

year  = {2022},

date = {2022-11-20},

journal = {Chemistry \textendash A European Journal},

volume = {n/a},

number = {n/a},

abstract = {Understanding molecular-scale reaction mechanisms is crucial for the design of modern catalysts with industrial prospect. Through joint experimental and computational studies, we investigate the direct coupling reaction of CH4 and CO2, two abundant greenhouse gases, mediated by Ta1,4+ ions to form larger oxygenated hydrocarbons. Coherent with proposed elementary steps, we expose products of CH4 dehydrogenation [Ta1,4CH2]+ to CO2 in a ring electrode ion trap. Product analysis and reaction kinetics indicate a predisposition of the tetramers for C\textendashO coupling with a conversion to products of CH2O, whereas atomic cations enable C\textendashC coupling yielding CH2CO. Many of the experimental findings are supported by thermodynamic computations, connecting structure, electronic properties, and catalyst function. Moreover, the study of bare Ta1,4+ compounds indicates that methane dehydrogenation is a significant initial step in the direct coupling reaction, enabling new, yet unknown reaction pathways.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {High-Performance Monolayer MoS2 Field-Effect Transistors on Cyclic Olefin Copolymer-Passivated SiO2 Gate Dielectric},

author = {S B Kalkan and E Najafidehaghani and Z Gan and J Drewniok and M F Lichtenegger and U H\"{u}bner and A S Urban and A George and A Turchanin and B Nickel},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202201653},

doi = {https://doi.org/10.1002/adom.202201653},

issn = {2195-1071},

year  = {2022},

date = {2022-11-18},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2201653},

abstract = {Abstract Trap states of the semiconductor/gate dielectric interface give rise to a pronounced subthreshold behavior in field-effect transistors (FETs) diminishing and masking intrinsic properties of 2D materials. To reduce the well-known detrimental effect of SiO2 surface traps, this work spin-coated an ultrathin (≈5 nm) cyclic olefin copolymer (COC) layer onto the oxide and this hydrophobic layer acts as a surface passivator. The chemical resistance of COC allows to fabricate monolayer MoS2 FETs on SiO2 by standard cleanroom processes. This way, the interface trap density is lowered and stabilized almost fivefold, to around 5 × 1011 cm−2 eV−1, which enables low-voltage FETs even on 300 nm thick SiO2. In addition to this superior electrical performance, the photoresponsivity of the MoS2 devices on passivated oxide is also enhanced by four orders of magnitude compared to nonpassivated MoS2 FETs. Under these conditions, negative photoconductivity and a photoresponsivity of 3 × 107 A W−1 is observed which is a new highest value for MoS2. These findings indicate that the ultrathin COC passivation of the gate dielectric enables to probe exciting properties of the atomically thin 2D semiconductor, rather than interface trap dominated effects.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Structure Determination of the Crystalline LiPON Model Structure Li5+ x P2O6− x N1+ x with x ≈ 0.9},

author = {S Schneider and L G Balzat and B V Lotsch and W Schnick},

url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202202984},

doi = {https://doi.org/10.1002/chem.202202984},

issn = {0947-6539},

year  = {2022},

date = {2022-11-16},

journal = {Chemistry \textendash A European Journal},

volume = {n/a},

number = {n/a},

abstract = {Non-crystalline lithium oxonitridophosphate (LiPON) is used as solid electrolyte in all-solid-state batteries. Crystalline lithium oxonitridophosphates are important model structures to retrieve analytical information that can be used to understand amorphous phases better. The new crystalline lithium oxonitridophosphate Li 5+ x P 2 O 6− x N 1+ x was synthesized as off-white powder by ampoule synthesis at 750\textendash800 °C under Ar atmosphere. It crystallizes in the monoclinic space group P 2 1 / c with a = 15.13087(11) r{A}},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Advances in ultrafast plasmonics},

author = {A N Koya and M Romanelli and J Kuttruff and N Henriksson and A Stefancu and G Grinblat and A De Andres and F Schnur and M Vanzan and M Marsili},

