Providing an emission-protecting layer in an OLED device
View Patent ↗An organic light-emitting device with improved performance including an anode formed over a substrate; a hole-transporting layer formed over the anode; and a light emitting layer formed over the hole-transporting layer for producing light in response to hole-electron recombination. The organic light-emitting device also includes an emission-protecting layer formed over the light-emitting layer, wherein the emission-protecting layer includes one or more materials selected to resist the surface contamination on the organic light-emitting layer and to ensure that there will be less surface contamination than if such layer had not been provided; an electron-transporting layer formed over the emission-protecting layer; and a cathode formed over the electron-transporting layer.
1. An organic light-emitting device with improved performance comprising:
a) an anode formed over a substrate;
b) a hole-transporting layer formed over the anode;
c) a light-emitting layer formed over the hole-transporting layer for producing light in response to hole-electron recombination;
d) an emission-protecting layer formed over the light-emitting layer, wherein the emission-protecting layer includes one or more materials selected to resist the surface contamination on the organic light-emitting layer and to ensure that there will be less surface contamination than if such layer had not been provided;
e) an electron-transporting layer formed over the emission-protecting layer; and
f) a cathode formed over the electron-transporting layer.
2. The organic light-emitting device of claim 1 wherein the light-emitting layer includes at least one host and one dopant and the emission-protecting layer includes one or more materials having their ionization potentials equal to or greater than the ionization potential of the host material of the light-emitting layer.
3. The organic light-emitting device of claim 1 wherein the emission-protecting layer has an optical band gap higher than 3.0 eV.
4. The organic light-emitting device of claim 1 wherein the emission-protecting layer is more hydrophobic than the light-emitting layer.
5. The organic light-emitting device of claim 1 wherein the emission-protecting layer has a thickness in a range of from 0.1 to 10 nm.
6. The organic light-emitting device of claim 5 wherein the emission-protecting layer has a thickness in the range of from 0.5 to 5.0 nm.
7. The organic light-emitting device of claim 1 wherein the emission-protecting layer includes TBADN and B-Alq.
8. A method for preventing contamination of a light-emitting layer for use in an organic light-emitting device with improved performance comprising:
a) forming an emission-protecting layer on the light-emitting layer, wherein the emission-protecting layer includes one or more materials selected to resist the surface contamination on the organic light-emitting layer and to ensure that there will be less surface contamination than if such layer had not been provided; and
b) completing the organic light-emitting device.
9. The method of claim 8 wherein the emission-protecting layer is formed by evaporation.
10. The method of claim 8 wherein the emission-protecting layer can be formed by two or more different materials sequentially deposited or co-deposited.
11. The method of claim 8 wherein the emission-protecting layer has a thickness in a range of from 0.1 to 10 nm.
12. The method of claim 11 wherein the emission-protecting layer has a thickness in the range of from 0.5 to 5.0 nm.
13. The method of claim 8 wherein the emission-protecting layer includes TBADN and B-Alq.
14. A method for preventing contamination of full color-emitting pixels with improved performance comprising:
a) forming a first color light-emitting layer on selected subpixels;
b) forming an emission-protecting layer over the color-emitting layer on the same subpixel area with the same pixelation technique, wherein the emission-protecting layer includes one or more materials selected to resist the surface contamination on the organic light-emitting layer and to ensure that there will be less surface contamination than if such layer had not been provided; and
c) repeating steps a) and b) for each different color emissive layer; and
d) completing the organic light-emitting device.
15. The method of claim 14 wherein the emission-protecting layers are formed by evaporation.
16. The method of claim 14 wherein the emission-protecting layers can be formed by two or more different materials sequentially deposited or co-deposited.
17. The method of claim 14 wherein each of the emission-protecting layers has a thickness in a range of from 0.1 to 10 nm.
18. The method of claim 17 wherein each of the emission-protecting layers has a thickness in the range of from 0.5 to 5.0 nm.
19. The method of claim 14 wherein the emission-protecting layer includes TBADN and B-Alq.
20. A method for preventing contamination of a light-emitting layer for use in a polymeric organic light-emitting device with improved performance comprising:
a) forming an emission-protecting layer on the light-emitting layer including one or more materials before thermal annealing, wherein the emission-protecting layer includes one or more materials selected to resist the surface contamination on the organic light-emitting layer and to ensure that there will be less surface contamination than if such layer had not been provided;
b) thermally annealing the emission-protecting layer; and
c) completing the polymeric organic light-emitting device.
21. The method of claim 20 wherein the emission-protecting layer is formed by spin-coating or by ink-jet printing.
22. The method of claim 20 wherein the emission-protecting layer has a thickness in a range of from 0.5 to 100 nm.
23. The method of claim 22 wherein the emission-protecting layer has a thickness in a range of from 1.0 to 50 nm.