A comprehensive review of filler, plasticizer, and ionic liquid as an additive in GPE for DSSCs

Low ionic conductivity in gel polymer electrolytes (GPEs) affects low dye-sensitized solar cells (DSSCs) performance is a crucial issue. Generally, the GPEs contain polymer (act as solvent holder), solvent, and salt (as ions provider). Usually, the GPE-based DSSCs are assembly with three necessary compartments: working electrode, GPE, and platinum electrode. The DSSCs parameters are included open-circuit voltage, Voc; short-circuit current density, Jsc; fill factor, ff and efficiency, %. This review's main objective was to explore an additive such as plasticizer, filler, and ionic liquid effects on the ionic conductivity in GPEs by improving ions mobility and expanding the free volume of the GPE. The impact of additives in the GPE is also expected to enhance the DSSCs performance by increasing the J_sc, V_oc, ff, and efficiency. This comprehensive review discussed the latest progress of GPE utilizing the additive by listing the literature from the recent ten years.