342 results about "Vanadium dioxide" patented technology

The invention discloses a light-operated reconfigurable metasurface for full-space terahertz wave beam regulation and control, solves the problem of how to provide ubiquitous full-space wave beam coverage for multi-user wireless communication application, and belongs to the field of artificial electromagnetic metamaterials. The super subunit comprises N super subunits which are arranged periodically, each super subunit comprises 4 * 4 identical coding units, corresponding codes are '0' and '1' respectively when illumination exists or not, and the phase response difference of the two coding units at 0.7 THz is 180 degrees. Each super subunit comprises five layers, the third layer is used for switching between reflection and transmission, when vanadium dioxide is in a medium state, the super surface is in a transmission mode, and when vanadium dioxide is in a metal state, the super surface is in a reflection mode. The first layer, the second layer, the fourth layer and the fifth layer are used for controlling the amplitude and the phase of the total-space terahertz wave, the conductivity of the photosensitive silicon pattern is changed under excitation of light with different intensities, the phase of the total-space terahertz wave beam is effectively modulated, and one-bit terahertz information coding is achieved.

The invention discloses a dual-frequency / broadband switchable dynamic tuning metamaterial terahertz absorber which comprises M * N terahertz absorption units of a multi-layer structure, the M * N terahertz absorption units of the multi-layer structure are distributed in an M * N two-dimensional mode, and M and N are positive integers. Each terahertz absorption unit with the multi-layer structure comprises a metal substrate, a dielectric layer and a resonance layer which are sequentially arranged from bottom to top; the dielectric layer and the metal substrate are square and have the same side length; the resonance layer comprises a single-layer graphene layer with a hollow cross, and a solid cross-shaped vanadium dioxide layer is embedded in the hollow part of the single-layer graphene layer with the hollow cross; and the appearance of the single-layer graphene layer with the hollow cross is cross-shaped. The absorber can be dynamically tuned, has the characteristic of polarization insensitivity, and can keep stable absorption in an incidence angle range of 0-60 degrees. The invention further discloses a preparation method of the dual-frequency / broadband switchable dynamic tuning metamaterial terahertz absorber.

The invention relates to the technical field of artificial electromagnetic metasurfaces, in particular to a full-space multifunctional terahertz metasurface. The metasurface is composed of a plurality of metasurface units arranged periodically, and each metasurface unit sequentially comprises a first metal structure layer, a first middle dielectric layer, a grating layer, a second middle dielectric layer and a second metal structure layer from top to bottom. The first metal structure layer and the second metal structure layer are the same in structure and each comprise two C-shaped metal rings, and the two C-shaped metal rings are connected in a staggered mode to form a disconnected and staggered S shape. The first intermediate dielectric layer and the second intermediate dielectric layer are consistent in thickness; the grating layer comprises vanadium dioxide and copper which are alternately arranged, and multifunctional dynamic regulation and control of transmission, reflection and the whole space are achieved by controlling phase change of the vanadium dioxide. The metasurface provided by the invention can respectively realize the functions of polarization conversion, linear-circular polarization wave conversion, circular dichroism, asymmetric transmission and the like in different states.

The invention discloses a composite thermochromic window with a dual-band dynamic regulation and control function. The composite thermochromic window comprises a first transparent substrate, a tungsten-doped vanadium dioxide film, a second transparent substrate and a hydrogel layer. The tungsten-doped vanadium dioxide film is deposited on the upper surface of the first transparent substrate, and the phase transition temperature is 25-32 DEG C; the hydrogel layer is thermo-sensitive poly (N-isopropylacrylamide) and is encapsulated between the two transparent substrates, and the low critical phase transition temperature is 32 + / -2 DEG C. When the temperature is lower than 25 DEG C, the infrared transmittance of the tungsten-doped vanadium dioxide film is larger than or equal to 75%, and the visible light scattering rate of the hydrogel layer is smaller than or equal to 10%; when the temperature is higher than 32 DEG C, the near-infrared transmittance of the tungsten-doped vanadium dioxide film is reduced to the minimum value, and the visible light scattering rate of the hydrogel layer is increased to 35% or above. Compared with the prior art, the system and the method have the advantages that dual-band dynamic regulation and control of visible light and near-infrared light are achieved, the indoor photo-thermal environment can be automatically regulated according to the environment temperature, and the building energy utilization efficiency is improved.