url = {https://arxiv.org/abs/2211.08241},

doi = {https://doi.org/10.48550/arXiv.2211.08241},

year  = {2022},

date = {2022-11-15},

journal = {arXiv preprint arXiv:2211.08241},

abstract = {In the past twenty years, we have reached a broad understanding of many light-driven phenomena in nanoscale systems. The temporal dynamics of the excited states are instead quite challenging to explore, and, at the same time, crucial to study for understanding the origin of fundamental physical and chemical processes. In this review we examine the current state and prospects of ultrafast phenomena driven by plasmons both from a fundamental and applied point of view. This research area is referred to as ultrafast plasmonics and represents an outstanding playground to tailor and control fast optical and electronic processes at the nanoscale, such as ultrafast optical switching, single photon emission and strong coupling interactions to tailor photochemical reactions. Here, we provide an overview of the field, and describe the methodologies to monitor and control nanoscale phenomena with plasmons at ultrafast timescales in terms of both modeling and experimental characterization. Various directions are showcased, among others recent advances in ultrafast plasmon-driven chemistry and multi-functional plasmonics, in which charge, spin, and lattice degrees of freedom are exploited to provide active control of the optical and electronic properties of nanoscale materials. As the focus shifts to the development of practical devices, such as all-optical transistors, we also emphasize new materials and applications in ultrafast plasmonics and highlight recent development in the relativistic realm. The latter is a promising research field with potential applications in fusion research or particle and light sources providing properties such as attosecond duration.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Static and Dynamic Disorder in Formamidinium Lead Bromide Single Crystals},

author = {G Reuveni and Y Diskin-Posner and C Gehrmann and S Godse and G G Gkikas and I Buchine and S Aharon and R Korobko and C C Stoumpos and D A Egger},

url = {https://arxiv.org/abs/2211.06904},

doi = {https://doi.org/10.48550/arXiv.2211.06904},

year  = {2022},

date = {2022-11-13},

journal = {arXiv preprint arXiv:2211.06904},

abstract = {We show that formamidinium lead bromide is unique among the halide perovskite crystals because its inorganic sub-lattice exhibits intrinsic local static disorder that co-exists with a well-defined average crystal structure. Our study combines THz-range Raman-scattering with single-crystal X-ray diffraction and first-principles calculations to probe the inorganic sub-lattice dynamics evolution with temperature in the range of 10-300 K. The temperature evolution of the Raman spectra shows that low-temperature, local static disorder strongly affects the crystal's structural dynamics and phase transitions at higher temperatures.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Microfluidic quantum sensing platform for lab-on-a-chip applications},

author = {R D Allert and F Bruckmaier and N R Neuling and F A Freire-Moschovitis and K S Liu and C Schrepel and P Sch\"{a}tzle and P Knittel and M Hermans and D B Bucher},

url = {http://dx.doi.org/10.1039/D2LC00874B},

doi = {10.1039/D2LC00874B},

issn = {1473-0197},

year  = {2022},

date = {2022-11-10},

journal = {Lab on a Chip},

volume = {22},

number = {24},

pages = {4831-4840},

abstract = {Lab-on-a-chip (LOC) applications have emerged as invaluable physical and life sciences tools. The advantages stem from advanced system miniaturization, thus, requiring far less sample volume while allowing for complex functionality, increased reproducibility, and high throughput. However, LOC applications necessitate extensive sensor miniaturization to leverage these inherent advantages fully. Atom-sized quantum sensors are highly promising to bridge this gap and have enabled measurements of temperature, electric and magnetic fields on the nano- to microscale. Nevertheless, the technical complexity of both disciplines has so far impeded an uncompromising combination of LOC systems and quantum sensors. Here, we present a fully integrated microfluidic platform for solid-state spin quantum sensors, like the nitrogen-vacancy (NV) center in diamond. Our platform fulfills all technical requirements, such as fast spin manipulation, enabling full quantum sensing capabilities, biocompatibility, and easy adaptability to arbitrary channel and chip geometries. To illustrate the vast potential of quantum sensors in LOC systems, we demonstrate various NV center-based sensing modalities for chemical analysis in our microfluidic platform, ranging from paramagnetic ion detection to high-resolution microscale NV-NMR. Consequently, our work opens the door for novel chemical analysis capabilities within LOC devices with applications in electrochemistry, high-throughput reaction screening, bioanalytics, organ-on-a-chip, or single-cell studies.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Mirror-coupled plasmonic bound states in the continuum for tunable perfect absorption},

