Enhancing the stability and efficiency of eye-sensitized solar cells with MIL-125 metal-organic framework as an electrolyte additive

Abstract

This study investigates how to improve the stability of liquid electrolyte (LE) dye-sensitized solar cells (DSSCs) by incorporating a titanium-based metal-organic framework (MIL-125). MIL-125, created through the coordination of Ti4+ ions with benzene-1,4-dicarboxylic acid, forms a structure that can effectively accommodate I−/I3− electrolytes, resulting in a MIL-125@electrolyte assembly. This innovative assembly successfully prevents electrolyte leakage while preserving the LE properties. The study examines how the MIL-125@electrolyte enhances both stability and power conversion efficiency (PCE) of DSSCs. The inclusion of the large-surface-area of MIL-125 improves ionic conductivity, reduces charge transfer resistance, and stops leakage. The optimized MIL-125@electrolyte achieves a high PCE of 10.51%, with a peak value of 10.99%, and a notable short-circuit current density of 20.97 mA/cm², peaking at 22.27 mA/cm², under standard AM 1.5, 100 mW/cm² conditions. It maintains about 75% of its PCE after 1400 h at approximately 23 °C. For indoor applications using LED lighting, the quasi-solid-state DSSC reaches a record PCE of 27.6%, with an average of 25.9%, under 6000 lx illumination.