The invention discloses a bifunctional chiral metamaterial surface capable of switching polarization conversion and wave absorption, and belongs to the technical field of electromagnetic metamaterials. The method is used for solving the problem that most existing chiral super-structure surfaces cannot realize dynamic adjustability and quantitative controllability and cannot have dual functions of polarization conversion and wave absorption at the same time. The super-structure surface unit structure is composed of a graphene film layer, a gold-vanadium dioxide resonance layer, a silicon dielectric layer and a bottom-layer continuous gold film. Switching of two functions of polarization conversion and wave absorption is realized by changing the conductivity of vanadium dioxide; polarization conversion and dynamic regulation and control of the wave absorbing efficiency are realized by changing the Fermi level of the graphene; quantitative controllability of polarization conversion and a wave absorbing function is realized by controlling a function weighting function. Besides, the chiral super-structure surface also has the advantages of incident angle robustness, small thickness and small size, has double functions of broadband, and has potential application value in the fields of optical devices, communication equipment, biomedical sensors and the like.

The invention belongs to the field of semiconductor bridge current protection, and particularly relates to a semiconductor bridge current protection method based on a vanadium dioxide thick film thermistor. Firstly, copper, nickel and gold interdigital electrodes are deposited and grown on an aluminum oxide ceramic substrate, then a methanol solution of vanadyl acetylacetonate is sprayed on the surface of the heated interdigital electrode, a vanadium dioxide thermistor device is obtained, the vanadium dioxide thermistor device is connected with a semiconductor bridge in parallel, and current protection of the semiconductor bridge thermistor is achieved. Vanadium dioxide with a single valence state can be synthesized by adjusting the synthesis method and process, M-phase vanadium dioxide is synthesized on the interdigital electrode in one step, the vanadium dioxide prepared by the method avoids the tedious process that vanadium dioxide powder is firstly prepared and then transplanted to the surface of the interdigital electrode, and the preparation method is simple and convenient to operate. And the vanadium dioxide can be more stably combined on the surface of the interdigital electrode.

The invention provides a coding metasurface with terahertz wave absorption and reflection functions and application, the coding metasurface comprises at least one coding unit arranged in an array, each coding unit comprises a top resonance layer, a dielectric layer and a metal reflection layer which are sequentially arranged from top to bottom, the top resonance layer comprises a graphene resonance layer and a vanadium dioxide phase change layer, and the dielectric layer comprises a dielectric layer and a metal reflection layer. The graphene resonance layer comprises square graphene, the vanadium dioxide phase change layer comprises a square vanadium dioxide outer ring and a vanadium dioxide strip embedded in the vanadium dioxide outer ring, the vanadium dioxide outer ring is located on the inner side of the graphene, and the square edge of the vanadium dioxide outer ring and the square edge of the graphene are arranged in parallel at an interval; wherein the vanadium dioxide strips are arranged at the diagonal positions of the vanadium dioxide outer ring and are arranged at intervals with the vanadium dioxide outer ring, the advantages of a wave-absorbing metasurface and a reflection coding metasurface are integrated, and the signal generation power of 6G communication is greatly optimized.

The invention provides a vanadium dioxide composite electrode material and a preparation method and application thereof. The method comprises the following steps: taking vanadium leachate as a raw material, reacting with a reducing agent under the condition that the pH value is 2-6, mixing the obtained tetravalent vanadium solution with a precipitator, carrying out precipitation reaction, filtering, washing and drying the precipitate to obtain vanadium dioxide precursor particles, grafting a silane coupling agent with sulfydryl onto the surface of the vanadium dioxide precursor through coupling reaction, and carrying out vacuum drying to obtain the vanadium dioxide precursor. Silver ions are chelated under the action of sulfydryl, and silver elementary substances are deposited on the surfaces of vanadium dioxide precursor particles through reduction. And coating the composite slurry of the vanadium dioxide precursor and the carbon nanotube on the surface of a substrate, and calcining to obtain the vanadium dioxide composite electrode material. The vanadium dioxide composite electrode material is used as a negative electrode material of a battery, and the obtained battery is found to have excellent stability and reaction dynamic characteristics.

