Charge transport in nanostructured thin-film electrodes

A review. Recent work on the charge transport in mesoscopic nanostructured film electrodes is summarized. Results from intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS) studies are given, and the attempts to model the charge transport through the dye-sensitized semiconductor (SC) film are discussed. The charge transport is mainly diffusional and the electrons are driven by a 1D concn. gradient of the electrons normal to the conducting substrate. The SC and the electrolyte are regarded as one effective medium. The charge sepn. and kinetics at the nanostructured-semiconductor, electrode/electrolyte interface (NSEI) is strongly affected by the redistribution of ions and dipoles between the soln. in the pores and the surface of the nanostructured SC. Trapping and detrapping of electrons is regarded as the main cause of the slow transport.