Study Of Gel Polymer Electrolyte In Dye-Sensitized Solar Cell

Dye-sensitized solar cell (DSSC) has been investigating intensively because of its low-cost, easy-made and high-efficiency. The electrolyte plays an important role in dye-sensitized solar cells. Liquid electrolytes were usually used in Dye-sensitized solar cell (DSSC).However, liquid electrolytes caused the degradation of DSSC performance after long-term operation due to their high volatilities and solvent losses.To overcome these problems, solid and quasi-solid electrolytes have been investigated to replace the liquid electrolytes.Since DSSC with solid electrolyte has lower conversion efficiencies, the quasi-solid electrolytes have been attracting intensive attentions.Poly(Methyl methacrylate-N-vinyl pyrrolidone) P(MMA-NVP) and Poly(Hydroxy ethyl methacrylate-N-vinyl pyrrolidone) P(HEMA-NVP) were prepared by a solution copolymerization technique. Two series of copolymers could absorb and capture amount of liquid electrolyte within its chain networks structure to form quasi-solid-state electrolyte.(1) The preparation conditions of the P (MMA-NVP) were optimizd by change the the content of NVP, the amount of initiator AIBN, and the amount of crosslinking agent TEGDMA.The highest conductivity of the copolymer gel was 2.17mS·cm-1 at 25℃. Based on the P(MMA-NVP) gel electrolyte, a quasi-solid dye-sensitized solar cell was fabricated with an overall conversion efficiency of 3.05% under 100 mW·cm-2 irradiation (AM 1.5).(2) The preparation conditions of the P(HEMA-NVP) were optimizd by change the the content of NVP, the amount of initiator AIBN, and the amount of crosslinking agent TEGDMA.The highest conductivity of the copolymer gel was 6.15mS·cm-1 at 25℃. Based on the P(HEMA-NVP) gel electrolyte, a quasi-solid dye-sensitized solar cell was fabricated with an overall conversion efficiency of 5.54% under 100 mW·cm-2 irradiation (AM1.5). By comparing these two series of copolymers, it was found that the gel polymer electrolyte and quasi-solid-state dye-sensitized solar cells based on the copolymer P(HEMA-NVP) can obtain relatively higher performance.(3) The effects of the proportion of 1,4-butyrolactone(GBL) and N-methyl pyrrolidone(NMP) on the properties of the polymer gel electrolyte were studied. The results indicated that the optimum volume proportion of GBL and NMP was 7:3, and the polymer gel electrolyte based on copolymer P(HEMA-NVP) has an improved conductivity.(4) The effects of the preparation conditions of the copolymers, the thicknesses of nanocrystalline TiO2 film and additive on the properties of DSSC were studied. It was showed that the photovoltaic performances of the cells were improved when the TiO2 film thickness was 8.86μm and PY was added. The influences of the synthesis conditions of the copolymers on the interfaces of the cells were also investigated by electrochemical impedance spectroscopy, which influent the performance of the cells.