Superhydrophilicity and XPS study of boron-doped TiO 2

N. Masahashi, M. Oku

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

This study examines the superhydrophilicity and chemical state of boron-doped TiO 2 prepared by the ion implantation method and explores the effect of annealing on them. XRD measurements show that the implanted sample forms a polycrystalline structure of anatase with no trace of rutile. Their water-contact angles are significantly reduced upon irradiation with ultraviolet light. The Ti 2p XPS spectra of the oxide exhibit a shoulder peak at the lower binding energy side of the main peak, whereas no shoulder is observed in single-crystal and annealed TiO 2 . This suggests that the titanium ions with lower valences are produced by boron doping and they disappear on subsequent annealing. The SIMS depth profile of boron in the as-implanted TiO 2 exhibits a peak at a depth of 15-20 nm, whereas this peak disappears upon annealing. The water-contact angles increased on annealing under ultraviolet light illumination. It is concluded that the improvement in the superhydrophilicity by boron doping is due to the reduction of titanium, and the deterioration of superhydrophilicity with the subsequent annealing is due to the oxidation of reduced titanium and the inward diffusion of boron.

Original languageEnglish
Pages (from-to)7056-7060
Number of pages5
JournalApplied Surface Science
Volume254
Issue number21
DOIs
Publication statusPublished - 2008 Aug 30

Keywords

  • Chemical composition
  • Chemical state
  • Crystal structure
  • Ion implantation
  • Superhydrophilicity

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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