Sn doped In2O3 nanowires for enhanced photocurrent generation for photoelectrodes

High-quality single-crystalline Sn-doped In2O3 (ITO) nanowires (NWs) with diameters of about 60-80 nm and lengths of several tens of micrometers were produced using a simple thermal co-evaporation method at a substrate temperature of ~540 °C. The electrical conductivity of as-synthesized ITO NW was ~115.9 S/cm at room temperature. Photocurrent generation devices were prepared by self-assembling di(3-aminopropyl)viologen and Ru(2,2′-bipyridine-4,4′-dicarboxylic acid)2(NCS)2 on the surface of ITO NWs. The maximum photocurrent density of the device with an ITO NW electrode under illumination of 100 mW/cm2 was 11.05 μA/cm2, which is about three orders of magnitude larger than that of the device with a bare ITO thin film electrode. The high photocurrent density could be attributed to the large surface area, high crystallinity, and electrical conductivity of the ITO NW electrode.