Novel chemically cross-linked solid state electrolyte for dye-sensitized solar cells

Poly(vinylpyridine- co-ethylene glycol methyl ether methacrylate) (P(VP- co-MEOMA)) and α,ω-diiodo poly(ethylene oxide- co-propylene oxide) (I[(EO) 0.8- co-(PO) 0.2] y I) were synthesized and used as chemically cross-linked precursors of the electrolyte for dye-sensitized solar cells. Meanwhile, α-iodo poly(ethylene oxide- co-propylene oxide) methyl ether (CH 3O[(EO) 0.8- co-(PO) 0.2] x I) was synthesized and added into the electrolyte as an internal plasticizer. Novel polymer electrolyte resulting from chemically cross-linked precursors was obtained by the quaterisation at 90 °C for 30 min. The characteristics for this kind of electrolyte were investigated by means of ionic conductivity, thermogravimetric and photocurrent–voltage. The ambient ionic conductivity was significantly enhanced to 2.3 × 10 −4 S cm −1 after introducing plasticizer, modified-ionic liquid. The weight loss of the solid state electrolyte at 200 °C was 1.8%, and its decomposition temperature was 287 °C. Solid state dye-sensitized solar cell based on chemically cross-linked electrolyte presented an overall conversion efficiency of 2.35% under AM1.5 irradiation (100 mW cm −2). The as-fabricated device maintained 88% of its initial performance at room temperature even without sealing for 30 days, showing a good stability.