An efficient organogelator for ionic liquids to prepare stable quasi-solid-state dye-sensitized solar cells

A low molecular weight amphiphilic organogelator capable of forming intermolecular hydrogen bonds and well-organized supramolecular structures was found to efficiently gel low-viscosity binary mixtures of ionic liquids at low concentrations. With this gelator it is possible to prepare stable quasi-solid-state dye-sensitized solar cells (DSCs). At a gelator concentration of only 2 wt%, the sol-gel transition temperature (T-gel) based on the lowest viscosity ionic liquid mixture was at 108 degrees C, well above the service temperature. Due to the thermoreversible nature of the system, the cells can be conveniently filled with a low-viscosity liquid. Upon cooling and formation of the gel a mechanically stable quasi-solid-state electrolyte was obtained. We successfully employed this quasi-solid ionic liquid electrolyte in DSCs and obtained an efficiency of 6.3% at full sunlight irradiation and maintained its stability during the light soaking accelerating stress test at 60 degrees C over 1000 h.