Biopolymer-Based Electrolytes for Dye-Sensitized Solar Cells: A Critical Review

Continual escalation of our world population demands a vast and safe energy supply, the majority of which has been produced by fossil fuel sources. However, because of the huge energy demand, exponential depletion of these nonrenewable energy sources is inescapable and forthcoming in the coming century. Hence, utilization of renewable energy such as solar energy has gained attention because of its direct conversion of light energy into electrical power without any harmful environmental impacts. Solar energy has been harvested by different types of solar cells varying from inorganic to organic to the combination of both. Among them, the dye-sensitized solar cell (DSSC) with a biopolymer-based electrolyte has gained enormous consideration from researchers because of its sustainability, abundance of available raw material, low production cost, and easy production in addition to the low volatilization of electrolytes compared to liquid state electrolytes. This review aims to give an overview of the recent inputs in the development of biopolymer-based DSSCs. The performance of the biopolymers as electrolytes in DSSCs will be critically reviewed based on the physicochemical properties of the biopolymers. Key technical challenges and future research areas for the advancement of biopolymer-based DSSCs are also discussed.