Publications

@article{nokey,

title = {Optimizing hydrogen binding on Ru sites with RuCo alloy nanosheets for efficient alkaline hydrogen evolution},

author = {C Cai and K Liu and Y Zhu and P Li and Q Wang and B Liu and S Chen and H Li and L Zhu and H Li and J Fu and Y Chen and E Pensa and J Hu and Y-R Lu and T-S Chan and E Cortes and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202113664},

doi = {https://doi.org/10.1002/anie.202113664},

issn = {1433-7851},

year  = {2021},

date = {2021-11-25},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

abstract = {Ruthenium (Ru)-based catalysts, with considerable performance and desirable cost, become highly concerned candidates to replace platinum (Pt) in alkaline hydrogen evolution reaction (HER). The hydrogen binding at Ru sites (Ru-H) is an important factor limiting the HER activity. Herein, density functional theory (DFT) simulations show that the essence of Ru-H binding energy is the strong interaction between the 4dz 2 orbital of Ru and 1s orbital of H. The charge transfer between Ru sites and substrates (Co and Ni) causes the appropriate downward shift of the 4dz 2 -band center of Ru, which results in a Gibbs free energy of 0.022 eV for H* in RuCo system, much decrease compared to 0.133 eV in pure Ru system. This theoretical prediction has been experimentally confirmed using RuCo alloy nanosheets (RuCo ANSs). They were prepared via fast co-precipitation method followed with a mild electrochemical reduction. Structure characterizations reveal that the Ru atoms are embed into Co substrate as isolated active sites with the planar symmetric and Z-direction asymmetric coordination structure, obtaining an optimal 4dz 2 modulated electronic structure. Hydrogen sensor and temperature program desorption (TPD) tests demonstrate the enhanced Ru-H interactions in RuCo ANSs than pure Ru nanoparticles. As a result, the RuCo ANSs reach an ultra-low overpotential of 10 mV at 10 mA/cm 2 and a Tafel slope of 20.6 mV/dec in 1 M KOH, outperforming that of the commercial Pt/C. This holistic work provides a new insight to promote alkaline HER by optimizing metal-H binding energy of active sites.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Kernel Charge Equilibration: Efficient and Accurate Prediction of Molecular Dipole Moments with a Machine-Learning Enhanced Electron Density Model},

author = {C Staacke and S Wengert and C Kunkel and G Cs\'{a}nyi and K Reuter and J T Margraf},

doi = {10.26434/chemrxiv-2021-73w0p},

year  = {2021},

date = {2021-11-25},

journal = {ChemRxiv, Cambridge: Cambridge Open Engage},

abstract = {State-of-the-art machine learning (ML) interatomic potentials use local representations of atomic environments to ensure linear scaling and size-extensivity. This implies a neglect of long-range interactions, most prominently related to electrostatics. To overcome this limitation, we herein present a ML framework for predicting charge distributions and their interactions termed kernel Charge Equilibration (kQEq). This model is based on classical charge equilibration models like QEq, expanded with an environment dependent electronegativity. In contrast to previously reported neural network models with a similar concept, kQEq takes advantage of the linearity of both QEq and Kernel Ridge Regression to obtain a closed-form linear algebra expression for training the models. Furthermore, we avoid the ambiguity of charge partitioning schemes by using dipole moments as reference data. As a first application, we show that kQEq can be used to generate accurate and highly data-efficient models for molecular dipole moments.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Achromatic frequency doubling of supercontinuum pulses for transient absorption spectroscopy},

author = {E Keil and P Malevich and J Hauer},

url = {http://www.osapublishing.org/oe/abstract.cfm?URI=oe-29-24-39042},

doi = {10.1364/OE.442400},

year  = {2021},

date = {2021-11-22},

journal = {Optics Express},

volume = {29},

number = {24},

pages = {39042-39054},

abstract = {We present achromatic frequency doubling of supercontinuum pulses from a hollow core fiber as a technique for obtaining tunable ultrashort pulses in the near UV and blue spectral range. Pulse energies are stable on a 1.1% level, averaged over 100 000 shots. By the use of conventional optics only, we compress a 0.2 µJ pulse at a center wavelength of 475 nm to a pulse duration of 12 fs, as measured by X-FROG. We test the capabilities of the approach by employing the ASHG-pulses as a pump in a transient absorption experiment on β-carotene in solution.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {How Exciton\textendashPhonon Coupling Impacts Photoluminescence in Halide Perovskite Nanoplatelets},

author = {M Gramlich and C Lampe and J Drewniok and A S Urban},

url = {https://doi.org/10.1021/acs.jpclett.1c03437},

doi = {10.1021/acs.jpclett.1c03437},

year  = {2021},

date = {2021-11-18},

journal = {The Journal of Physical Chemistry Letters},

pages = {11371-11377},

abstract = {Semiconductor nanocrystals are receiving increased interest as narrow-band emitters for display applications. Here, we investigate the underlying photoluminescence (PL) linewidth broadening mechanisms in thickness-tunable 2D halide perovskite (Csn−1PbnBr3n+1) nanoplatelets (NPLs). Temperature-dependent PL spectroscopy on NPL thin films reveals a blue-shift of the PL maximum for thicker NPLs, no shift for three monolayer (ML) thick NPLs, and a red-shift for the thinnest (2 ML) NPLs with increasing temperature. Emission linewidths also strongly depend on NPL thickness, with the thinnest NPLs showing the smallest temperature-induced broadening. We determine the combined interaction of exciton\textendashphonon coupling and thermal lattice expansion to be responsible for both effects. Additionally, the 2 ML NPLs exhibit a significantly larger Fr\"{o}hlich coupling constant and optical phonon energy, possibly due to an inversion in the exciton fine structure. These results illustrate that ultrathin halide perovskite NPLs could illuminate the next generation of displays, provided a slightly greater sample homogeneity and improved stability.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Static and dynamic water structures at interfaces: A case study with focus on Pt(111)},

author = {A C D L\'{o}pez and T Eggert and K Reuter and N G H\"{o}rmann},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0067106},

doi = {10.1063/5.0067106},

year  = {2021},

date = {2021-11-18},

journal = {The Journal of Chemical Physics},

volume = {155},

number = {19},

pages = {194702},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Exploration of the Electrical Double Layer Structure: Influence of Electrolyte Components on the Double Layer Capacitance and Potential of Maximum Entropy},

author = {R W Haid and X Ding and T K Sarpey and A S Bandarenka and B Garlyyev},

url = {https://www.sciencedirect.com/science/article/pii/S2451910321001964},

doi = {https://doi.org/10.1016/j.coelec.2021.100882},

issn = {2451-9103},

year  = {2021},

date = {2021-11-17},

journal = {Current Opinion in Electrochemistry},

pages = {100882},

abstract = {Understanding the electrical double layer structure is of paramount importance for designing efficient electrochemical energy conversion systems. Under this aspect, this short review explores the influence of the electrolyte on parameters such as the double layer capacitance and the potential of maximum entropy. Investigation of those parameters offers a deeper understanding on how the interfacial structure changes near reaction conditions. As a consequence, one can tune the catalyst activity by creating a more favorable environment in the electrolyte. The aim of this short review is to provide the reader with recent studies examining the electrode/electrolyte interface from experimental and theoretical standpoints.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Charge transport in semiconducting polymers at the nanoscale},

