Method for in-situ reduction plating of vanadium dioxide film on glass surface and application thereof

Abstract

The invention provides a method for in-situ reduction plating of a vanadium dioxide film on the surface of glass and application of the method. According to the method, in the presence of inert gas and reducing gas, a pentavalent vanadium source and glass are placed in a temperature gradient environment, and after high-temperature reaction, the glass plated with the vanadium dioxide film is obtained. Therefore, the method is rapid in technological process, simple in procedure, low in cost, mild in condition, high in expansibility and suitable for large-scale production, and has important technical value and market prospects in the field of intelligent windows. Meanwhile, the method can improve the additional value of a vanadium product, and has a great application effect and high economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of vanadium dioxide film preparation, and specifically relates to a method for in-situ reduction coating of vanadium dioxide film on glass surface and application thereof. Background Art

[0002] Vanadium is called "MSG of modern industry" and is an indispensable raw material for the development of modern industry, national defense and science and technology. As a typical thermotropic phase change material, vanadium dioxide (VO2) has excellent semiconductor-metal phase change characteristics close to room temperature. Its structure, electrical and optical properties will change reversibly and significantly with temperature, making VO2 thin film have broad application prospects in smart windows, thermal switches, laser protection and other aspects.

[0003] At present, the preparation methods of vanadium dioxide thin films include magnetron sputtering, pulsed laser deposition, chemical vapor deposition, molecular beam epitaxy and sol-gel method, but the above methods all have disadvantages such as high energy consumption, poor repeatability or serious environmental pollution to varying degrees.

[0004] Based on this, patent CN 117945790 A uses polymer-assisted deposition (PAD) to prepare a 2.5-inch vanadium dioxide film, but it is difficult to achieve large-scale production due to the limitation of the tube furnace, and the use of nitrogen-containing organic substances such as organic solvents (acetone, ethanol) and polymers (polyetherimide, ethylenediaminetetraacetic acid) is also prone to danger or environmental problems. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for in-situ reduction coating of vanadium dioxide thin film on glass surface and its application. The method directly adopts in-situ chemical reduction of evaporation on the glass surface to prepare vanadium dioxide thin film, which has simple technical route, low cost and easy operation.

[0006] To achieve this object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for in-situ reduction coating of a vanadium dioxide film on a glass surface, comprising the following steps: In the presence of an inert gas and a reducing gas, a pentavalent vanadium source and glass are placed in a temperature gradient environment, and after reaction, glass coated with a vanadium dioxide film is obtained.

[0007] Preferably, the temperature of the pentavalent vanadium source is 400-800°C.

[0008] Preferably, the temperature of the pentavalent vanadium source is 20-300° C. higher than the glass temperature.

[0009] More preferably, the temperature of the pentavalent vanadium source is 500-600°C.

[0010] More preferably, the temperature of the pentavalent vanadium source is 50-200° C. higher than the glass temperature.

[0011] Preferably, before the reaction, an inert gas is first introduced for 5 to 30 min.

[0012] Preferably, the flow rate of the inert gas is 50-150 mL / min.

[0013] Preferably, the pentavalent vanadium source is selected from any one or more of ammonium metavanadate, ammonium polyvanadate, sodium polyvanadate, vanadium pentoxide or vanadium acetylacetonate.

[0014] Preferably, the reducing gas is selected from any one or more of sulfur dioxide, carbon monoxide, ammonia, methane or coal gas.

[0015] Preferably, the inert gas is selected from nitrogen and / or argon.

[0016] Preferably, the volume ratio of the reducing gas to the inert gas is 5-20%.

[0017] Preferably, the reaction time is 1 to 5 h.

