Effect of electronic-insulating oxides overlayer on the performance of zinc oxide based dye sensitized solar cells

Zinc oxide (ZnO) nanoparticles were successfully synthesized by facile microwave assisted route and the prepared ZnO was coated on the indium tin oxide (ITO) substrate by doctor blade technique. An ultrathin alumina (Al2O3) and silica (SiO2) overlayer were coated on the ZnO electrodes by liquid phase deposition method. In the overlayer coating, ZnO electrodes were dipped into the respective overlayer precursor solutions at various time interval (30, 60, and 90s) followed by sintering at 400 degrees C. These working electrodes were used to fabricate the dye sensitized solar cells (DSSCs) and their performances were analyzed. Low cost Rose Bengal (RB) dye was used as sensitizer for all the fabricated DSSCs. The role of dipping time on the performance of DSSCs was investigated. The results show that DSSCs with overlayer coated ZnO electrodes had higher power conversion efficiency (PCE) than those with bare ZnO electrode. Compared with bare ZnO electrodes, the increased dye loading and reduction of recombination contributed to the enhanced photovoltaic performance of overlayer coated ZnO electrodes. (C) 2015 Elsevier B.V. All rights reserved.