Semiconductor nanoparticle-based light emitting materials

• US 10,312,418 B2
• Filed: 02/03/2017
• Issued: 06/04/2019
• 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, Harris, James, Pickett, Nigel
• Primary Examiner(s): Gumedzoe, Peniel M
• Assistant Examiner(s): Johnson, Christopher A
• Application Number:
  US15/424,556
• Publication Number:
  US 20170148956A1
• Time in Patent Office: 851 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, trimethylol propane trimethacrylate (TMPTM) and lauryl methacrylate;

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 said dispersion possesses a viscosity that makes it suitable for deposition by printing or drop casting.

3. The method recited in claim 1 wherein deposition of said dispersion is effected by printing or drop casting.

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

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

6. The method of claim 1, wherein the host matrix material is a methacrylate.

7. The method of claim 1, wherein the dispersion further comprises polyisobutylene.

8. The method of claim 1, wherein annealing comprises heating said film up to a temperature of around 300°

C.

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