Succinonitrile-based solid-state electrolytes for dye-sensitised solar cells

Succinonitrile (SCN), a solid ion conductor (10−4 to 10−3 S/cm) in solid form at room temperature, is mixed with either 1,2-dimethyl-3-propylimidazoliuum iodide or 1-butyl-3-methyl imidazolium iodide ionic liquids for forming a solid plastic phase electrolyte for use in dye-sensitised solar cell (DSSC). Cells containing these two electrolytes showed best energy conversion efficiencies of 6.3% and 5.6%, respectively. The commonly used DSSC electrolyte additives inhibit the formation of the SCN plastic phase. However, for the first time, an SCN-additive (additive = guanidinium thiocyanate) electrolyte composition is reported here, which remains as a solid at room temperatures. By using these new solid electrolytes, a simple and rapid single-step filling procedure for making solid-state DSSC is outlined. This process, which reduces the required manufacturing steps from four to one, is most suitable for continuous, high-throughput, commercial DSSC manufacturing lines. These new electrolytes have been tested under low incident light levels (200 lx) to investigate their suitability for indoor DSSC applications