author = {J Lenz and R T Weitz},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0068098},

doi = {10.1063/5.0068098},

year  = {2021},

date = {2021-11-17},

journal = {APL Materials},

volume = {9},

number = {11},

pages = {110902},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Modular Assembly of Vibrationally and Electronically Coupled Rhenium Bipyridine Carbonyl Complexes on Silicon},

author = {J D Bartl and C Thomas and A Henning and M F Ober and G Savasci and B Yazdanshenas and P S Deimel and E Magnano and F Bondino and P Zeller and L Gregoratti and M Amati and C Paulus and F Allegretti and A Cattani-Scholz and J V Barth and C Ochsenfeld and B Nickel and I D Sharp and M Stutzmann and B Rieger},

url = {https://doi.org/10.1021/jacs.1c09061},

doi = {10.1021/jacs.1c09061},

issn = {0002-7863},

year  = {2021},

date = {2021-11-12},

journal = {Journal of the American Chemical Society},

abstract = {Hybrid inorganic/organic heterointerfaces are promising systems for next-generation photocatalytic, photovoltaic, and chemical-sensing applications. Their performance relies strongly on the development of robust and reliable surface passivation and functionalization protocols with (sub)molecular control. The structure, stability, and chemistry of the semiconductor surface determine the functionality of the hybrid assembly. Generally, these modification schemes have to be laboriously developed to satisfy the specific chemical demands of the semiconductor surface. The implementation of a chemically independent, yet highly selective, standardized surface functionalization scheme, compatible with nanoelectronic device fabrication, is of utmost technological relevance. Here, we introduce a modular surface assembly (MSA) approach that allows the covalent anchoring of molecular transition-metal complexes with sub-nanometer precision on any solid material by combining atomic layer deposition (ALD) and selectively self-assembled monolayers of phosphonic acids. ALD, as an essential tool in semiconductor device fabrication, is used to grow conformal aluminum oxide activation coatings, down to sub-nanometer thicknesses, on silicon surfaces to enable a selective step-by-step layer assembly of rhenium(I) bipyridine tricarbonyl molecular complexes. The modular surface assembly of molecular complexes generates precisely structured spatial ensembles with strong intermolecular vibrational and electronic coupling, as demonstrated by infrared spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy analysis. The structure of the MSA can be chosen to avoid electronic interactions with the semiconductor substrate to exclusively investigate the electronic interactions between the surface-immobilized molecular complexes.},

keywords = {Foundry Inorganic, Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Probing the Role of Atomic Defects in Photocatalytic Systems through Photoinduced Enhanced Raman Scattering},

author = {D Glass and R Quesada-Cabrera and S Bardey and P Promdet and R Sapienza and V Keller and S A Maier and V Caps and I P Parkin and E Cort\'{e}s},

url = {https://doi.org/10.1021/acsenergylett.1c01772},

doi = {10.1021/acsenergylett.1c01772},

year  = {2021},

date = {2021-11-10},

journal = {ACS Energy Letters},

pages = {4273-4281},

abstract = {Even in ultralow quantities, oxygen vacancies (VO) drastically impact key properties of metal oxide semiconductors, such as charge transport, surface adsorption, and reactivity, playing central roles in functional materials performance. Current methods used to investigate VO often rely on specialized instrumentation under far from ideal reaction conditions. Hence, the influence of VO generated in situ during catalytic processes has yet to be probed. In this work, we assess in situ extrinsic surface VO formation and lifetime under photocatalytic conditions which we compare to photocatalytic performance. We show for the first time that lifetimes of in situ generated atomic VO play more significant roles in catalysis than their concentration, with strong correlations between longer-lived VO and higher photocatalytic activity. Our results indicate that enhanced photocatalytic efficiency correlates with goldilocks VO concentrations, where VO densities must be just right to encourage carrier transport while avoiding charge carrier trapping.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {How Blinking Affects Photon Correlations in Multichromophoric Nanoparticles},

author = {T Schr\"{o}der and S Bange and J Schedlbauer and F Steiner and J M Lupton and P Tinnefeld and J Vogelsang},

url = {https://doi.org/10.1021/acsnano.1c06649},

doi = {10.1021/acsnano.1c06649},

issn = {1936-0851},

year  = {2021},

date = {2021-11-04},

journal = {ACS Nano},

abstract = {A single chromophore can only emit a maximum of one single photon per excitation cycle. This limitation results in a phenomenon commonly referred to as photon antibunching (pAB). When multiple chromophores contribute to the fluorescence measured, the degree of pAB has been used as a metric to “count” the number of chromophores. But the fact that chromophores can switch randomly between bright and dark states also impacts pAB and can lead to incorrect chromophore numbers being determined from pAB measurements. By both simulations and experiment, we demonstrate how pAB is affected by independent and collective chromophore blinking, enabling us to formulate universal guidelines for correct interpretation of pAB measurements. We use DNA-origami nanostructures to design multichromophoric model systems that exhibit either independent or collective chromophore blinking. Two approaches are presented that can distinguish experimentally between these two blinking mechanisms. The first one utilizes the different excitation intensity dependence on the blinking mechanisms. The second approach exploits the fact that collective blinking implies energy transfer to a quenching moiety, which is a time-dependent process. In pulsed-excitation experiments, the degree of collective blinking can therefore be altered by time gating the fluorescence photon stream, enabling us to extract the energy-transfer rate to a quencher. The ability to distinguish between different blinking mechanisms is valuable in materials science, such as for multichromophoric nanoparticles like conjugated-polymer chains as well as in biophysics, for example, for quantitative analysis of protein assemblies by counting chromophores.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optical dipole orientation of interlayer excitons in MoSe2-WSe2 heterostacks},

author = {L Sigl and M Troue and M Katzer and M Selig and F Sigger and J Kiemle and M Brotons-Gisbert and K Watanabe and T Taniguchi and B D Gerardot},

year  = {2021},

date = {2021-11-02},

journal = {Cond-Mat. Mes-Hall},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {The Effect of Dynamic Structural Flexibility in Halide Perovskites},

author = {C Gehrmann and S Caicedo-D\'{a}vila and X Zhu and D A Egger},

year  = {2021},

date = {2021-11-01},

journal = {J. Mater. Sci.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Scalable Fabrication of Metallic Nanogaps at the Sub-10 nm Level},

author = {S Luo and B H Hoff and S A Maier and J C De Mello},

doi = {10.1002/advs.202102756},

issn = {2198-3844},

year  = {2021},

date = {2021-10-31},

journal = {Adv Sci (Weinh)},

pages = {e2102756},

abstract = {Metallic nanogaps with metal-metal separations of less than 10 nm have many applications in nanoscale photonics and electronics. However, their fabrication remains a considerable challenge, especially for applications that require patterning of nanoscale features over macroscopic length-scales. Here, some of the most promising techniques for nanogap fabrication are evaluated, covering established technologies such as photolithography, electron-beam lithography (EBL), and focused ion beam (FIB) milling, plus a number of newer methods that use novel electrochemical and mechanical means to effect the patterning. The physical principles behind each method are reviewed and their strengths and limitations for nanogap patterning in terms of resolution, fidelity, speed, ease of implementation, versatility, and scalability to large substrate sizes are discussed.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Bifurcations of Clusters and Collective Oscillations in Networks of Bistable Units},