The invention relates to a phase change regulation and control Van der Waals junction type transistor infrared detection chip and a preparation method and application thereof. The unit structure of the Van der Waals junction type transistor infrared detection chip comprises a two-dimensional material layer, a metal electrode, a vanadium dioxide micro-nano structure, an electrical channel and a CMOS reading circuit from top to bottom. The metal electrode comprises a metal grid electrode, an auxiliary electrode, a metal source electrode and a metal drain electrode; two ends of the vanadium dioxide micro-nano structure are respectively connected with the metal grid electrode and the auxiliary electrode, and two ends of the two-dimensional material layer are respectively connected with the metal source electrode and the metal drain electrode; and the electrical channel is connected with the metal electrode and the CMOS reading circuit on the substrate. According to the infrared detection chip prepared by the invention, the response speed of a device is remarkably improved, the response range is widened, ultra-sensitive detection is realized, a self-powered infrared detection chip can be realized, and the infrared detection chip has important significance for reducing the power consumption and the cost of the device.

The invention discloses a vanadium dioxide-based spin coupling and decoupling dynamic switching metasurface. The unit structure of the metasurface is divided into three reflecting layers; a dielectric layer; the metal layer is of an S-shaped structure and comprises a rectangle in the middle and circular arcs at the two ends, the rectangle is made of gold, and the circular arcs are made of vanadium dioxide; when vanadium dioxide is in a metal state, adjusting an opening angle alpha between the arc and the rectangle and a rotation angle theta of the metal layer around an X axis, and realizing decoupling of left-handed polarized light and right-handed polarized light through combination of a PB phase and a transmission phase; when vanadium dioxide is in an insulated state, the PB phase is regulated and controlled only by rotating the angle theta, and coupling of left-handed polarized light and right-handed polarized light is achieved. Compared with other coding metasurfaces, the modulation mode is simpler, the design is more flexible, the functions are more diversified, the defect that the function of the metasurface is fixed is overcome, the coupling characteristic and the decoupling characteristic of left-handed and right-handed polarized light are integrated together, and the application prospect of a coding metasurface device is expanded.

The invention discloses an AgVO material with modified vanadium dioxide doped with silver ions, a preparation method of the AgVO material and application of the AgVO material in an aqueous zinc ion battery. The silver ion doped modified vanadium dioxide AgVO material is prepared by the following steps: firstly, enabling vanadium pentoxide and anhydrous oxalic acid to react in water to obtain a clear dark blue solution; and then carrying out hydrothermal reaction on the dark blue solution and silver nitrate at 175-185 DEG C to obtain the silver vanadium oxide composite material with a nanofiber bundle microstructure, wherein the silver vanadium oxide composite material is formed by doping silver ions on the surface and inside of a VO2 material. The silver ion doped modified vanadium dioxide AgVO material provided by the invention has a nanofiber bundle microstructure, and an aqueous zinc ion battery taking the silver ion doped modified vanadium dioxide AgVO material as a positive electrode active material has excellent capacity, cycling stability and rate capability and excellent electrochemical performance.

The invention belongs to the field of functional nano materials, and relates to a method for large-scale preparation of monoclinic phase vanadium dioxide nano powder, a heat insulation film and application of the heat insulation film, and large-scale preparation of the monoclinic phase vanadium dioxide nano powder is successfully achieved by combining a coprecipitation method with low-temperature calcination. The obtained product has excellent size uniformity (the average particle size is 65 + / -10 nm) and an adjustable phase change characteristic (61-68 DEG C). The polymer-based composite film prepared based on the nano powder shows excellent optical performance, and the method has the advantages of mild reaction conditions (less than or equal to 600 DEG C), controllable product morphology and phase transition temperature and the like, and provides a reliable solution for industrial production of nano functional materials for intelligent windows.

