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A non-stoichiometric nanovo for controlling phase transition temperature 2-x Preparation method of powder

A technology of phase change temperature and vo2-x, which is applied in the direction of nanotechnology, nanotechnology, nanotechnology, etc. for materials and surface science, can solve the problem of high cost, high equipment requirements, and the reduction of thermally induced phase transition performance of vanadium dioxide and other problems, to achieve the effect of mild reaction conditions, breakthrough application bottlenecks, and short production cycle

Inactive Publication Date: 2016-08-17
GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the doping ratio in vanadium dioxide cannot be adjusted flexibly. For example, in the process of magnetron sputtering, the doping ratio has been fixed in the target, so the ratio of the sputtered material is also fixed, and the doping ratio cannot be flexibly changed. Impurities will greatly reduce the thermally induced phase transition performance of vanadium dioxide
In addition, the phase transition temperature of vanadium dioxide can also be changed by changing the stress and nano-size effect, but the adjustment range is limited, and continuous adjustment cannot be achieved, and the process repeatability is poor, so it cannot be used in actual production
In addition, the phase transition temperature of the vanadium dioxide film can also be adjusted by adjusting the oxygen partial pressure during the magnetron sputtering process, but the vanadium dioxide film prepared by this physical method requires high equipment requirements, is expensive, and is not easy to produce. Fabrication of large-area vanadium dioxide thin films limits its application in smart windows

Method used

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  • A non-stoichiometric nanovo for controlling phase transition temperature <sub>2-x</sub> Preparation method of powder
  • A non-stoichiometric nanovo for controlling phase transition temperature <sub>2-x</sub> Preparation method of powder
  • A non-stoichiometric nanovo for controlling phase transition temperature <sub>2-x</sub> Preparation method of powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Add 1.891g of oxalic acid to the beaker, add 75mL of deionized water, and stir magnetically in a water bath at a constant temperature of 30°C for 15 minutes. Stir for 0.5h, put the above-mentioned precursor into the reaction kettle, conduct a hydrothermal reaction at 160°C for 48h, centrifuge the product, wash it with a mixture of absolute ethanol and deionized water with a volume ratio of 1:2, and then put it into vacuum drying The oven was treated at 60°C for 4 hours, and the dried samples were put into the furnace for annealing treatment, and the protective atmosphere was introduced: argon gas 0.5L / min; heat treatment conditions: 30°C heating for 94min to 500°C, constant temperature for 1h, natural cooling in the furnace to room temperature to obtain VO with a phase transition temperature of 63.0°C 2.0 Powder. The phase transition parameters are shown in Table 1, and the differential scanning calorimetry (DSC) spectrum is shown in figure 1 The X-ray diffraction (XR...

Embodiment 2

[0027] Add 1.891g of oxalic acid to the beaker, add 75mL of deionized water, and stir magnetically in a water bath at a constant temperature of 30°C for 15 minutes. Stir for 1 hour, put the above-mentioned precursor into the reaction kettle, conduct a hydrothermal reaction at 280°C for 48 hours, centrifuge the product, wash it with a mixture of absolute ethanol and deionized water with a volume ratio of 1:3, and then put it in a vacuum drying oven Treat at 60°C for 4 hours, put the dried samples into the furnace for annealing treatment, and introduce a protective atmosphere: high-purity nitrogen 0.5L / min; heat treatment conditions: 30°C heating for 114min to 600°C, constant temperature for 2h, natural cooling in the furnace to room temperature to obtain VO with a phase transition temperature of 53.5°C 1.95 Powder. The phase transition parameters are shown in Table 1, and the differential scanning calorimetry (DSC) spectrum is shown in figure 1 The X-ray diffraction (XRD) pat...

Embodiment 3

[0029] Add 1.891g of oxalic acid to the beaker, add 75mL of deionized water, stir in a water bath at a constant temperature of 30°C for 15 minutes, add 2.445g of vanadyl sulfate to the above solution, stir in a water bath at a constant temperature of 30°C for 10 minutes, adjust the temperature of the water bath to 100°C, and stir at a constant temperature 2h, put the above-mentioned precursor into the reaction kettle, hydrothermally react at 280°C for 48h, centrifuge the product, wash it with a mixture of absolute ethanol and deionized water with a volume ratio of 1:5, and then put it in a vacuum drying oven for 60 ℃ treatment for 4 hours, and naturally cooled to room temperature to obtain VO with a phase transition temperature of 55.8℃ 1.96 Powder. Its phase transition parameters are shown in Table 1, and the differential scanning calorimetry (DSC) spectrum is shown in figure 1 The X-ray diffraction (XRD) pattern is shown as figure 2 As shown, the scanning electron microsc...

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Abstract

The invention discloses a preparation method for non-stoichiometric ratio type nanometer VO2-x powder for regulating and controlling phase transition temperature. A target product is obtained through carrying out hydrothermal reaction and annealing treatment on a precursor made of oxalic acid, de-ionized water and vanadium source, the stoichiometric ratio of the product is controllable (x=0-0.05), the phase change temperature can be regulated in the range of Tc=63.0-53.5 degrees centigrade, and the material is more excellent in phase change performance and better for manufacturing a thermochromic smart window, a field effect transistor and the like. The preparation method for the non-stoichiometric ratio type nanometer VO2-x powder for regulating and controlling the phase transition temperature is short in production period, simple in technique, moderate in reaction condition, environmental friendly, low in cost and suitable for large-scale production; the prepared powder can be prepared into a piece of large VO2-x film with adjustable phase change temperature through combining with a powder film forming technology; the preparation method is good for breaking through the application bottleneck of a vanadium dioxide smart window.

Description

Technical field: [0001] The invention relates to the field of photothermal technology, in particular to a non-stoichiometric nanometer VO for regulating the phase transition temperature 2-x Powder preparation method. Background technique: [0002] Vanadium dioxide is a transition metal oxide that undergoes a metal-semiconductor structural phase transition around 68°C. When it is lower than 68°C, its crystal is a monoclinic structure with high infrared transmittance; and when it is higher than 68°C, Vanadium dioxide crystals have a tetragonal structure and low infrared transmittance. Therefore, with the change of the crystal structure before and after the phase transition of vanadium dioxide, its optical properties will also change greatly, and its phase transition temperature is slightly higher than room temperature. By changing the infrared light transmittance of vanadium dioxide at different temperatures, the incident amount of infrared heat radiation is automatically ad...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G31/02B82Y30/00
Inventor 苗蕾陈如周建华程浩亮刘呈燕
Owner GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI
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