Charge carrier kinetics in ZnO films and nanorods

The kinetics of charge carriers in ZnO films and nanorods was analyzed by contactless transient photoconductance (TPC) measurements. The use of two excitation wavelengths allowed to identify the decay processes. The TPC signal displayed a significantly accelerated decay in ZnO films after sensitization with a ruthenium bipyridyl dye which was attributed to a higher electron–hole recombination whereas the electron–dye cation recombination was relatively slow. ZnO nanorods displayed no such destructive influence of the dye adsorption. Recombination processes took place over a large time range because of the heterogeneity of the samples.