Dye-Sensitised Solar Cells (DSSC)
Dye-sensitised solar cells (DSSC) nowadays represent one of the most promising routes for photovoltaic power generation, which could eventually provide an abundant supply of clean and renewable energy.
Typical DSSC devices consist of an electrode made of a semiconducting oxide such as TiO2, ZnO, or SnO2, whose surface is covered by photoactive molecules (chromophores) absorbing light in the visible range. Photons impinging on the chromophores excite electrons, injecting them into the conduction band of the semiconducting electrode. To reach a steady state, the electron charge on the chromophores has to be replenished by a current flowing through an electrolyte solution, which is therefore a third essential component of these devices.
Many years of constant development have raised the overall efficiency of DSSC to a level slightly in excess of 10%, close to the limit of economic viability. A major weakness of the standard set-up is the heterogeneous character of the device, encompassing solid and liquid phases. Innovative electrolytes such as room temperature ionic liquids (RTIL's) could overcome this problem, providing a decisive step towards the deployment of DSSC in the field.At the conditions of DSSC operation, RTIL's display liquid-like electric conductivity, but solid-like mechanical properties.