ZnO Nanorod-TiO2-Nanoparticulate Electrode for Dye-Sensitized Solar Cells

Highly dense ZnO nanorods were synthesized on TiO2-nanoparticulate coated fluorine-doped tin oxide (FTO) substrates by the chemical vapor deposition method for dye-sensitized solar cells (DSSCs). The uniformly grown ZnO nanorod layer has a thickness of similar to 4 mu m on the TiO2-nanoparticulate layer with a wurtzite structures as confirmed by the X-ray diffraction pattern. The DSSC fabricated with a ZnO nanorod/TiO2-nanoparticulate electrode had an overall light-to-electricity conversion efficiency eta of 3.7% with a short-circuit current density J(SC) of 8.12 mA/cm(2), open-circuit voltage V-OC of 0.76 V, and fill factor FF of 0.59, whereas ZnO nanowire/TiO2-nanoparticulate-electrode-based DSSCs exhibited a low eta of 1.1% with J(SC) of 2.14 mA/cm(2) and slightly high V-OC of 0.79 V. It is expected that the enhanced photovoltaic performance of the ZnO nanorod/TiO2-nanoparticulate electrode can be attributed to high dye loading and high light harvesting through large surface areas of ZnO nanorods incorporated with TiO2-nanoparticulate as compared with the ZnO nanowire/TiO2-nanoparticulate electrode. (C) 2009 The Japan Society of Applied Physics