Study On The Preparation And Optical Properties Of TiO₂ And Its Multilayer Composite Film

TiO₂ has been used in the fields of environmental protection and construction due to its excellent optical transmittance,high refractive index,high dielectric constant,chemical stability,good adhesion and life and photocatalytic performance.However,the band gap width of TiO₂ limits its spectral response range in the ultraviolet region,and its reflectivity in the infrared region is low,which cannot meet the requirements of low radiation energy saving.In this paper,TiN/Ag/Cu₂O/TiO₂ composite films were designed and successfully prepared by magnetron sputtering method on the basis of studying the optical properties of TiO₂ films and other monolayer films.X-ray diffraction(XRD),atomic force microscopy(AFM),UV-VIS-NIR spectrophotometer,Essential Macleod software and spectroscopic ellipsometry(SE)were used to characterize the crystal structure and optical properties of the films.The research contents are as follows:(1)The effect of sputtering time on the crystal structure and optical properties of TiO₂ thin films were studied.The results show that the prepared TiO₂ films are all anatase type.With the increase of sputtering time,the crystallinity of the films becomes more and more perfect,forming anatase type TiO₂ films with(101)crystal plane selective growth.The thickness of the films increases with the increase of sputtering time,and the average deposition rate is calculated to be 2.133nm/min.With the increase of sputtering time,the transmittance of the 550 nm band which is the most sensitive to human eye decreases from 85.7%to 70.5%,the reflectivity in the near infrared light range increases,the band gap of the film also decreases from 3.66e V to 3.53e V,and the photocatalytic efficiency increases from 8.5%to 12.7%.(2)The crystal structure and photoelectric properties of TiN thin films were studied.The results show that with the increase of sputtering time,the crystallinity of the films becomes more and more perfect,forming the TiN films with(200)crystal plane.The SE test showed that the thickness of the film increased with the increase of sputtering time,and the average deposition rate under this condition was calculated to be 7.650nm/min.With the increase of sputtering time,the transmittance of 550 nm band decreases from 68.3%to 18.7%.The infrared emissivity of the film is 0.494(?=2.5?m)and 0.156(?=25?m),respectively,which shows the better low radiation properties.(3)The crystal structure and optical properties of Ag and Cu₂O films were studied by controlling the sputtering time.The results show that with the increase of sputtering time,the crystallinity and thickness of the films increase,the transmittance of the visible light region decreases,and the reflectance of the near infrared region increases.The deposition rates of Ag and Cu₂O films were calculated as 17.278nm/min and0.749nm/min,respectively.(4)On this basis,TiN/Ag/Cu₂O/TiO₂ composite film was successfully prepared.The optical properties of the composite film were mainly studied,and the photocatalytic mechanism of the composite film was mainly analyzed.The results show that the transmittance and reflectivity of the composite film with the best comprehensive optical properties at 550nm,the most sensitive region for human eyes,are 66.6%,and the reflectivity in the near-infrared region is about 50%.Cu₂O composite membrane with p-N formed between TiO₂ heterojunction,greatly reduce the band gap contrast TiO₂ thin film,the spectral response of the TiO₂ film range by ultraviolet area expanded to visible light area,photocatalytic efficiency improved significantly,at the same time TiN and Ag provide a certain selection of transmission and low radiation performance,that by designing multilayer composite thin films to improve the optical properties of TiO₂ thin film is promising.