Construction Of SnO₂/VO₂ Composite Film Based On Phase Change

In the 21st century,science and technology is advancing by leaps and bounds,and a variety of new materials have sprung up into the public field.The ultra-fast phase transition characteristics of vanadium dioxide and its huge differences of electrical properties and optical properties before and after the phase transition make it extensively useful in military industry,electronics and even daily life.So,Vanadium dioxide attracts most researchers due to its peculiar phase transition properties.However,in light of the wide variety of vanadium oxides with different chemical valence,the conditions for preparing pure vanadium dioxide are relatively severe.At the same time,the annoying"optical defect"of vanadium dioxide(the visible light band transmittance is low due to its narrow band gap)causes many problems on practical applications.In this study,the easily available vanadium pentoxide with highest chemical valence,was used as a precursor to obtain vanadium dioxide by means of oxygen regulation.Moreover,Sn elements were introduced to construct a SnO₂/VO₂ composite structure with high-performance.X-ray Diffractometer,Field Emission Scanning Electron Microscope,Ultraviolet-Visible Spectrophotometer,Variable Temperature Raman Spectroscopy,and Electrochemical Workstation were used to characterize the phase composition,microscopic morphology,optical properties,and phase transition properties of the test materials,and then the following results were obtained:(1)Thermal deoxidation mechanism and thermal decomposition mechanism were explained the transformation from V₂O₅ to VO₂ during the annealing process:For thermal deoxidation mechanism,the amorphous V₂O₅ were crystallized at 400?;most of the V₂O₅ lossed oxygen to transform to V₆O₁₃ at 500?;At 600?,V₂O₅ was largely loss of oxygen to transform into VO₂ as well as other vanadium oxides.For the thermal decomposition mechanism,the orthorhombic V₂O₅ directly decomposed into the monoclinic VO₂ when the temperature arrived at 700?.(2)The Sn-incorporated film was completely composed of a ternary amorphous system of V,Sn,and O,which promotes the transformation of V₂O₅ to VO₂.The ternary amorphous would be crystallized to transform to the"intermediate phase"(the mixed state of Sn,V and O)at 500?;The ternary amorphous would be effectively deoxidized to become crystallized SnO₂/VO₂ composite structure at 600?;when the temperature is 700?,ternary amorphous was directly decomposed into SnO₂/VO₂composite structure of VO₂ embedding in SnO₂.(3)The performance of the SnO₂/VO₂ composite film was affected by the Sn content.The phase transition temperature of the composite film with 10%Sn content was 48?through variable temperature Raman,which was 12?lower than the 60?of Sn-free VO₂.Moreover,its resistance changed by 2 orders of magnitude after the phase transition.The introduction of Sn compensated the terrible"optical defect"of VO₂to increase its light transmittance by 26%.