Effect of Copper and Cobalt Metal Complex Redox Mediator Based Xanthan Gum Gel Electrolyte Materials on Performance of Dye Sensitized Solar Cells

Abstract

AbstractIn this study, we report the first application of (4‐(tert‐butyl) benzyl or 4‐methyl benzyl)‐substituted 2‐(pyridin‐2‐yl)‐1H‐benzo[d]‐imidazole coordinated copper and cobalt redox shuttles Cu [((tbb) pbi)2]+1/+2, Cu [(mbpbi)2]+1/+2, Co [((tbb) pbi)3]+2/+3 and Co [(mbpbi)3]+2/+3 based xanthan gum gel electrolytes (XGE‐1, XGE‐2, XGE‐3 and XGE‐4) in fabrication of Dye sensitized solar cells. Interestingly, XGE‐1 and XGE‐2 obtained higher efficiency of 4.08 and 3.04 % under 1sun illumination. Specifically, highly donor moiety 4‐(tert‐butyl)benzyl)‐substituted (on N−H position) 2‐(pyridin‐2‐yl)‐1H‐benzo[d]‐imidazole ligands coordinated, Cu [((tbb) pbi)2]+1/+2 gel electrolyte achieved best performance due to its appropriate redox potential of 0.80 V versus Normal Hydrogen Electrode. This high performance also confirmed with the interfacial studies of the devices. As per the computational results, the copper redox mediators conquered lower reorganization energy and free energy about (0.11‐0.20 & 0.18–0.27 eV) due to the effect of ligands structure. Overall, Cu [((tbb) pbi)2]+1/+2 act as redox shuttle for highly proficient DSSCs.