The invention discloses a VO2-based polarization modulator, a polarization characteristic analysis method and a modulation method, and belongs to the field of optical devices, the VO2-based polarization modulator comprises a metal substrate layer, a Si dielectric layer and a metasurface unit periodically arranged at the top end of the Si dielectric layer, and the metasurface unit is of a chiral structure formed by compounding VO2 and metal; each metasurface unit comprises a middle structure composed of a first middle metal frame and a second middle metal frame and side metal strips arranged on the two sides of the middle structure, and VO2 is embedded in the middle positions of the opposite sides of the first middle metal frame and the second middle metal frame. Metal protrusions are connected to the middle positions of the opposite sides of the first middle metal frame and the second middle metal frame. By adopting the VO2-based polarization modulator, the polarization characteristic analysis method and the modulation method, the polarization state of incident light can be adjusted by the metasurface by adjusting the conductivity of vanadium dioxide, and a dynamic tunable function is realized.

The invention relates to the technical field of building energy-saving intelligent windows, and discloses a sunlight and heat radiation multi-adjustment intelligent window and a preparation method and application thereof. The intelligent window comprises an outer surface layer, a middle layer and an inner surface layer which are stacked in sequence. The outer surface layer comprises an infrared transparent layer, and an infrared reflecting layer and a doped vanadium dioxide layer which are respectively arranged on two opposite surfaces of the infrared transparent layer; the inner surface layer comprises a transparent substrate and a conductive layer attached to the surface of one side of the transparent substrate; the middle layer is a liquid crystal / polymer dimming layer, one side of the liquid crystal / polymer dimming layer is bonded with the infrared reflecting layer, and the other side of the liquid crystal / polymer dimming layer is bonded with the conductive layer. According to the intelligent window, multiple cooperative regulation and control of sunlight and heat radiation can be achieved, the regulation and control wave band is wide, the response speed is high, and the energy-saving effect is good. The regulation and control wave band covers visible light, near infrared and middle and far infrared ranges, reversible change can be realized along with the change of environment temperature, and all-year-round and all-weather energy saving is realized.

The invention belongs to the technical field of building glass and coating materials thereof, and discloses a one-step chemical synthesis method of W-VO2 (M) nano-particles and application of the W-VO2 (M) nano-particles in thermochromic smart windows.The method comprises the steps that firstly, ammonium metavanadate, hydrazine hydrate and ammonium metatungstate serve as raw materials, tungsten-doped M-phase vanadium dioxide nano-particles are chemically synthesized through a one-step hydrothermal method, and the tungsten-doped M-phase vanadium dioxide nano-particles are prepared; the obtained W-VO2 (M) nanoparticles are high in crystallinity, small in particle size (10-40nm), high in purity and low in phase change temperature; then, by taking a polyvinylpyrrolidone material as a parent material, uniformly distributing the W-VO2 (M) nanoparticles in PVP (Polyvinyl Pyrrolidone) to form a uniformly dispersed thin film; according to the application of the W-VO2 (M) nanoparticles in the thermochromic intelligent window, not only can high visible light transmittance be obtained, but also the solar energy regulation and control capability of the W-VO2 (M) nanoparticles can be improved, and the application of the W-VO2 (M) nanoparticles in the fields of the thermochromic intelligent window and radiation refrigeration is further promoted.

The application relates to a preparation method and application of a ball milling-calcination process-prepared cesium vanadium tungstate mixed heat insulation coating, and belongs to the technical field of heat insulation coatings. The application aims to solve the problems of high preparation cost, strict requirement on equipment, long preparation time and difficult morphology control of vanadium dioxide and cesium tungsten bronze used in the existing cooling coating. The prepared cesium vanadium tungstate mixed heat insulation coating is coated on the surface of glass, mainly aiming at blocking the infrared light thermal radiation in sunlight, the new type of high-efficiency heat insulation film utilizes the light absorption and phase change reflection characteristics of nanometer cesium tungsten bronze and vanadium dioxide to realize heat insulation. The application adjusts the proportion of cesium, vanadium and tungstate to adjust the heat insulation performance, the heat insulation coating is prepared through different proportions of acrylic resin / organic silicon resin, solvent, cesium vanadium tungstate mixed heat insulation coating and the like, and the heat insulation film with excellent infrared blocking property, good stability and excellent light transmittance is obtained.

