阅读说明：本技术 一种微波辅助液相合成的窄带绿色荧光粉及其合成方法 (Narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase and synthesis method thereof ) 是由 王得印 蔺杰 陶英芳 洪子方 郭君路 王育华 于 2021-02-01 设计创作，主要内容包括：本发明公开了一种微波辅助液相合成的窄带绿色荧光粉及其合成方法,该窄带绿色荧光粉的化学通式为Cs-3MnBr-5。按化学通式中元素的化学计量比,称取溴化铯和溴化锰,加入去离子水中,完全溶解,轻轻摇动至溶液澄清,得澄清溶液；澄清溶液置于微波炉中,微波加热反应完成后,合成淡绿色的微波辅助液相合成的窄带绿色荧光粉。该合成方法操作简便、合成速度快、反应时间短、无需高温煅烧,制得的荧光粉发光性能优异。(The invention discloses narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase and a synthesis method thereof, wherein the chemical general formula of the narrow-band green fluorescent powder is Cs 3 MnBr 5 . Weighing cesium bromide and manganese bromide according to the stoichiometric ratio of elements in the chemical general formula, adding the cesium bromide and the manganese bromide into deionized water, completely dissolving, and slightly shaking until the solution is clear to obtain a clear solution; and (3) placing the clear solution in a microwave oven, and synthesizing light green narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase after microwave heating reaction is finished. The synthesis method has the advantages of simple operation, high synthesis speed, short reaction time, no need of high-temperature calcination, and excellent luminescent performance of the prepared fluorescent powder.)

1. The narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase is characterized in that the chemical general formula of the narrow-band green fluorescent powder is Cs₃MnBr₅。

2. A synthesis method of narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase as claimed in claim 1, which is characterized by comprising the following steps:

1) respectively weighing cesium bromide and manganese bromide according to the stoichiometric ratio of elements in the chemical general formula, mixing, adding into deionized water to completely dissolve the cesium bromide and the manganese bromide, and shaking until the solution is clear to obtain a clear solution;

2) and (3) placing the clear solution in a microwave oven, and obtaining the light green narrow-band green fluorescent powder after the microwave heating reaction is finished.

3. The synthesis method of the narrow-band green phosphor synthesized by microwave-assisted liquid phase according to claim 2, wherein in the step 2), the reaction time is 1-10 min by microwave heating.

Technical Field

The invention belongs to the technical field of synthesis, and relates to narrow-band green fluorescent powder Cs synthesized by microwave-assisted liquid phase₃MnBr₅(ii) a Also relates to a synthetic method of the green fluorescent powder.

Background

The white light LED has the advantages of energy saving, environmental protection and light emissionThe LCD backlight display device has the advantages of long service life and the like, and is widely applied to the field of LCD backlight display, however, how to realize display with wider color gamut becomes a research hotspot at present. In the white LED-based backlight display technology, a phosphor as a key material determines a color gamut range, a light emitting efficiency, and reliability of a backlight unit, and thus it is required to have a suitable emission wavelength and a narrow emission half-width. In addition, the human eye is most sensitive to green light, and the improvement of the green color gamut area will significantly enrich the colors of the display device. Therefore, in order to realize wider color gamut display, it is important to develop a green phosphor emitting in narrow band. Beta-sialon Eu²⁺The fluorescent powder is considered to be the most suitable green fluorescent powder for backlight display at present due to the advantages of stable chemical properties, high luminous intensity, small thermal quenching, narrow half-peak width and the like, but the synthesis condition is harsh, and the fluorescent powder is usually synthesized under the harsh conditions of 2000 ℃, 1MPa nitrogen pressure and the like, so that the synthesis cost is very high, and the application of the fluorescent powder is greatly restricted. Therefore, in order to further improve the color gamut of liquid crystal display, developing a novel narrow-band green phosphor is one of the problems to be solved in the field of LCD backlight sources.

Disclosure of Invention

The invention aims to provide narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase, which improves the color gamut of liquid crystal display.

The invention also aims to provide a synthesis method of the narrow-band green fluorescent powder.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: narrow-band green fluorescent powder synthesized by microwave-assisted liquid phase and having chemical general formula of Cs₃MnBr₅。

The other technical scheme adopted by the invention is as follows: a synthesis method of the narrow-band green fluorescent powder specifically comprises the following steps:

1) according to the general chemical formula Cs₃MnBr₅Respectively weighing cesium bromide and manganese bromide according to the stoichiometric ratio of the medium elements, mixing, adding into deionized water to completely dissolve the cesium bromide and the manganese bromide, and slightly shaking until the solution is clear to obtain a clear solution;

2) and (3) placing the clear solution in a microwave oven with the power of 600-900W, carrying out microwave heating reaction for 1-10 min, and obtaining light green narrow-band green fluorescent powder after the reaction is finished.

