Behavior and energy state of photogenerated charge carriers in single-crystalline and polycrystalline powder SrTiO3 studied by time-resolved absorption spectroscopy in the visible to mid-infrared region

Akira Yamakata, Junie Jhon M. Vequizo, Masayuki Kawaguchi

Research output: Contribution to journalArticlepeer-review

73 Citations (Scopus)

Abstract

The effects of defects on the behavior of photogenerated charge carriers in SrTiO3 (STO) are studied by time-resolved absorption spectroscopy from the visible to mid-IR region. In the case of defect-free single-crystalline STO, free and shallowly trapped electrons are dominant, but they recombine within 50 ns. By contrast, in the case of defect-rich powder STO, the electron lifetime is much longer than 1 ms. The transient absorption spectra show that most of the charge carriers in powder STO are trapped in the defects, which elongates their lifetime. We found that these trapped carriers are nevertheless reactive toward O2 or CH3OH that depends on the trap depth. The steady-state photocatalytic activity is strongly correlated with the lifetime and the reactivity of the trapped charge carriers: the energy state of electrons can be deduced from the spectral shape, especially in the mid-IR region. (Figure Presented).

Original languageEnglish
Pages (from-to)1880-1885
Number of pages6
JournalJournal of Physical Chemistry C
Volume119
Issue number4
DOIs
Publication statusPublished - Jan 29 2015
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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