INVESTIGATION OF THE ELECTRONIC TRANSPORT-PROPERTIES OF NANOCRYSTALLINE PARTICULATE TIO2 ELECTRODES BY INTENSITY-MODULATED PHOTOCURRENT SPECTROSCOPY

The transport of photogenerated electrons through nanocrystalline part iculate TiO2 electrodes has been investigated by intensity modulated p hotocurrent spectroscopy, using UV light for electron-hole pair genera tion. The optoelectrical admittance has been compared with that obtain ed with nanoporous crystalline GaP electrodes in which the transport o f electrons through the porous network is simply diffusive. It is foun d that transport of photogenerated electrons through particulate TiO2 electrodes is limited by trapping/detrapping in band gap states distri buted in energy. It is argued that the electron traps are located at t he TiO2/electrolyte interface.