The synthesized fluorescent powder emits green light under the irradiation of ultraviolet light, and the main emission peak of the fluorescent powder is 520-525 nm.

When the microwave oven is heated, heat energy comes from a magnetron arranged on the top of the oven, high-frequency electromagnetic wave emitted by the magnetron can penetrate into the cesium bromide and manganese bromide solution immediately, and at the moment, the microwave meets polar molecules (water molecules), so that the molecules oscillate violently, and the intermolecular friction can generate a large amount of heat quickly.

Microwave heating is used as a green material synthesis technology, and compared with other synthesis technologies, the microwave synthesis technology has incomparable advantages: because the microwave is strong electromagnetic wave, and the synthesis method of the invention uses water as solvent, the water molecule belongs to polar molecule, the dielectric constant is large, the dielectric loss factor is also large, the microwave has strong absorption capacity, and the electromagnetic energy can be effectively absorbed and converted into heat energy, so the microwave heating can effectively save energy; when microwave heating is carried out, the inside and the outside of the material are simultaneously heated, the heating is uniform, and the temperature rising speed is higher, so that the heating time is obviously shortened; in the microwave heating, the object to be heated generates heat by itself, and there is no heat conduction process in the ambient air during heating, so that the heating efficiency is high.

The synthesis method is simple, convenient, easy to operate, rapid and low in cost. High-temperature calcination is not needed, the reaction time is short, the reaction temperature is low, the operation is simple, and the fluorescent powder can be obtained in one step. And the prepared fluorescent powder has the characteristics of excellent luminous performance and the like. The fluorescent powder synthesized by the synthesis method can be excited by near ultraviolet light in the range of 370-400 nm and blue light in the range of 430-470 nm to emit narrower green light with the half-peak width of 42 nm.

Drawings

FIG. 1 is an X-ray diffraction pattern of the phosphor synthesized in example 1.

FIG. 2 shows the excitation and emission spectra of the phosphor synthesized in example 1.

FIG. 3 is a graph showing the change of the luminous intensity of the phosphor synthesized in example 1 with temperature.

Detailed description of the invention

The present invention will be further described with reference to the following examples. However, the present invention is not limited to these examples.

Example 1

2.5 mmol CsBr and 0.82 mmol MnBr were weighed₂Mixing and putting into a beaker; 5mL of deionized water was added and the CsBr and MnBr were gently shaken₂Dissolving until the solution is clear and transparent to obtain a clear solution; and (3) placing the clear solution into a microwave oven, carrying out microwave heating reaction for 2 min, and obtaining light green narrow-band green fluorescent powder after the reaction is finished, wherein the light green narrow-band green fluorescent powder emits bright green light under a 365 nm ultraviolet lamp.

FIG. 1 is an X-ray diffraction pattern of the narrow-band green-emitting phosphor synthesized in example 1. The X-ray diffraction pattern shows that the sample is pure phase Cs₃MnBr₅The fluorescent powder with pure phase structure is obtained by the synthesis method.

The excitation and emission spectra of the phosphor synthesized in example 1 are shown in FIG. 2. As can be seen from FIG. 2, the phosphor can be excited by near ultraviolet light in the range of 370-400 nm and blue light in the range of 430-470 nm, the peak of the emission peak is 522 nm, the full width at half maximum is 42 nm²⁺Is/are as follows⁴T₁→⁶A₁And (4) transition.

The thermal stability test results of the synthesized phosphor of example 1 are shown in fig. 3. As can be seen from FIG. 3, the phosphor gradually decreased in luminescence intensity with increasing temperature, maintaining 63% of the original photoluminescence intensity at 120 deg.C, and still glowed and maintained 46% of the original photoluminescence intensity when heated to 220 deg.C, indicating that the phosphor has good thermal stability.

Example 2

According to the general chemical formula Cs₃MnBr₅Respectively weighing cesium bromide and manganese bromide according to the stoichiometric ratio of the medium elements, mixing, adding into 5mL of deionized water to completely dissolve the cesium bromide and the manganese bromide, and slightly shaking until the solution is clear to obtain a clear solution; placing the clear solution in a microwave oven, heating with microwave for 10 min, and reacting to obtain lightGreen narrow-band green phosphor, which emits bright green light under a 365 nm ultraviolet lamp.

Example 3

According to the general chemical formula Cs₃MnBr₅Respectively weighing cesium bromide and manganese bromide according to the stoichiometric ratio of the medium elements, mixing, adding into 2 mL of deionized water to completely dissolve the cesium bromide and the manganese bromide, and slightly shaking until the solution is clear to obtain a clear solution; and (3) placing the clear solution into a microwave oven, carrying out microwave heating reaction for 2 min, and obtaining light green narrow-band green fluorescent powder after the reaction is finished, wherein the fluorescent powder emits bright green light under a 365 nm ultraviolet lamp.