Device including quantum dots
View Patent ↗A device including an emissive material comprising quantum dots is disclosed. In one embodiment, the device includes a first electrode and a second electrode, a layer comprising quantum dots disposed between the first electrode and the second electrodes, and a first interfacial layer disposed at the interface between a surface of the layer comprising quantum dots and a first layer in the device. In certain embodiments, a second interfacial layer is optionally further disposed on the surface of the layer comprising quantum dots opposite to the first interfacial layer. In certain embodiments, a device comprises a light-emitting device. Other light emitting devices and methods are disclosed.
1. A method for preparing a light emitting device including a first electrode and a second electrode, an emissive layer comprising quantum dots disposed between the first electrode and the second electrode, a first layer disposed between the first electrode and the layer comprising quantum dots, and a first interfacial layer disposed at the interface between a surface of the layer comprising quantum dots and the first layer, the method comprising:
forming the first electrode on a substrate;
forming the first layer thereover, the first layer comprising a first charge transport material comprising an inorganic material comprising a metal chalcogenide;
applying the first interfacial layer thereover for protecting the quantum dots included in the emissive layer from charge quenching sites in a contiguous device layer, the first interfacial layer being applied as a distinct layer having a thickness in a range from a monolayer thickness to about 5 nm and comprising a material that is non-quenching to quantum dot photoluminescent emission and does not impede charge flow;
applying the emissive layer comprising quantum dots thereover; and
forming the second electrode thereover.
2. A method in accordance with claim 1 further comprising forming a second interfacial layer over the surface of the layer comprising quantum dots opposite the first interfacial layer.
3. A method in accordance with claim 1 wherein the first interfacial layer comprises a surfactant.
4. A method in accordance with claim 1 wherein the first interfacial layer comprises a silicon-containing coupling agent.
5. A method in accordance with claim 1 wherein the first interfacial layer comprises a metal oxide.
6. A method in accordance with claim 1 wherein the first interfacial layer comprises an organic small molecule material.
7. A method in accordance with claim 1 wherein the first interfacial layer comprises a metal oxide including an alkali metal or alkaline earth metal dopant.
8. A method in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting nanoparticles having a bandgap that is the same or similar to the bandgap of quantum dots included in the emissive layer comprising quantum dots.
9. A method in accordance with claim 2 further comprising forming a second layer between the second interfacial layer and the second electrode.
10. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by phase separation of a mixture including quantum dots and a small molecule material.
11. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by spincasting.
12. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by atomic layer deposition (ALD).
13. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by molecular layer deposition (MLD).
14. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by physical vapor deposition.
15. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by chemical vapor deposition (CVD).
16. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by plasma-enhanced chemical vapor deposition (PECVD).
17. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by contact printing.
18. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by inkjet printing.
19. A method in accordance with claim 2 wherein the first interfacial layer and/or the second interfacial layer is formed by self-assembly.
20. A method in accordance with claim 9 wherein the first layer comprises a material capable injecting and transporting electrons, the second layer comprises a material capable of transporting holes, and wherein the method further includes forming a hole injection layer over the second layer.