A preparation method of cerium-based halogen perovskite phosphor and its product

Abstract

The invention discloses a preparation method of a cerium-based halogen perovskite phosphor and a product thereof, and belongs to the technical field of luminescent materials. The invention adds 4,4-difluoropiperidine and CeCl3·7H2O to a mixed solution of concentrated hydrochloric acid and methanol, and obtains a solid powder by heating; the solid powder is dissolved in methanol, single crystals are precipitated under the action of anti-solvent ether, and the cerium-based halogen perovskite phosphor is obtained after washing and drying. The cerium-based halogen perovskite phosphor of the invention is prepared by a solution method, so it is low in cost and meets the requirements of industrial production. The luminescent wavelength of the material covers 350 to 450nm, does not contain high-energy ultraviolet radiation, and thus meets the requirements of safe ultraviolet light emission. The material also has excellent luminescent properties, and the fluorescence quantum yield reaches 100%, which exceeds most ultraviolet fluorescent materials.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials, and in particular relates to a preparation method of a cerium-based halogen perovskite phosphor and a product thereof. Background Art

[0002] Luminescent materials with emission wavelengths less than 400nm are extremely rare, but such luminescent materials are crucial for the development of ultraviolet light-emitting diodes (LEDs). Ultraviolet LEDs are widely used in the industrial, sanitary and medical fields, especially ultraviolet light with a spectral range of 315 to 400nm, which is widely used in modern white light LED lighting. Traditional ultraviolet LEDs mainly use low-pressure mercury vapor discharge as the ultraviolet light source. However, the emission spectrum produced by mercury vapor discharge also includes high-energy ultraviolet radiation (wavelength less than 300nm), which is highly dangerous to human eyes and skin. Group III nitride materials, such as GaN and AlGaN, have gradually become ideal alternative materials for ultraviolet light sources due to their narrow spectral bandwidth and low power consumption. However, such ultraviolet LEDs usually require the use of expensive silicon or sapphire substrates, and the processing technology of such devices often requires high vacuum heat treatment, which is not conducive to controlling production costs. In addition, some emerging nanomaterials, such as CdZnS@ZnS nanocrystals, have been found to emit ultraviolet light. However, the photoluminescence quantum yield (PLQY) of these materials is generally low, at around 20%, which seriously hinders their commercial application prospects. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a preparation method of a cerium-based halogen perovskite phosphor and its product. The cerium-based halogen perovskite phosphor of the present invention has a luminescent wavelength covering 350 to 450nm and does not contain high-energy ultraviolet radiation, thereby meeting the requirements for safe ultraviolet light emission; the material has excellent luminescent properties, and the fluorescence quantum yield reaches 100%, which exceeds most ultraviolet fluorescent materials.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] One of the purposes of the present invention is to provide a method for preparing a cerium-based halogen perovskite phosphor, comprising the following steps: adding 4,4-difluoropiperidine (DFPD) and CeCl3·7H2O to a mixed solution of concentrated hydrochloric acid and methanol, and heating to obtain a solid powder; dissolving the solid powder in methanol, precipitating a single crystal under the action of an anti-solvent ether, and washing and drying to obtain a (DFPD)4CeCl7 single crystal, i.e., a cerium-based halogen perovskite phosphor.

[0006] Furthermore, the mass volume ratio of the 4,4-difluoropiperidine, CeCl3·7H2O and the mixed solution is 0.2-1 mL: 0.2-0.5 g: 1-2 mL.

[0007] Furthermore, the volume ratio of the concentrated hydrochloric acid to methanol is 1:0.3-0.6.

[0008] Furthermore, the heating is carried out by stirring and heating in an oil bath, heating to 80° C. to form a light yellow transparent solution, and further heating to 120-130° C. and maintaining for 3-5 hours to obtain a solid powder.

[0009] Furthermore, the ratio of the solid powder to methanol is 0.1-0.5 g:1 mL.

[0010] Furthermore, after the solid powder is dissolved in methanol, it is placed in an open glass bottle, and then the open glass bottle is placed in a sealed container containing ether and left to stand at room temperature for 12 hours to precipitate single crystals.

[0011] Furthermore, the cleaning is performed by ether cleaning; and the drying is performed by vacuum drying.

[0012] The second object of the present invention is to provide a cerium-based halogen perovskite phosphor prepared by the preparation method of the cerium-based halogen perovskite phosphor.

[0013] Beneficial effects of the present invention:

[0014] Compared with the existing technology, the present invention proposes a new type of ultraviolet fluorescent material - cerium-based halogen perovskite phosphor, which is prepared by a solution method, so it is low-cost and meets the requirements of industrial production. The luminescent wavelength of the material covers 350 to 450nm, does not contain high-energy ultraviolet radiation, and thus meets the requirements of safe ultraviolet light emission. Finally, the material has excellent luminescent properties, and the fluorescence quantum yield reaches 100%, which exceeds most ultraviolet fluorescent materials. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with embodiments.

