A5069346417- Advanced Photocatalysis Techniques
- Silicon and Solar Cell Technologies
- Electrocatalysts for Energy Conversion
- Thin-Film Transistor Technologies
- Organic Electronics and Photovoltaics
- Catalytic Processes in Materials Science
- Semiconductor materials and interfaces
- Perovskite Materials and Applications
- Conducting polymers and applications
- Quantum Dots Synthesis And Properties
- Molecular Junctions and Nanostructures
- Fluid Dynamics and Thin Films
- TiO2 Photocatalysis and Solar Cells
- Semiconductor materials and devices
- Chalcogenide Semiconductor Thin Films
- nanoparticles nucleation surface interactions
- Force Microscopy Techniques and Applications
- Silicon Carbide Semiconductor Technologies
- Luminescence Properties of Advanced Materials
- Electron and X-Ray Spectroscopy Techniques
- Silicon Nanostructures and Photoluminescence
- Solidification and crystal growth phenomena
- Copper-based nanomaterials and applications
- Fuel Cells and Related Materials
- Radiation Detection and Scintillator Technologies
Friedrich-Alexander-Universität Erlangen-Nürnberg
2015-2025
Forschungsinstitut für Anwendungsorientierte Wissensverarbeitung
2020
Institute of Crystallography
2017
University of Colorado Colorado Springs
1996
Oracle (United States)
1996
Itasca Consultants (Germany)
1991
University of Regensburg
1983
Abstract Light-induced halide segregation limits the bandgap tunability of mixed-halide perovskites for tandem photovoltaics. Here we report that light-induced is strain-activated in MAPb(I 1−x Br x ) 3 with concentration below approximately 50%, while it intrinsic over 50%. Free-standing single crystals CH NH Pb(I 0.65 0.35 (35%Br) do not show until uniaxial pressure applied. Besides, 35%Br grown on lattice-mismatched substrates (e.g. single-crystal CaF 2 inhomogeneous due to heterogenous...
With recent advances in the field of single-atoms (SAs) used photocatalysis, an unprecedented performance atomically dispersed co-catalysts has been achieved. However, stability and agglomeration SA on semiconductor surface may represent a critical issue potential applications. Here, photoinduced destabilization Pt SAs benchmark photocatalyst, TiO2 , is described. In aqueous solutions within illumination timescales ranging from few minutes to several hours, light-induced ensembles (dimers,...
Trapping sites in single atom (SA) catalysts are critical to the stabilization and reactivity of isolated atoms. Herein, we show that anchoring Pt SAs on TiO2 nanosheets is strongly aided by lattice incorporated fluorine species. Tailoring speciation a key factor for uniform stable dispersion high efficiency SA co-catalyzed photocatalytic H2 production. Fluorine-stabilized uniformly dispersed (001) surface can provide remarkable activity (a production rate 45.3 mmol h–1 mg–1 65 mW/cm2 365 nm...
Abstract In the present work, it is shown that anodic TiO 2 nanotubes (NTs) can be decorated with Pt, Pd, Rh, and Au single atoms (SAs) by a simple “dark deposition” approach. Such NTs surface trapped noble metal SAs provide high activity for photocatalytic H generation from pure water, i.e., in absence of sacrificial agent. However, metals also act as active centers undesired hydrogen back‐oxidation ( + O → ), leading to decrease overall production efficiency. Here reported use...
We disperse Pt single atoms (SAs) with different loading densities on anatase TiO2 thin films and evaluate the photocatalytic H2 generation as a function of incident light intensity. show that under common illumination intensities (such terrestrial solar illumination), minuscule SA ∼105 μm–2 (surface content ∼0.1 at.%) is sufficient to achieve maximized production rate. This results in maximum turnover frequency at atom site ∼300 molecules s–1. For vast majority conditions suitable surface...
Abstract The widespread application of green hydrogen production technologies requires cost reduction crucial elements. To achieve this, a viable pathway to reduce the iridium loading in proton exchange membrane water electrolysis (PEMWE) is explored. Herein, scalable synthesis method based on photodeposition process for TiO 2 @IrO x core–shell catalyst with reduced content as low 40 wt.% presented. Using this method, titania support particles homogeneously coated thin oxide shell only 2.1 ±...
Abstract Solid‐state dewetting is the heat‐induced agglomeration of thin metal films into defined nanoparticles (NPs). Dewetted Pt are investigated on F‐doped SnO 2 (FTO) substrates as model binder‐free electrodes for hydrogen evolution reaction (HER). Dewetting particles exposes FTO substrate and metal/support (Pt‐FTO) contact line. Despite decrease in electrochemical surface area (ECSA) upon dewetting, dewetted NPs show a >3‐fold increase ECSA‐normalized HER activity compared to...
Supported catalytically active liquid metal solutions (SCALMS) are materials composed of a alloy deposited on porous support. Due to the dynamic properties alloy, these systems suggested form single atom sites, resulting in unique catalytic properties. Ga-Ni SCALMS were successfully applied ethylene oligomerization, yielding catalysts that stable up 120 h time stream. A workflow based synchrotron-based X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) as well...
Direct measurements of concentration and velocity profiles in a polymeric lithium-ion battery electrolyte provide insights into the transference number.
Here, we evaluate three different noble metal co-catalysts (Pd, Pt, and Au) that are present as single atoms (SAs) on the classic benchmark photocatalyst, TiO2. To trap surface, introduced controlled surface vacancies (Ti3+-Ov) anatase TiO2 nanosheets by a thermal reduction treatment. After anchoring identical loadings of Pd, Au, measure photocatalytic H2 generation rate compare it to nanoparticle nanosheets. While nanoparticles yield well-established hydrogen evolution reaction activity...
