The influence of ionic liquid and plastic crystal electrolytes on the photovoltaic characteristics of dye-sensitised solar cells

In the drive towards efficient and commercially viable dye-sensitised solar cells, there is an increasing requirement for alternative electrolyte materials that can replace the volatile and toxic molecular solvent-based systems. Ionic liquids offer a promising alternative as their non-volatility, good electrical and thermal stability and non-flammability, in addition to the ability to tailor their physical properties through structural manipulation, make them ideal for electrochemical applications. Alternatively, plastic crystals are an attractive solution to the problems of leakage that can be associated with liquid electrolytes. This review discusses the development of these new electrolytes from the perspective of two key parameters; diffusion of the I ^-/I ₃ ^- redox couple through the different materials, and the influence that they can have on the energy levels within the device.