IP Library › Granted Patent US 10,403,690
Granted Patent B2
US 10,403,690 · App. 15/862,157 · Granted Sep 3, 2019

Light emitting device including tandem structure with quantum dots and nanoparticles

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Quick Facts
Patent No.
US 10,403,690
App. No.
15/862,157
Granted
Sep 3, 2019
Kind
B2
Abstract

A light emitting device comprising: a pair of electrodes; two or more light emitting elements disposed between the electrodes in a stacked arrangement, wherein a light emitting element comprises a layer comprising an emissive material, and a charge generation element disposed between adjacent light emitting elements in the stacked arrangement, the charge generation element comprising a first layer comprising an inorganic n-type semiconductor material, and a second layer comprising a hole injection material. A charge generation is also disclosed.

Claims (22)

1. A light emitting device comprising:

a pair of electrodes;

two or more light emitting elements disposed between the electrodes in a stacked arrangement, wherein each of the two or more light emitting elements comprises a layer comprising an emissive material, and wherein the emissive material included in each of the two or more light emitting elements comprises quantum dots; and

a charge generation element disposed between adjacent light emitting elements in the stacked arrangement, the charge generation element comprising a first layer comprising nanoparticles of an inorganic n-type semiconductor material and a second layer comprising a hole injection material, where the nanoparticles of the inorganic n-type semiconductor material are in direct contact with at least one of the layers that comprise the emissive material.

2. The light emitting device in accordance with claim 1 wherein the light emitting device is encapsulated.

3. The light emitting device in accordance with claim 1 wherein the quantum dots included in the at least one of the light emitting elements have a monodisperse size distribution.

4. The light emitting device in accordance with claim 3 wherein at least one of the light emitting elements includes an emissive material comprising an organic electroluminescent material.

5. The light emitting device in accordance with claim 1 wherein the emissive material included in each of the light emitting elements comprises quantum dots with a monodisperse size distribution.

6. The light emitting device in accordance with claim 1 wherein the inorganic n-type semiconductor material comprises a Group II-VI compound, a Group III-V compound, a Group IV-VI compound, a Group compound, a Group II-IV-VI compound, a Group II-IV-V compound, a Group IV element, an alloy including any of the foregoing and/or a mixture including any of the foregoing.

7. The light emitting device in accordance with claim 1 wherein the nanoparticles of the inorganic n-type semiconductor material include non-light emitting nanoparticles of the inorganic n-type semiconductor material.

8. The light emitting device in accordance with claim 1 wherein the nanoparticles are not surface passivated.

9. The light emitting device in accordance with claim 1 wherein the nanoparticles of the inorganic n-type semiconductor material include n-type zinc oxide nanoparticles.

10. The light emitting device in accordance with claim 1 wherein the hole injection material comprises an organic material without an inorganic dopant.

11. The light emitting device in accordance with claim 1 wherein the first layer comprising the nanoparticles of the inorganic n-type semiconductor material injects electrons into the contiguous light emitting element and the second layer comprising a hole injection material inject holes into the contiguous light emitting element.

12. The light emitting device in accordance with claim 1 wherein at least one of the light emitting elements further comprises one or more additional layers.

13. The light emitting device in accordance with claim 1 wherein at least one of the light emitting elements comprises:

a first layer comprising a charge transport material; and

where the layer comprising the emissive material constitutes a second layer.

14. The light emitting device in accordance with claim 13 wherein each of the at least one of the light emitting elements further comprises a third layer comprising a second charge transport material on a side of the second layer opposite the first layer.

15. The light emitting device in accordance with claim 1 wherein the charge generation element is at least 80% transparent to light passage.

16. The light emitting device in accordance with claim 1 wherein the layer comprising the emissive material is contiguous to the first layer of the charge generation element.

17. The light emitting device in accordance with claim 1 wherein the light emitting element contiguous to the second layer of the charge generation element includes a layer comprising a hole transport material between the layer comprising the emissive material and the second layer.