Highly conductive redox-couple solid polymer electrolyte system: Blend-KI-I 2 for dye-sensitized solar cells

Abstract

Ionic conductivity of a redox-couple solid polymer electrolyte system, (1 - x) blend: x [0.9KI:0.1I2] with x = 0 - 0.15 in weight fraction, is reported. A blend of poly(ethylene oxide) (abbreviated as PEO) and succinonitrile in equal weight fraction was used as a polymeric matrix instead of the PEO and succinonitrile because of its low-cost, electrical conductivity superior to the PEO, and thermal stability better than the succinonitrile. The electrolyte with x = 0.15 showed ionic conductivity of 7 × 10-4 Scm-1 and iodine ion diffusivity of nearly 4 × 10-7 cm2s-1 at 25°C. The conductivity and diffusivity values were nearly two orders of magnitude higher than those of the PEO-KI-I2 due to the improved PEO crystallinity. It also exhibited dye-sensitized solar cell efficiency of 2.2% at 100mWcm-2, which is twice of the cell prepared using the PEO-KI-I2 only. © 2011 Ravindra Kumar Gupta and Hee-Woo Rhee.