Current Progress in Solid-State Electrolytes for Dye-Sensitized Solar Cells: A Mini-Review

Low-cost and high-performance dye-sensitized solar cells (DSSCs) are considered promising candidates for commercial application. As one of the crucial components, electrolytes are considered the limiting factor for long-term DSSC stability. As alternative materials, solid-state electrolytes have been used in DSSCs, which may solve the problem of liquid electrolytes, such as leakage and volatilization. In this review, we define solid-state electrolytes as inorganic hole transport materials (HTMs), organic HTMs, ionic conductive polymer electrolytes, and ionic liquid polymer electrolytes according to the different types of carriers and summarize the latest development trends of these electrolytes. We discuss in detail the mechanism of solid-state dye-sensitized solar cells (ssDSSCs), including the hole transfer process at the dye/hole-conductor interface and factors that reduce the efficiency of ssDSSCs, and summarize several methods to improve the efficiency and long-term stability of ssDSSCs. These may facilitate the research and development of electrolytes for ssDSSCs.