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

year  = {2021},

date = {2021-10-28},

journal = {arXiv preprint arXiv:2110.15004},

abstract = {We investigate dynamics and bifurcations in a mathematical model that captures electrochemical experiments on arrays of microelectrodes. In isolation, each individual microelectrode is described by a one-dimensional unit with a bistable current-potential response. When an array of such electrodes is coupled by controlling the total electric current, the common electric potential of all electrodes oscillates in some interval of the current. These coupling-induced collective oscillations of bistable one-dimensional units are captured by the model. Moreover, any equilibrium is contained in a cluster subspace, where the electrodes take at most three distinct states. We systematically analyze the dynamics and bifurcations of the model equations: We consider the dynamics on cluster subspaces of successively increasing dimension and analyze the bifurcations occurring therein. Most importantly, the system exhibits an equivariant transcritical bifurcation of limit cycles. From this bifurcation, several limit cycles branch, one of which is stable for arbitrarily many bistable units.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Biopolymer-Templated Deposition of Ordered and Polymorph Titanium Dioxide Thin Films for Improved Surface-Enhanced Raman Scattering Sensitivity},

author = {Q Chen and M Betker and C Harder and C J Brett and M Schwartzkopf and N M Ulrich and M E Toimil-Molares and C Trautmann and L D S\"{o}derberg and C L Weindl and V K\"{o}rstgens and P M\"{u}ller-Buschbaum and M Ma and S V Roth},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202108556},

doi = {https://doi.org/10.1002/adfm.202108556},

issn = {1616-301X},

year  = {2021},

date = {2021-10-27},

journal = {Adv. Funct. Mater.},

volume = {n/a},

number = {n/a},

pages = {2108556},

abstract = {Abstract Titanium dioxide (TiO2) is an excellent candidate material for semiconductor metal oxide-based substrates for surface-enhanced Raman scattering (SERS). Biotemplated fabrication of TiO2 thin films with a 3D network is a promising route for effectively transferring the morphology and ordering of the template into the TiO2 layer. The control over the crystallinity of TiO2 remains a challenge due to the low thermal stability of biopolymers. Here is reported a novel strategy of the cellulose nanofibril (CNF)-directed assembly of TiO2/CNF thin films with tailored morphology and crystallinity as SERS substrates. Polymorphous TiO2/CNF thin films with well-defined morphology are obtained by combining atomic layer deposition and thermal annealing. A high enhancement factor of 1.79 × 106 in terms of semiconductor metal oxide nanomaterial (SMON)-based SERS substrates is obtained from the annealed TiO2/CNF thin films with a TiO2 layer thickness of 10 nm fabricated on indium tin oxide (ITO), when probed by 4-mercaptobenzoic acid molecules. Common SERS probes down to 10 nm can be detected on these TiO2/CNF substrates, indicating superior sensitivity of TiO2/CNF thin films among SMON SERS substrates. This improvement in SERS sensitivity is realized through a cooperative modulation of the template morphology of the CNF network and the crystalline state of TiO2.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Cation disorder in stoichiometric MgSnN2 and ambipolar self-doping behavior in off-stoichiometric MgSnN2},

author = {D Han and S S Rudel and W Schnick and H Ebert},

year  = {2021},

date = {2021-10-27},

journal = {arXiv preprint arXiv:2110.14289},

abstract = {Investigations on II-Sn-N2 (II = Mg, Ca) have been started very recently compared to the intense research of the Zn-IV-N2 (IV = Si, Ge, Sn). In this work, we perform a comprehensive study of cation disorder in stoichiometric MgSnN2 and crystal structure characteristic, doping behavior of off-stoichiometric Mg1+xSn1-xN2 (x = -0.8, -0.6, -0.5, -0.4, -0.2, 0.2, 0.4, 0.5, 0.6, 0.8) by using the cluster expansion method and first principles calculations. It is found that cation disorder in stoichiometric MgSnN2 induces a band gap reduction because of a violation of the octet rule. Moreover, the local disorder, namely forming (4,0) or (0,4) tetrahedra, would lead to an appreciable band gap reduction and hinder the enhancement of the optical absorption. An off-stoichiometric Mg/Sn ratio can strongly affect the morphology of Mg1+xSn1-xN2 samples due to the higher ionicity of the Mg-N bonds in comparison with Zn-N bonds. Furthermore, Mg1+xSn1-xN2 compounds show an ambipolar self-doping behavior, i.e., Mg-rich Mg1+xSn1-xN2 show p-type doping while Sn-rich ones exhibit n-type doping owing to the formation of acceptor-type antisite defect MgSn or donor-type antisite defect SnMg, respectively.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Bimolecular Generation of Excitonic Luminescence from Dark Photoexcitations in Ruddlesden\textendashPopper Hybrid Metal-Halide Perovskites},

author = {M Nuber and D Sandner and T Neumann and R Kienberger and F Deschler and H Iglev},

url = {https://doi.org/10.1021/acs.jpclett.1c03099},

doi = {10.1021/acs.jpclett.1c03099},

year  = {2021},

date = {2021-10-21},

journal = {The Journal of Physical Chemistry Letters},

volume = {12},

number = {42},

pages = {10450-10456},

abstract = {The nature of photoexcitations in Ruddlesden\textendashPopper (RP) hybrid metal halide perovskites is still under debate. While the high exciton binding energy in the hundreds of millielectronvolts indicates excitons as the primary photoexcitations, recent reports found evidence for dark, Coulombically screened populations, which form via strong coupling of excitons and the atomic lattice. Here, we use time-resolved mid-infrared spectroscopy to gain insights into the nature and recombination of such dark excited states in (BA)2(MA)n−1PbnI3n+1 (n = 1,2,3) via their intraband electronic absorption. In stark contrast to results in the bulk perovskites, all samples exhibit a broad, unstructured mid-IR photoinduced absorbance with no infrared activated modes, independent of excitonic confinement. Further, the recombination dynamics are dominated by a bimolecular process. In combination with steady-state photoluminescence experiments, we conclude that screened, dark photoexcitations act as a population reservoir in the RP hybrid perovskites, from which nongeminate formation of bright excitons precedes generation of photoluminescence.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Water jet space charge spectroscopy: Route to direct measurement of electron dynamics for organic systems in their natural environment},

