High performance solid-state dye-sensitized solar cells based on poly(acrylonitrile- co -vinyl acetate)/TiO 2 nanoparticles redox electrolytes

A novel copolymer, poly(acrylonitrile- co -vinyl acetate) (PAN-VA), is used as the solidification agent to prepare solid-state redox electrolytes for dye-sensitized solar cell (DSSC) applications. TiO 2 nano-particles are used as the fillers to enhance the performance of the solid electrolytes. Furthermore, to improve the penetration of solid electrolytes in the mesoporous TiO 2 matrixes, an external pressure is applied on the electrodes during the solvent evaporation process. The results show that the ionic conductivities of the solid-state electrolytes are comparable with those of gel electrolyte, indicating that the PAN-VA matrix itself may contribute to the charge transfer through the Grotthuss charge transfer mechanism. Based on the temperature-controllable viscosity of the polymer electrolytes, as well as the effect of an applied force, the solid electrolyte can penetrate well in the TiO 2 film, making good contact with the photoelectrode. It is also found that the introduction of TiO 2 fillers does not affect the conductivity of the electrolyte, but greatly enhance the charge transfer at the interface of the electrolyte and Pt counter electrode. On based of the high performance of the electrolyte system, an energy conversion efficiency of 8.65% is achieved for the solid-state DSSC.