Nanoscale imaging of charge carrier transport in water splitting photoanodes

• DOI: 10.1038/s41467-018-04856-8
• Publication Date: 2018-06-27T15:40:55Z
• Authors: Johanna Eichhorn; Christoph Kastl; Jason K. Cooper; Dominik Ziegler; Adam M. Schwartzberg; Ian D. Sharp; Francesca M. Toma
• Keywords: Science; 02 engineering and technology; Microscopy, Atomic Force; 530; Physical Chemistry; 7. Clean energy; Article; Engineering; Solar Energy; Nanotechnology; Electrodes; Microscopy; Spectrum Analysis; Q; Electric Conductivity; Atomic Force; Water; Materials Engineering; 540; Photochemical Processes; Nanostructures; Semiconductors; Chemical Sciences; Vanadates; 0210 nano-technology; Bismuth

AbstractThe performance of energy materials hinges on the presence of structural defects and heterogeneity over different length scales. Here we map the correlation between morphological and functional heterogeneity in bismuth vanadate, a promising metal oxide photoanode for photoelectrochemical water splitting, by photoconductive atomic force microscopy. We demonstrate that contrast in mapping electrical conductance depends on charge transport limitations, and on the contact at the sample/probe interface. Using temperature and illumination intensity-dependent current–voltage spectroscopy, we find that the transport mechanism in bismuth vanadate can be attributed to space charge-limited current in the presence of trap states. We observe no additional recombination sites at grain boundaries, which indicates high defect tolerance in bismuth vanadate. These findings support the fabrication of highly efficient bismuth vanadate nanostructures and provide insights into how local functionality affects the macroscopic performance.