# US 10,246,638 B1 · Quantum dot light emitting diode (LED) with suppressed photobrightening

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- Number: US 10,246,638 B1
- Document ID: US10246638B1
- Status: Granted
- Kind: B1
- Application number: 15/817,440
- Filed: 2017-11-20
- Granted: 2019-04-02
- Earliest claimed: 2017-11-20
- Assignees: eLux, Inc.
- Applicants: eLux Inc.
- Inventors: Alexey Koposov
- Web page: https://patentgrep.com/patent/US10246638B1

## CPC

- H10H 20/8512: {Wavelength conversion materials}
- C09K 11/70: containing phosphorus
- C09K 11/7492: {Arsenides; Nitrides; Phosphides}
- C09K 11/883: {with zinc or cadmium}
- H10H 20/8513: {having two or more wavelength conversion materials}
- H10H 20/854: characterised by their material, e.g. epoxy or silicone resins
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- B82Y 40/00: Manufacture or treatment of nanostructures
- H10H 20/036: {of packages}
- H10H 20/0361: {of wavelength conversion means}
- H10H 20/0362: {of encapsulations}
- H10H 20/872: {Periodic patterns for optical field-shaping, e.g. photonic bandgap structures}
- Y10S 977/774: Exhibiting three-dimensional carrier confinement, e.g. quantum dots
- Y10S 977/813: Of specified inorganic semiconductor composition, e.g. periodic table group IV-VI compositions
- Y10S 977/816: III-N based compounds, e.g. AlxGayInzN
- Y10S 977/818: III-P based compounds, e.g. AlxGayIn2P
- Y10S 977/819: III-As based compounds, e.g. AlxGayInzAs
- Y10S 977/824: Group II-VI nonoxide compounds, e.g. CdxMnyTe
- Y10S 977/892: Liquid phase deposition
- Y10S 977/90: having step or means utilizing mechanical or thermal property, e.g. pressure, heat
- Y10S 977/95: Electromagnetic energy
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A device and associated method are provided for a light emitting diode device (LED) with suppressed quantum dot (QD) photobrightening. The QD surfaces, with a maximum cross-sectional dimension of 10 nanometers, are treated with a solution including a multi-valent cation salt. In response to heating the solution, multi-valent cations become attached to the surface of the QD nanocrystals, forming treated QDs that are deposited overlying a top surface of an LED. The LED device emits a non-varying intensity of first wavelength light in the visible spectrum from the treated QDs, when subjected to a continuous exposure of a second wavelength of LED light having an intensity of greater than 50 watts per square centimeter. For example, blue, green, or red color light may be emitted when exposed to LED light in the ultraviolet (UV) spectrum, or a green or red color light when exposed to a blue color LED light.

## Claims

### Claim 1

A treated quantum dot (QD) with suppressed photobrightening comprising:
a QD nanocrystal having a surface with a maximum cross-sectional dimension of 10 nanometers (nm), capable of emissions in the visible spectrum of light;
elements attached to the surface of the QD nanocrystal consisting of cations; and,
wherein the treated QD emits a non-varying intensity of first wavelength of light in the visible spectrum when subjected to a continuous exposure of a second wavelength of light having an intensity of greater than 50 watts per square centimeter (W/cm2).

### Claim 2 (depends on 1)

The treated QD of claim 1 wherein the QD nanocrystal has a structure selected from the group consisting of a solitary core and a core-single shell structure.

### Claim 3 (depends on 1)

The treated QD of claim 1 wherein the QD nanocrystal comprises a binary or binary alloyed material surface; and,
wherein the cations are divalent cations.

### Claim 4 (depends on 3)

The treated QD of claim 3 wherein the QD nanocrystal surface is selected from the group consisting of CdS, CdSe, CdTe, GaAs, InAs, InN, InP, ZnS, ZnSe, ZnTe, and combinations thereof.

### Claim 5 (depends on 1)

The treated QD of claim 1 wherein the QD nanocrystal comprises a tertiary or tertiary alloyed surface; and,
wherein the cations are selected from the group consisting of trivalent cations, divalent cations, monovalent cations, and combinations thereof.

