Preparation And Photoelectric Properties Of TiO₂/MWCNTs-ZnO Nanocomposite Photoanode

As an important part of dye-sensitized solar cells?DSSC?,photoanode plays the role of adsorbing dyes and transporting electrons,which has a great influence on the performance of the DSSC.At present,TiO₂ is the most widely used photoanode material,some progress has been made in DSSC performance through compound optimization of TiO₂ materials,but its actual conversion efficiency is still very low.In this paper,TiO₂/multi-walled carbon nanotubes?MWCNTs?composite photoanode and TiO₂/MWCNTs-Zn O composite photoanode were prepared separately to increase the electron transmission rate and reduce the electron recombination rate.The effects of various parameters on composite film and the properties of the assembled DSSC were investigated.The following is the specific research content of this paper.TiO₂/MWCNTs composite films were successfully prepared by sol-gel hydrothermal method and Electro-hydro Dynamics?EHD?.SEM,TEM,UV-vis and EIS characterization methods are used to analyze the films,it was found that the addition of MWCNTs promotes the formation of the mesoporous structure of the films,increases the adsorption of dye and the penetration of the electrolyte.The excellent electron transport characteristic of the MWCNTs accelerates the electron transport in the TiO₂/MWCNTs composite film and reduces the electron recombination probability.The DSSC based on the CNT-0.12?0.12 wt.%?composite photoanode achieves a conversion efficiency of 6.21%,which is 35.9%higher than the 4.57%of the pure TiO₂-based DSSC.TiO₂/MWCNTs-Zn O composite films were prepared by one-step dipping method based on TiO₂/MWCNTs composite film with MWCNTs content of 0.12wt.%.The addition of Zn O has further improved the dye adsorption capacity and light absorption intensity of the film,and the electron recombination on the film surface has been effectively suppressed.The dipping time also affects the morphology of films,the amount of dye adsorption,and the electron transfer resistance.Excessive dipping time results in a decrease in the adsorption of the dye,increase the electron recombination,and affect the electron injection rate.When the dipping time is 6 min,the DSSC based on TiO₂/MWCNTs-Zn O composite photoanode achieves an energy conversion efficiency of 6.60%.In addition,when the dipping time of 6 min,by changing the thickness of the TiO₂/MWCNTs-Zn O thin film to investigate its effect on the DSSC performance.An energy conversion efficiency of 7.21%is obtained when the thickness of the film is 12.5?m,which is 57.8%higher than that of pure TiO₂-based DSSC.