Bandgap-adjustment and enhanced surface photovoltage in Y-substituted LaTaIVO2N
| Autor: | Cora Bubeck, Eberhard Goering, Eduardo Salas Colera, Mauro Coduri, Alexandra T. De Denko, Anke Weidenkaff, Songhak Yoon, Hongbin Zhang, Gunther Richter, Marc Widenmeyer, Frank E. Osterloh |
|---|---|
| Přispěvatelé: | Publica |
| Rok vydání: | 2020 |
| Předmět: |
crystal structure
X-ray photoelectron spectroscopy Materials science surface property Band gap Surface photovoltage Analytical chemistry carrier generation crystal structure analysis 02 engineering and technology 010402 general chemistry 01 natural sciences Ingeniería Industrial microcrystals surface photovoltage spectroscopy lanthanum compounds General Materials Science charge carrier recombination transparent conductor Spectroscopy density functional theory perovskite charge carrier Photons Materiales Renewable Energy Sustainability and the Environment N-type semiconductors Física Química tantalum compounds General Chemistry 021001 nanoscience & nanotechnology XANES 0104 chemical sciences energy gap Energías Renovables absorption structure Charge carrier Orthorhombic crystal system films weight fractions 0210 nano-technology Visible spectrum |
| Zdroj: | Journal of Materials Chemistry A. 8:11837-11848 |
| ISSN: | 2050-7496 2050-7488 |
| Popis: | Bubeck, C., et al. (2020). Correction: Bandgap-adjustment and enhanced surface photovoltage in Y-substituted LataivO2N. Journal of Materials Chemistry A, 8(26). https://doi.org/10.1039/D0TA90138E The authors regret that the affiliations for author Eduardo Salas Colera were not listed correctly on the original manuscript. The corrected list of affiliations for this paper is as shown here. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. Perovskite-type oxynitrides AB(O,N)3 are photocatalysts for overall water splitting under visible light illumination. In the past, structurally labile perovskite-type oxynitrides (e.g. YTaON2) were predicted to be highly suitable. In this work, we tackle the challenging YTa(O,N)3 synthesis by Y-substitution in LaTaIVO2N resulting in phase-pure La0.9Y0.1TaIVO2N, La0.75Y0.25TaIVO2N, and La0.7Y0.3TaIVO2N. By using microcrystalline YTaO4 together with an unconventional ammonolysis protocol we synthesized the highest reported weight fraction (82(2) wt%) of perovskite-type YTa(O,N)3. Ta4+ in La1−xYxTaIVO2N was verified by X-ray photoelectron spectroscopy (XPS) and X-ray near edge absorption structure (XANES) analysis. Density functional theory (DFT) calculations revealed a transparent conductor-like behavior explaining the unusual red/orange color of the Ta4+-containing perovskites. In combination with crystal structure analysis the DFT calculations identified orthorhombic strain as the main descriptor for the unexpected trend of the optical bandgap (EG,x=0.3 ≈ EG,x=0 < EG,x=0.1 < EG,x=0.25). Surface photovoltage spectroscopy (SPS) of particulate La1−xYxTaIVO2N (x = 0, 0.1, 0.25, 0.3) films revealed negative photovoltages at photon energies exceeding 1.75 eV, confirming that these materials are n-type semiconductors with effective bandgaps of ∼1.75 eV irrespective of the Y content. The photovoltage values increased with the Y content, suggesting an improved carrier generation and separation in the materials. However, increasing the Y content also slowed down the timescales for photovoltage generation/decay indicating trap states in the materials. Based on our results, we suggest a significantly weaker as classically assumed impact of reduced B-site metal cations such as Ta4+ on the photovoltage and charge carrier recombination rate. This work was supported by the Deutsche Forschungsgemeinschaft within the priority program SPP 1613 "Solar H2" (WE 2803/7-1). Support for surface photovoltage spectroscopy measurements was provided by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Grant DOE-SC0015329 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|