Moisture-resistant fluoride red fluorescent powder and preparation method thereof

Abstract

The invention discloses moisture-resistant fluoride red fluorescent powder, which comprises Mn<4+>-doped fluoride red fluorescent powder and an alkaline earth metal fluoride waterproof layer, whereinthe alkaline earth metal fluoride waterproof layer coats the surface of the Mn<4+>-doped fluoride red fluorescent powder; and the alkaline earth metal fluoride waterproof layer is one or a mixture ofmore than one of CaF2, SrF2 and BaF2. The preparation method comprises the steps of puttingMn<4+>-doped fluoride red fluorescent powder into a potassium bifluoride aqueous solution, fully stirring, dropwise adding an aqueous solution of alkaline-earth metal salt, standing, filtering, washing the obtained precipitate, and drying to obtain the moisture-resistant fluoride red fluorescent powder. On the basis that the luminous efficiency is not obviously reduced, the stability of the Mn<4+>-doped fluoride red fluorescent powder in a high-humidity environment is remarkably improved.

Description

technical field [0001] The invention relates to the technical field of LED phosphor preparation, in particular to a moisture-resistant fluoride red phosphor and a preparation method thereof. [0002] technical background [0003] White LED has outstanding advantages such as high efficiency, energy saving, fast response, no flicker, and long life, and is known as a new generation of green solid-state lighting source. Currently, mainstream commercial white LEDs are made of InGaN blue chips and Y 3 al 5 o 12 : Ce 3+ (YAG:Ce 3+ ) yellow fluorescent powder combination. YAG:Ce 3+ After absorbing the blue light emitted by the chip, it emits yellow light, which mixes with the unabsorbed blue light to form white light. Since YAG:Ce 3+ The lack of red light components in the spectrum makes it difficult for the light and color performance of the device (such as color temperature, color rendering index, etc.) to meet the high-quality requirements of indoor and outdoor lighting an...

AI Technical Summary

Problems solved by technology

[0006] It is worth noting that Mn 4+ Fluoride-doped red phosphors tend to absorb water and deliquesce in high humidity environments, resulting in reduced or even lost luminous performance, which seriously affects the luminous performance and service life of white LEDs

Therefore, researchers have improved the moisture resistance of phosphor powder by coating organic or inorganic waterproof layer materials. Currently, the following methods are mainly reported: (1) The hydrophilic groups of amphiphilic organic compounds are chemically bonded on the surface of phosphor powder, exposing The external hydrophobic groups resist the erosion of water (Angew.Chem.Int.Ed.2015,54(37),10862-6; ACS Appl.Mater.Interfaces 2017,9(8),7232-7240; ACS Appl .Mater.Interfaces 2018,10(1),880-889); However, the organic coating layer is usually not uniform and dense, and it is easy to age under the long-term irradiation of high-power chips, resulting in problems such as reduced luminous intensity and color shift.

(2) The core-shell structure phosphor is prepared by using the matrix material as the shell layer, which effectively prevents the Mn 4+ Migrate to the surface of the phosphor and be hydrolyzed (Angew Chem.Int.Ed.2019,58(12),3843-3847; ACS Appl.Mater.Interfaces 2018,10(21),18082-18092); Soluble in water, the weather resistance of phosphor needs to be strengthened

(3) Phosphor powder is coated with heterogeneous inorganic materials, and the inorganic inert outer layer resists the erosion of water (patent CN201910630976.X; Chem. Mater. 2019, 31(18), 7192-7202), but the light at the interface Scattering is strong, and the luminous performance of the phosphor is significantly reduced

In addition, the implementation process of the above coating technology is relatively complicated, which is not conducive to the mass production of phosphors

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