Dye sensitization of low-bandgap semiconductor electrodes: cuprous oxide photocathode sensitized with methyl violet

Abstract

When illuminated, dye-coated semiconductor electrodes inject electrons (holes) into the conduction (valence) band so that the photoresponse of high-bandgap semiconductors is extended to the visible region. It is found that when low-bandgap semiconductor electrodes are coated with dyes, the photocurrent in the bandgap region wavelengths is also enhanced. The effect is explained as originating from suppression of the recombination of carriers generated by photons captured directly by the semiconductor surface.