Efficiency Enhancement of ZnO Nanocrystalline Dye-Sensitized Solar Cells by Post-Treatment

Abstract

In this paper, ZnO nanocrystalline photoanodes were treated by zinc acetate aqueous solution. The effect of surface chemical modification processing on the photovoltaic performance and electrochemical properties of ZnO nanocrystalline dye-sensitized solar cells (DSSCs) were studied systematically. The SEM results revealed that the surface of the ZnO photoanode films were rough and some aggregations were formed after the surface chemical modification processing. The number of aggregations increased with increasing processing time, and showed wide grain size distribution simultaneously, which effectively increased the light scattering and decreased the grain boundaries to suppress the electron recombination. Moreover, the surface of these photoanode films were filled with micropores, which was benefit to the infiltration of electrolyte solution. The short circuit current density increased from 7.20 mA•cm-2 to 8.61 mA • cm-2 when post-treatment 20 min, and the maximum energy conversion efficiency reached 3.61%, which enhanced 43% compared with that without post-treatment.