author = {M Mittermair and F Martin and M W\"{o}rle and D Blo\ss and A Duensing and R Kienberger and A Hans and H Iglev and A Knie and W Helml},

year  = {2021},

date = {2021-10-19},

journal = {arXiv preprint arXiv:2110.10044},

abstract = {The toolbox for time-resolved direct measurements of electron dynamics covers a variety of methods. Since the experimental effort is increasing rapidly with achievable time resolution, there is an urge for simple and robust measurement techniques. Within this paper prove of concept experiments and numerical simulations are utilized to investigate the applicability of a new setup for the generation of ultrashort electron pulses in the energy range of 300 eV up to 1.6 keV. The experimental approach combines an in-vacuum liquid microjet and a few-cycle femtosecond laser system, while the threshold for electron impact ionization serves as a gate for the effective electron pulse duration. The experiments prove that electrons in the keV regime are accessible and that the electron spectrum can be easily tuned by laser intensity and focal position alignment with respect to the water jet. Numerical simulations show that a sub-picosecond temporal resolution is achievable.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Scalable transparent conductive thin films with electronically passive interfaces for direct chemical vapor deposition of 2D materials},

author = {T Gr\"{u}nleitner and A Henning and M Bissolo and A Kleibert and C A Vaz and A V Stier and J J Finley and I D Sharp},

year  = {2021},

date = {2021-10-15},

journal = {Appl. Phys. Res.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tip Coupling and Array Effects of Gold Nanoantennas in Near-Field Microscopy},

author = {R B\"{u}chner and T Weber and L K\"{u}hner and S A Maier and A Tittl},

url = {https://doi.org/10.1021/acsphotonics.1c00744},

doi = {10.1021/acsphotonics.1c00744},

year  = {2021},

date = {2021-10-14},

journal = {ACS Photonics},

abstract = {Scattering-type scanning near-field optical microscopy (s-SNOM) is one of the predominant techniques for the nanoscale characterization of optical properties. The optical response of nanoantennas in s-SNOM is highly sensitive to their environment, including influences of the probing tip or neighboring resonators. Dielectric tips are commonly employed to minimize tip-related perturbations, although they provide a comparatively weak scattering signal. Here we show that when using metallic tips, it is possible to select between distinct weak and strong tip\textendashantenna coupling regimes by careful tailoring of the illumination conditions and resonator orientation. This enables the use of highly scattering metallic instead of dielectric tips for mapping plasmonic modes with comparatively higher signal strengths. This is a particular advantage for the retrieval of near-field spectra, which simultaneously require high near-field signals and unperturbed field patterns. We leverage our approach to analyze the collective effects of nanoantenna arrays, phenomena that are well understood in the optical far-field but have not been extensively studied in the near-field. Probing the dependence of the optical response on the array field size, we identify three regimes: the single rod regime, the intermediate regime, and the array-like regime. We show that these array effects give rise to characteristic spectral features originating from a complex interplay of radiative coupling and plasmon hybridization. These results provide evidence that long-range interactions of antennas also influence the local optical response that is probed in s-SNOM and demonstrate how collective resonances emerge from single building blocks, providing guidelines for optimized array designs for near- and far-field applications.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A self-healing catalyst for electrocatalytic and photoelectrochemical oxygen evolution in highly alkaline conditions},

author = {C Feng and F Wang and Z Liu and M Nakabayashi and Y Xiao and Q Zeng and J Fu and Q Wu and C Cui and Y Han and N Shibata and K Domen and I D Sharp and Y Li},

url = {https://doi.org/10.1038/s41467-021-26281-0},

doi = {10.1038/s41467-021-26281-0},

issn = {2041-1723},

year  = {2021},

date = {2021-10-13},

journal = {Nature Communications},

volume = {12},

number = {1},

pages = {5980},

abstract = {While self-healing is considered a promising strategy to achieve long-term stability for oxygen evolution reaction (OER) catalysts, this strategy remains a challenge for OER catalysts working in highly alkaline conditions. The self-healing of the OER-active nickel iron layered double hydroxides (NiFe-LDH) has not been successful due to irreversible leaching of Fe catalytic centers. Here, we investigate the introduction of cobalt (Co) into the NiFe-LDH as a promoter for in situ Fe redeposition. An active borate-intercalated NiCoFe-LDH catalyst is synthesized using electrodeposition and shows no degradation after OER tests at 10 mA cm−2 at pH 14 for 1000 h, demonstrating its self-healing ability under harsh OER conditions. Importantly, the presence of both ferrous ions and borate ions in the electrolyte is found to be crucial to the catalyst’s self-healing. Furthermore, the implementation of this catalyst in photoelectrochemical devices is demonstrated with an integrated silicon photoanode. The self-healing mechanism leads to a self-limiting catalyst thickness, which is ideal for integration with photoelectrodes since redeposition is not accompanied by increased parasitic light absorption.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Critical Outlook for the Pursuit of Lower Contact Resistance in Organic Transistors},

author = {J W Borchert and R T Weitz and S Ludwigs and H Klauk},

doi = {10.1002/adma.202104075},

issn = {0935-9648},

year  = {2021},

date = {2021-10-07},

journal = {Adv Mater},

pages = {e2104075},

abstract = {To take full advantage of recent and anticipated improvements in the performance of organic semiconductors employed in organic transistors, the high contact resistance arising at the interfaces between the organic semiconductor and the source and drain contacts must be reduced significantly. To date, only a small portion of the accumulated research on organic thin-film transistors (TFTs) has reported channel-width-normalized contact resistances below 100 Ωcm, well above what is regularly demonstrated in transistors based on inorganic semiconductors. A closer look at these cases and the relevant literature strongly suggests that the most significant factor leading to the lowest contact resistances in organic TFTs so far has been the control of the thin-film morphology of the organic semiconductor. By contrast, approaches aimed at increasing the charge-carrier density and/or reducing the intrinsic Schottky barrier height have so far played a relatively minor role in achieving the lowest contact resistances. Herein, the possible explanations for these observations are explored, including the prevalence of Fermi-level pinning and the difficulties in forming optimized interfaces with organic semiconductors. An overview of the research on these topics is provided, and potential device-engineering solutions are discussed based on recent advancements in the theoretical and experimental work on both organic and inorganic semiconductors.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ion Dynamics and Polymorphism in Cu20Te11Cl3},

