Preparation And Study Of KGd(WO₄)₂ Film On Its Fluorescence Properties

Potassium gadolinium tungstate KGd(WO₄)₂(KGW for short),as a matrix material with excellent performance,has been widely studied and applied in the fields of laser devices,communications,and medical testing.Compared with crystalline materials,thin film materials have excellent luminescence performance,strong electrical and thermal conductivity,and high photocatalytic activity.Tungstate films have stimulated people's research interest with their unique properties and application prospects.In this thesis,Re(Re=Eu³⁺,Tb³⁺):KGW films with different doping concentrations are prepared on a quartz substrate by dipping and pulling.Coating on the quartz substrate and introducing the KGW,Si O₂and Ti O₂buffer layer on the quartz substrate by dipping and pulling method,exploring the best preparation process of KGW film,and preparing doped Re:KGW(Re=Eu³⁺,Tb³⁺)film.Discuss the influence of different controllable factors,buffer layer and rare earth ion doping concentration on the phase,morphology,roughness,ultraviolet and fluorescence properties of the film.The main work results are as follows:1.Preparation of KGW film by dipping and pulling method,to study the effects of heat treatment temperature,number of coating layers,surfactants,absolute ethanol,the influence of the secondary coating method and different buffer layer types on the film The results show that when the heat treatment temperature is 950?,the crystallinity of the film is 92.38%,and the film is grown preferentially on the left mathrm(002)right crystal plane,.The number of coating layers is 5,10 and 15,with 10 being the best.The use of SDBS surfactant can significantly reduce the voids of the film and increase the density of the film.After adding absolute ethanol,the wetting angle between the substrate and the precursor solution is 13.37°.and the prepared film has uniform crystal grain distribution and high density.When the two coating temperature is 950?,the density and crystallinity of the film will be improved.After introducing KGW,Si O₂and Ti O₂buffer layers on the quartz substrate,the c-axis of the film is strengthened preferentially,and the crystalline quality of the film is improved.After the introduction of Si O₂and Ti O₂ buffer layers,the surface of the film is denser and the grain size becomes larger.The buffer layer increases the wettability between the film and the substrate material,so that the surface roughness of the film is reduced.The adhesion of the KGW film with the buffer layer is gradually increasing,and the adhesion of the film with Ti O₂as the buffer layer can reach 43.19 n N.3.Preparation of Eu³⁺:KGW film by dipping and pulling method to study the fluorescence performance.Excitation and emission spectra show that 256 nm excitation light can emit 614 nm red light,and the fluorescence lifetime at 614 nm is 0.65 ms.As the Eu³⁺concentration continues to increase,the position of the diffraction peak corresponding to the film moves to a high angle direction as a whole.(002)The distance between the crystal planes decreases,and the lattice distortion ratio becomes larger.SEM characterization shows that doping with an appropriate concentration of Eu³⁺can increase the density of the film.The transmission spectrum shows that the average transmittance of the film reaches about 70%.When the Eu³⁺concentration increases from 10%to 30%,the optical band gap of the film gradually decreases.When the Eu³⁺ion concentration is in the range of 10%-20%,the fluorescence intensity increases as the Eu³⁺concentration increases.After 25%,the fluorescence intensity drops,and fluorescence quenching occurs.The difference of the coating process affect the fluorescence intensity of the film.When both coatings are used at 950°C and the Ti O₂ buffer layer film is introduced,the fluorescence intensity of the film will increase.The Tb³⁺ions concentration is in the range of 5%-15%,and the fluorescence intensity of the film gradually increases with the increase of the Tb³⁺concentration.When it exceeds 15%,the fluorescence intensity decreases.4.The growth type of the KGW film on the quartz substrate is:island growth.During the growth process,small crystal grains grow up,and large crystal grains are connected and combined to form a large island.The combination of island and island forms a complete continuous film.After KGW,Si O₂and Ti O₂buffer layers are introduced into the quartz substrate,the KGW film is plated,and the half-value width of the(002)crystal plane of the film becomes smaller than that of the non-incorporated buffer layer.The introduction of Si O₂ and Ti O₂ buffer layers can reduce the lattice mismatch between the film and the quartz substrate,and the minimum lattice mismatch between the Ti O₂ buffer layer film and the quartz substrate is 1.3%.