Study On Polymer Gel Electrolyte And TiO₂-Ordered Thin Film For Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSC) has been investigating intensively because of its low-cost, easy-made and high-efficiency. In this paper, different kinds of polymer gel electrolytes based on different polymer gelators were researched in order to improve the oerall solar energy conversion efficiency and long-term stability of the DSSC. The transmission mechanism of electrolytes and the affects of different polymer gelators and iodide salt on the ionic conductivity and the performances of quasi-solid-state dye-sensitized solar cells were discussed. The method of preparing TiO2-ordered thin film by using polystyrene colloid crystal as template was also researched, and the influences of the microstructure of TiO2 ordered-film was discussed.There are some major works in the following:(1) A novel polymer gel electrolyte AS-EC/PC/DMC-C10H10N+I-/I2 was prepared. The influences of polymer host, different organic solvents, N-methyl-quinoline iodide(C10H10N+I-) and temperature on ionic conductivity of the polymer gel electrolyte and the performances of the DSSC were discussed. The difference performances of quasi-solide-state DSSC based on AS-EC/PC/DMC-C10H10N+I- and AS-EC/PC/DMC-NaI/I2 were compared. The results show that when the concentration of AS is 17 wt. %, the mass ratio of the mixture solvents of EC, PC and DMC is 4:2:1, the concentration of C10H10N+I- and iodine are 0.6 M and 0.06M, respectively, the ionic conductivity of the AS-EC/PC/DMC-C10H10N+I-/I2 reaches 5.12 mS·cm-1 at 25 oC. The quasi-solide-state DSSC based on the electrolyte possesses better long-term stability and overall solar energy conversion efficiency of 4.04 % under irradiation of 100 mW/cm2 simulated sunlight. The photoelectric performance of the quasi-solid-state DSSC fabricated with the polymer gel electrolyte AS-EC/PC/DMC-C10H10N+I-/I2 is better than that of the AS-EC/PC/DMC-NaI/I2.(2) A novel polymer gel electrolyte PMMA-EC/PC/DMC-NaI/I2 was prepared. This polymer gel electrolytes has weight lost of 3.73% below 124°C, indicating that it has a better thermostability and can satisfy the requirements of the DSSC'usage. With a quasi-solid-state DSSC based on the PMMA-EC/PC/DMC-NaI/I2 with ionic conductivity of 6.89 mS·cm-1 at 25°C, an overall solar energy energy conversion efficiency of 4.78 % was achieved at irradiation of 100 mW/cm2 simulated sunlight.(3) TiO2-ordered thin film was prepared by using polystyrene colloid crystal as template, and the microstructure of polystyrene colloid crystal and TiO2 ordered-film were characterized. The results show that the quality of the template is much better through using the naturally horizontal deposition method. A dye-sensitized solar cell assembled with the TiO2-ordered thin film possesses relatively high open voltage.