Embodiments described herein relate to a self-adaptive thermal management system. The thermal management system includes a first body, a second body, and a third body. The second body has a first layer and a second layer formed from a Weyl semimetal and a third layer sandwiched between the first layer and the second layer. The third layer is formed from a vanadium dioxide film. The second body is spaced apart from the first body. The third body is spaced apart from the second body. The second body is a modulator configured to transition between a metallic phase and an insulating phase dependent on a temperature to regulate a heat from the first body to the third body through the second body in a self-adaptive manner dependent on the temperature.

The invention relates to the technical field of terahertz metamaterial devices, in particular to an ultra wide band / double narrow band switchable terahertz wave absorber based on vanadium dioxide and sensing application. The wave absorber is formed by periodically arranging and combining a plurality of metamaterial square structure units, and no gap exists between adjacent periodic units. Each metamaterial square structure unit is composed of six layers from top to bottom, namely a VO2 resonance layer, a photonic crystal plate dielectric layer, a VO2 thin film, a metal resonance layer, a polycrystalline silicon dielectric layer and a gold substrate. The reversible phase change process of vanadium dioxide from a metal state to an insulation state is realized through external excitation (light, temperature and voltage). When vanadium dioxide is in a metal state, the terahertz ultra-bandwidth absorption function is achieved, when vanadium dioxide is in an insulated state, the terahertz wave double-narrow-band absorption function is achieved, and conversion between the ultra-wide band and the double narrow bands of the wave absorber is achieved. According to the terahertz wave absorber, the ultra-wideband / dual-narrowband conversion function of terahertz wave absorption can be achieved on one device, the defects that an existing terahertz wave absorber is complex in structure and the absorption characteristic is fixed once the terahertz wave absorber is manufactured are overcome, and the sensing function application of a single narrowband in the terahertz wave absorber is researched.

The invention relates to the technical field of sensors, and mainly relates to a narrow hysteresis width thin film material and a preparation method and application thereof. By doping the vanadium dioxide film and introducing magnetic rare earth elements gadolinium (Gd) and titanium (Ti), the rare earth elements as impurity ions can effectively replace or destroy V4 +-V4 + covalent bonds of vanadium ions, so that defects in the film are increased to regulate and control the phase change characteristic of the vanadium dioxide film, and the provided film material also has a narrow hysteresis width and can be applied to the field of thin film materials. And the wide application breakthrough of zero hysteresis width can be realized, and meanwhile, the material also has excellent reversible phase change and cycling stability and ultra-sensitive temperature response and rapid switching characteristics, and can provide powerful support for the development of the sensor field.

Methods for preparing catalysts for oxidative dehydrogenation (ODH) of alkanes such as ethane are provided. An exemplary method includes forming a slurry including metal oxides; one or more of a bismuth compound, an antimony compound, and a tellurium compound; a reducing agent; and water; and heating the slurry to form the catalyst. The metal oxides include an oxide of molybdenum and an oxide of vanadium. The bismuth compound includes bismuth oxide, bismuth hydroxide, or a bismuth carbonate. The antimony compound includes an oxide of antimony, an antimony acetate, or an antimony ethoxide. The tellurium compound includes tellurium dioxide. The reducing agent includes molybdenum dioxide and may further include vanadium dioxide. The methods use all inorganic reagents, with no build up COx pressure observed during the hydrothermal synthesis.

The invention belongs to the technical field of glass for buildings, and discloses a thermochromic intelligent window based on a vanadium dioxide nanoparticle film concentration gradient structure and a preparation method thereof.The preparation method comprises the steps that firstly, two parts of W-VO2 nanoparticles with different masses and PVP are added into absolute ethyl alcohol to be subjected to ultrasonic oscillation, and the W-VO2 nanoparticles and PVP are stirred to be evenly distributed and then stand for use; the method comprises the following steps: sequentially coating the surface of a pretreated glass substrate with W-VO2amp with relatively high concentration from bottom to top; a PVP dispersion liquid, a PMMA dispersion liquid, and low-concentration W-VO2amp are added; a PVP dispersion liquid; therefore, a W-VO2 gradient structure with low concentration at the top layer and high concentration at the bottom layer is formed on the surface of the glass substrate. The visible light transmittance of the thermochromic intelligent window is greatly improved, meanwhile, the solar modulation capacity is improved, the antagonism between the two optical properties of the visible light transmittance and the solar modulation efficiency is weakened or even broken through, and thermochromic development of the intelligent window and the radiation refrigeration field is further promoted.

