Dye-sensitized Solar Cells Based On Mesoporous TiO₂ Spheres And Their Photoelectric Properties

Submicrometer-Sized Mesoporous TiO₂ Spheres have been widely employed as the photoanodes of dye-sensitized solar cells?DSSC?,due to their large specific surface area and strong light scattering ability,and excellent photo-generated charge separation and transport properties.In this paper,a simple two-step synthesis method prepared the mesoporous TiO₂ spheres by changing the solvothermal reaction time and temperature,and then employed as the photoanodes to study the effects of photoelectric performance on DSSC.In this paper,firstly,TiO₂ precursor spheres prepared under the sol-gel method.After further solvent treatment,it shows that an important effect on the mesoporous TiO₂ spheres with changing the time and temperature.The characteristics of the mesoporous TiO₂ spheres was investigated by SEM,TEM and XRD,the result suggests that the TiO₂ precursor spheres are monodisperse and uniformly amorphous TiO₂ with an average diameter of ⁶00 nm,furthermore,their surface is smooth.The results show that the organic matter in the precursor sphere is gradually burned and the surface roughness increases with the increase of the treatment time or the temperature increase.The composition of the TiO₂ nanoparticles gradually grows from the amorphous TiO₂ sphere to anatase phase mesoporous TiO₂ spheres transformation.This three-dimensional multistage structure,which is composed of smaller nanometer particle sub-structures,not only has a large specific surface area,but also has strong light scattering ability and excellent charge transport properties.N2 adsorption-desorption study found that the mesoporous TiO₂ spheres surface area reached a maximum of 95.6 m2/g at 15 h,160 ° C.The mesoporous TiO₂ spheres synthesized under the different solvothermal reaction time and temperature,and then employed as the photoanodes of DSSC by screen printing technique.The photoelectric characteristics of DSSCS analyzed by some measurements such as J-V,IPCE and EIS.The relationship between the structures of mesoporous TiO₂ spheres and photoelectric properties of DSSC was extensively analysed.The results show that the dye-sensitized solar cells based on mesoporous TiO₂ spheres were excellent when the solvothermal reaction time,temperature and the thickness of the anodic film is 15 h,160 °C,14.4 ?m,respectively.At this time,the external quantum efficiency achieved 87.67%.The short-circuit current density,the open circuit voltage and the filling factor is 17.38 m A/cm2,770 m V,76.6%,respectively,and the photoelectric conversion efficiency achieved a maximum up to 10.3%.