author = {A Vogel and T Nilges},

url = {https://doi.org/10.1021/acs.inorgchem.1c01764},

doi = {10.1021/acs.inorgchem.1c01764},

issn = {0020-1669},

year  = {2021},

date = {2021-10-04},

journal = {Inorganic Chemistry},

volume = {60},

number = {20},

pages = {15233-15241},

abstract = {Coinage metal polychalcogenide halides are an intriguing class of materials, and many representatives are solid ion conductors and thermoelectric materials. The materials show high ion mobility, polymorphism, and various attractive interactions in the cation and anion substructures. Especially the latter feature leads to complex electronic structures and the occurrence of charge-density waves (CDWs) and, as a result, the first p\textendashn\textendashp switching materials. During our systematic investigations for new p\textendashn\textendashn switching materials in the Cu\textendashTe\textendashCl phase diagram, we were able to isolate polymorphic Cu20Te11Cl3, which we characterized structurally and with regard to its electronic and thermoelectric properties. Cu20Te11Cl3 is trimorphic, with phase transitions occurring at 288 and 450 K. The crystal structures of two polymorphs, the α phase, stable above 450 K, and the β polymorph (288\textendash450 K), are reported, and the complex structure chemistry featuring twinning upon a phase change is illustrated. We identified a dynamic cation substructure and a static anion substructure for all polymorphs, characterizing Cu20Te11Cl3 as a solid Cu-ion conductor. Temperature-dependent measurements of the Seebeck coefficient and total conductivity were performed and substantiated a linear response of the Seebeck coefficient, a lack of CDWs, and no p\textendashn\textendashp switching. Reasons for a lack of CDWs in Cu20Te11Cl3 are discussed and illustrated in the context of existing p\textendashn\textendashp switching materials.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dark and Bright Excitons in Halide Perovskite Nanoplatelets},

author = {M Gramlich and M W Swift and C Lampe and M D\"{o}blinger and J L Lyons and A L Efros and P C Sercel and A S Urban},

year  = {2021},

date = {2021-10-01},

journal = {arXiv preprint arXiv},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Degradation mechanisms of perovskite solar cells under vacuum and one atmosphere of nitrogen},

author = {R Guo and D Han and W Chen and L Dai and K Ji and Q Xiong and S Li and L K Reb and M A Scheel and S Pratap and N Li and S Yin and T Xiao and S Liang and A L Oechsle and C L Weindl and M Schwartzkopf and H Ebert and P Gao and K Wang and M Yuan and N C Greenham and S D Stranks and S V Roth and R H Friend and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1038/s41560-021-00912-8},

doi = {10.1038/s41560-021-00912-8},

issn = {2058-7546},

year  = {2021},

date = {2021-10-01},

journal = {Nature Energy},

volume = {6},

number = {10},

pages = {977-986},

abstract = {Extensive studies have focused on improving the operational stability of perovskite solar cells, but few have surveyed the fundamental degradation mechanisms. One aspect overlooked in earlier works is the effect of the atmosphere on device performance during operation. Here we investigate the degradation mechanisms of perovskite solar cells operated under vacuum and under a nitrogen atmosphere using synchrotron radiation-based operando grazing-incidence X-ray scattering methods. Unlike the observations described in previous reports, we find that light-induced phase segregation, lattice shrinkage and morphology deformation occur under vacuum. Under nitrogen, only lattice shrinkage appears during the operation of solar cells, resulting in better device stability. The different behaviour under nitrogen is attributed to a larger energy barrier for lattice distortion and phase segregation. Finally, we find that the migration of excessive PbI2 to the interface between the perovskite and the hole transport layer degrades the performance of devices under vacuum or under nitrogen.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Role of Polycyclic Aromatic Alkylammonium Cations in Tuning the Electronic Properties and Band Alignment of Two-Dimensional Hybrid Perovskite Semiconductors},

author = {D Han and S Chen and M-H Du},

url = {https://doi.org/10.1021/acs.jpclett.1c02603},

doi = {10.1021/acs.jpclett.1c02603},

year  = {2021},

date = {2021-09-30},

journal = {The Journal of Physical Chemistry Letters},

volume = {12},

number = {40},

pages = {9754-9760},

abstract = {Two-dimensional hybrid organic\textendashinorganic perovskites (HOIPs) have recently drawn intense attention as potential photovoltaic materials. However},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {The Effect of Photoinduced Surface Oxygen Vacancies on the Charge Carrier Dynamics in TiO2 Films},

author = {O E Dagdeviren and D Glass and R Sapienza and E Cort\'{e}s and S A Maier and I P Parkin and P Gr\"{u}tter and R Quesada-Cabrera},

url = {https://doi.org/10.1021/acs.nanolett.1c02853},

doi = {10.1021/acs.nanolett.1c02853},

issn = {1530-6984},

year  = {2021},

date = {2021-09-28},

journal = {Nano Letters},

volume = {21},

number = {19},

pages = {8348-8354},

abstract = {Metal-oxide semiconductors (MOS) are widely utilized for catalytic and photocatalytic applications in which the dynamics of charged carriers (e.g., electrons, holes) play important roles. Under operation conditions, photoinduced surface oxygen vacancies (PI-SOV) can greatly impact the dynamics of charge carriers. However, current knowledge regarding the effect of PI-SOV on the dynamics of hole migration in MOS films, such as titanium dioxide, is solely based upon volume-averaged measurements and/or vacuum conditions. This limits the basic understanding of hole-vacancy interactions, as they are not capable of revealing time-resolved variations during operation. Here, we measured the effect of PI-SOV on the dynamics of hole migration using time-resolved atomic force microscopy. Our findings demonstrate that the time constant associated with hole migration is strongly affected by PI-SOV, in a reversible manner. These results will nucleate an insightful understanding of the physics of hole dynamics and thus enable emerging technologies, facilitated by engineering hole-vacancy interactions.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Out-of-equilibrium processes in crystallization of organic-inorganic perovskites during spin coating},

author = {S Pratap and F Babbe and N S Barchi and Z Yuan and T Luong and Z Haber and T-B Song and J L Slack and C V Stan and N Tamura and C M Sutter-Fella and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1038/s41467-021-25898-5},

doi = {10.1038/s41467-021-25898-5},

issn = {2041-1723},

year  = {2021},

date = {2021-09-24},

journal = {Nature Communications},

volume = {12},

number = {1},

pages = {5624},

abstract = {Complex phenomena are prevalent during the formation of materials, which affect their processing-structure-function relationships. Thin films of methylammonium lead iodide (CH3NH3PbI3, MAPI) are processed by spin coating, antisolvent drop, and annealing of colloidal precursors. The structure and properties of transient and stable phases formed during the process are reported, and the mechanistic insights of the underlying transitions are revealed by combining in situ data from grazing-incidence wide-angle X-ray scattering and photoluminescence spectroscopy. Here, we report the detailed insights on the embryonic stages of organic-inorganic perovskite formation. The physicochemical evolution during the conversion proceeds in four steps: i) An instant nucleation of polydisperse MAPI nanocrystals on antisolvent drop, ii) the instantaneous partial conversion of metastable nanocrystals into orthorhombic solvent-complex by cluster coalescence, iii) the thermal decomposition (dissolution) of the stable solvent-complex into plumboiodide fragments upon evaporation of solvent from the complex and iv) the formation (recrystallization) of cubic MAPI crystals in thin film.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Real-time observation of nucleation and growth of Au on CdSe quantum dot templates},