The invention relates to a preparation process and method for preparing core-shell nanoparticles and a polymer (PVP) film on a substrate of a common glass slide, wherein the core-shell nanoparticles are coated with tungsten-doped vanadium dioxide nanoparticles on the surface of silicon dioxide, and the process sequentially comprises the following steps of: pretreating a silicon dioxide and tungsten-doped vanadium dioxide core-shell structure and preparing a PVP mixed solution; the method comprises the basic operation procedures of ethanol dispersion of the core-shell structure, PVP dispersion, setting of stirring parameters, spin-coating parameters, drying parameters and the like. The invention also relates to an application of the core-shell nanoparticles and a polymer (PVP) film which are prepared on a substrate of a common glass slide and are coated with tungsten-doped vanadium dioxide nanoparticles on the surface of silicon dioxide in the fields of intelligent windows, infrared stealth, energy-saving glass and radiation refrigeration in the aspects of adjustable transmittance and adjustable radiation capability. The problems that a traditional vanadium dioxide nanoparticle film is low in visible light transmittance, poor in near-infrared modulation capacity, reverse in infrared radiance and the like are solved.

The invention relates to a memristor based on a molybdenum-doped vanadium dioxide phase change thin film material and a preparation method of the memristor, an amorphous molybdenum-doped vanadium dioxide phase change thin film material is prepared on a Si-based substrate through co-sputtering, annealing is carried out for 30-60 minutes in a high-purity argon atmosphere at 400-450 DEG C, and a high-quality MoxV1-xO2 thin film is obtained. The invention further provides a preparation method of the memristor based on the molybdenum-doped vanadium dioxide phase change film. The memristor structurally comprises a substrate layer, a functional layer and a top electrode layer. The prepared molybdenum-doped vanadium dioxide film shows excellent thermal stability, a wide thermal hysteresis interval and a low phase transition temperature. By using the MoxV1-xO2 material as the functional layer of the memristor, the device has the advantages of small size, low turn-on voltage, high room temperature stability and the like.

The invention provides metal ion intercalation vanadium dioxide as well as a preparation method and application thereof, belongs to the technical field of aqueous iron ion batteries, and aims to solve the technical problem of low energy density of an aqueous iron ion battery positive electrode material. The preparation method of the metal ion intercalation vanadium dioxide comprises the following steps: dispersing vanadium pentoxide, a reducing agent and a metal source into a solvent to obtain a mixed solution; and reacting the mixed solution to obtain the metal ion intercalation vanadium dioxide nanosheet. The synthesis method provided by the invention is a one-step hydrothermal method, the synthesis method is relatively simple, environment-friendly and relatively low in cost, and the prepared material is a relatively uniform nanosheet. The prepared metal ion intercalation vanadium dioxide nanosheet is used as a positive electrode material of an iron ion battery, 284.32 mAh g <-1 > can be provided under the current density of 0.1 A g <-1 >, and the average discharge efficiency is as high as 99%.

The invention provides a broadband infrared tunable polarization device and an imaging method thereof, and belongs to the technical field of metamaterials and metasurfaces. The problem that an existing polarization device cannot meet the requirement of being suitable for a broadband infrared range, and polarization imaging resolution cannot be lost while full polarization information can be obtained is solved. The chiral metasurface structure comprises a dielectric layer, a plurality of vanadium dioxide gratings and a chiral metasurface structure arranged above the dielectric layer, wherein the plurality of vanadium dioxide gratings are fixedly arranged in the dielectric layer; in the chiral metasurface structure, a first component, a third component and a fifth component are arranged in parallel, the two ends of a second component are fixedly connected with the first component and the third component respectively, the first component and the third component are located on the two sides of the second component respectively and are both perpendicular to the second component, and the two ends of a fourth component are fixedly connected with the third component and the fifth component respectively. The third component and the fifth component are located on the two sides of the fourth component respectively and are both perpendicular to the fourth component. And full polarization information can be obtained.

