Optimizing photoabsorbers for water splitting: ab initio calculation of defective WO$_{3}$

ORAL

Abstract

Tungsten trioxide (WO$_{3}$) is a promising photoabsorber for water splitting [1], widely studied in the last decade. By means of ab initio simulations with dielectric-dependent hybrid functionals [2], we investigated a realistic model of the most stable surface of WO$_{3}$, which presents a high concentration of oxygen vacancies. We found multiple, stable local minima of the WO$_{3}$ surface, that may be attained depending on the type of lattice distortions occurring close to defects at finite temperature. Our results showed that the potential energy surface of the defective WO$_{3}$ surface is highly corrugated, with singlet and triplet states close in energy, and associated frontier orbitals with different localization properties. We gained insight on the effect on transport properties and of charge localization at the surface by using first principles molecular dynamics. [1] Q.X. Mi, Y. Ping, Y. Li, B.F. Cao, B.S. Brunschwig, P.G. Khalifah, G. Galli, H.B. Gray, and N.S. Lewis, J. Am. Chem. Soc. 134, 18318 (2012) [2] J.H. Skone, M. Govoni, and G. Galli, Phys. Rev. B 89, 195112 (2014)

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Authors

  • Matteo Gerosa

    University of Chicago, Chicago, IL 60637, USA

  • Francois Gygi

    Department of Computer Science, University of California Davis, Davis, CA 95616, University of California, Davis, CA 95616, USA, University of California, Davis, University of California Davis

  • Giulia Galli

    Univ of Chicago and Argonne National Laboratory, Univ of Chicago, University of Chicago; Argonne National Laboratory, Institute for Molecular Engineering, University of Chicago; Argonne National Laboratory, Institute for Molecular Engineering, University of Chicago and Materials Science Division, Argonne Natl Lab, Institute for Molecular Engineering, University of Chicago; Materials Science Division, Argonne National Laboratory, Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637 and Materials Science Division, Argonne National Laboratory, Lemont, IL, Institute for Molecular Engineering, University of Chicago and Argonne Natl Lab, University of Chicago, Chicago, IL 60637, USA, The University of Chicago, Institute for Molecular Engineering and Argonne National Laboratory, Argonne National Laboratory and University of Chicago, Institute for Molecular Engineering, University of Chicago and Materials Science Division, Argonne National Laboratory, University of Chicago, The University of Chicago, University of Chicago and Argonne National Laboratory