High efficiency quasi-solid state dye-sensitized solar cells based on a novel mixed-plasticizer modified polymer electrolyte

Quasi-solid-state dye-sensitized solar cells (DSSCs) fabricated with the mixed-plasticizer (MP) modified polymer electrolyte are reported in this paper. The mixture of hydroxyethyl methylacrylate (HEMA) and ethylene glycol (EG) as plasticizer are added into the original composite polymer electrolyte (CPE) based on poly(ethylene oxide)/poly(vinylidene fluoride-hexafluoropropylene) (PEO/P(VDF-HFP)) and KI/I2. The olefinic bonds in HEMA and hydroxyl bonds in EG provide strong molecular polarity to effectively reduce the crystallinity of the polymer electrolyte, thus largely improve the ionic conductivity of the CPE. On account of MP, the decrease of crystallinity provides a better photovoltaic performance, the best photon-to-current conversion efficiency is 6.79% with a short current density Jsc of 15.23 mA cm−2 under AM 1.5 illumination. Fourier transforms infrared (FT-IR), differential scanning calorimetry (DSC), ionic conductivity, electrochemical impedance spectroscopy are test to analyze superior property of DSSCs assembled with MP-modified CPEs. It shows that the performance of the CPEs can be largely improved by MP.