Effect of Nano-Filler on Structural and Ionic Transport Properties of Plasticized Polymer Electrolyte

Abstract

A novel CuI-based iodine-free gel electrolyte using polyethylene oxide (PEO, MW = 100,000) as plasticizer and lithium perchlorate (LiClO4) as salt additive was developed for dye-sensitized solar cells (DSSCs). Such CuI-based gel electrolyte can avoid the problems caused by liquid iodine electrolyte and has relative high conductivity and stability. The effects of PEO and LiClO4concentrations on the viscosity and ionic conductivity of the mentioned iodine-free electrolyte, as well as the performance of the corresponding quasi solid-state DSSCs were investigated comparatively. Experimental results indicate that the performance of DSSCs can be dramatically improved by adding LiClO4and PEO, and there are interactions (Li+-O coordination) between LiClO4and PEO, these Li+-O coordination interactions have important influence on the structure, morphology and ionic conductivity of the present CuI-based electrolyte. Addition of PEO into the electrolyte can inhibit the rapid crystal growth of CuI, and enhance the ion and hole transportation property owing to its long helix chain structure. The optimal efficiency (2.81%) was obtained for the quasi solid-state DSSC fabricated with CuI-based electrolyte containing 3 wt% LiClO4and 20 wt% PEO under AM 1.5 G (1 sun) light illumination, with a 116.2% improvement in the efficiency compared with the cell without addition of LiClO4, indicating the promising application in solar cells of the present CuI-based iodine-free electrolyte. © 2011 Elsevier Ltd. All rights reserved.