Plasmon-induced charge separation (PICS) by continuous electron injection from plasmonic compound nanoparticles to a semiconductor was achieved by using solid-state cells based on tin-doped indium oxide (ITO) nanoparticles with a short capping agent and a TiO₂ film. The cells extended the PICS range to longer wavelengths and exhibited photoresponses to 1500–2200 nm near-infrared light.