Abstract
A quaternary ammonium salt based room temperature ionic liquid (RTIL) is developed to serve as the solvent and redox ion source for the preparation of low volatility electrolytes of dye sensitized solar cells (DSSCs). As compared with the conventional imidazolium-based RTILs for low volatility electrolytes, the present system possesses the advantages of cost effectiveness, easy preparation, and better environmental friendliness. For a specific case, acetylcholine iodide is mixed with ethylene glycol at a molar ratio of 1:9 to form an RTIL by heating the mixture at 70 °C. This RTIL exhibits a loss rate of 0.0017 g h -1 at 70 °C, showing its low volatility. The electrolyte prepared by dissolving 0.8M LiI, 0.1M I 2 , and 0.5M N-methylbenzimidazole in the RTIL exhibits a viscosity of 24.5cp, an ionic conductivity of 5.47 mS cm -1 , and an ionic diffusion coefficient of 3.98×10 -7 cm 2 s -1 . When applied to a DSSC that uses a metal-free indoline dye D-149 as the sensitizer, the above electrolyte gives a power conversion efficiency of 3.36%, 82% of that achieved by using the electrolyte prepared with the traditional organic solvent, acetonitrile, under the same measurement conditions. © 2011 by ESG.