Non-contact pumping of light emitters via non-radiative energy transfer

• US 20050253152A1
• Filed: 05/11/2004
• Published: 11/17/2005
• Est. Priority Date: 05/11/2004
• Status: Active Grant

• Current Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Original Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Inventors: Klimov, Victor I., Achermann, Marc
• Granted Patent: US 7,642,557 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H10K 2102/331 Nanoparticles used in non-emissive layers, e.g. in packaging layer

Abstract

A light emitting device is disclosed including a primary light source having a defined emission photon energy output, and, a light emitting material situated near to said primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur yielding light emission from said light emitting material.

Claims

1. A light emitting device comprising:

a primary light source having a defined emission photon energy output; and

,

a light emitting material proximately situated near said primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur yielding light emission from said light emitting material.

2. The device of claim 1 wherein said light emitting material is within about 15 nanometers of said primary light source.

3. The device of claim 1 wherein said primary light source is selected from the group consisting of a semiconductor light emitting diode, a laser diode, an organic light emitting diode, and semiconductor nanocrystals.

4. The device of claim 3 wherein said primary light source is either electrically pumped or optically pumped.

5. The device of claim 1 wherein said primary light source is a semiconductor light emitting diode comprising at least one material selected from the group consisting of GaN, InGaN, AlGaN, GaAs, AlGaAs and InGaAs.

6. The device of claim 1 wherein said light emitting material is selected from the group consisting of semiconductor nanocrystals, organic light emitting molecules and organic light emitting polymers.

7. The device of claim 1 wherein said light emitting material comprises semiconductor nanocrystals selected from the group consisting of M₁X, M₁M₂X, and M₁M₂M₃X, where M₁, M₂, and M₃ are each selected from the group consisting of Zn, Cd, Hg, Al, Ga, In, Tl, Pb, Sn, Mg, Ca, Sr, Ba, mixtures and alloys thereof and X is selected from the group consisting of S, Se, Te, As, Sb, N, P and mixtures thereof.

8. The device of claim 1 wherein said light emitting material comprises semiconductor nanocrystals are selected from the group consisting of ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, PbS, PbSe and PbTe.

9. The device of claim 1 wherein said primary light source is a semiconductor quantum well on a substrate of a material selected from the group consisting of sapphire, silicon carbide and silicon.

10. The device of claim 7 wherein said semiconductor nanocrystals are either a layer of colloidal nanocrystals or a layer of epitaxially formed semiconductor nanocrystals.

11. The device of claim 7 wherein said semiconductor nanocrystals are characterized by a size distribution in rms of less than about 10 percent.

12. The device of claim 7 wherein said semiconductor nanocrystals include a mixture of different size semiconductor nanocrystals.

13. The device of claim 12 wherein each different size semiconductor nanocrystals is characterized by a size distribution in rms of less than about 10 percent.

14. The device of claim 7 wherein said semiconductor nanocrystals are within a host matrix.

15. The device of claim 14 wherein said host matrix is selected from the group consisting of polystyrene, polyimide, epoxy, silica glasses, titania glasses, silica sol-gels or titania sol-gels.

16. A light emitting diode comprising:

an injection layer including colloidal nanocrystals embedded in a semiconductor material selected from the group consisting of a p-type semiconductor and a n-type semiconductor.

17. The device of claim 16 wherein said n-type semiconductor or said p-type semiconductor are selected from the group consisting of GaN, InGaN, AlGaN, GaAs, AlGaAs and InGaAs.

18. A method of non-contact non-radiative energy transfer into a light emitting material comprising:

forming a structure with a layer of light emitting material proximately situated near a primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur;

pumping the primary light source whereby a non-radiative emission from the primary light source occurs, said non-radiative emission sufficient to result in a output of light from said light emitting material layer.

19. The method of claim 18 wherein said light emitting material is selected from the group consisting of semiconductor nanocrystals, organic light emitting molecules and organic light emitting polymers.

20. The method of claim 18 wherein said light emitting material is within about 15 nanometers of said primary light source.