Preparation Of Porous Photoanode Of Nanocrystalline TiO₂ And Research On Photoelectric Properties Of Solar Cells

Porous photoanode films with high absorption of dyes,rapid separation of photoelectric charges and rapid transport of electrons are important factors affecting the photoelectric conversion efficiency of dye-sensitized solar cells（DSSC）.In this paper,the TiO₂nanoparticles and nanorods were prepared with the hydrothermal method mainly,respectively.The nano TiO₂coating sols were synthesized by mixed with with a certain amount of organic polymer dispersant PVA.TiO₂porous film on the conductive glass substrate film was obtained by sintering at high temperature using doctor blade method and EHD technology,respectively.The dye sensitized solar cells（DSSC）were prepared by using N719 dye sensitization and using ionic liquid electrolyte and platinum electrode as counter-electrode.The effects of pore structure,thickness and irradiation intensity on the photoelectric properties of DSSC films were investigated.Anatase TiO₂nanoparticles and nanorods were synthesized by hydrothermal method,respectively.The size of nanoparticles was about 20nm.The length of nanorods is about 200-300nm,the diameter of the middle segment is about 20nm,with uniform grain size,complete crystal shape and the high degree of crystallization.The porous titanium oxide films were prepared by using doctor blade method and electrohydro-dynamic（EHD）technique on the surface of the prefabricated dense films.Compared with the two methods of film formation,the film by EHD has a wide range of micro and nano pore distribution,while the pores in the film prepared by doctor blade method are mainly nanometer size.The photoelectric performance and electrochemical impedance of the dye-sensitized cells were compared and analyzed.It was found that the photoanode films prepared by EHD with micro and nano holes had higher charge transfer effect and higher photoelectric conversion efficiency than those prepared by doctor blade method.Compared with the two film forming technologies,the influences of photoanode film thickness and light intensity on the performance of solar cell are different.When under the simulated sunlight intensity is 100 mW/cm²,the photoelectric response characteristics of the films of the 8-10μm thickness are high.The photoelectric conversion efficiency of the films of micro-nano channels with 10μm thickness prepared by EHD is 7.01%.When the light intensity is 25mW/cm²,the higher filling factor reflects the higher photoelectric conversion efficiency.