Preparation Of TiO₂Hollow Spheres With Hierarchical Micro/Nano Architectures And Its Application In Dye Sensitized Solar Cells

Since O’Regan and Grazel in1991introduced dye-sensitized solar cell (DSSC), DSSC have attracted extensive interest due to easy fabrication process, light weight, cheap cost.Nano-TiO2film is an important part of the dye-sensitized solar cell. Its structure and performance have great impact on cell’s photoelectric performance. Recently, hollow structure TiO22has received more and more attention due to their large specific surface area and high pore volume. In this thesis, valuable explorations have been carried out on the synthesis of hollow structure TiO2, and study of their properties. The main points could be summarized as follows:(1)Various carbon spheres (250-500nm) have been prepared by using glucose as precursor through hydrothermal method, the factors influencing the formation of carbon spheres has been discussed; TiO2hollow spheres with different diameters (200-500nm) have been successfully prepared by using hydrophilic colloidal carbon spheres as template and TBT (tetrabutyl titanate) as precursor, the factors influencing the formation of T1O2hollow spheres has been discussed.(2)Solid precursory microspheres composed of TiO2species were in situ formed on the surface of a colloid carbon microsphere tem-plate derived from glucose polymerization and carbonization by a one-pot hydrothermal method using ammonium fluorosilicate, and glucose as source materials. TiO22hollow microspheres were then obtained after calcination and removal of the carbon microsphere template at high temperature. This new one-pot hydrothermal method makes the process more simple and more complete morphology compared to the traditional three step template method.(3)TiO2hollow spheres are used in Dye-sensitized Solar Cell (DSSC) as Scattering layer to increase the light scattering. By fabrication of TiO2P25/HS double-layer film electrode, a higher performance of the DSSC (Jsc=15.79mAcm-2, Voc=0.653V, FF=0.55, η=6.66%) is obtained compared with the pure P25nanocrystalline DSSC (Jsc=13.5mAcm-2,Voc=0.653V, FF=0.53,η=4.95%)or HS nanocrystalline DSSC(Jsc=6.32mAcm-2,Voc=0.694V, FF=0.44,η=2.03%).