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

url = {https://arxiv.org/abs/2211.03673},

doi = {https://doi.org/10.48550/arXiv.2211.03673},

year  = {2022},

date = {2022-11-07},

journal = {arXiv preprint arXiv:2211.03673},

abstract = {Tailoring critical light-matter coupling is a fundamental challenge of nanophotonics, impacting diverse fields from higher harmonic generation and energy conversion to surface-enhanced spectroscopy. Plasmonic perfect absorbers (PAs), where resonant antennas couple to their mirror images in adjacent metal films, have been instrumental for obtaining different coupling regimes by tuning the antenna-film distance. However, for on-chip uses, the ideal PA gap size can only match one wavelength, and wide range multispectral approaches remain challenging. Here, we introduce a new paradigm for plasmonic PAs by combining mirror-coupled resonances with the unique loss engineering capabilities of plasmonic bound states in the continuum (BICs). Our BIC-driven PA platform leverages the asymmetry of the constituent meta-atoms as an additional degree of freedom for reaching the critical coupling (CC) condition, delivering resonances with unity absorbance and high quality factors approaching 100 in the mid-infrared. Such a platform holds flexible tuning knobs including asymmetry parameter, dielectric gap, and geometrical scaling factor to precisely control the coupling condition, resonance frequency, and selective enhancement of magnetic and electric fields while maintaining CC. We demonstrate a pixelated PA metasurface with optimal absorption over a broad range of mid-infrared frequencies (950 ~ 2000 1/cm) using only a single spacer layer thickness and apply it for multispectral surface-enhanced molecular spectroscopy in tailored coupling regimes. Our concept greatly expands the capabilities and flexibility of traditional gap-tuned PAs, opening new perspectives for miniaturized sensing platforms towards on-chip and in-situ detection.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

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

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

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

doi = {10.1103/PhysRevMaterials.6.114601},

year  = {2022},

date = {2022-11-07},

journal = {Physical Review Materials},

volume = {6},

number = {11},

pages = {114601},

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

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Mapping structure heterogeneities and visualizing moisture degradation of perovskite films with nano-focus WAXS},

author = {N Li and S Pratap and V K\"{o}rstgens and S Vema and L Song and S Liang and A Davydok and C Krywka and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1038/s41467-022-34426-y},

doi = {10.1038/s41467-022-34426-y},

issn = {2041-1723},

year  = {2022},

date = {2022-11-05},

journal = {Nature Communications},

volume = {13},

number = {1},

pages = {6701},

abstract = {Extensive attention has focused on the structure optimization of perovskites, whereas rare research has mapped the structure heterogeneity within mixed hybrid perovskite films. Overlooked aspects include material and structure variations as a function of depth. These depth-dependent local structure heterogeneities dictate their long-term stabilities and efficiencies. Here, we use a nano-focused wide-angle X-ray scattering method for the mapping of film heterogeneities over several micrometers across lateral and vertical directions. The relative variations of characteristic perovskite peak positions show that the top film region bears the tensile strain. Through a texture orientation map of the perovskite (100) peak, we find that the perovskite grains deposited by sequential spray-coating grow along the vertical direction. Moreover, we investigate the moisture-induced degradation products in the perovskite film, and the underlying mechanism for its structure-dependent degradation. The moisture degradation along the lateral direction primarily initiates at the perovskite-air interface and grain boundaries. The tensile strain on the top surface has a profound influence on the moisture degradation.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Picosecond Charge-Transfer-State Dynamics in Wide Band Gap Polymer\textendashNon-Fullerene Small-Molecule Blend Films Investigated via Transient Infrared Spectroscopy},

