Buffer layers for organic electroluminescent devices and methods of manufacture and use
View Patent ↗Organic electroluminescent device can be formed with multiple layers including an electrode, an emission layer, and a buffer layer. The emission layer includes a light emitting material. The buffer layer is disposed between and in electrical communication with the electrode and the emission layer and includes a triarylamine hole transport material and an electron acceptor material. The buffer layer optionally includes one or more of a) a polymeric binder, b) a color converting material, and c) light scattering particles. The buffer layer can also be formed using a polymeric hole transport material having a plurality of triarylamine moieties.
1. A method of making an electroluminescent device comprising:
forming an electrode on a receptor substrate;
forming a buffer layer over the electrode, the buffer layer comprising a triarylamine hole transport material, and an electron acceptor material;
forming a transfer layer on a donor substrate, the transfer layer comprising an emission layer; and
selectively thermally transferring a portion of the transfer layer from the donor to the buffer layer,
wherein the electrode, buffer layer, and transfer layer are in electrical communication, and the emission layer comprises a light emitting material.
2. The method of claim 1 , where the transfer layer further comprises at least one of a hole transport layer, a hole blocking layer, an electron transport layer, an electron blocking layer, an electron injection layer and a second electrode layer.
3. The method of claim 1 , further comprising disposing a hole transport layer over the buffer layer prior to selectively transferring the transfer layer over the buffer layer.
4. The method of claim 1 , wherein the buffer layer further comprises at least one of a polymeric binder and a crosslinked polymeric binder.
5. The method of claim 4 , wherein the polymeric binder or the crosslinked polymeric binder is electroactive.
6. The method of claim 4 , wherein the polymeric binder or the crosslinked polymeric binder is electrically inert.
7. The method of claim 1 , wherein the buffer layer further comprises a color converting material.
8. A method of making an electroluminescent device comprising:
forming an electrode on a receptor substrate,
forming a first transfer layer on a donor substrate, the first transfer layer comprising a buffer layer, wherein the buffer layer comprises a triarylamine hole transport material and an electron acceptor material;
selectively thermally transferring a portion of the first transfer layer onto the receptor substrate, and in electrical communication with the electrode;
forming a second transfer layer on a donor substrate, the second transfer layer comprising an emission layer; and
selectively thermally transferring a portion of the second transfer layer from the donor to the first transfer layer on the receptor substrate,
wherein the electrode, first transfer layer, and second transfer layer are in electrical communication, and the emission layer comprises a light emitting material.
9. The method of claim 8 , where the second transfer layer further comprises at least one of a hole transport layer, a hole blocking layer, an electron transport layer, an electron blocking layer, an electron injection layer and a second electrode layer.
10. The method of claim 8 , further comprising disposing a hole transport layer over the buffer layer prior to selectively transferring the transfer layer over the buffer layer.
11. The method of claim 8 , wherein the buffer layer further comprises at least one of a polymeric binder and a crosslinked polymeric binder.
12. The method of claim 11 , wherein the polymeric binder or the crosslinked polymeric binder is electroactive.
13. The method of claim 11 , wherein the polymeric binder or the crosslinked polymeric binder is electrically inert.
14. The method of claim 8 , wherein the buffer layer further comprises a color converting material.