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采用溶胶-凝胶法于不同温度下制备出了不同厚度、均匀透明、机械性能和光电特性稳定的TiO_2多孔纳米薄膜．光电测试结果表明,焙烧温度和膜厚能够显著影响薄膜电极的光电特性．450℃焙烧制得的电极由结晶度高、光电活性相对较强的锐钛矿相构成,其光电流最大．低于此温度,薄膜结晶度较差,膜内缺陷较多,不利于光生载流子的传输；而高于此温度,薄膜因发生由锐钛矿到金红石的相变,使得光电活性相对较弱的金红石含量不断增大,从而降低了光电流．膜厚的增加有利于提高紫外光的吸收强度从而提高电极的光电活性,但过厚的膜厚将加大光生电子一空穴对的复合几率,引起电极光电活性的降低．另外,薄膜电极的紫外光电流响应灵敏度和光生电流稳定性与电极电位有关．电位为0．4 V时,光电流趋于饱和,其强度为30．8μA,光电响应时间约1 s,基本具备了在紫外光传感器方面应用的性能．
The porous TiO 2 films with different thickness, uniform transparency, mechanical properties and photoelectric properties were prepared by sol-gel method at different temperatures. The photoelectric test results show that the firing temperature and film thickness can significantly affect the photoelectric properties of the film electrode. The electrode prepared by calcination at 450 ℃ is composed of anatase phase with high crystallinity and relatively high photoelectrical activity, and the photocurrent is the largest. Below this temperature, the film has poor crystallinity and more defects in the film, which is not conducive to the transport of photo-generated carriers. Above this temperature, the film undergoes phase transition from anatase to rutile to make the photoactivity relatively Weak rutile content continues to increase, thereby reducing the photocurrent. The increase of the film thickness is beneficial to increase the absorption intensity of ultraviolet light and improve the photoelectric activity of the electrode. However, if the film thickness is too thick, the recombination probability of photogenerated electron-hole pair will be increased and the photoelectric activity of the electrode will be decreased. In addition, the UV electrode current sensitivity and photo-current stability of the film electrode are related to the electrode potential. When the potential is 0.4 V, the photocurrent tends to be saturated, the intensity is 30.8 μA, and the photoelectric response time is about 1 s, basically having the performance applied in the ultraviolet light sensor.