[0018] In a second aspect, the present invention provides a smart window, which is prepared according to the above method.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention innovatively provides a method for in-situ reduction coating of vanadium dioxide thin film on glass surface, which has rapid process, simple procedure, low cost, mild conditions, strong scalability and is suitable for large-scale production. At the same time, the technology breaks through the general thinking of ordinary technicians, breaks the technical prejudice of traditional preparation of nanomaterials, especially in-situ evaporation reduction (different from traditional evaporation or sputtering), overcomes the shortcomings of existing synthesis or preparation technology, solves long-standing technical problems, has greater feasibility and good promotion and application prospects in the field of smart windows, and has achieved unexpected results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the device for in-situ reduction coating of vanadium dioxide thin film on glass surface in Example 1; Figure 2 Schematic diagram of the device for in-situ reduction coating of vanadium dioxide thin film on glass surface in Example 2; Among them, 1 is a vanadium source, 2 is glass, 3 is a vanadium dioxide film, 4 is an inert gas inlet, 5 is a reducing gas inlet, and 6 is an outlet. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In view of the problems of high energy consumption and environmental pollution in the preparation of vanadium dioxide thin films in the prior art, the present invention provides a method for in-situ reduction coating of vanadium dioxide thin films on glass surfaces, comprising the following steps: In the presence of an inert gas and a reducing gas, a pentavalent vanadium source and glass are placed in a temperature gradient environment, and after a high-temperature reaction, glass coated with a vanadium dioxide film is obtained.

[0023] In the present invention, the presence of the temperature gradient environment can allow pentavalent vanadium to be deposited on the glass more quickly and achieve in-situ reduction.

[0024] In the present invention, the pentavalent vanadium source is selected from any one or more of ammonium metavanadate, ammonium polyvanadate, sodium polyvanadate, vanadium pentoxide or vanadium acetylacetonate, which is heated by a heat source at a temperature of 400-800°C, preferably 500-600°C. Within this temperature range, the pentavalent vanadium source will decompose and / or volatilize.

[0025] In the present invention, the temperature of the glass is lower than the temperature at which the pentavalent vanadium source is heated, so as to ensure that the gaseous substance generated after the pentavalent vanadium source is heated can move toward the glass under the action of the temperature gradient, and gradually reduce to vanadium dioxide under the action of the reducing gas during the movement, and finally deposit on the surface of the glass to form a vanadium dioxide film. Wherein, the reducing gas is selected from any one or more of sulfur dioxide, carbon monoxide, ammonia, methane or coal gas.

[0026] At the same time, in order to ensure that as much vanadium dioxide as possible can be deposited on the glass surface, the temperature of the pentavalent vanadium source is generally controlled to be 20-300°C higher than the glass temperature, preferably higher than 50-200°C.

[0027] In some preferred embodiments of the present invention, in order to avoid the presence of air and reduce the reaction efficiency, it is preferred that an inert gas is first introduced for 5 to 30 minutes, preferably 10 to 20 minutes, before the reaction; the flow rate of the inert gas is 50 to 150 mL / min, preferably 80 to 100 mL / min. In the present invention, the inert gas is selected from nitrogen and / or argon.

[0028] In some embodiments of the present invention, an inert gas is introduced at the same time as the reducing gas, and the volume ratio of the reducing gas to the inert gas is 5-20%, preferably 10-15%.

[0029] In the present invention, the reducing gas and the inert gas can be recycled.

[0030] In some specific embodiments of the present invention, the above method is preferably carried out in a furnace device with interval temperature control, such as a box-type heating furnace with interval temperature control, a tubular furnace with interval temperature control, etc. Figure 1 and 2 The pentavalent vanadium source can be placed at the bottom (or middle) of the furnace, and the glass can be placed at the top (or side) of the furnace. A certain temperature gradient is formed according to the set temperature, and a reducing gas is passed through the middle of the furnace to perform in-situ high-temperature chemical evaporation reduction for a certain period of time, so that the glass with a vanadium dioxide film coated on the surface can be obtained, presenting colored glass with different transmittances. The time can generally be controlled at 1 to 5 hours, preferably 2 to 4 hours.

[0031] Based on this, the present invention also provides a smart window obtained according to the above method.

[0032] In summary, the present invention innovatively provides a method for in-situ reduction coating of vanadium dioxide thin film on glass surface, which has rapid process, simple procedure, low cost, mild conditions, strong scalability, and is suitable for large-scale production. It will have important technical value and market prospects in the field of "smart windows". At the same time, the method can be applied to the preparation of high value-added vanadium products, with greater application effect and higher economic benefits.

[0033] In order to further illustrate the present invention, the following examples are provided for detailed description. The experimental raw materials used in the following examples of the present invention are all common commercially available products.