[0016] Example 1

[0017] 0.5 mL of 4,4-difluoropiperidine (DFPD) and 0.3 g of CeCl3·7H2O were added to a mixed solution of 1.5 mL of concentrated hydrochloric acid and methanol (the volume ratio of concentrated hydrochloric acid to methanol was 1:0.5). The mixed solution was stirred and heated to 80°C in an oil bath to form a light yellow transparent solution. The solution was then heated to 120°C. After 4 hours, the solution was fully volatilized to obtain a solid powder. 0.1 g of the solid powder was dissolved in 1 mL of methanol and placed in an open glass bottle. The open glass bottle was then placed in a sealed container containing ether and allowed to stand at room temperature for 12 hours to precipitate a single crystal. The obtained single crystal was washed with ether and dried in vacuum to obtain a (DFPD)4CeCl7 single crystal, i.e., a cerium-based halogen perovskite phosphor.

[0018] Example 2

[0019] 0.2 mL of 4,4-difluoropiperidine (DFPD) and 0.2 g of CeCl3·7H2O were added to a mixed solution of 1 mL of concentrated hydrochloric acid and methanol (the volume ratio of concentrated hydrochloric acid to methanol was 1:0.3). The mixed solution was stirred and heated to 80°C in an oil bath to form a light yellow transparent solution. The solution was then heated to 125°C. After 3 hours, the solution was fully volatilized to obtain a solid powder. 0.5 g of the solid powder was dissolved in 1 mL of methanol and placed in an open glass bottle. The open glass bottle was then placed in a sealed container containing ether and allowed to stand at room temperature for 12 hours to precipitate a single crystal. The obtained single crystal was washed with ether and vacuum dried to obtain a (DFPD)4CeCl7 single crystal, i.e., a cerium-based halogen perovskite phosphor.

[0020] Example 3

[0021] 1 mL of 4,4-difluoropiperidine (DFPD) and 0.5 g of CeCl3·7H2O were added to a mixed solution of 2 mL of concentrated hydrochloric acid and methanol (the volume ratio of concentrated hydrochloric acid to methanol was 1:0.6). The mixed solution was stirred and heated to 80°C in an oil bath to form a light yellow transparent solution. The solution was then heated to 130°C. After 5 hours, the solution was fully volatilized to obtain a solid powder. 0.3 g of the solid powder was dissolved in 1 mL of methanol and placed in an open glass bottle. The open glass bottle was then placed in a sealed container containing ether and allowed to stand at room temperature for 12 hours to precipitate a single crystal. The obtained single crystal was washed with ether and dried in vacuum to obtain a (DFPD)4CeCl7 single crystal, i.e., a cerium-based halogen perovskite phosphor.

[0022] Comparative Example 1

[0023] The same as Example 1, except that the mass volume ratio of 4,4-difluoropiperidine to CeCl3·7H2O is 0.5 mL:1 g.

[0024] The emission wavelengths and fluorescence quantum yields of the cerium-based halogen perovskite phosphors of all the examples and comparative examples are summarized in Table 1:

[0025] Table 1

[0026] project Emission wavelength (nm) Fluorescence quantum yield (%) Example 1 350-450 100 Example 2 350-450 99.7 Example 3 350-450 100 Comparative Example 1 320-355 27

[0027] As shown in Table 1, the cerium-based halogen perovskite phosphor of the present invention has a luminescent wavelength covering 350 to 450 nm and does not contain high-energy ultraviolet radiation, thus meeting the requirements for safe ultraviolet light emission. The material has a fluorescence quantum yield of 100% and has excellent luminescent properties.

[0028] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a cerium-based halogen perovskite phosphor, characterized in that: The method comprises the following steps: adding 4,4-difluoropiperidine and CeCl3·7H2O to a mixed solution of concentrated hydrochloric acid and methanol, and heating to obtain solid powder; dissolving the solid powder in methanol, precipitating single crystals under the action of ether, and washing and drying to obtain cerium-based halogen perovskite phosphor; The added amounts of the 4,4-difluoropiperidine, CeCl3·7H2O and the mixed solution of concentrated hydrochloric acid and methanol are 0.5 mL, 0.3 g and 1.5 mL respectively, and the volume ratio of the concentrated hydrochloric acid to methanol is 1:0.5, or the added amounts of the 4,4-difluoropiperidine, CeCl3·7H2O and the mixed solution of concentrated hydrochloric acid and methanol are 0.2 mL, 0.2 g and 1 mL respectively, and the volume ratio of the concentrated hydrochloric acid to methanol is 1:0.3, or the added amounts of the 4,4-difluoropiperidine, CeCl3·7H2O and the mixed solution of concentrated hydrochloric acid and methanol are 1 mL, 0.5 g and 2 mL respectively, and the volume ratio of the concentrated hydrochloric acid to methanol is 1:0.

6.

2. The method for preparing the cerium-based halogen perovskite phosphor according to claim 1, characterized in that: The heating is carried out by stirring and heating in an oil bath, heating to 120-130° C., and maintaining for 3-5 hours to obtain a solid powder.

3. The method for preparing the cerium-based halogen perovskite phosphor according to claim 1, characterized in that: The ratio of the solid powder to methanol is 0.1-0.5 g:1 mL.

4. The method for preparing the cerium-based halogen perovskite phosphor according to claim 1, characterized in that: The washing is performed by washing with ether; and the drying is performed by vacuum drying.

5. A cerium-based halogen perovskite phosphor prepared by the method for preparing a cerium-based halogen perovskite phosphor as claimed in any one of claims 1 to 4.