Quantum dot light emitting diode (LED) with suppressed photobrightening

• US 10,246,638 B1
• Filed: 11/20/2017
• Issued: 04/02/2019
• Est. Priority Date: 11/20/2017
• Status: Active Grant

• Current Assignee: Elux Inc.
• Original Assignee: Elux Inc.
• Inventors: Koposov, Alexey
• Primary Examiner(s): Nguyen, Cuong Q
• Assistant Examiner(s): Kim, Tong-Ho
• Application Number:
  US15/817,440
• Time in Patent Office: 498 Days
• Field of Search: 257 98
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C09K 11/70 containing phosphorus
• CPC Class Codes: C09K 11/7492 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: Y10S 977/774 Exhibiting three-dimensional carrier confinement, e.g. quantum dots
• CPC Class Codes: Y10S 977/813 Of specified inorganic semiconductor composition, e.g. periodic table group IV-VI compositions
• CPC Class Codes: Y10S 977/816 III-N based compounds, e.g. AlxGayInzN
• CPC Class Codes: Y10S 977/818 III-P based compounds, e.g. AlxGayIn2P
• CPC Class Codes: Y10S 977/819 III-As based compounds, e.g. AlxGayInzAs
• CPC Class Codes: Y10S 977/824 Group II-VI nonoxide compounds, e.g. CdxMnyTe
• CPC Class Codes: Y10S 977/892 Liquid phase deposition
• CPC Class Codes: Y10S 977/90 having step or means utilizing mechanical or thermal property, e.g. pressure, heat
• CPC Class Codes: Y10S 977/95 : Electromagnetic energy

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

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).

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

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

9. 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.

10. 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.

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).

12. 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.

13. The device of claim 11 wherein the QD nanocrystal comprises a binary or binary alloyed material surface;

and,

wherein the cations are divalent cations.

14. 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.

15. 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.

16. 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.

17. 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.

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

19. 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.

20. 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.

21. 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.