Photoeffects of Semiconductor Electrolyte Interfaces
Abstract
Materials based on modified transition metal oxide semiconductors for the photoelectrochemical decomposition of H2O were investigated. Single crystals of TiO2 doped with VO2 were made and it was demonstrated that the bandgap was decreased from 3.03 eV to 1.99 eV. The flatband potential was increased from -1. 0 V to 0,25 V. Both effects are attributed to the existence of an empty vanadium d-band located in the TiO2 bandgap. Another approach was taken with FeTiO3-Fe203 alloys in the form of amorphous thin films and single crystals, where it was anticipated that the charge-transfer interactions observed in such alloys could be exploited in the materials' photoelectrochemical properties. The effect of FeTiO3 had very little effect on the overall properties of FE2O3 single crystals. On the other hand the effect on the Fe/Ti oxide thin films was quite dramatic. Optical absorption, photoconductivity and photoelectrolytic spectral measurement demonstrate a photometric enhancement at energies above the bandgap for Ti concentrations in the range of 5% to 8%. There is some suggestion that the bandgap has been reduced in this concentration regime. Higher concentrations of Ti result in a change from n-type to p-type. Efficiency and stability of thermally oxidized Fe/Ti oxide films are comparable to single crystal results. Keywords include: Photoelectrolysis, Photoanode, Transition metal semiconductor, TiO, VO2, FE2O3, FeTiO3, Reduced bandgap, Charge transfer absorption, Amorphoous film, and Photoconductivity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA154163
Entities
People
- J. C. Murphy
- K. Moorjani
- T. O. Poehler
- Terry E. Phillips
Organizations
- Johns Hopkins University