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

Abstract

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.

Fabrication of Functional Materials for Dye-sensitized Solar Cells

“…Electrolytes are an important part of dye charge regeneration from its oxidized state to neutral state form by receiving electrons from redox mediators. The electrolyte-based redox couple system provides several benefits when applying an electrolyte to a device, such as (Krishna et al, 2019;Sang-aroon et al, 2019;Hasan et al, 2020):…”

“…Indeed, a great deal of research has been conducted to evaluate various WEs, photosensitizers, electrolytes, and CEs, as detailed in Figure 1 and (Hagfeldt et al, 2010). In an efficient DSSC, the photoelectrode should have the following characteristics (Hasan et al, 2020):…”

“…A modified photoelectrode was developed by adding nitrogen heterocycles as electron-donors, which produced a negative shift in the conduction band and reduced electron recombination (Lau and Soroush, 2019). Other additives in the semiconductor materials with a suitable cation/anion have also sufficient conduction band edge providing high electron injection rate (Hasan et al, 2020). A DSSC-based metal oxide semiconductor co-adsorbed with guanidinium [C(NH 2 ) + 3 ] cations achieved an efficiency of 11.04% (Grätzel, 2004).…”

“…A DSSC-based metal oxide semiconductor co-adsorbed with guanidinium [C(NH 2 ) + 3 ] cations achieved an efficiency of 11.04% (Grätzel, 2004). Furthermore, adding other cation dopants, such as Ni, W, Al, Nb, Sn, Li, Fe, Cu, Zn, Ce, La, and Eu, to semiconductor materials can change by the interfacial energy levels leading to faster electron hole separation from dye to mesoporous electrodes and also reduced the recombination of photoelectrons at the electrolyte-semiconductor interface (Watson and Meyer, 2004;Roose et al, 2015;Hasan et al, 2020). The anionic dopants, including N, B, C, S, P, F, I, and Br, have also been reported (Zhang et al, 2010;Cheng et al, 2015).…”

“…The anionic dopants, including N, B, C, S, P, F, I, and Br, have also been reported (Zhang et al, 2010;Cheng et al, 2015). In comparison to cationic dopants, anionic dopants have a greater electrical conductivity because of their superior thermal and photochemical stabilities (Hasan et al, 2020).…”