Research On Novel Structure Nano-TiO₂ Photoanode

Dye-sensitized solar cells（DSSC）have become an effective means to solve the energy crisis because of their low cost and stable performance,and are favored by many researchers.The main structure of DSSC includes four parts:photoanode,electrolyte,dye,and counter electrode.Among them,the photoanode plays the role of receiving electrons excited from dye molecules and transmitting electrons to external circuits.In order to improve the photoelectric performance of DSSC,low-cost metal oxides（TiO₂,Zn O,Sn O₂,Nb₂O₅,Al₂O₃,In₂O₃,etc.）have been widely studied as photoanode materials,among which TiO₂ has a wider band gap and has more advantages than other materials.In recent years,the research on TiO₂ photoanode mainly includes the change of microstructure,ion doping,composite structure design and so on.These modifications are aimed at the combination of low specific surface area and electrons,and have the disadvantages of harsh preparation conditions and complicated fabrication.The preparation of new nanostructured TiO₂ photoanode and improving the photoelectric conversion efficiency of the battery are the research points.The research focus of this project is to prepare a new nanostructured TiO₂ photoanode to solve the problems of low specific surface area and high electron recombination.The research contents are as follows:1.Synthesis of titanium-based metal-organic framework materials,followed by pyrolysis to form mesoporous titanium dioxide（M-TiO₂）.The photoanode film was prepared by scraping,and the influence of mesoporous materials on the properties of photoanode and DSSC was studied.The specific surface area of M-TiO₂ is as high as 155.47 m²·g^-1,which is more than three times that of P25.The photoanode was prepared by mixing M-TiO₂ with P25,and the results showed that when the M-TiO₂ content reached 50%,the open-circuit voltage reached a maximum of 0.76V,and the highest photoelectric conversion efficiency of 1.88%was obtained.With P5M5 as the bottom layer and M-TiO₂ as the light scattering layer,the performance of the photoanode was optimized,and the highest photoelectric conversion efficiency of 2.03%was obtained.2.Using polystyrene（PS）as a template,the titanium precursor solution filled the template to prepare a regular structure assembly,calcined to remove the polymer to form a regular titanium dioxide photoanode,and the effects of PS doping amount and template filler on the performance of photoanode and DSSC were studied.The results showed that the photoelectric conversion efficiency of DSSC doped with5%PS with titanium tetrachloride as template filler was 1.64%.The photoelectric conversion efficiency of DSSC doped with 5%PS with isopropyl titanate as template filler was 1.67%.3.In the case of not using the crystal seed layer,the direct hydrothermal treatment of the film of uniform size on the surface of FTO glass is used,and the influence of hydrothermal time,temperature,raw material ratio,etc.on the photoanode is studied after further heat treatment.The results show that the photoanode film with hydrothermal growth presents an ordered one-dimensional structure,and when the ratio of DEG to water volume is 7:1,the photoelectric conversion efficiency of0.73%is obtained after the photoanode prepared by reacting at 170℃ for10 h is assembled into DSSC.