Preparation and performance of dye-sensitized solar cells based on ZnO-modified TiO2 electrodes

The ZnO-modified TiO2 electrode was prepared by adding Zn(CH3COO)(2)center dot 2H(2)O to the TiO2 colloid during the sol-gel production process, and was used in dye-sensitized solar cells (DSCs). The open circuit voltage (V-OC) and fill factor (ff) of the cells were improved significantly. The performance of the ZnO-modified TiO2 electrode such as dark current, transient photocurrent, impedance, absorption spectra, and flat band potential (V-fb) were investigated. It is found that the interface charge recombination impedance increases and V-fb shifts about 200 mV toward the cathodic potential. The effect mechanism of ZnO modification on the performance of DSCs may be that ZnO occupies the surface states of the TiO2 film.