SEMICONDUCTOR NANOPARTICLE-BASED LIGHT EMITTING MATERIALS

• US 20190267515A1
• Filed: 03/20/2019
• Published: 08/29/2019
• Est. Priority Date: 09/23/2011
• Status: Active Grant

• Current Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Original Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Inventors: Naasani, Imad, Pickett, Nigel
• Granted Patent: US 10,644,207 B2
• Time in Patent Office: Days
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• 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 33/52 Encapsulations

Abstract

A light emitting layer including a plurality of light emitting particles embedded within a host matrix material. Each of said light emitting particles includes a population of semiconductor nanoparticles embedded within a polymeric encapsulation medium. A method of fabricating a light emitting layer comprising a plurality of light emitting particles embedded within a host matrix material, each of said light emitting particles comprising a population of semiconductor nanoparticles embedded within a polymeric encapsulation medium. The method comprises providing a dispersion containing said light emitting particles, depositing said dispersion to form a film, and processing said film to produce said light emitting layer.

Claims

1. A method of fabricating a light emitting device incorporating a light emitting layer comprising a plurality of light emitting beads dispersed within a host matrix material, each of said light emitting beads comprising a population of semiconductor nanoparticles embedded within a polymeric encapsulation medium, the method comprising:

providing a dispersion containing said light emitting beads, an initiator, a cross-linker, and a monomer;

depositing said dispersion on a surface of a diffuser sheet to form a film thereon;

annealing said film to produce said light emitting layer on the surface of the diffuser sheet; and

placing the diffuser sheet over a light source such that the diffuser sheet is between the light source and the light emitting layer.

2. The method recited in claim 1 wherein the initiator is a photoinitiator.

3. The method recited in claim 2 wherein the photoinitiator is bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide.

4. The method recited in claim 1 wherein the cross-linker is trimethylol propane trimethacrylate (TMPTM).

5. The method recited in claim 1 wherein the cross-liner is divinyl benzene.

6. The method recited in claim 1 wherein the monomer is an acrylate monomer.

7. The method recited in claim 6 wherein the acrylate monomer is lauryl methacrylate.

8. The method recited in claim 1 wherein said dispersion possesses a viscosity suitable for deposition by printing or drop casting.

9. The method recited in claim 1 wherein depositing said dispersion on a surface of a diffuser sheet is by printing or drop casting.

10. The method recited in claim 1 wherein said film has a thickness less than about 250 nm.

11. The method recited in claim 1 wherein the host matrix material is a polystyrene resin.

12. The method recited in claim 1 wherein the dispersion further comprises a polystyrene resin and toluene, and wherein the host matrix material is the polystyrene resin.

13. The method recited in claim 1 wherein the host matrix material is a methacrylate.

14. The method recited in claim 1 wherein the dispersion further comprises polyisobutylene.

15. The method recited in claim 1 wherein annealing comprises heating said film to a temperature of about 300°

C.