author = {N Paul and J Huang and C Liu and T Lin and C Ouyang and Z Liu and C Chen and Z Chen and Z Weng and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum and A Paul},

url = {https://doi.org/10.1038/s41598-021-97485-z},

doi = {10.1038/s41598-021-97485-z},

issn = {2045-2322},

year  = {2021},

date = {2021-09-21},

journal = {Scientific Reports},

volume = {11},

number = {1},

pages = {18777},

abstract = {Semiconductor quantum dot (QD) arrays can be useful for optical devices such as lasers, solar cells and light-emitting diodes. As the size distribution influences the band-gap, it is worthwhile to investigate QDs prepared using different solvents because each of them could influence the overall morphology differently, depending on the ligand network around individual QDs. Here, we follow the nucleation and growth of gold (Au) on CdSe QD arrays to investigate the influence of surface ligands and thereby realized interparticle distance between QDs on Au growth behaviour. We particularly emphasize on the monolayer stage as the Au decoration on individual QDs is expected at this stage. Therefore, we sputter-deposit Au on each QD array to investigate the morphological evolution in real-time using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). The growth kinetics - independent of the template - signifies that the observed template-mediated nucleation is limited only to the very first few monolayers. Delicate changes in the Au growth morphology are seen in the immediate steps following the initial replicated decoration of the QD arrays. This is followed by a subsequent clustering and finally a complete Au coverage of the QD arrays.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Acoustic Coupling between Plasmonic Nanoantennas: Detection and Directionality of Surface Acoustic Waves},

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

url = {https://doi.org/10.1021/acsphotonics.1c00741},

doi = {10.1021/acsphotonics.1c00741},

year  = {2021},

date = {2021-09-17},

journal = {ACS Photonics},

abstract = {Hypersound waves can be efficient mediators between optical signals at the nanoscale. Having phase velocities several orders of magnitude lower than the speed of light, they propagate with much shorter wavelengths and can be controlled, directed, and even focused in a very small region of space. This work shows how two optical nanoantennas can be coupled through an acoustic wave that propagates with a certain directionality. An “emitter” antenna is first optically excited to generate acoustic coherent phonons that launch surface acoustic waves through the underlying substrate. These waves travel until they are mechanically detected by a “receiver” nanoantenna whose oscillation produces a detectable optical signal. Generation and detection are studied in detail, and new designs are proposed to improve the directionality of the hypersonic surface acoustic wave.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Engineering gallium phosphide nanostructures for efficient nonlinear photonics and enhanced spectroscopies},

author = {G Q Moretti and E Cort\'{e}s and S A Maier and A V Bragas and G Grinblat},

url = {https://doi.org/10.1515/nanoph-2021-0388},

doi = {doi:10.1515/nanoph-2021-0388},

year  = {2021},

date = {2021-09-16},

journal = {Nanophotonics},

number = {000010151520210388},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Multistate Nonvolatile Metamirrors with Tunable Optical Chirality},

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

url = {https://doi.org/10.1021/acsami.1c14204},

doi = {10.1021/acsami.1c14204},

issn = {1944-8244},

year  = {2021},

date = {2021-09-14},

journal = {ACS Applied Materials & Interfaces},

abstract = {Compared with conventional mirrors that behave as isotropic electromagnetic (EM) reflectors, metamirrors composed of periodically aligned artificial meta-atoms exhibit increased degrees of freedom for EM manipulations. However, the functionality of most metamirrors is fixed by design, and how to achieve active EM control is still elusive. Here, we propose a multistate metamirror based on the nonvolatile phase change material Ge2Sb2Te5 (GST) with four distinct functionalities that can be realized in the infrared region by exploiting the temperature-activated phase transition. When varying the crystallinity of GST, the metamirror has the capability to perform as a right-handed circular polarization chiral mirror, a narrowband achiral mirror, a left-handed circular polarization chiral mirror, or a broadband achiral mirror, respectively. The inner physics is further explained by the construction or cancellation of extrinsic two-dimensional chirality. As a proof of concept, experimental verification is carried out and the measured results agree well with their simulated counterparts. Such a multifunctional tunable metamirror could address a wide range of applications from sensing and spectroscopy to analytical chemistry and imaging.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Conductivity mechanism in ionic 2D carbon nitrides: from hydrated ion motion to enhanced photocatalysis},

author = {J Kr\"{o}ger and F Podjaski and G Sava\c{s}\c{c}ı and I Moudrakovski and A Jimenez-Solano and M W Terban and S Bette and V Duppel and M Joos and A Senocrate},

year  = {2021},

date = {2021-09-12},

journal = {Cambridge University Press},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Single-step-fabricated disordered metasurfaces for enhanced light extraction from LEDs},

author = {P Mao and C Liu and X Li and M Liu and Q Chen and M Han and S A Maier and E H Sargent and S Zhang},

url = {https://doi.org/10.1038/s41377-021-00621-7},

doi = {10.1038/s41377-021-00621-7},

issn = {2047-7538},

year  = {2021},

date = {2021-09-06},

journal = {Light: Science & Applications},

volume = {10},

number = {1},

pages = {180},

abstract = {While total internal reflection (TIR) lays the foundation for many important applications, foremost fibre optics that revolutionised information technologies, it is undesirable in some other applications such as light-emitting diodes (LEDs), which are a backbone for energy-efficient light sources. In the case of LEDs, TIR prevents photons from escaping the constituent high-index materials. Advances in material science have led to good efficiencies in generating photons from electron\textendashhole pairs, making light extraction the bottleneck of the overall efficiency of LEDs. In recent years, the extraction efficiency has been improved, using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum. However, the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and time-consuming fabrication, which causes a gap between lab demonstration and industrial-level applications. Inspired by lightning bugs, we propose and realise a disordered metasurface for light extraction throughout the visible spectrum, achieved with single-step fabrication. By applying such a cost-effective light extraction layer, we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs, demonstrating a substantial potential for global energy-saving and sustainability.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