### Claim 6 (depends on 5)

The treated QD of claim 5 wherein the QD nanocrystal surface is selected from the group consisting of ZnSSe, ZnSeTe, ZnSTe, CdSSe, CdSeTe, CdSTe, ZnCdS, ZnCdSe, ZnCdTe, ZnCdSSe, ZnCdSeTe, InGaAs, GaAlAs, InGaN, CuInS2, CuGaS2, Cu(In,Ga)Se2, Cu(Zn,Sn)Se2, Cu(Zn,Sn)S2, CuIn(Se,S)2, CuZn(Se,S)2, CuSn(Se,S)2, Cu(Zn,Sn)(Se,S)2, and combinations thereof.

### Claim 7 (depends on 1)

The treated QD of claim 1 wherein the QD nanocrystal comprises a Type III-V semiconductor surface; and,
wherein the cations are selected from the group consisting of trivalent cations, divalent cations, and combinations thereof.

### Claim 8 (depends on 7)

The treated QD of claim 7 wherein the trivalent cations are selected from the group consisting of Al, Ga, In, Fe, Sb, and Bi.

### Claim 9 (depends on 1)

The treated QD of claim 1 wherein the treated quantum dot emits light selected from the group consisting of blue, green, and red color light when exposed to light in the ultraviolet (UV) spectrum.

### Claim 10 (depends on 1)

The treated QD of claim 1 wherein the treated quantum dot emits a light color selected from the group consisting of red and green light when exposed to a blue color light.

### Claim 11

A quantum dot (QD) light emitting diode (LED) device with suppressed photobrightening, the device comprising:
an LED with a top surface;
a plurality of treated QDs with suppressed photobrightening overlying the LED top surface, each treated QD comprising:
a QD nanocrystal having a surface with a maximum cross-sectional dimension of 10 nanometers (nm), capable of emissions in the visible spectrum of light;
elements attached to the surface of the QD nanocrystal consisting of cations; and,
wherein the device emits a non-varying intensity of first wavelength of light from the treated QDs in the visible spectrum when subjected to a continuous exposure of a second wavelength of LED light having an intensity of greater than 50 watts per square centimeter (W/cm2).

### Claim 12 (depends on 11)

The device of claim 11 wherein the QD nanocrystal has a structure selected from the group consisting of a solitary core and a core-single shell structure.

### Claim 13 (depends on 11)

The device of claim 11 wherein the QD nanocrystal comprises a binary or binary alloyed material surface; and,
wherein the cations are divalent cations.

### Claim 14 (depends on 13)

The device of claim 13 wherein the QD nanocrystal surface is selected from the group consisting of CdS, CdSe, CdTe, GaAs, InAs, InN, InP, ZnS, ZnSe, ZnTe, and combinations thereof.

### Claim 15 (depends on 11)

The device of claim 11 wherein the QD nanocrystal comprises a tertiary or tertiary alloyed surface; and,
wherein the cations are selected from the group consisting of trivalent cations, divalent cations, monovalent cations, and combinations thereof.

### Claim 16 (depends on 15)

The device of claim 15 wherein the QD nanocrystal surface is selected from the group consisting of ZnSSe, ZnSeTe, ZnSTe, CdSSe, CdSeTe, CdSTe, ZnCdS, ZnCdSe, ZnCdTe, ZnCdSSe, ZnCdSeTe, InGaAs, GaAlAs, InGaN, CuInS2, CuGaS2, Cu(In,Ga)Se2, Cu(Zn,Sn)Se2, Cu(Zn,Sn)S2, CuIn(Se,S)2, CuZn(Se,S)2, CuSn(Se,S)2, Cu(Zn,Sn)(Se,S)2, and combinations thereof.

### Claim 17 (depends on 11)

The device of claim 11 wherein the QD nanocrystal comprises a Type III-V semiconductor surface; and,
wherein the cations are selected from the group consisting of trivalent cations, divalent cations, and combinations thereof.

### Claim 18 (depends on 17)

The device of claim 17 wherein the trivalent cations are selected from the group consisting of Al, Ga, In, Fe, Sb, and Bi.

### Claim 19 (depends on 11)

The device of claim 11 wherein the device emits a light selected from the group consisting of blue, green, and red color light from the treated QDs when exposed to LED light in the ultraviolet (UV) spectrum.

### Claim 20 (depends on 11)

The device of claim 11 wherein the device emits a light color selected from the group consisting of red and green light from the treated QDs when exposed to a blue color LED light.

### Claim 21 (depends on 11)

The device of claim 11 further comprising:
a matrix material selected from the group consisting of epoxy, silicon, and acrylate based polymers overlying the top surface of the LED; and,
wherein the treated QDs are embedded in the matrix material.