author = {M Nuber and L V Spanier and S Roth and G N Vayssilov and R Kienberger and P M\"{u}ller-Buschbaum and H Iglev},

url = {https://doi.org/10.1021/acs.jpclett.2c02864},

doi = {10.1021/acs.jpclett.2c02864},

year  = {2022},

date = {2022-11-03},

journal = {The Journal of Physical Chemistry Letters},

pages = {10418-10423},

abstract = {Organic solar cells based on wide band gap polymers and nonfullerene small-molecule acceptors have demonstrated remarkably good device performances. Nevertheless, a thorough understanding of the charge-transfer process in these materials has not been achieved yet. In this study, we use Fano resonance signals caused by the interaction of broad electronic charge carrier absorption and the molecular vibrations of the electron acceptor molecule to monitor the charge-transfer state dynamics. In our time-resolved infrared spectroscopy experiments, we find that in the small-molecule acceptor, they have additional dynamics on the order of a few picoseconds. A change in the solvent used in thin film deposition, leading to different morphologies, influences this time further. We interpret our findings as the dynamics of the charge-transfer state at the interface of the electron donor and the electron- acceptor. The additional mid-infrared transient signal is generated in this state, as both electron and hole polarons can interact with small-molecule acceptor vibrational modes.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Permittivity-asymmetric quasi-bound states in the continuum},

author = {R Bert\'{e} and T Weber and L D S Menezes and L K\"{u}hner and A Aigner and M Barkey and F J Wendisch and Y S Kivshar and A Tittl and S A Maier},

url = {https://arxiv.org/abs/2211.01176},

doi = {https://doi.org/10.48550/arXiv.2211.01176},

year  = {2022},

date = {2022-11-02},

journal = {arXiv preprint arXiv:2211.01176},

abstract = {Broken symmetries lie at the heart of nontrivial physical phenomena. Breaking the in-plane geometrical symmetry of optical systems allows to access a set of electromagnetic states termed symmetry-protected quasi-bound states in the continuum (qBICs). Here we demonstrate, theoretically, numerically and experimentally, that such optical states can also be accessed in metasurfaces by breaking the in-plane symmetry in the permittivity of the comprising materials, showing a remarkable equivalence to their geometrically-asymmetric counterparts. However, while the physical size of atoms imposes a limit on the lowest achievable geometrical asymmetry, weak permittivity modulations due to carrier doping and electro-optical Pockels and Kerr effects, usually considered insignificant, open up the possibility of infinitesimal permittivity asymmetries for on-demand, and dynamically tuneable optical resonances of extremely high quality factors. We probe the excitation of permittivity-asymmetric qBICs (ε-qBICs) using a prototype Si/TiO2 metasurface, in which the asymmetry in the unit cell is provided by the refractive index contrast of the dissimilar materials, surpassing any unwanted asymmetries from nanofabrication defects or angular deviations of light from normal incidence. ε-qBICs can also be excited in 1D gratings, where quality-factor enhancement and tailored interference phenomena via the interplay of geometrical and permittivity asymmetries are numerically demonstrated. The emergence of ε-qBICs in systems with broken symmetries in their permittivity may enable to test time-energy uncertainties in quantum mechanics, and lead to a whole new class of low-footprint optical and optoelectronic devices, from arbitrarily narrow filters and topological sources, biosensing and ultrastrong light-matter interaction platforms, to tuneable optical switches.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Alkali metal cations change the hydrogen evolution reaction mechanisms at Pt electrodes in alkaline media},

