A5044776032- Advanced Photocatalysis Techniques
- Copper-based nanomaterials and applications
- Chalcogenide Semiconductor Thin Films
- Electronic and Structural Properties of Oxides
- Quantum Dots Synthesis And Properties
- Gas Sensing Nanomaterials and Sensors
- Perovskite Materials and Applications
- Transition Metal Oxide Nanomaterials
- ZnO doping and properties
- Iron oxide chemistry and applications
- TiO2 Photocatalysis and Solar Cells
- Semiconductor materials and devices
- Ga2O3 and related materials
- Electrocatalysts for Energy Conversion
- Luminescence Properties of Advanced Materials
- Machine Learning in Materials Science
- Pigment Synthesis and Properties
- Advanced Condensed Matter Physics
- Solid-state spectroscopy and crystallography
- Silicon Nanostructures and Photoluminescence
- Silicon and Solar Cell Technologies
- Semiconductor materials and interfaces
- Anodic Oxide Films and Nanostructures
- Conducting polymers and applications
- Multiferroics and related materials
Helmholtz-Zentrum Berlin für Materialien und Energie
2016-2025
Solar Fuels Institute
2017-2020
Total (Belgium)
2017
Joint Center for Artificial Photosynthesis
2015-2017
California Institute of Technology
2015-2017
Helmholtz-Zentrum Dresden-Rossendorf
2013
Broad Institute
2007
Leibniz Institute for Zoo and Wildlife Research
2007
Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute
2006
Fraunhofer Institute for Silicon Technology
1995
CuBi2O4 is a multinary p-type semiconductor that has recently been identified as promising photocathode material for photoelectrochemical (PEC) water splitting. It an optimal bandgap energy (∼1.8 eV) and exceptionally positive photocurrent onset potential (>1 V vs RHE), making it ideal candidate the top absorber in dual PEC device. However, photocathodes made from have not yet demonstrated high photoconversion efficiencies, factors limit efficiency fully identified. In this work we...
A new strategy of using forward gradient self-doping to improve the charge separation efficiency in metal oxide photoelectrodes is proposed. Gradient self-doped CuBi2O4 photocathodes are prepared with and reverse gradients copper vacancies a two-step, diffusion-assisted spray pyrolysis process. Decreasing Cu/Bi ratio introduces Cu that increase carrier (hole) concentration lowers Fermi level, as evidenced by shift flat band toward more positive potentials. Thus, leads an internal electric...
Abstract Addressing the intrinsic charge transport limitation of metal oxides has been significance for pursuing viable PEC water splitting photoelectrodes. Growing a photoelectrode with conductive nanoobjects embedded in matrix is promising enhanced but remains challenge technically. We herein show strategy embedding laser generated nanocrystals BiVO 4 photoanode matrix, which achieves photocurrent densities up to 5.15 mA cm −2 at 1.23 V RHE (from original 4.01 ) single configuration, and...
Interest in delafossite (CuFeO2) as a candidate p-type photocathode for photoelectrochemical (PEC) solar fuel production has recently been increasing, mainly due to its excellent stability aqueous environments and favorable light absorption properties. However, PEC performance remained poor reasons that have not yet specifically determined. Herein, we report detailed investigation on sol–gel-processed CuFeO2 with range of spectroscopic, PEC, microscopy techniques aimed at unraveling the...
Interfacial CoO x layers provide a route to stable, high-performance Si photoanodes for water splitting, without requiring np + homojunctions.
BiVO4 is a promising photoanode candidate for water splitting applications, but its microscopic charge carrier transport properties are not yet fully understood. We investigated the photoinduced mobility undoped and 1% tungsten-doped thin films in an early time window from 1 ps to ns using THz spectroscopy. The combined electron–hole effective gradually decreases with by order of magnitude starting at upper limit ∼0.4 cm2 V–1 s–1. loss attributed localization. provide first direct...
Abstract Widespread application of solar water splitting for energy conversion is largely dependent on the progress in developing not only efficient but also cheap and scalable photoelectrodes. Metal oxides, which can be deposited with techniques are relatively cheap, particularly interesting, high efficiency still hindered by poor carrier transport properties (i.e., mobility lifetime). Here, a mild hydrogen treatment introduced to bismuth vanadate (BiVO 4 ), one most promising metal oxide...
Heat treatment under different atmospheres influences defect formation and suppression in BiVO<sub>4</sub>, which significantly affect its carrier dynamics.
Abstract Mobilities and lifetimes of photogenerated charge carriers are core properties photovoltaic materials can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model current‐voltage characteristics a solar cell such To this end, impact measurement conditions, alternate interpretations, experimental inter‐laboratory variations discussed using (Cs,FA,MA)Pb(I,Br) 3 halide perovskite...
