The nature of photogenerated charge separation among different crystal facets of BiVO4 studied by density functional theory

Taifeng Liu, Xin Zhou, Michel Dupuis, Can Li

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Charge separation among different crystal facets of a semiconductor has been observed experimentally, but the underlying reasons behind this phenomenon are unknown. In this work, the activation energies of carrier hopping and the mobility of electron/hole transport along seven low-index crystal orientations of bulk BiVO4 have been calculated using a small polaron model. The calculated mobility and our previous experimental results reveal that there is a parallel relationship between the carrier mobility along the crystal axis and the carrier preferred accumulation on the corresponding crystal facets. It is proposed that the mobility of electrons (or holes) along the crystal axis [hkl] might be essentially related to the charge separation among the indices of corresponding facets (hkl); namely, the mobility of electrons (or holes) along the crystal axis [hkl] is the largest among all possible crystal axes, and the photogenerated electrons (or holes) tend to be accumulated on the indices of the corresponding facet (hkl) when the surface factors like surface band bending, surface energetic differences, etc. are not considered.

Original languageEnglish
Pages (from-to)23503-23510
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number36
DOIs
Publication statusPublished - Aug 6 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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