Photoelectrochemical studies of vanadyl phthalocyanine (VOPc) thin film electrodes

Thomas Klofta, Clovis Linkous, Neal R. Armstrong

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Photoactive vanadyl phthalocyanine (VOPc) thin films have been prepared by vacuum deposition on gold metallized plastic optically transparent electrode (MPOTE) substrates. The morphology of the film as determined by scanning electron microscopy (SEM) revealed the existence of two types of crystallites at the surface. Photoelectrochemical studies of these thin films were undertaken using different redox couples in aqueous solution. For redox couples with standard electrochemical potentials negative of +0.33 V vs. Ag/AgCl, positive photopotentials were observed (i.e., the films behave as photocathodes). Those redox couples with E°'s situated positive of +0.33 V exhibited reversible electrochemical behavior independent of illumination at the VOPc electrode. These results suggest a clear p-type semiconducting nature for the VOPc system. Mott-Schottky capacitance data revealed an acceptor density of 6×1018 cm-3 which is speculated to be attributed to the inclusion of dioxygen within the VOPc lattice as supported by X-ray photoelectron spectroscopy (XPS). A power conversion efficiency of 0.1% was observed for the photoassisted evolution of hydrogen which did not require the addition of micro-islands of platinum to the VOPc surface.

Original languageEnglish (US)
Pages (from-to)73-92
Number of pages20
JournalJournal of Electroanalytical Chemistry
Volume185
Issue number1
DOIs
StatePublished - Apr 10 1985

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

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