Study And Optimization On The Photoanode Of Dye-sensitized Solar Cells

Due to the high cost and complex operation of the silicon-based solar cells, it isnecessary to develop a new solar cell to replace the silicon-based solar cells.Dye-sensitized solar cells （DSSCs） have gat rapid development as their low-cost,non-toxicity, craftwork simplicity and high photo-to-electricity conversion efficiency.Therefore, DSSCs are considered to replace silicon-based solar cells and becomedominant in the solar industry. In this paper, we research the preparation technologyof DSSCs and the photoelectric performance of the cells based on nano-SiO₂/TiO₂composite film. Then the composite film is optimized by post-treating with TiCl₄aqueous solution.（1） Optimizing the preparation technology of DSSCs based on commercial P25powderA stable nano-TiO₂paste based on commercial P25powder is prepared bytraditional technology, and is deposited on the FTO via screen-printing method. Aftersintered and sensitized, we get a porous nanocrystalline TiO₂thin film. In order toresearch the influence of film thickness, roasting temperature, roasting curve andsensitization time, the structure and morphology of the film, the photoelectricperformance of the cell have been analyzed by XRD, SEM, UV-visible absorptionspectra and J-V curves.（2） Research based on SiO₂/TiO₂composite film of DSSCsIn view of the traditional process, a stable paste is prepared by dispersingnano-SiO₂into P25, and seven batches of SiO₂/TiO₂composite film with differentmass ratio is prepared by this way. Then the hybrid films are deposited on the FTOsurface via screen-printing method and fabricated to be DSSCs. The structure andmorphology of composite photoanode, the photoelectric performance of cells havebeen analyzed by XRD, Roman, SEM, TEM, FT-IR, pore distribution and UV-visibleabsorption spectra. The results show that the particles in nano-SiO₂/TiO₂compositefilm are relatively uniform, and there is a better adhesion between hybrid film andFTO surface; when the mass mixing ratio of SiO₂/TiO₂is7.5%, thephoto-to-electricity efficiency of DSSCs is the highest （η=8.4%）, and thecorresponding Jscis18.72mA/cm2, the Vocis0.78V and the fill factor （FF） is57.39%,that is45%higher than the efficiency of the pure TiO₂sensitized sample.（3） Research of the TiCl₄post-treatment on SiO₂/TiO₂composite photoanodeThe SiO₂/TiO₂composite film is further treated by TiCl₄aqueous solution with seven concentrations before of assembling. The influence of TiCl₄post-treatment onthe morphology of the hybrid film and the photoelectric performance of DSSCs issystematically investigated by SEM, N2adsorption-desorption curve, UV-visibleabsorption spectra and IPCE, J-V curves. The results show that the nano TiO₂particles hydrolysed from TiCl₄aqueous solution reduce the pore volume and porosityof the composite film, but enlarge the particle size; the conversion efficiency of thedye-sensitized solar cells treated with75mM TiCl₄solution is enhanced about105%compared to that without post-treatment cell, while Voc and FF basically remainedconstant.