[0034] Example 1 This embodiment provides a device for in-situ reduction coating of vanadium dioxide thin film on glass surface. The device has a temperature control function. The schematic diagram is shown in FIG. Figure 1 As shown, it includes a vanadium source 1, glass 2, a vanadium dioxide film 3, an inert gas inlet 4, a reducing gas inlet 5, and an outlet 6. This embodiment uses a pentavalent vanadium source as a raw material and a reducing gas as an in-situ reducing agent to prepare VO2 coated glass in a gradient reduction system. The steps include: (1) Reference Figure 1 Place ammonium metavanadate and glass with a distance of 50 cm between them, and introduce inert protective gas nitrogen for 20 min to exclude air, with the flow rate controlled at 100 mL / min; (2) Then, the interval temperature control is started, the temperature of ammonium metavanadate is controlled at 500°C, and the temperature of the glass at the end is controlled at 450°C. At the same time, in a gradient temperature environment with a temperature drop of 50°C within a distance of 50 cm, ammonium metavanadate is decomposed into vanadium pentoxide vapor and diffuses upward; (3) At the same time, sulfur dioxide is introduced as a reducing gas with a concentration of 10% (v / v, reducing gas / inert gas). At this time, vanadium pentoxide is reduced in situ and deposited on the glass surface to form a vanadium dioxide film; (4) The reaction time is 2 h, and uniform and transparent colored glass is obtained.

[0035] Example 2 This embodiment provides a device for in-situ reduction coating of vanadium dioxide thin film on glass surface. The device has a temperature control function. The schematic diagram is shown in FIG. Figure 2 As shown, it includes a vanadium source 1, glass 2, a vanadium dioxide film 3, an inert gas inlet 4, a reducing gas inlet 5, and an outlet 6. This embodiment uses a pentavalent vanadium source as a raw material and a reducing gas as an in-situ reducing agent to prepare VO2 coated glass in a gradient reduction system. The steps include: (1) Reference Figure 1 Place vanadium pentoxide and glass at a distance of 100 cm between them, and introduce inert protective gas nitrogen for 20 min to exclude air, with the flow rate controlled at 200 mL / min; (2) Then, the interval temperature control is started, the temperature of vanadium pentoxide is controlled to 600°C, and the temperature of the glass at the end is controlled to 400°C. At the same time, in a gradient temperature environment with a temperature drop of 200°C within a distance of 100 cm, vanadium pentoxide is volatilized by heat and diffuses to the side; (3) At the same time, a reducing gas, carbon monoxide, is introduced at a concentration of 10% (v / v, reducing gas / inert gas). At this time, the vanadium pentoxide vapor is reduced in situ and deposited on the glass surface to form a vanadium dioxide film; (4) The reaction time is 1 h, and uniform and transparent colored glass is obtained.

[0036] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for in-situ reduction coating of vanadium dioxide thin film on glass surface, characterized in that: The following steps are involved: In the presence of an inert gas and a reducing gas, a pentavalent vanadium source and glass are placed in a temperature gradient environment, and after reaction, glass coated with a vanadium dioxide film is obtained; The temperature of the pentavalent vanadium source is 400-800° C. The temperature of the pentavalent vanadium source is 20-300° C. higher than the glass temperature.

2. The method according to claim 1, characterized in that The temperature of the pentavalent vanadium source is 500-600°C.

3. The method according to claim 1 or 2, characterized in that: The temperature of the pentavalent vanadium source is 50-200° C. higher than the glass temperature.

4. The method according to any one of claims 1 to 3, characterized in that Before the reaction, an inert gas is first introduced for 5 to 30 min; The flow rate of the inert gas is 50-150 mL / min.

5. The method according to any one of claims 1 to 4, characterized in that The pentavalent vanadium source is selected from any one or more of ammonium metavanadate, ammonium polyvanadate, sodium polyvanadate, vanadium pentoxide or vanadium acetylacetonate.

6. The method according to any one of claims 1 to 5, characterized in that The reducing gas is selected from any one or more of sulfur dioxide, carbon monoxide, ammonia, methane or coal gas.

7. The method according to any one of claims 1 to 6, characterized in that The inert gas is selected from nitrogen and / or argon.

8. The method according to any one of claims 1 to 7, characterized in that The volume ratio of the reducing gas to the inert gas is 5-20%.

9. The method according to any one of claims 1 to 8, characterized in that The reaction time is 1 to 5 h.

10. A smart window, characterized in that: Prepared according to the method according to any one of claims 1 to 9.

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