Light Intensity Independent Electron Transport and Slow Charge Recombination in Dye-Sensitized In 2 O 3 Solar Cells: In Contrast to the Case of TiO 2

Dye-sensitized solar cells (DSCs) were fabricated from In 2 O 3 nanoparticles with an electrolyte containing the I − /I 3 − redox couple. Current transients were measured by a pulsed laser and a diode laser, showing light intensity independent current transients, which have not been seen from dye-sensitized TiO 2, ZnO, and SnO 2 solar cells. The response of the current transients was altered when bias potential was applied, suggesting that the electron transport is not due to diffusion. On the other hand, the lifetime of injected electrons in the In 2 O 3, while showing longer values than electrons in TiO 2, displayed similar light intensity dependence to that observed in TiO 2 DSCs, suggesting the interfacial electron transfer occurs in the Marcus normal region.