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

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

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

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

issn = {2352-9407},

year  = {2021},

date = {2021-09-01},

journal = {Applied Materials Today},

volume = {24},

pages = {101134},

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

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Single Antibody Detection in a DNA Origami Nanoantenna},

author = {M Pfeiffer and K Trofymchuk and S Ranallo and F Ricci and F Steiner and F Cole and V Glembockyte and P Tinnefeld},

url = {https://www.sciencedirect.com/science/article/pii/S2589004221010403},

doi = {https://doi.org/10.1016/j.isci.2021.103072},

issn = {2589-0042},

year  = {2021},

date = {2021-09-01},

journal = {iScience},

pages = {103072},

abstract = {Summary DNA nanotechnology offers new biosensing approaches by templating different sensor and transducer components. Here, we combine DNA origami nanoantennas with label-free antibody detection by incorporating a nanoswitch in the plasmonic hotspot of the nanoantenna. The nanoswitch contains two antigens that are displaced by antibody binding thereby eliciting a fluorescent signal. Single antibody detection is demonstrated with a DNA origami integrated anti-digoxigenin antibody nanoswitch. In combination with the nanoantenna, the signal generated by the antibody is additionally amplified. This allows the detection of single antibodies on a portable smartphone microscope. Overall, fluorescence enhanced antibody detection in DNA origami nanoantennas shows that fluorescence enhanced biosensing can be expanded beyond the scope of the nucleic acids realm.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Indirect bandgap, optoelectronic properties, and photoelectrochemical characteristics of high-purity Ta3N5 photoelectrodes},

author = {J Eichhorn and S P Lechner and C-M Jiang and G Folchi Heunecke and F Munnik and I D Sharp},

url = {http://dx.doi.org/10.1039/D1TA05282A},

doi = {10.1039/D1TA05282A},

issn = {2050-7488},

year  = {2021},

date = {2021-08-26},

journal = {Journal of Materials Chemistry A},

abstract = {The (opto)electronic properties of Ta3N5 photoelectrodes are often dominated by defects, such as oxygen impurities, nitrogen vacancies, and low-valent Ta cations, impeding fundamental studies of its electronic structure, chemical stability, and photocarrier transport. Here, we explore the role of ammonia annealing following direct reactive magnetron sputtering of tantalum nitride thin films, achieving near-ideal stoichiometry, with significantly reduced native defect and oxygen impurity concentrations. By analyzing structural, optical, and photoelectrochemical properties as a function of ammonia annealing temperature, we provide new insights into the basic semiconductor properties of Ta3N5, as well as the role of defects on its optoelectronic characteristics. Both the crystallinity and material quality improve up to 940 °C, due to elimination of oxygen impurities. Even higher annealing temperatures cause material decomposition and introduce additional disorder within the Ta3N5 lattice, leading to reduced photoelectrochemical performance. Overall, the high material quality enables us to unambiguously identify the nature of the Ta3N5 bandgap as indirect, thereby resolving a long-standing controversy regarding the most fundamental characteristic of this material as a semiconductor. The compact morphology, low defect content, and high optoelectronic quality of these films provide a basis for further optimization of photoanodes and may open up further application opportunities beyond photoelectrochemical energy conversion.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Influence of environmental conditions and surface treatments on the photoluminescence properties of GaN nanowires and nanofins},

author = {M Kraut and F Pantle and S W\"{o}rle and E Sirotti and A Zeidler and F Eckmann and M Stutzmann},

issn = {0957-4484},

year  = {2021},

date = {2021-08-16},

journal = {Nanotechnology},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Full Dynamics Description of Mg Phthalocyanine Crystalline and Amorphous Semiconductor Systems},

author = {D Potamianos and M Nuber and A Schletter and M Schnitzenbaumer and M Haimerl and P Scigalla and M W\"{o}rle and L I Wagner and R Kienberger and H Iglev},

url = {https://doi.org/10.1021/acs.jpcc.1c04698},

doi = {10.1021/acs.jpcc.1c04698},

issn = {1932-7447},

year  = {2021},

date = {2021-08-16},

journal = {The Journal of Physical Chemistry C},

abstract = {Based on visible and mid-infrared transient absorption studies, probing the inter- and intraband dynamics, respectively, of magnesium phthalocyanine (MgPc) organic semiconductors, we were able to develop a model to describe the dynamics and the resulting optical response. We demonstrate how the model could offer insights into the dynamics of more complicated systems such as amorphous MgPc samples obtained by established preparation methods. In particular, we show a clear dimensionality difference of the exciton dissipation mechanism between crystalline and amorphous MgPc, which we resolve in the intraband dynamics, and how this result can also be deduced from the interband dynamics through the implementation of the developed model.},

keywords = {Foundry Inorganic, Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Short Excited‐State Lifetimes Mediate Charge‐Recombination Losses in Organic Solar Cell Blends with Low Charge‐Transfer Driving Force},

author = {R Shivhare and G J Moore and A Hofacker and S Hutsch and Y Zhong and M Hambsch and T Erdmann and A Kiriy and S C Mannsfeld and F Ortmann},

issn = {0935-9648},

year  = {2021},

date = {2021-08-15},

journal = {Advanced Materials},

pages = {2101784},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {All‐Dielectric Crescent Metasurface Sensor Driven by Bound States in the Continuum},

author = {J Wang and J K\"{u}hne and T Karamanos and C Rockstuhl and S A Maier and A Tittl},

issn = {1616-301X},

year  = {2021},

date = {2021-08-13},

journal = {Advanced Functional Materials},

pages = {2104652},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

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

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

issn = {1616-301X},

year  = {2021},

date = {2021-08-12},

journal = {Advanced Functional Materials},

pages = {2011210},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Morphology Transformation Pathway of Block Copolymer-Directed Cooperative Self-Assembly of ZnO Hybrid Films Monitored In Situ during Slot-Die Coating},

author = {T Tian and S Yin and S Tu and C L Weindl and K S Wienhold and S Liang and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202105644},

doi = {https://doi.org/10.1002/adfm.202105644},

issn = {1616-301X},

year  = {2021},

date = {2021-08-12},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2105644},

abstract = {Abstract Cooperative self-assembly (co-assembly) of diblock copolymers (DBCs) and inorganic precursors that takes inspiration from the rich phase separation behavior of DBCs can enable the realization of a broad spectrum of functional nanostructures with the desired sizes. In a DBC assisted sol\textendashgel chemistry approach with polystyrene-block-poly(ethylene oxide) and ZnO, hybrid films are formed with slot-die coating. Pure DBC films are printed as control. In situ grazing-incidence small-angle X-ray scattering measurements are performed to investigate the self-assembly and co-assembly process during the film formation. Combining complementary ex situ characterizations, several distinct regimes are differentiated to describe the morphological transformations from the initially solvent-dispersed to the ultimately solidified films. The comparison of the assembly pathway evidences that the key step in the establishment of the pure DBC film is the coalescence of spherical micelles toward cylindrical domains. Due to the presence of the phase-selective precursor, the formation of cylindrical aggregates in the solution is crucial for the structural development of the hybrid film. The pre-existing cylinders in the ink impede the domain growth of the hybrid film during the subsequent drying process. The precursor reduces the degree of order, prevents crystallization of the PEO block, and introduces additional length scales in the hybrid films.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Matrix Manipulation of Directly-Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering},

author = {F Li and Y Liu and G Shi and W Chen and R Guo and D Liu and Y Zhang and Y Wang and X Meng and X Zhang and Y Lv and W Deng and Q Zhang and Y Shi and Y Chen and K Wang and Q Shen and Z Liu and P M\"{u}ller-Buschbaum and W Ma},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202104457},

doi = {https://doi.org/10.1002/adfm.202104457},

issn = {1616-301X},

year  = {2021},

date = {2021-08-06},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2104457},

abstract = {Abstract The direct-synthesis of conductive PbS quantum dot (QD) ink is facile, scalable, and low-cost, boosting the future commercialization of optoelectronics based on colloidal QDs. However, manipulating the QD matrix structures still is a challenge, which limits the corresponding QD solar cell performance. Here, for the first time a coordination-engineering strategy to finely adjust the matrix thickness around the QDs is presented, in which halogen salts are introduced into the reaction to convert the excessive insulating lead iodide into soluble iodoplumbate species. As a result, the obtained QD film exhibits shrunk insulating shells, leading to higher charge carrier transport and superior surface passivation compared to the control devices. A significantly improved power-conversion efficiency from 10.52% to 12.12% can be achieved after the matrix engineering. Therefore, the work shows high significance in promoting the practical application of directly synthesized PbS QD inks in large-area low-cost optoelectronic devices.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Polaron-Assisted Charge Transport in Li-Ion Battery Anode Materials},

