Study On Thixotropy Electrolyte For Dye-sensitized Solar Cells

Nowadays, dye-sensitized solar cell (DSSC) is of great interests because of itsrelatively low cost and reasonably high efficiency. However, DSSC is a complexmulti-component system, electrolyte is the core parts of its constituents. At present,DSSCs based on liquid electrolyte exhibits the highest efficiency in the electrolytes.The liquid DSSC has met industrial requirements in practical problem of volatilesolvent, electrolyte leakage and difficult to package, resulting in poor device stabilityand short life. Thus, quasi-solid and solid electrolytes are becoming a researchhotspot in recent years. DSSC based on quasi-solid or solid electrolytes has a littlelower efficiency than that of the liquid，the main reason is these electrolytes can notfull into porous films, with leading to the poor interfacial bonding and low ionicmobility.In the paper, nanometer TiO2sol for coating film was prepared by cooperatinghydrothermal colloidal sol. Nanocrystalline TiO2porous films were prepared byusing electro-hydrodynamic technique(EHD). The two kinds of thixotropic quasi-solid electrolytes were prepared with inorganic nanomaterials SiO2sol and SiO2nanoparticles mixed in ionic liquid electrolyte composition. The anode films wereinvestigated by using XRD, SEM and optical spectrum etc. The results showed thefilms prepared by EHD technique have multilevel hierarchical structure and betteroptical absorbance properties. The electrolytes have excellent thixotropy, thermalstability, high ionic conductivity and the better filling in the pores.The thixotropic electrolytes are adopted in DSSCs, their photoelectric andelectrochemical properties are studied. Under an AM-1.5illumination at100mW/cm2, the overall energy conversion efficiency are6.44and6.04%, which areobtained from the DSSC devices of NAPEs cell and TOPEs cell respectively. The higher fill factors(≥0.65) are also obtained. The results of electrochemistryimpedance analysis indicate these thixotropy electrolytes show the equal chargetransmittablity relative to ionic liquid electrolyte. Measured in10days, the DSSCdevices of TOPEs and NAPEs both show higher stability than that of device withionic liquid electrolyte without any sealing.