Chemically grown ZnO nanorods for dye-sensitized solar cells

We report the synthesis and characterization of DSSCs based on N719 dye and ZnO nanorods. The nanorods were synthesized on fluorine doped tin oxide coated glass (FTO) substrate via chemical bath deposition method at 85 °C using zinc nitrate hexahydrate and hexamethylenetetramine. Prior to nanorods deposition, the substrates were coated with ZnO seed layer by spray pyrolysis technique. Our ZnO nanorods showed the hexagonal wurtzite structure and preferentially grew along the (002) direction. The lattice spacing between the crystal planes is estimated to be around 0.26 nm. The overall energy efficiencies of our DSSCs are ranged from 0.17% to 1.47%. These devices are found to be highly dependent on the dimensions of the ZnO nanorods. The best efficiency is obtained from solar cells composed of nanorods grown using 0.01 M precursor concentration, displaying 505 mV open circuit voltage, 6.415 mA/cm² short-circuit current and 1.47% overall conversion efficiency.