PREPARATION AND OPTICAL PROPERTIES OF THE Fe-DOPED POROUS TIO₂ THIN FILMS

Porous Fe-doped TiO₂ thin films we prepared on the glass by spin coating of the TiO₂ sol including the polyethylene glycol 2000（PEG 2000） and Fe ions.The morphology,crystalline structure,and optical properties of the as-grown specimens were characterized by using of the scanning probe microscopy,X-ray diffraction,UV-VIS transmittance spectroscopy,and photoluminescence（PL） measurement,respectively.It was found that the Fe-doped TiO₂ thin films exhibited porous structure with well-distributed pores,a red shift of the absorption edge occurred with the increase of Fe-doped concentration.And the maximum red shift was 150 nm as the concentration of Fe is 0.15 M,indicating that the Fe doping could reduce the band-gap of TiO₂.Additionally,the recombination rates of the excitation were strong dependant on the doping concentration of Fe,for instance,the photoluminescence signal of the Fe-doped TiO₂ thin films firstly decreases and then increases with the increasing of doping,and reaches its minimum in 0.10 M.Obviously,the optimized parameter would be beneficial to improve the photoelectric performances of porous TiO₂ thin films.