Influence of Fe2O3 in ZnO/GO-based dye-sensitized solar cell

Abstract

This work aims to study the influence of Fe2O3 in ZnO/GO-based DSSC incorporating PAN-based gel electrolyte. ZnO–Fe2O3/GO thin films and gel electrolyte were prepared using the sol–gel technique via spin-coating and polymerization of polyacrylonitrile (PAN) methods, respectively. The insertion of Fe2O3 in ZnO/GO improved the open-circuit voltage and fill factor significantly. However, large amount of Fe2O3 (0.3%) inhibited the electron transport with high electron recombination rate (keff = 3044.62 s−1). The main reason for the low efficiency in ZnO–Fe2O3(0.3%)/GO is due to the energy band misalignment with the failure of the excited electron from the LUMO of dye into the conduction band of ZnO–Fe2O3(0.3%)/GO. The study found that the optimum concentration of Fe2O3 is 0.2% for an efficient DSSC. ZnO–Fe2O3(0.2%)/GO-based DSSC exhibited slow electron recombination of 0.751 s−1. Moreover, the fine nanoparticles of ZnO–Fe2O3(0.2%)/GO observed through field emission electron microscopy show a more porous structure that improved the short-circuit current density in DSSC.