The invention relates to an antimony-doped tin dioxide-vanadium dioxide composite film and a preparation method thereof. The antimony-doped tin dioxide-vanadium dioxide composite film disclosed by the invention is provided with an amorphous substrate layer, an antimony-doped tin dioxide middle layer and a vanadium dioxide film layer, wherein the antimony-doped tin dioxide middle layer is a SnO2 film doped with Sb2O3. The antimony-doped tin dioxide-vanadium dioxide composite film disclosed by the invention has an obvious semiconductor-metal conversion effect and a thermochromic effect, and the phase change temperature is reduced. According to the preparation method of the antimony-doped tin dioxide-vanadium dioxide composite film disclosed by the invention, the antimony-doped tin dioxide film is introduced as a middle buffer layer, and the vanadium dioxide film is grown on the antimony-doped tin dioxide film in situ. As a result, the deposition temperature at the time of growing the vanadium dioxide thin film can be reduced.

The invention relates to the technical field of electromagnetic wave polarization conversion, in particular to a transmission and reflection switchable multifunctional polarization converter based on a metasurface, and the polarization converter comprises four layers, namely a TOPAS (cycloolefin copolymer) dielectric layer, a crossed I-shaped metal resonance layer, a silicon dioxide dielectric layer and a metal-VO2 alternating grating layer from top to bottom. According to the design, conversion between a transmission function and a reflection function can be realized by changing the conductivity of vanadium dioxide: 1, in a transmission mode, incident polarized waves can be converted into cross polarized waves with broadband characteristics; and 2, in a reflection mode, incident linearly polarized waves can be converted into left-hand circularly polarized waves in a frequency band of 0.8 THz-1. 83 THz, and the incident linearly polarized waves can be converted into right-hand circularly polarized waves in a frequency band of 2.7 THz-3. 06 THz. According to the invention, the conversion functions are more, cross polarization conversion and linear-circular polarization conversion can be realized, and the engineering applicability is higher.

The invention relates to a coated doped vanadium dioxide film and a preparation method and application thereof. The preparation method comprises the following steps: preparing a precursor vanadium solution by taking a first vanadium source and a first reducing agent as raw materials; adding a first film-forming agent and a doping agent, fully reacting, and performing aging treatment to obtain a doped precursor liquid; preparing a dispersion liquid from the M-phase VO2 nano-powder, adding a coating material precursor into the dispersion liquid, and reacting to prepare VO2 core-shell nano-powder; and uniformly mixing the VO2 core-shell nano powder and the doped precursor liquid to obtain a VO2-based coating, and carrying out coating film forming, drying and annealing treatment to obtain the coated doped vanadium dioxide film. According to the invention, through doping modification, the film has high transmittance, the phase change temperature is reduced, the core-shell structure effectively enhances the weather resistance of the material, under the combined action of doping and modification, the performance of the obtained film is effectively improved, and the film can be applied to thermochromic intelligent energy-saving windows and is long in service life.

A phase shifter including a 90 degree hybrid circuit having two reflection ends, a varactor having a variable capacitance layer made of vanadium dioxide and disposed at the reflection end of the 90 degree hybrid circuit, and a stub connected to the reflection end of the 90 degree hybrid circuit via the varactor.

The present invention discloses an ultra-wideband, multi-frequency switchable terahertz absorber based on vanadium dioxide, belonging to the field of terahertz wave technology. The absorber comprises: an ultra-wideband, multi-frequency switchable terahertz absorber unit having a multi-layer structure, wherein, from top to bottom, a mutually bonded upper patterned VO2 layer, an upper SiO2 dielectric layer, a lower VO2 layer, an intermediate patterned gold layer, a lower SiO2 dielectric layer, and a bottom gold layer are sequentially arranged; the upper patterned VO2 layer is disc-shaped, with a square annular slit disposed within the disc; the intermediate patterned gold layer comprises an inner ring, an outer ring, and an open square ring, spaced from the inside out, with the opening of the open square ring disposed in the middle of each edge. The present invention is based on an ultra-wideband, multi-frequency switchable terahertz absorber based on vanadium dioxide. The designed absorber can achieve switching from ultra-wideband absorption to multi-frequency absorption by adjusting the conductivity of the vanadium dioxide through temperature control.