热处理对溶胶-凝胶TiO_2薄膜的晶相转变和性能影响

Influence of heat treatment on the properties and crystal phase transfer of TiO_2 gel films

以钛酸丁酯(TPOT)为有机醇盐前驱体,采用溶胶 凝胶技术制备了TiO2溶胶。为测量方便起见,分别制备了凝胶粉体和薄膜,并对样品进行了不同温度的热处理。X射线衍射(XRD)、椭偏仪和紫外 可见光谱(UV vis)的测量表明:随热处理温度的升高,TiO2的结构由非晶到锐钛矿再到金红石相转变,400℃为锐钛矿相,600℃开始出现金红石相,800℃完全转变为金红石相;晶粒尺寸随热处理温度的升高而逐渐增大,锐钛矿结构的晶粒尺寸范围是2.5～5.5nm,金红石结构的晶粒尺寸范围是5.9～6.8nm;TiO2薄膜的折射率随热处理温度的升高而增大,同时薄膜厚度降低;禁带宽度随热处理温度升高而变窄,锐钛矿结构的禁带宽度为3.45eV,而金红石结构的禁带宽度为3.30eV。

TiO2 gel films are prepared via solgel method with the TPOT as precursor. Under different heat treatment temprature, the properties and crystal phase transfer are investigated by using XRD, ellipsometry and UVvis spectroscopy and the reason is also explained.