Advanced polymeric matrices for gel electrolytes in quasi-solid-state dye-sensitized solar cells: recent progress and future perspective

Using volatile organic solvent as a medium of redox shuttles in dye-sensitized solar cells (DSSCs) causes sealing and leakage issues, limitation of flexibility in device architecture, and safety concerns for practical outdoor and indoor applications. Polymers are promising materials for converting liquid electrolytes (LEs) into gel-state due to their structural variations, multi-functionalities, easy modification, cheap manufacturing process, and excellent retention ability of LEs. The ultimate properties of the polymer depend on the molecular weight, functionality, and structure. It is possible to improve the ion transport of redox mediators and the retention capacity of LEs inside the polymer network through proper structure design, tuning the molecular weights, and functionalities. The current advancement of PGEs-based quasi-solid-state (QSS) DSSCs ensures their high feasibility for commercial indoor applications as a clean energy source for the Internet of Things (IoT) and low-energy consumption electronic devices. This review exclusively discussed and analyzed advanced polymeric materials developed during the last three decades as matrices of redox LEs for QSS-DSSCs. The optimized and developed polymeric materials for QSS-DSSCs can also be potential candidates for various QSS-energy storage fields through proper plasticization and optimization. Therefore, a broad research community is expected to benefit from this review.