Dye-sensitizing effect of TiOPc thin film on n-TiO2 (001) surface

Hisao Yanagi, Siying Chen, Paul A. Lee, Ken W. Nebesny, Neal R. Armstrong, Akira Fujishima

Research output: Contribution to journalArticle

70 Scopus citations

Abstract

Dye-sensitization processes for the (001) surface of n-type titanium oxide (n-TiO2) single crystal coated with vacuum-deposited titanylphthalocyanine (TiOPc) were investigated by means of photoelectrochemical measurements and X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS). The electrode of n-TiO2 coated with TiOPc exhibited two photooxidation current bands in an aqueous electrolyte including hydroquinone (H2Q), due to direct excitation of n-TiO2 below 420 nm and electron transfer from TiOPc to n-TiO2 under the Q-band absorption of TiOPc at 600-800 nm, respectively. The former photocurrent process due to n-TiO2 excitation was remarkably decreased by presence of surface states, which originated from defects of oxygen induced by Ar ion bombardment of the n-TiO2 surface. The photooxidation process sensitized by the latter was evaluated from the determined energy levels of electronic bands for n-TiO2 and TiOPc. The LUMO level of TiOPc was located 0.3 eV above that of n-TiO2, which enabled electrons to transfer from TiOPc to n-TiO2. The excited state of TiOPc was not quenched by the surface states of n-TiO2 but was efficiently transferred to n-TiO2 at the n-TiO2/TiOPc interface.

Original languageEnglish (US)
Pages (from-to)5447-5451
Number of pages5
JournalJournal of physical chemistry
Volume100
Issue number13
StatePublished - Mar 28 1996

ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

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    Yanagi, H., Chen, S., Lee, P. A., Nebesny, K. W., Armstrong, N. R., & Fujishima, A. (1996). Dye-sensitizing effect of TiOPc thin film on n-TiO2 (001) surface. Journal of physical chemistry, 100(13), 5447-5451.