Preparation And Photoelectric Properties Of TiO₂ Mesoporous Thin Films

TiO₂ mesoporous thin film has attracted much recent attention for its potential applications in areas such as photocatalysis, UV photoresponce, electrochromism device and photovoltaics, due to its larger surface area, highly organized mesoporous channels and semiconductive framework.In chapter 2, TiO₂ mesoporous thin films were synthesized through evaporation-induced self-assembly (EISA) technique using TiCl₄ as Ti inorganic precursor and triblock copolymer (Pluronic F127) as structure-directing agents. The structure and morphology of TiO₂ mesoporous films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM), the results show that the mesopourous sample have a high periodicity, highly organized mesoporous channels, and nanocrystaline anatase framework, We also find out a simple and well-repeated experiment condition.In chapter 3, the UV-Vis absorption spectra measurements revealed that TiO₂ mesoporous thin films have strong absorbance in UV regions (λ<400 nm). We also characterized the current-voltage (I-V) characteristics of TiO₂ mesoporous thin film, the results show that the I-V characteristics have changed when UV light is on and off, which indicate that TiO₂ mesoporous thin films have UV photoresponse.In chapter 4, TiO₂ mesoporous thin films were synthesized through EISA technique and aged for 4 days, then they were calcined in NH3 atmosphere in order to get N-doped TiO₂ mesoporous thin films. The structure, morphology and surface component of TiO₂ films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The results show that N-doped TiO₂ mesoporous thin films have high periodicity, highly organized mesoporous channels, and N element exist as Ti-N type.