La掺杂TiO_2薄膜的制备及其光电流研究

Study on Preparation and Photocurrent of La-doped TiO_2 Thin Films

采用溶胶凝胶-浸渍提拉法在ITO导电玻璃表面制备了纯TiO2薄膜和La掺杂TiO2薄膜,对其进行350℃、450℃、550℃保温2 h热处理。利用XRD、SEM、EDS、XPS对样品结构、形貌、成分进行表征,利用电化学工作站对薄膜进行光电流测试,研究了La掺杂以及不同热处理温度对TiO2薄膜结构及光电流的影响。结果表明:La掺杂有细化TiO2晶粒和抑制锐钛矿相向金红石相转变的作用。随热处理温度提高,纯TiO2薄膜与La掺杂TiO2薄膜光电流密度均先增大后减小,450℃热处理后纯TiO2薄膜光电流密度为180μA·cm-2,此温度下La掺杂TiO2薄膜光电流密度为650μA·cm-2,是纯TiO2薄膜的3.6倍。

The pure TiO2 and La-doped TiO2 thin films were prepared on the ITO glass by sol-gel and dipcoating method. The heat treatment at 350 ℃,450 ℃,550 ℃ for 2 h were proceeded on the films. The crystal structure,morphology,composition and photocurrent of the samples were analyzed by XRD,SEM,EDS,XPS and Electrochemical workstation respectively. The influence of doping La and different heat treatment temperature on the structure and photocurrent of TiO2 thin films was studied. The result shows that the grain size of TiO2 is refinement and phase transformation from anatase to rutile is restrained by La-doped. The photocurrent density of pure TiO2 and La-doped TiO2 films first increases then decreases with the heat treatment temperature increasing. The photocurrent density of pure TiO2 film is180 μA · cm- 2after 450 ℃ heat treatment. The photocurrent density of the La-doped TiO2 film is improved 3. 6 times compared with pure TiO2 film which is 650 μA·cm- 2at the same temperature.