The Optical Properties Of Ag-Zn Co-doped TiO₂ Thin Films By Sol-gel Spin-coating Method

There are many kinds of thin film materials,such as zinc oxide?Zn O?,nickel oxide?Ni O?,titanium dioxide?TiO₂?and doped oxide films.Among them,nano-scale TiO₂ thin films have attracted much attention because of their low price,excellent chemical stability and optical properties.At present,TiO₂ thin films have been widely used in the development of new energy,solar energy utilization and environmental purification.In this paper,the structure,properties,uses,common modification methods and preparation methods of TiO₂ films are first introduced.Secondly,undoped TiO₂ films with different sol concentrations,Ag doped TiO₂ films and Ag-Zn co-doped TiO₂ films were prepared by sol-gel spin coating on Silicon pellet and glass substrates.Finally,the effects of different sol concentrations,Ag doping content and Zn doping content on lattice structure,surface absorbance,and optical band gap of TiO₂ films were investigated by means of X-ray diffraction?XRD?,scanning electron microscope?SEM?and ultraviolet-vis spectrophotometer?Uv-Vis?.Test and analysis results are as follows:1)The prepared samples were all anatase phase.The optimum sol concentration is 0.5mol/L.At this time,the crystallinity of the sample is the highest,the number of pores on the surface of the film is the least,the absorption of visible light is the best,and the band gap is reduced to 3.515 e V.2)Ag-doped TiO₂ films are still anatase phase.Proper amount of Ag doping is beneficial to the crystallization quality and optical properties of TiO₂ films.When the Ag doping amount is 1.5 at%,the sample grows along the C axis with the best preferential orientation,the grain size is uniform,the absorption edge of the absorbance has a red shift phenomenon,and the band-gap width decreases to 3.476 e V.3)On the basis of constant doping amount of fixed Ag,Zn elements were further incorporated.The?101?diffraction peak intensity of the sample decreases first and then increases.The surface morphology of the Ag-Zn co-doped TiO₂ film has obvious changes,and the grain size and the number of pores decrease.When the doping amount of Zn element is 2.00 at%,the?101?diffraction peak intensity of the sample is the largest,the grain size is uniform,the surface of the film is the most flat and compact,the absorption edge of the absorbance curve is red-shifted,and the band gap is further reduced to 3.419 eV.