The semiconductor-liquid junction (SCLJ), the dominant place in photoelectrochemical (PEC) catalysis, determines interfacial activity and stability of photoelectrodes, whcih directly affects viability PEC hydrogen generation. Though efforts dedicated past decades, a challenge remains regarding creating synchronously active stable SCLJ, owing to technical hurdles simultaneously overlaying two advantages. present work demonstrates that an SCLJ with unique configuration dual layers can yield...
Abstract The knowledge of minority and majority charge carrier properties enables controlling the performance solar cells, transistors, detectors, sensors, LEDs. Here, we developed constant light induced magneto transport method which resolves electron hole mobility, lifetime, diffusion coefficient length, quasi-Fermi level splitting. We demonstrate implication for silicon metal halide perovskite films. resolve electrons holes predicting material’s effectiveness cell application without...
Mesoporous WO<sub>3</sub> thin film exhibits a higher photocurrent compared to the dense obtained in same conditions.
α-SnWO4 is an n-type metal oxide semiconductor that has recently attracted attention as a top absorber material in D4-tandem device for highly efficient solar water splitting due to the combination of ideal bandgap (∼1.9 eV) and relatively negative photocurrent onset potential (∼0 V vs RHE). However, up now, photoanodes have not shown high photoconversion efficiencies reasons yet been fully elucidated. In this work, phase-pure films are successfully prepared by pulsed laser deposition. The...
Monoclinic copper vanadate (n-type Cu2V2O7) thin film photoanodes were prepared for the first time by spray pyrolysis and evaluated photoelectrochemical (PEC) water oxidation. The parameters optimized to obtain phase-pure of β-Cu2V2O7 (ziesite). bandgap energy is ∼2.0 eV, which corresponds a theoretical solar-to-hydrogen (STH) efficiency 16% if it can be paired with an appropriate photocathode in tandem device drive overall splitting. However, all Cu2V2O7 so far have shown relatively low...
Molybdenum doping in FeVO<sub>4</sub> photoanodes enhances the charge carrier mobility and lifetime, resulting a 45% AM1.5 photocurrent increase.
Abstract Highly (001)-textured, photoactive WSe 2 thin films have been prepared by an amorphous solid-liquid-crystalline solid process promoted palladium. By increasing the thickness of Pd promoter film (≥10 nm) structure and texture can be improved significantly. However, these as-crystallized are only weakly in a 0.5 М H SO 4 electrolyte under AM 1.5 solar irradiation which we attribute to inefficient photogenerated charge transfer across /electrolyte interface via prevailing van der Waals...
Recent progress on bismuth vanadate (BiVO4) has shown it to be among the highest performing metal oxide photoanode materials. However, further improvement, especially in form of thin film photoelectrodes, is hampered by its poor charge carrier transport and relatively wide bandgap. Here, sulfur incorporation used address these limitations. A maximum bandgap decrease ∼0.3 eV obtained, which increases theoretical solar-to-hydrogen efficiency from 9 12%. Hard X-ray photoelectron spectroscopy...
Abstract Cuprous oxide (Cu 2 O) is a promising material for solar-driven water splitting to produce hydrogen. However, the relatively small accessible photovoltage limits development of efficient Cu O based photocathodes. Here, femtosecond time-resolved two-photon photoemission spectroscopy has been used probe electronic structure and dynamics photoexcited charge carriers at surface as well interface between platinum (Pt) adlayer. By referencing ultrafast energy-resolved sensitive bulk data...
Abstract Sb 2 Se 3 has emerged as an important photoelectrochemical (PEC) and photovoltaic (PV) material due to its rapid rise in photoconversion efficiencies. However, a complex defect chemistry, which reduces the maximum photovoltage. Thus, it is understand these defects develop passivation strategies . A comprehensive investigation of charge carrier dynamics influence sulfur treatment on optoelectronic properties performed using time‐resolved microwave conductivity (TRMC),...
Abstract It is widely accepted that metal oxide‐based photoelectrodes (MOPs) hold great promise for future solar hydrogen generation but are facing awkward challenge arising from their low intrinsic carrier mobility. The highly polarized nature of the predominantly ionic metal‐oxygen bond always leads to formation small polarons responsible localized trapping photo‐generated carriers. Present study explores reduction carriers transport barrier via bulk embedding ferroelectric nanodomains...
Abstract AlInP (001) is widely utilized as a window layer in optoelectronic devices, including world‐record III‐V multi‐junction solar cells and photoelectrochemical (PEC) cells. The chemical electronic properties of depend on its surface reconstruction, which impacts interaction with electrolytes PEC applications passivation layers. This study investigates reconstructions using density functional theory experimental methods. Phosphorus‐rich (P‐rich) indium‐rich (In‐rich) surfaces are...