Organic light emitting devices with hole impeding materials
View Patent ↗An organic electroluminescent device includes an anode, a cathode, and a light emitting zone including a hole transport region and an electron transport region. The hole transport region include a hole impeding material located non-adjacent the anode.
1. An organic electroluminescent device comprising:
an anode,
a cathode, and
a light emitting zone including a hole transport region and an electron transport region, wherein the hole transport region includes at least one hole impeding material located non-adjacent the anode and within the hole transport region.
2. The device according to claim 1 , wherein the at least one hole impeding material is a layer.
3. The device according to claim 1 , wherein the at least one hole impeding material includes CuPc.
4. The device according to claim 1 , wherein the at least one hole impeding material includes AlQ 3 .
5. The device according to claim 1 , wherein the electron transport region includes AlQ 3 .
6. The device according to claim 1 , wherein the hole transport region includes at least one hole transport material, and wherein the at least one hole impeding material has a hole transport rate less than that of the at least one hole transport material.
7. The device according to claim 1 , wherein the at least one hole impeding material has an electron transport rate at least ten times greater than a hole transport rate.
8. The device according to claim 1 , wherein the light emitting zone is capable of emitting blue light.
9. The device according to claim 1 , wherein the light emitting zone is capable of emitting red light.
10. The device according to claim 1 , wherein the light emitting zone is capable of emitting green light.
11. The device according to claim 1 , wherein the light emitting zone is capable of emitting white light.
12. The device of claim 1 , wherein the at least one hole impeding material is selected such that the luminance stability ratio is greater than about 2.
13. The device of claim 1 , wherein the at least one hole impeding material is selected such that the luminance stability ratio is greater than about 5.
14. The device of claim 1 , wherein the at least one hole impeding material is selected such that the luminance stability ratio is greater than about 10.
15. The device of claim 1 , wherein the at least one hole impeding material is arranged such that voltage is not substantially increased relative to a corresponding device without the hole impeding material.
16. The device of claim 1 , wherein the hole transport region has a thickness, and wherein the at least one hole impeding material is provided at a distance measured from the anode at least about one third of the thickness of the hole transport region.
17. The device of claim 1 , wherein the hole transport region has a thickness, and wherein the at least one hole impeding material is provided at a distance measured from the anode at least about one half of the thickness of the hole transport region.
18. The device of claim 1 , wherein the hole transport region has a thickness, and wherein the at least one hole impeding material is provided at a distance measured from the anode at least about two thirds of the thickness of the hole transport region.