Glutathione-protected Au-25 as well as Au-n (n = 15, 18, 22, 29, 33, 39) clusters adsorbed on TiO2 electrodes exhibit anodic photocurrents and negative shifts of photopotential in response to visible and/or near-infrared light. (400 < lambda < 900 nm) on the basis of HOMO-LUMO and similar transitions, indicating that the electrodes are applicable to the conversion of light to electricity (see figure).