Direct observation of anisotropic small-hole polarons in an orthorhombic structure of BiVO₄ films
Name
PhysRevB.97.195150.pdf
Size
2.04 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Chaudhuri, A.
Mandal, L.
Chi, X.
Yang, M.
Scott, M. C.
Motapothula, M.
Yu, X. J.
Yang, P.
Venkatesan, T.
Wee, A. T. S.
Date Issued
May 2018
Journal
Physical Review B
Publisher
American Physical Society
Citation
Chaudhuri, A. et al. "Direct observation of anisotropic small-hole polarons in an orthorhombic structure of BiVO₄ films." Physical Review B 97, 19 (May 2018): 195150 © 2018 American Physical Society
Version
Final published version
Abstract
Here, we report an anisotropic small-hole polaron in an orthorhombic structure of BiVO₄ films grown by pulsed-laser deposition on yttrium-doped zirconium oxide substrate. The polaronic state and electronic structure of BiVO₄ films are revealed using a combination of polarization-dependent x-ray absorption spectroscopy at VL[subscript 3,2] edges, spectroscopic ellipsometry, x-ray photoemission spectroscopies, and high-resolution x-ray diffraction with the support of first-principles calculations. We find that in the orthorhombic phase, which is slightly different from the conventional pucherite structure, the unoccupied V 3d orbitals and charge inhomogeneities lead to an anisotropic small-hole polaron state. Our result shows the importance of the interplay of charge and lattice for the formation of a hole polaronic state, which has a significant impact in the electrical conductivity of BiVO₄, hence its potential use as a photoanode for water splitting.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.97.195150