The use of single atoms (SAs) has become a highly investigated topic in heterogeneous catalysis, electrocatalysis, and most recently also photocatalysis. In the field photocatalysis, Pt SAs on TiO 2 have been reported to be efficient co‐catalyst solar H production. Herein, deposition nanoparticles titania nanosheets is investigated. particular, species responsible for high co‐catalytic activity using cyanide leaching process elucidated. It shown that neither 0 nor majority do significantly...
Ti-deficient TiO2 nanosheets derived from lepidocrocite-type titanate delamination show a p-type conductivity with band gap widened by the quantum confinement effect to 3.7 eV. This shift in extended positions─and thus electron transfer level─allows direct photocatalytic nitrate reduction ammonia without use of any hole scavengers; this contrast classic TiO2. The deposition Pt single atoms as cocatalysts onto significantly enhances activity and selectivity toward ammonia, which outperforms...
In this contribution, the effect of Au alloying on solid state dewetting (SSD) kinetics and texture evolution AuNi AuAg thin films is investigated. For that bilayers a high (AuNi) low (AuAg) atomic mismatch system are fabricated different substrates annealed utilizing rapid thermal annealing furnace. Afterwards, degree SSD, as well texturing, investigated by correlating X-ray diffraction electron microscopy techniques. A quantitative analysis yields pure metal (Ni, Au, Ag) exhibit same 〈111〉...
Herein we introduce for the first time a reduced “grey” brookite TiO<sub>2</sub>photocatalyst, produced by thermal hydrogenation of nanoparticles, that shows remarkable noble metal free photocatalytic H<sub>2</sub>evolution.
X-ray reflectivity measurements of increasingly more complex interfaces involving silicon (001) substrates reveal the existence a thin low-density layer intruding between single-crystalline and amorphous native SiO2 terminating it. The importance accounting for this in modeling silicon/liquid silicon-supported monolayers is demonstrated by comparing fits measured curves models including excluding layer. inclusion layer, with 6–8 missing electrons per unit cell area, consistent one oxygen...
Current–voltage hysteresis is a major issue for normal architecture organo-halide perovskite solar cells. In this manuscript we reveal several-angstrom thick methylammonium iodide-rich interface between the and metal oxide. Surface functionalization via self-assembled monolayers allowed us to control composition of monolayer from Pb poor rich, which, in parallel, suppresses The bulk films not affected by engineering remains highly crystalline surface-normal direction over whole film...
Abstract Recently, the use of Pt in form single atoms (SA) has attracted considerable attention to promote cathodic hydrogen production reaction from water electrochemical or photocatalytic settings. First, produce suitable electrodes by SA deposition on Direct current (DC)‐sputter deposited titania (TiO 2 ) layers graphene—these allow characterization properties and their investigation high‐resolution HAADF‐STEM. For SAs loaded TiO , H evolution shows only a very small overpotential....
Metal-halide-perovskites revolutionized the field of thin-film semiconductor technology, due to their favorable optoelectronic properties and facile solution processing. Further improvements perovskite devices require structural coherence on atomic scale. Such perfection is achieved by epitaxial growth, a method that based use high-end deposition chambers. Here growth enabled via ≈1000 times cheaper device, single nozzle inkjet printer. By printing, single-crystal micro- nanostructure arrays...
In situ TEM utilizing windowed gas cells is a promising technique for studying catalytic processes, wherein temperature one of the most important parameters to be controlled. Current are only capable measurement on global (mm) scale, although local at spot observation (µm nm scale) may significantly differ. Thus, fluctuations caused by flow and heat dissipation dynamics remain undetected when solely relying device feedback. this study, we overcome limitation measuring specimen in...
This document is the unedited not peer-reviewed Author’s version of a Submitted Work to Chemistry Materials. The controlled assembly supraparticles using spray-drying enables synthesis nanoporous materials. Changing size constituent nanoparticles or their agglomeration states provides access diverse range pore frameworks. turns into ideal scaffolds in heterogeneous catalysis. combination with atomic layer deposition (ALD) as surface functionalization technique offers excellent control over...
Solid-state-Dewetting (SSD) of thin films is increasingly utilized to fabricate nanoparticles for catalysis. In-depth understanding particle formation mechanism crucial control key properties catalytic particles such as size, size distribution, and structure. In contrast most studies on SSD metal smooth substrates (e.g., SiO2/Si, …), here we investigate how the topography practical substrates, electrically conductive F-SnO2 (FTO), affects Pt – with potential use nanoparticle electrodes,...
Antimony sulfide (Sb$_2$S$_3$), a compound of earth-abundant elements with highly anisotropic, quasi-layered crystal structure, triggered growing interest as solar absorber in photovoltaics and phase change material memory devices, yet challenges remain achieving high-quality thin films controlled nucleation growth for optimal performance. Here, we investigate the transformation, structure properties, degradation atomic layer deposited Sb$_2$S$_3$ using situ TEM correlative ex analysis. The...
We demonstrate elastically filtered 3D Electron Diffraction (3D ED) as a powerful alternative technique to Grazing Incidence Wide-Angle X-ray Scattering (GIWAXS) for quantitatively characterizing the structure of organic semiconductor films. Using model material system solvent vapor annealed DRCN5T:PC71BM thin film, which is employed in solar cells (OSCs), we extract structural data obtained from ED and compare with that GIWAXS, utilizing both laboratory synchrotron sources. Quantitative...