â… Fabrication And Properties Study Of TiO₂ Inversed Opal Film â…¡Fabrication Of Porous TiO₂ And PLZT Composite Film

Among plenty of semi-conductive nanomaterials, TiO₂ has been the focus of numerous investigations in photo electrochemical system for its thermal stability, biologically inert, nontoxic and simple preparation. However, TiO₂ has high band-gap energy (3.2eV), which means its spectral response is limited to UV regime. And also a short life of the photon induced electron-hole pair lowers the quantum field for charge injection. According to some report, inversed opal TiO₂ film could increase the photo-collecting efficiency by shifting the onset of the response from the UV to the visible region. Based on this fact, we fabricated inversed opal TiO₂ film and had a study on its properties.First, we fabricate polystyrene (PS) particles by a non-soap emulsion polymerization method. The mono-dispersed particles have 200-250nm in size. Then the PS opal-template were organized by a vertical deposition method. According to different sizes of PS particles, the template has a different color. Third, different sols were compared in filling degree in the PS template. After being calcinated, the template was burned to inversed opal TiO₂ film, which has a highly ordered microscopic structure. The SEM pictures show that the pore diameter is 190-230nm, which is contracted by 15% compared with PS particle. Last, the electrochemical test was applied to the inversed opal TiO₂ film. The results show that the film calcinated at 550℃had best photoelectrical properties, and the photo conversion efficiency was about 0.728%.Otherwise, we were also dedicated to fabricate a composite film consist of PLZT and TiO₂. As to the self-polarization of PLZT, which could apply a bias voltage to the TiO₂ film, the quantum field for charge injection would rise. First, the wet film was made by spin-coating method. Then we determined the heat treatment on the film according to XRD patterns of PLZT, PT, and TiO₂. Last, we obtained the composite film annealed at 550℃,with a good ferroelectric properties, and the remnant polarization Pr of the film is 0.372μC/cm2.