Study On Surface And Transient Photovoltage Characters Of Mesoporous Nanocrystalline TiO₂

La-undoped and La-doped molar percentage of 0.5% mesoporous nano-TiO2 samples were prepared by sol-gel method with polyethylene glycol (PEG) surfactant as template, and the samples were also prepared with composite template using different types and ratio of the template.The X-ray diffraction (XRD) was used to analyze the component of the samples, and the crystal size was obtained by calculating; Laser Raman was used to analyze the situation of the bond; differential thermal analysis (DSC-TG) was used to analyze the change of precursor undergoing heat treatment; transmission electron microscopy (TEM) and specific surface area (BET) method were used to analyze and characterize the microstructure of the samples; the surface charge transfer of samples was characterized by surface photovoltage spectroscopy (SPS), photoacoustic spectroscopy (PAS) and transient photovoltage spectroscopy (TPS) .The results showed that La-doped can effectively inhibit the growth of anatase and control phase transition from anatase to rutile; via the determination of specific surface area, confirmed that the TiO2 samples prepared are mesoporous materials, La-doped can increase the surface area and pore volume of TiO2 samples; La-doped can also increase the surface photovoltaic response intensity dramatically , improve the optoelectronic properties significantly, reduce non-radioactive transitions, and can increase the transient photovoltaic response intensity obviously within the scope of short time; the type of composite template have a significant effect on the surface photoelectronic property of the La-doped nano-TiO2; the samples had a stronger surface photovoltage response when the molar ratio of the polyethylene glycol and cetyl trimethyl ammonium bromide (CTAB) or Octadecylamine (ODA) were 1︰1 as compare with the samples with the others molar ratio; the composite template of PEG and ODA can also be significantly enhanced the transient photovoltaic response of TiO2 samples, and can increase the band - band transition with the proportion.