Highly efficient quasi-solid state dye-sensitized solar cell with ion conducting polymer electrolyte

Abstract

Quasi-solid state dye-sensitized solar cells were fabricated using an oligomer having three polymerizable reactive groups. Only 7% polymer concentration in the polymer electrolyte is found enough to form a stable quasi-solid structure and a three-dimensional polymer network structure is proposed. Conductivity measurement of the polymer electrolyte in different organic solvents shows that the ionic conductivity increases with decreasing the viscosity of the solvent and a high ionic conductivity of 9 mS/cm is observed for the polymer electrolyte composition of 0.2 M DMPII, 0.5 M LiI, 0.05 M I 2 in the mixed solvent of ethylene carbonate and γ-butyrolactone (30:70 v/v). A short circuit photocurrent density of 14.8 mA/cm 2, an open circuit voltage of 0.78 V, a fill factor of 0.70 and an overall conversion efficiency of 8.1% under AM1.5 irradiation (100 mW/cm 2) was observed when fabricated a quasi-solid state dye-sensitized solar cells using these high conducting polymer electrolyte. The quasi-solid cells with the polymer electrolyte show higher open circuit voltage than that of the liquid cells that may be due to the suppression of the back electron transfer between the conduction band of the TiO 2 electrode and the triiodide ion in the electrolyte.