Effect of a locust bean gum based gel electrolyte with nanocomposite additives on the performance of a dye-sensitized solar cell

Abstract

In this study, we proposed Mn₃O₄ and Mn₃O₄·CuS nanocomposites as novel inorganic additives in locust bean gum (LBG) gel electrolytes for application in an aqueous dye-sensitized solar cell (DSSC). The morphology of Mn₃O₄ and Mn₃O₄·CuS nanocomposites was characterized by XRD; UV-vis, FTIR, EDX, and XPS spectroscopies; SEM; and TEM. The as-synthesized metal oxide nanocomposites additives are incorporated with iodine/triiodide and an LBG biopolymer gel matrix to construct new aqueous gel electrolyte materials LGE2 (Mn₃O₄), LGE3 (Mn₃O₄·CuS) and LGE1 (without additive). Interestingly, an enhanced photoconversion efficiency (PCE) of 3.47% under a 100 mW cm⁻² light condition was observed for LGE3 compared to electrolytes (LGE1 and LGE2) due to an effective role of the Mn₃O₄·CuS additive with TiO₂ and the I₃⁻ ion of the electrolyte which reduces the recombination reaction. This PCE result was sustained with some criteria of high conductivity, lower charge transfer resistance, high chemical capacitance, and longer electron lifetime. This novel electrolyte material consists of an inorganic additive (Mn₃O₄·CuS) and aqueous bio gel polymer (LBG) and opens a way for the replacement of costly additive and organic solvents in DSSCs.