Study On The Influence Of Nd And W Doping On The Preparation And Performance Of Vanadium Dioxide Thin Films

The VO₂ film undergoes a reversible phase transition from a semiconductor state to a metal state at 68°C.This thermally induced phase change allows the VO₂ film to be widely used in smart window materials,switching devices and other fields,but the higher phase transition temperature(68°C)),still limiting its practical application.In order to reduce the phase transition temperature of the VO₂ film,the study of element doping and film recombination was carried out in this paper.The pure VO₂ film with glass substrate was prepared by hydrothermal synthesis combined with high temperature heat treatment,and the effects of Nd,W doping concentration and Sn O₂ recombination on the microstructure and phase transition properties of the VO₂ film were investigated.A two-step method of hydrothermal reaction and annealing in an autoclave prepared a VO₂ film with uniform surface distribution,single crystal item,and high purity.DSC test results showed that the phase transition temperature of VO₂(M)was 68.87?.FITR results show that the phase change transmittance of the VO₂ film below the phase transition temperature is about 50%,and the phase transition temperature above the phase transition temperature is about 10%.The infrared transmittance before and after the VO₂phase transition changes to 40%.Nd doping has an effect on the structure and phase change properties of VO₂ films.As the amount of Nd doping increases,the diffraction peak shifts to a small angle to the left.XPS results show that the Nd element is+3 valence,indicating that Nd doping into the VO₂ film.The DSC results show that the phase transition temperature of the VO₂ film can be effectively reduced by doping with Nd element.The phase transition temperature of VO₂ film doped with 9 at%Nd is reduced to 50.38?.In addition,Nd doping will reduce the infrared transmittance of VO₂,and the infrared transmittance of the VO₂ film doped with 4 at%Nd changes to 35%before and after the phase change.W doping will also affect the structure and phase change performance of the VO₂film.As the W doping content increases,the diffraction peaks also tend to shift to a small angle.XPS results show that the W element is+6 valence,indicating that W is doped into the VO₂ film.DSC results show that W doping has a greater effect on the phase transition temperature of VO₂ films,and the phase transition temperature of VO₂ films doped with3 at%W decreases to 26.91?.W doping will also reduce the infrared transmittance of VO₂.The infrared transmittance of the VO₂ film doped with 4 at%W changes to 30%before and after the phase change.A composite film of SnO₂ and VO₂(M)was prepared by hydrothermal synthesis.The SEM results showed that the dense VO₂ nanorod array was grown vertically on the FTO substrate.The VO2(M)film was detected by DSC.The phase transition temperature is63.23?,which is lower than that of pure VO₂(M)film.The infrared transmittance?T of the VO₂(M)film prepared on FTO conductive glass is about 45%,which improves the infrared transmittance of VO₂.