Preparation and property of dye-sensitized solar cells based ZnO-TiO₂ composite photoanodes

The composite photoanodes with different mass ratios of ZnO nano-flowers to TiO₂ nano-particles were prepared on transparent conductive fluorine-doped SnO₂ (FTO) substrates by doctor-blade technique. These anodes were sealed together with Pt-counter electrode to assemble into dye-sensitized solar cell(DSSC). The effect of mass ratio of ZnO nano-flowers to TiO₂ nano-particles on the performance and electron transport properties of DSSC were studied by means of the photocurrent-voltage curve and electrochemical impedance spectroscopy. The results show that open-circuit voltage and fill factor of DSSC increase with increasing the mass ratio of TiO₂ nanopartices in composite photoanodes. The energy conversion efficiency reaches 3.20% when the mass ratio of ZnO to TiO₂ is 83∶17. The impedance spectrum of DSSC assembled from ZnO-TiO₂ composite anodes is similar to Gerisher impedance, and the impedance of diffusion is coupled with impedance of recombination.