Ionic conductivity enhancement of 'soggy sand' electrolytes with AlOOH nanofibers for dye-sensitized solar cells

As one of the main components, inorganic nanofillers have important effect on the performance of “soggy sand” electrolytes. In this study, we first incorporate AlOOH nanofibers into ionic liquid electrolytes to enhance the mechanical property and ionic conductivity of the electrolytes. The AlOOH nanofiber has high aspect ratio coupled with favorable surface properties such as rich hydroxyl groups, which facilitate to interact with cations of ionic liquids, promote salt dissociation, and form stable gels by self-assembly. In addition, the nanofiber fillers with high aspect ratio can form ion-conducting network channels and longer-range continuous ion transport pathways. The enhancing ionic conductivity of “soggy sand” electrolytes and performance of DSSCs due to addition of AlOOH nanofibers are systematically investigated by various techniques. The highest ionic conductivity of “soggy sand” electrolyte reaches 3.69 mS cm−1 at room temperature, which is 4 times than that of the pristine ionic liquid electrolyte. The effective solidification by AlOOH nanofibers provides substantial improvements in stability. The “soggy sand” electrolytes with AlOOH nanofibers can significantly improve the performance of devices by accelerating charge transport, reducing electron recombination and increasing charge collection efficiency. The DSSC with AlOOH nanofibers in electrolyte yields a high efficiency up to 7.89%, which is 29% higher than that of the reference device.