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

url = {https://doi.org/10.1021/acsaem.1c01767},

doi = {10.1021/acsaem.1c01767},

year  = {2021},

date = {2021-08-04},

journal = {ACS Applied Energy Materials},

abstract = {Lithium-ion batteries are without a doubt a key technology in the coming energy revolution. It is thus all the more surprising that one of the more prevalent Li battery anode materials, reduced lithium titanium oxide (LTO, Li4Ti5O12), is still poorly understood on a microscopic level. While recent theoretical and experimental evidence suggests that a polaron hopping mechanism is responsible for the increased electronic conductivity of reduced LTO, no such explanation exists for the concurrent improvements to the ionic mobility. In this computational study, we show that the presence of polaronic Ti3+ centers can indeed lead to a significant lowering of Li hopping barriers in both bulk and surface reduced LTO. For the latter, we find a reduced barrier height of roughly 40 meV compared to that of our pristine reference. This is in accordance with experimental findings showing that lithium-ion diffusion in reduced LTO is twice as high as that for pristine LTO. Finally, we show that\textemdashin accordance with experimental observations\textemdashpolaron formation upon lithiation of LTO leads to a similar behavior. Altogether, our analysis hints at a correlated movement of Li ions and polarons, highlighting LTO’s potential for rational defect engineering.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Interfacial Synthesis of Layer-Oriented 2D Conjugated Metal\textendashOrganic Framework Films toward Directional Charge Transport},

author = {Z Wang and L S Walter and M Wang and P S Petkov and B Liang and H Qi and N N Nguyen and M Hambsch and H Zhong and M Wang and S Park and L Renn and K Watanabe and T Taniguchi and S C B Mannsfeld and T Heine and U Kaiser and S Zhou and R T Weitz and X Feng and R Dong},

url = {https://doi.org/10.1021/jacs.1c05051},

doi = {10.1021/jacs.1c05051},

issn = {0002-7863},

year  = {2021},

date = {2021-08-03},

journal = {Journal of the American Chemical Society},

abstract = {The development of layer-oriented two-dimensional conjugated metal\textendashorganic frameworks (2D c-MOFs) enables access to direct charge transport, dial-in lateral/vertical electronic devices, and the unveiling of transport mechanisms but remains a significant synthetic challenge. Here we report the novel synthesis of metal-phthalocyanine-based p-type semiconducting 2D c-MOF films (Cu2[PcM\textendashO8]},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Advanced Printed Semiconductors for Energy and Electronic Applications},

author = {T Ameri and L Ke and N Gasparini and R Soltani and M G\"{u}nther and A Buyruk and A A Amin},

doi = {10.5185/vpoam.2021.05171},

year  = {2021},

date = {2021-08-03},

journal = {Video Proceedings of Advanced Materials},

volume = {2},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

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

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

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

doi = {10.1021/jacs.1c06403},

issn = {0002-7863},

year  = {2021},

date = {2021-08-02},

journal = {Journal of the American Chemical Society},

volume = {143},

number = {31},

pages = {12369-12379},

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

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Metamorphosis of Heterostructured Surface-Mounted Metal\textendashOrganic Frameworks Yielding Record Oxygen Evolution Mass Activities},

author = {S Hou and W Li and S Watzele and R M Kluge and S Xue and S Yin and X Jiang and M D\"{o}blinger and A Welle and B Garlyyev and M Koch and P M\"{u}ller-Buschbaum and C W\"{o}ll and A S Bandarenka and R A Fischer},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202103218},

doi = {https://doi.org/10.1002/adma.202103218},

issn = {0935-9648},

year  = {2021},

date = {2021-08-01},

journal = {Advanced Materials},

volume = {n/a},

number = {n/a},

pages = {2103218},

abstract = {Abstract Materials derived from surface-mounted metal\textendashorganic frameworks (SURMOFs) are promising electrocatalysts for the oxygen evolution reaction (OER). A series of mixed-metal, heterostructured SURMOFs is fabricated by the facile layer-by-layer deposition method. The obtained materials reveal record-high electrocatalyst mass activities of ≈2.90 kA g−1 at an overpotential of 300 mV in 0.1 m KOH, superior to the benchmarking precious and nonprecious metal electrocatalysts. This property is assigned to the particular in situ self-reconstruction and self-activation of the SURMOFs during the immersion and the electrochemical treatment in alkaline aqueous electrolytes, which allows for the generation of NiFe (oxy)hydroxide electrocatalyst materials of specific morphology and microstructure.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Temperature dependences of the double layer capacitance of some solid/liquid and solid/solid electrified interfaces. An experimental study},

author = {S A Watzele and L Katzenmeier and J P Sabawa and B Garlyyev and A S Bandarenka},

url = {https://www.sciencedirect.com/science/article/pii/S0013468621012597},

doi = {https://doi.org/10.1016/j.electacta.2021.138969},

issn = {0013-4686},

year  = {2021},

date = {2021-07-30},

journal = {Electrochimica Acta},

volume = {391},

pages = {138969},

abstract = {This study investigates the influence of the temperature on the electrical double layer capacitance (CDL) of various materials, which are essential for fuel cells and solid-state Li-ion batteries. Electrochemical impedance spectroscopy is utilized to measure the CDL of polycrystalline Pt/aqueous electrolytes interfaces, cathode catalyst layers of polymer electrolyte membrane fuel cells (PEMFC), and Au or Li electrodes in contact with a solid-state electrolyte (SSE), a prime example for solid-state ionics. Our results show that within the investigated temperature ranges, the CDL decreases with an increase in the temperature for Pt electrodes in an aqueous acidic electrolyte. However, for SSE and PEMFC cathode catalyst layers, the CDL increases with temperature. The CDL behavior with the temperature of herein presented systems is important for understanding and modeling of the interface processes for renewable energy conversion systems such as fuel cells, water electrolyzers, and batteries.},

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

pubstate = {published},

tppubtype = {article}

}