SYNTHESIS AND CHARACTERIZATION OF SOL-GEL DERIVED TiO_2 THIN FILMS: EFFECT OF DIFFERENT PRETREATMENT PROCESS

摘要

Titanium dioxide (TiO_2) thin films have been successfully synthesized deposited on glass substrates by the sol-gel dip-coating method through different pretreating processes, including heated at 100, 500 deg C, via freeze drying, microwave heating for 10 min and subsequently annealed at 500 deg C for 2h. The as-synthesized TiO_2 films were characterized using X-ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) absorption spectra analysis technologies. The preparation of the precursor sols and TiO_2 films were described in detail. Effects of 100, 500 deg C, freeze drying and microwave healing prelrcatmcnl on crystalline structure, surface morphology, roughness, particle size, optical property and electronic transition of TiO_2 thin films have been primarily investigated. The XRD results demonstrated that the TiO_2 films were well-crystallized and consisted of analase TiO_2 phase only with (101) plane. The average crystalline size is only about 15 nm at 100 deg C pretreatment and the absorption edge shifts to shorter wavelength comparing with that at 500 deg C, freeze drying and microwave heating pretreatment. Pretreatment process is important during the preparation of thin films and has obviously effect on the structure and optical property of TiO_2 films due to the different heating mechanisms.