Fabrication of In2O3 functionalized ZnO based nanoheterojunction photoanode for improved DSSC performance through effective interfacial charge carrier separation

Abstract

This report is to address the limitation of conventional dye-sensitized solar cells (DSSCs) designed using pristine ZnO and N719 dye, which suffers from low performance due to the high charge carrier recombination and the formation of Zn2+-N719 complex over the surface of photoanode. Here we demonstrate the fabrication of ZnO–In2O3 heterojunction based photoanode to extend the charge carrier lifetime by effective interfacial transfer and to boost the light harvesting capacity in dye sensitized solar cells. This opted strategy also helps to prevent the formation dye complex over the photoanode surface. As a result, ZnO–In2O3 heterojunction with optimal composite ratio (1:1) could show better DSSC performance compared to remaining samples when applied as photoanode. Optical analyses and impedance measurements confirmed the enhanced visible light absorption and reduced charge transfer resistance of the composite photoanode due to the modification of ZnO using In2O3 as a counterpart. The results showed that the optimally designed photoanode with superior charge carrier life time and low charge transfer resistance exhibits power conversion efficiency (PCE) of 1.22%, which is nearly 4 times than the pristine ZnO.