Effect of calcination temperature on performance of ZnO nanoparticles for dye-sensitized solar cells

The photovoltaic performances of ZnO-based dye-sensitized solar cells (DSSCs) were studied using ZnO nanoparticles prepared via the sol–gel method in gelatin medium at different calcination temperatures. The effects of the calcination temperature on the size, surface area, photoluminescence properties, and dye adsorption ability of ZnO nanoparticles were investigated. The results showed that the size of the nanoparticles increased and the surface area decreased with an increase in the calcination temperature. In addition, the oxygen vacancies of the nanoparticles increased with an increase in the calcination temperature. Moreover, although the surface area of the nanoparticles prepared at 600 °C was lower than that of those prepared at 500 °C, their dye adsorption abilities were the same, and both were higher than that of those prepared at 700 °C. Electrochemical impedance spectroscopy and open-circuit voltage decay measurements were carried out to investigate the cell functions. The DSSC based on ZnO nanoparticles calcined at 600 °C exhibited the highest conversion efficiency because of its higher dye adsorption ability and lower recombination rate compared to the others.