High Photocurrent Quantum Yields in Short Wavelengths for Nanocrystalline Anatase-Type TiO2 Film Electrodes Compared with Those for Rutile-Type

Abstract

Abstract Photoelectrochemical activity of nanocrystalline TiO2 film electrodes prepared by use of various TiO2 particles has been studied comparatively. It is confirmed that the photocurrent (or photoactivity) for anatase-type TiO2 is in general higher than that for the rutile-type. The photocurrent quantum yield (ηpc) for anatase-type TiO2 is nearly equal to that for rutile-type in long wavelengths but increases more and more with decreasing wavelength in contrast to the ηpc for rutile-type, and thus the ηpc for anatase-type becomes much higher than the ηpc for rutile-type in short wavelengths around 300 nm, indicating that the high photoactivity for anatase-type TiO2 is due to this high ηpc in short wavelengths. There are some discussions on the reasons for the high ηpc for anatase-type TiO2 in short wavelengths, including the possibility of contribution of hot electrons or holes in the TiO2 film.