author = {Y Taji and A Zagalskaya and I Evazzade and S Watzele and K-T Song and S Xue and C Schott and B Garlyyev and V Alexandrov and E Gubanova and A S Bandarenka},

url = {https://www.sciencedirect.com/science/article/pii/S2589965122000514},

doi = {https://doi.org/10.1016/j.nanoms.2022.09.003},

issn = {2589-9651},

year  = {2022},

date = {2022-10-29},

journal = {Nano Materials Science},

abstract = {The effects of seemingly inert alkali metal (AM) cations on the electrocatalytic activity of electrode materials towards reactions essential for energy provision have become the emphasis of substantial research efforts in recent years. The hydrogen and oxygen evolution reactions during alkaline water electrolysis and the oxygen electro-reduction taking place in fuel cells are of particular importance. There is no universal theory explaining all the details of the AM cation effect in electrocatalysis. For example, it remains unclear how “spectator” AM-cations can change the kinetics of electrocatalytic reactions often more significantly than the modifications of the electrode structure and composition. This situation originates partly from a lack of systematic experimental and theoretical studies of this phenomenon. The present work exploits impedance spectroscopy to investigate the influence of the AM cations on the mechanism of the hydrogen evolution reaction at Pt microelectrodes. The activity follows the trend: Li+≥Na+>K+>Cs+, where the highest activity corresponds to 0.1 ​M LiOH electrolytes at low overpotentials. We demonstrate that the nature of the AM cations also changes the relative contribution of the Volmer\textendashHeyrovsky and Volmer\textendashTafel mechanisms to the overall reaction, with the former being more important for LiOH electrolytes. Our density functional theory-based thermodynamics and molecular dynamics calculations support these findings.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ultra-Sensitive Extinction Measurements of Optically Active Defects in Monolayer MoS2},

author = {F Sigger and I Amersdorffer and A H\"{o}tger and M Nutz and J Kiemle and T Taniguchi and K Watanabe and M F\"{o}rg and J Noe and J J Finley and A H\"{o}gele and A W Holleitner and T H\"{u}mmer and D Hunger and C Kastl},

url = {https://doi.org/10.1021/acs.jpclett.2c02386},

doi = {10.1021/acs.jpclett.2c02386},

year  = {2022},

date = {2022-10-28},

journal = {The Journal of Physical Chemistry Letters},

pages = {10291-10296},

abstract = {We utilize cavity-enhanced extinction spectroscopy to directly quantify the optical absorption of defects in MoS2 generated by helium ion bombardment. We achieve hyperspectral imaging of specific defect patterns with a detection limit below 0.01% extinction, corresponding to a detectable defect density below 1 × 1011 cm\textendash2. The corresponding spectra reveal a broad subgap absorption, being consistent with theoretical predictions related to sulfur vacancy-bound excitons in MoS2. Our results highlight cavity-enhanced extinction spectroscopy as efficient means for the detection of optical transitions in nanoscale thin films with weak absorption, applicable to a broad range of materials.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Q-Band relaxation in chlorophyll: new insights from multireference quantum dynamics},

