Dye-sensitized solar cells based on ZnO nanoflowers and TiO2 nanoparticles composite photoanodes

ZnO nanoflowers were synthesized by low temperature solution-phase method. ZnO nanoflowers/TiO2 nanoparticles composite photoanodes with various mass ratios were prepared on transparent conductive fluorine-doped tin oxide substrates by doctor-blade technique. The dye-sensitized solar cells (DSSCs) were assembled. The morphology characteristics of ZnO nanoflowers and ZnO/TiO2 composite photoanodes have been analyzed by scanning electron microscopy. The effect of the ZnO nanoflowers/TiO2 nanoparticles mass ratio on the performance of DSSCs was systematically investigated by I–V characteristics and electrochemical impedance spectroscopy. Results show that the conversion efficiency of the dye-sensitized solar cell with a ZnO/TiO2 mass ratio of 25:75 was increased by about 35 % compared to that of pure TiO2-based solar cell. Addition of ZnO nanoflowers can enhance the light harvesting and improve electron transport.