Fe掺杂TiO_2纳米多孔薄膜的制备及光学性质研究

PREPARATION AND OPTICAL PROPERTIES OF THE Fe-DOPED POROUS TIO_2 THIN FILMS

将Fe掺杂的TiO2-PEG 2 000溶胶旋涂在玻璃基底上,经过退火处理后得到Fe掺杂TiO2纳米多孔薄膜。用场发射扫描电子显微镜、X-射线衍射仪、紫外可见分光光度计和荧光光谱仪分别对样品的形貌、物相结构以及光学特性进行了表征。结果表明:制备的Fe掺杂TiO2纳米多孔薄膜,表面微孔分布均匀,其光吸收边随着Fe掺杂浓度的增加发生了显著红移,当掺杂量为0.15 M时红移量达到最大,约150 nm,说明Fe掺杂可减小TiO2纳米多孔薄膜的光学带隙。此外,样品的光致发光测试结果显示,随着Fe掺杂浓度的逐渐增加,样品的发光强度呈先抑后扬的变化趋势,这说明Fe掺杂浓度对TiO2纳米薄膜光生电子-空穴对的复合几率亦有很大影响,只有当Fe掺杂浓度为0.10 M时,TiO2薄膜的光生载流子复合几率最低。可见,这是一个益于改善TiO2纳米多孔薄膜光电转换性能的优化参数。

Porous Fe-doped TiO2 thin films we prepared on the glass by spin coating of the TiO2 sol including the polyethy- lene glycol 2000（ PEG 2000 ） and Fe ions. The morphology, crystalline structurc, and optical properties of the as-grown specimens were characterized by using of the scanning probe microscopy, X-ray diffraction, UV-VIS transmittance spectros- copy, and photoluminescence （PL） measurement, respectively. It was found that the Fe-doped TiO2 thin films exhibited por- ous structure with well-distributed pores, a red shift of the absorption edge occurred with the increase of Fe-doped concentra- tion. And the maximum red shift was 150 nm as the concentration of Fe is O. 15 M, indicating that the Fe doping could re- duce the band-gap of TiO2, Additionally, the recombination rates of the excitation were strong dependant on the doping con- centration of Fe, for instance, the photoluminescence signal of the Fe-doped TiO2 thin films firstly decreases and then increa- ses with the increasing of doping, and reaches its minimum in 0.10 M. Obviously, the optimized parameter would be benefi- cial to improve the photoelectric performances of porous TiO2 thin films.