author = {S Reiter and L B\"{a}uml and J Hauer and R De Vivie-Riedle},

url = {http://dx.doi.org/10.1039/D2CP02914F},

doi = {10.1039/D2CP02914F},

issn = {1463-9076},

year  = {2022},

date = {2022-10-27},

journal = {Physical Chemistry Chemical Physics},

abstract = {The ultrafast relaxation within the Q-bands of chlorophyll plays a crucial role in photosynthetic light-harvesting. Yet, despite being the focus of many experimental and theoretical studies, it is still not fully understood. In this paper we look at the relaxation process from the perspective of non-adiabatic wave packet dynamics. For this purpose, we identify vibrational degrees of freedom which contribute most to the non-adiabatic coupling. Using a selection of normal modes, we construct four reduced-dimensional coordinate spaces and investigate the wave packet dynamics on XMS-CASPT2 potential energy surfaces. In this context, we discuss the associated computational challenges, as many quantum chemical methods overestimate the Qx\textendashQy energy gap. Our results show that the Qx and Qy potential energy surfaces do not cross in an energetically accessible region of the vibrational space. Instead, non-adiabatic coupling facilitates ultrafast population transfer across the potential energy surface. Moreover, we can identify the excited vibrational eigenstates that take part in the relaxation process. We conclude that the Q-band system of chlorophyll a should be viewed as a strongly coupled system, where population is easily transferred between the x and y-polarized electronic states. This suggests that both orientations may contribute to the electron transfer in the reaction center of photosynthetic light-harvesting systems.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Hot Carrier Dynamics in InAs-AlAsSb Core-Shell Nanowires},

author = {D Sandner and H Esmaielpour and F Del Giudice and M Nuber and R Kienberger and G Koblm\"{u}ller and H Iglev},

url = {https://arxiv.org/abs/2210.11886},

doi = {https://doi.org/10.48550/arXiv.2210.11886},

year  = {2022},

date = {2022-10-25},

journal = {arXiv preprint arXiv:2210.11886},

abstract = {Semiconductor nanowires (NWs) have shown evidence of robust hot carrier effects due to their small dimensions. The relaxation dynamics of hot carriers in these nanostructures, generated by photo-absorption, are of great importance in optoelectronic devices and high efficiency solar cells, such as hot carrier solar cells. Among various III-V semiconductors, indium arsenide (InAs) NWs are promising candidates for their applications in advanced light harvesting devices due to their high photo-absorptivity and high mobility. Here, we investigate the hot carrier dynamics in InAs-AlAsSb core-shell NWs, as well as bare-core InAs NWs, using ultrafast pump-probe spectroscopy with widely tuned pump and probe energies. We have found a lifetime of 2.3 ps for longitudinal optical (LO) phonons and hot electron lifetimes of about 3 ps and 30 ps for carrier-carrier interactions and electron-phonon interactions, respectively. In addition, we have investigated the electronic states in the AlAsSb-shell and found that, despite the large band offset of the core-shell design in the conduction band, excited carriers remain in the shell longer than 100 ps. Our results indicate evidence of plasmon-tailored core-shell NWs for efficient light harvesting devices, which could open potential avenues for improving the efficiency of photovoltaic solar cells.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Switchable One-Compound Diode},

author = {A Vogel and A Rabenbauer and P Deng and R Steib and T B\"{o}ger and W G Zeier and R Siegel and J Senker and D Daisenberger and K Nisi and A W Holleitner and J Venturini and T Nilges},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202208698},

doi = {https://doi.org/10.1002/adma.202208698},

issn = {0935-9648},

year  = {2022},

date = {2022-10-25},

journal = {Advanced Materials},

volume = {n/a},

number = {n/a},

pages = {2208698},

abstract = {Abstract A diode or transistor requires the combination of p- and n-type semiconductors or at least the defined formation of such areas within a given compound. This is a prerequisite for any IT application, energy conversion technology, and electronic semiconductor devices. Since 2009, when the first pnp-switchable compound Ag10Te4Br3 was described, it is in principle possible to fabricate a diode from a single material without adjusting the semiconduction type by a defined doping level. After this discovery, a handful of other materials that are capable of reversibly switching between these two semiconducting stages was reported. In all cases, a structural phase transition accompanied by a dynamic change of charge carriers or a charge density wave (CDW) within certain substructures are responsible for this effect. Unfortunately, a certain feature hinders the application of this phenomenon in convenient devices, namely the pnp-switching temperature, which generally occurs well above room temperature, between 364 and 580 K. This effect is far removed from a suitable operation temperature at ambient conditions. Here, we report on Ag18Cu3Te11Cl3, a room temperature pnp-switching material, and the realization of the first single-material position-independent diode. The title compound shows the highest ever reported Seebeck coefficient drop that takes place within a few Kelvin at room temperature. Combined with its reasonably low thermal conductivity, this material offers great application potential within an easily accessible and applicable temperature window. Ag18Cu3Te11Cl3 and pnp-switching materials have the potential for applications and processes where diodes, transistors, or any defined charge separation with junction formation are utilized. This article is protected by copyright. All rights reserved},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Emerging noble metal-free Mo-based bifunctional catalysts for electrochemical energy conversion},

