Facile Synthesis of ZnO@TiO2 Core-Shell Nanorod Thin Films for Dye-Sensitized Solar Cells

Abstract

ZnO nanorod thin films grown on fluorine-doped tin oxide (FTO) glasses have been synthesized via facile thermal evaporation. To optimize the performance of dye-sensitized solar cells (DSSCs), we fabricated ZnO@TiO2 core-shell composite by a simple dip-coating method immersed in the mixed solution of Ti(OC4H9) and ethanol. Results of solar cell testing showed that ZnO@TiO2 core-shell nanorod thin films on FTO significantly increased open circuit voltage (from 0.47 V to 0.53 V), short circuit current (from 10.78 mA/cm2 to 13.98 mA/cm2), and fill factor (from 51% to 55%). The photoelectric conversion efficiency (PEC) increased from 3.3% for bare ZnO DSSCs to 4.85% for ZnO@TiO2 core-shell structured DSSCs. This is mainly ascribed to the improvement in light harvesting efficiency, electron transfer, and the effective suppression of charge recombination.