Molecular engineering of PMMA-based quasi-solid-state electrolytes for dye-sensitized solar cells: Tailoring ion conductivity and thermal stability through salt-ratio modulation

This study investigated the potential of polymer gel electrolytes (PGE) as a replacement for conventional liquid electrolytes in dye-sensitized solar cells (DSSCs) to enhance efficiency, stability, and long-term performance. Polymethyl methacrylate (PMMA) was utilized as the base polymer to improve the mechanical integrity of the gel electrolyte, while ammonium iodide salt was incorporated to enhance ionic conductivity. A comprehensive set of characterization techniques was employed: Scanning electron microscopy (SEM) provided detailed analysis of the surface morphology and uniformity of the electrolyte, X-ray diffraction (XRD) examined the crystalline structure and phase composition, thermal gravimetric analysis (TGA) evaluated the thermal stability, and electrochemical impedance spectroscopy (EIS) quantified the ionic conductivity. The results demonstrated that salt concentration significantly affected ionic conductivity, which in turn impacted the electrochemical performance of the DSSC. The optimized PGE achieved an energy conversion efficiency of 4.68%, with improved long-term stability compared to traditional liquid electrolytes, which exhibited an efficiency of 6.03%. However, the longevity of traditional liquid electrolyte-based DSSCs was significantly lower compared to PGE-based DSSCs. This work establishes PMMA-based PGEs as a viable alternative to liquid electrolytes, offering superior ionic conductivity, enhanced DSSC performance, greater durability, and extended longevity, positioning them for advanced renewable energy applications.