author = {S Santra and V Streibel and I D Sharp},

url = {https://doi.org/10.1007/s12274-022-5022-y},

doi = {10.1007/s12274-022-5022-y},

issn = {1998-0000},

year  = {2022},

date = {2022-10-22},

journal = {Nano Research},

volume = {15},

number = {12},

pages = {10234-10267},

abstract = {The transition from a global economy dependent on fossil fuels to one based on sustainable energy conversion technologies presents the primary challenge of the day. Equipping water electrolyzers and metal-air batteries with earth-abundant bifunctional transition metal (TM) catalysts that efficiently catalyse the hydrogen and oxygen evolution reactions (HER and OER) and the oxygen reduction and evolution reactions (ORR and OER), respectively, reduces the cost and system complexity, while also providing prospects for accelerated scaling and sustainable material reuse. Among the TMs, earth-abundant molybdenum (Mo)-based multifunctional catalysts are especially promising and have attracted considerable attention in recent years. Starting with a brief introduction to HER, OER, and ORR mechanisms and parameters governing their bifunctionality, this comprehensive review focuses on such Mo-based multifunctional catalysts. We review and discuss recent progress achieved through the formation of Mo-based compounds, heterostructures, and nanoscale composites, as well as by doping, defect engineering, and nanoscale sculpting of Mo-based catalysts. The systems discussed in detail are based on Mo chalcogenides, carbides, oxides, nitrides, and phosphides, as well as Mo alloys, highlighting specific opportunities afforded by synergistic interactions of Mo with both non-metals and non-noble metals. Finally, we discuss the future of Mo-based multifunctional electrocatalysts for HER/OER, ORR/OER, and HER/ORR/OER, analysing emerging trends, new opportunities, and underexplored avenues in this promising materials space.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Crystal side facet-tuning of GaN nanowires and nanofins grown by molecular beam epitaxy},

author = {F Pantle and M Karlinger and S W\"{o}rle and F Becker and T H\"{o}ldrich and E Sirotti and M Kraut and M Stutzmann},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0098016},

doi = {10.1063/5.0098016},

year  = {2022},

date = {2022-10-22},

journal = {Journal of Applied Physics},

volume = {132},

number = {18},

pages = {184304},

abstract = {GaN nanostructures are promising for a broad range of applications due to their 3D structure, thereby exposing non-polar crystal surfaces. The nature of the exposed crystal facets, i.e., whether they are a-, m-plane, or of mixed orientation, impacts the stability and performance of GaN nanostructure-based devices. In this context, it is of great interest to control the formation of well-defined side facets. Here, we show that we can control the crystal facet formation at the nanowire sidewalls by tuning the III\textendashV ratio during selective area growth by molecular beam epitaxy. Especially, the N flux serves as a tool for controlling the growth kinetics. In addition, we demonstrate the growth of GaN nanofins with either a- or m-plane side facets. Based on our observations, we present the underlying nanostructure growth mechanisms. Low temperature photoluminescence measurements show a correlation of the formation of structural defects like stacking faults with the growth kinetics. This article demonstrates the controlled selective epitaxy of GaN nanostructures with defined crystal side facets on large-scale available AlN substrates.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Probing the ultrafast dynamics of excitons in single semiconducting carbon nanotubes},

