# US 10,865,478 B2 · Method for producing luminescent particles with a protective layer and luminescent particles having a protective layer

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- Number: US 10,865,478 B2
- Document ID: US10865478B2
- Status: Granted
- Kind: B2
- Application number: 16/079,280
- Filed: 2017-03-01
- Published: 2019-02-14
- Granted: 2020-12-15
- Earliest claimed: 2016-03-08
- Assignees: OSRAM OLED GmbH
- Applicants: OSRAM Opto Semiconductors GmbH
- Inventors: Sonja Tragl; Tim Fiedler; Frank Jermann
- Web page: https://patentgrep.com/patent/US10865478B2

## CPC

- C23C 16/45553: {characterized by the use of precursors specially adapted for ALD}
- C09K 11/025: {non-luminescent particle coatings or suspension media}
- C09K 11/0883: {Arsenides; Nitrides; Phosphides}
- C09K 11/77348: {Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides}
- C23C 16/30: Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
- C23C 16/45555: {applied in non-semiconductor technology}
- C23C 16/56: After-treatment
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

A method for producing phosphor particles with at least one first protective layer and a phosphor particles having at least one protective layer are disclosed. In an embodiment, a method includes providing phosphor particles and applying at least one first protective layer to the surface of the phosphor particles, wherein the at least of first protective layer include depositing a first starting compound by a first atomic layer deposition on the surface of the phosphor particles and depositing a second starting compound by a second atomic layer deposition on the surface of the phosphor particles.

## Claims

### Claim 1

A method for producing phosphor particles with at least one first protective layer, the method comprising:
providing the phosphor particles; and
applying the at least one first protective layer to a surface of the phosphor particles, wherein the at least one first protective layer comprises:
depositing a first starting compound by a first atomic layer deposition on the surface of the phosphor particles; and
depositing a second starting compound by a second atomic layer deposition on the surface of the phosphor particles,
wherein a phosphor of the phosphor particles has the general formula:
Sr(SraM1−a)Si2Al2(N,X)6:Z,
wherein Z is selected from the group consisting of D, A, B, E, G, L and combinations thereof,
wherein M is selected from the group consisting of Ca, Ba, Mg alone and combinations thereof,
wherein D is selected from one, two or more elements from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Li, Na, K, Rb, Cs, Tm and Yb,
wherein A is selected from divalent metals which are different from M and D,
wherein B=trivalent metals,
wherein E=monovalent metals,
wherein G=tetravalent elements,
wherein L=trivalent elements, and
wherein X=O or halogen and 0.6≤a<1.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the first starting compound is selected form the group consisting of organometallic compounds and metal halides, and wherein the second starting compound is selected form the group consisting of H2O, H2S, NH3 and O3.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the metal of the organometallic compound or of the metal halide is selected from the group consisting of boron, aluminum, silicon, tin, zinc, titanium, zirconium, tantalum, niobium and hafnium.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the first starting compound comprises MCIx, MBrx, M(CH3)x, M(CH2—CH3)x, M(CH2—CH2—CH3)x, M(OCH3)x, M(OCH2—CH3)x or M(OCH2—CH2—CH3)x, and wherein M is one of B, Al, Si, Sn, Zn, Ti, Zr, Ta, Nb or Hf, and x corresponds to a valence of M.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the first starting compound comprises AlCl3, AlBr3, Al(CH3)3, Al(CH2—CH3)3, Al(CH2—CH2—CH3)3, Al(OCH3)3, Al(OCH2—CH3)3 or Al(OCH2—CH2—CH3)3.

### Claim 6 (depends on 1)

The method according to claim 1, wherein several first protective layers are applied to the surface of the phosphor particles such that the surface of the phosphor particles is coated with a plurality of first protective layers.

### Claim 7 (depends on 1)

The method according to claim 1, further comprising, after applying the at least one first protective layer to the surface of the phosphor particles, tempering the phosphor particles coated with the at least one first protective layer at a temperature between 200° C. and 500° C.

### Claim 8 (depends on 7)

The method according to claim 7, wherein tempering the phosphor particles comprises tempering the phosphor particles under an inert gas atmosphere, an oxygen-containing atmosphere or an H2—containing atmosphere.

### Claim 9 (depends on 7)

The method according to claim 7, wherein tempering the phosphor particles coated with the at least one first protective layer comprises tempering with an oxygen-containing atmosphere or an H2—containing atmosphere.

### Claim 10 (depends on 1)

The method according to claim 1, further comprising, before applying the at least one first protective layer to the surface of the phosphor particles, treating the phosphor particles with an acid solution, wherein a pH of the acid solution is kept within a range of pH 3.5 to 7 for a period of at least 1 h.

### Claim 11 (depends on 10)

The method according to claim 10, after treating the phosphor particles with the acid solution, tempering the treated phosphor particles at a temperature of at least 100° C.

### Claim 12 (depends on 10)

The method according to claim 10, wherein a Si-containing second protective layer is formed on the surface of the phosphor particles, the second protective layer having a higher content of Si than the phosphor particles.

### Claim 13 (depends on 12)

The method according to claim 12, after treating the phosphor particles with the acid solution, tempering the treated phosphor particles at a temperature of at least 100° C.

### Claim 14 (depends on 10)

The method according to claim 10, wherein an Al-containing second protective layer is formed on the surface of the phosphor particles, the second protective layer having a modified content of aluminum on the surface compared with the phosphor particles.

### Claim 15 (depends on 14)

The method according to claim 14, after treating the phosphor particles with the acid solution, tempering the treated phosphor particles at a temperature of at least 100° C.

### Claim 16 (depends on 1)

The method according to claim 1, wherein the phosphor has the general formula: Sr(SraM1−a)Si2Al2N6:D, wherein M is selected from the group consisting of Ca, Ba, Zn and Mg, and wherein D Eu.

### Claim 17

A method for producing phosphor particles with at least one first protective layer, the method comprising:
providing the phosphor particles; and
applying the at least one first protective layer to a surface of the phosphor particles, wherein the at least one first protective layer comprises:
depositing a first starting compound by a first atomic layer deposition on the surface of the phosphor particles; and
depositing a second starting compound by a second atomic layer deposition on the surface of the phosphor particles,
wherein a phosphor of the phosphor particles has the general formula: Sr(SraM1−a)Si2Al2N6:D, wherein M is selected from the group consisting of Ca, Ba, Zn and Mg, and wherein D is selected from the group consisting of Eu and Ce.

### Claim 18 (depends on 17)

The method according to claim 17, wherein the first starting compound is selected form the group consisting of organometallic compounds and metal halides, and wherein the second starting compound is selected form the group consisting of H2O, H2S, NH3 and O3.

### Claim 19 (depends on 18)

The method according to claim 18, wherein the metal of the organometallic compound or of the metal halide is selected from the group consisting of boron, aluminum, silicon, tin, zinc, titanium, zirconium, tantalum, niobium and hafnium.

### Claim 20 (depends on 17)

The method according to claim 17, wherein D is Ce.