Controlling Anisotropies in α-SnWO4 Photoanodes for Solar Water Oxidation

Controlling Anisotropies in α-SnWO4 Photoanodes for Solar Water OxidationRonen Gottesman aa Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Mount Scopus JerusalemProceedings of The Future of Hydrogen: Science, Applications and Energy Transition (H2Future)Ibiza, Spain, 2024 April 17th - 19thOrganizers: Carolina Gimbert Suriñach, Sixto Gimenez Julia and Emilio PalomaresInvited Speaker, Ronen Gottesman, presentation 001DOI: https://doi.org/10.29363/nanoge.hfuture.2024.001Publication date: 27th February 2024Unique insights into the synthesis-structure-properties dependencies of α-SnWO4 photoanodes will be presented, enabled by synthesis conditions far from thermodynamic equilibrium (i.e., non-equilibrium, NE) based on plasma deposition processes combined with rapid thermal processing (RTP).[1] Recently, we have shown that a highly controlled NE synthesis approach based on pulsed laser deposition (PLD) combined with RTP had significant effects on the crystallinity, morphology, crystallographic orientation, and sulfite oxidation performances of α-SnWO4, culminating in photocurrents ~ 70 % higher than PLD-grown photoanodes annealed via conventional furnaces (furnace heating, FH).[2] In a follow-up study of the structural and electronic properties of α-SnWO4 films annealed via RTP and FH, we utilized X-ray diffraction texture analysis, electron backscatter diffraction in scanning electron microscopy, and atomic force microscopy modes of Kelvin probe, electrical conductivity, and tapping mode for surface morphology. Our results show that the local (micrometer-scale) crystallographic orientation is very homogenous in the RTP-treated films, both in-plane and perpendicular to the substrate. Considering their reported higher crystallinity and the anisotropic charge transport nature of orthorhombic α-SnWO4,[2–4] the RTP-treated films demonstrate significant changes in contact potential difference (CPD) and conductivity. The CPD between α-SnWO4 and platinum-coated silicon tip was ~ 0.35 eV lower than the CPD of the FH-treated films, indicating increased band bending. This suggests that the RTP treatment strongly contributes to an increased driving force for charge injection. In addition, the local conductivity of the RTP-treated films was higher by more than two orders of magnitude than that of the FH-treated films. Our results can lead toward broader tunable materials synthesis and design pathways and more scalable discovery and development of new chemical spaces of multinary and multifunctional metal-oxide photoelectrodes inaccessible through conventional solid-state reactions.[5] References:[1] Gottesman, R.; Song, A.; Levine, I.; Krause, M.; Islam, A. T. . N.; Abou-Ras, D.; Dittrich, T.; van de Krol, R.; Chemseddine, A. Pure CuBi2O4 Photoelectrodes with Increased Stability by Rapid Thermal Processing of Bi2O3/CuO Grown by Pulsed Laser Deposition. Adv. Funct. Mater. 2020, 28, 1910832.[2] Gottesman, R.; Peracchi, I.; Gerke, J.; Irani, R.; Abdi, F. F.; van de Krol, R. Shining a Hot Light on Emerging Photoabsorber Materials : The Power of Rapid Radiative Heating in Developing Oxide Thin-Film Photoelectrodes. ACS Energy Lett. 2022, 7, 514–522.[3] Ziani, A.; Harb, M.; Noureldine, D.; Takanabe, K. UV-Vis Optoelectronic Properties of α-SnWO4: A Comparative Experimental and Density Functional Theory Based Study. APL Mater. 2015, 3, 3–8.[4] Kong, H.; Abdi, F. F. Recent Progress in the Development of Tin Tungstate (α-SnWO4) Photoanodes for Solar Water Oxidation. Inorg. Chem. Front. 2023, 10, 7109–7125.[5] Gottesman, R.; Levine, I.; Schleuning, M.; Irani, R.; Abou-ras, D.; Dittrich, T.; Friedrich, D.; van de Krol, R. Overcoming Phase-Purity Challenges in Complex Metal Oxide Photoelectrodes: A Case Study of CuBi2O4. Adv. Energy Mater. 2021, 11, 2003474.Acknowledgements:The work was done with Prof. Roel van de Krol from the Institute of Solar Fuels and Dr. Daniel Abou-Ras from the Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin, Germany, and Prof. Oded Millo and Dr. Doron Azulay from the Racah Institute of Physics, The Hebrew University of Jerusalem, Israel. © FUNDACIO DE LA COMUNITAT VALENCIANA SCITOnanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. 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