author = {K Birkmeier and T Hertel and A Hartschuh},

url = {https://doi.org/10.1038/s41467-022-33941-2},

doi = {10.1038/s41467-022-33941-2},

issn = {2041-1723},

year  = {2022},

date = {2022-10-21},

journal = {Nature Communications},

volume = {13},

number = {1},

pages = {6290},

abstract = {Excitonic states govern the optical spectra of low-dimensional semiconductor nanomaterials and their dynamics are key for a wide range of applications, such as in solar energy harvesting and lighting. Semiconducting single-walled carbon nanotubes emerged as particularly rich model systems for one-dimensional nanomaterials and as such have been investigated intensively in the past. The exciton decay dynamics in nanotubes has been studied mainly by transient absorption and time-resolved photoluminescence spectroscopy. Since different transitions are monitored with these two techniques, developing a comprehensive model to reconcile different data sets, however, turned out to be a challenge and remarkably, a uniform description seems to remain elusive. In this work, we investigate the exciton decay dynamics in single carbon nanotubes using transient interferometric scattering and time-resolved photoluminescence microscopy with few-exciton detection sensitivity and formulate a unified microscopic model by combining unimolecular exciton decay and ultrafast exciton-exciton annihilation on a time-scale down to 200 fs.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {High-Q nanophotonics over the full visible spectrum enabled by hexagonal boron nitride metasurfaces},

author = {L K\"{u}hner and L Sortino and B Tilmann and T Weber and K Watanabe and T Taniguchi and S A Maier and A Tittl},

url = {https://arxiv.org/abs/2210.11314},

doi = {https://doi.org/10.48550/arXiv.2210.11314},

year  = {2022},

date = {2022-10-20},

journal = {arXiv preprint arXiv:2210.11314},

abstract = {All-dielectric optical metasurfaces with high quality (Q) factors have so far been hampered by the lack of simultaneously lossless and high refractive index (RI) materials over the full visible spectrum. To achieve broad spectral coverage, the use of low-index materials is, in fact, unavoidable due to the inverse correlation between the band-gap energy (and therefore the optical losses) and the RI. However, for Mie resonant photonics, smaller RIs are associated with reduced Q factors and mode volume confinement. In this work, we leverage symmetry-broken bound states in the continuum (BICs) to efficiently suppress radiation losses from the low-index (n~2) van der Waals material hexagonal boron nitride (hBN), realizing metasurfaces with high-Q resonances over the complete visible spectrum. In particular, we analyze the rational use of low and high RI materials as resonator components and harness our insights to experimentally demonstrate sharp BIC resonances with Q factors above 300, spanning wavelengths between 400 nm and 1000 nm from a single hBN flake. Moreover, we utilize the enhanced electric near-fields to demonstrate second harmonic generation (SHG) with enhancement factors above 102. Our results provide a theoretical and experimental framework for the implementation of low RI materials as photonic media for metaoptics.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Near-Field Retrieval of the Surface Phonon Polariton Dispersion in Free-Standing Silicon Carbide Thin Films},

author = {A Mancini and L Nan and F J Wendisch and R Bert\'{e} and H Ren and E Cort\'{e}s and S A Maier},

url = {https://doi.org/10.1021/acsphotonics.2c01270},

doi = {10.1021/acsphotonics.2c01270},

year  = {2022},

date = {2022-10-20},

journal = {ACS Photonics},

abstract = {Surface phonon polaritons (SPhPs) are mixed light-matter states originating from strong coupling of photons with lattice vibrations. Thin films of polar dielectrics feature a splitting of the SPhP branch due to the hybridization of the top and bottom interface modes. Recently, enhanced in-plane thermal conductivity and near-field energy transfer have been experimentally demonstrated in free-standing polar films. These effects are determined by the SPhP dispersion in these systems, which, however, is yet to be reported experimentally. In this work, we retrieve the SPhP dispersion in silicon carbide free-standing membranes few hundreds of nanometers thick through near-field spectroscopy. We find several branches in the experimental dispersion, which we rationalize as multiple reflections of tip and edge launched SPhPs, in good agreement with theoretical predictions. Our work paves the way to employ large-area free-standing membranes as a platform for phonon polaritonics, with foreseeable applications in the field of thermal management at the nanoscale.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}