White phosphorescent organic light emitting devices

• US 8,513,658 B2
• Filed: 09/04/2009
• Issued: 08/20/2013
• Est. Priority Date: 09/04/2008
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: D'Andrade, Brian, Esler, James, Adamovich, Vadim
• Primary Examiner(s): Ho, Anthony
• Application Number:
  US13/062,162
• Publication Number:
  US 20110215309A1
• Time in Patent Office: 1,446 Days
• Field of Search: 257/40, 257/E51.001
• US Class Current: 257/40
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/636 comprising heteroaromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

A device is provided. The device includes an anode, a cathode and a double emissive layer disposed between the anode and the cathode. The double emissive layer includes a first organic emissive layer and a second organic emissive layer. The second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer. The device also includes a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode. The device also includes a hole transport layer disposed between the blocking layer and the anode. At least one of the anode and the cathode is transmissive.

Claims

1. A device, comprising:

an anode;

a cathode;

a first organic emissive layer, further comprising;

first phosphorescent material having a concentration of 15-35 wt % in the first organic emissive layer, wherein the first phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 400 nm and 500 nm; and

a first host material having a triplet energy at least 0.2 eV and not more than 1.0 eV greater than the triplet energy of the first phosphorescent material;

wherein the first organic emissive layer is disposed between the anode and the cathode;

a second organic emissive layer further comprising;

a second phosphorescent material having a concentration of 15-35 wt % in the second organic emissive layer, wherein the second phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 500 nm and 600 nm;

a third phosphorescent material having a concentration of 0.1-3 wt % in the second organic emissive layer, wherein the third phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 600 nm and 700 nm;

a second host material having a triplet energy greater than that of the third phosphorescent emissive material;

wherein the second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer;

a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode, the blocking layer having a lowest unoccupied molecular orbital that is at least 0.1 eV greater than the lowest unoccupied molecular orbital of the second host material;

a hole transport layer disposed between the blocking layer and the anode;

wherein at least one of the anode and the cathode is transmissive.

2. The device of claim 1, wherein the anode is transmissive and the cathode is reflective.

3. The device of claim 2, wherein the second organic emissive layer is disposed closer to the anode than the first organic emissive layer.

4. The device of claim 1, wherein the anode is reflective and the cathode is transmissive.

5. The device of claim 4, wherein the second organic emissive layer is disposed closer to the cathode than the first organic emissive layer.

6. The device of claim 1, wherein the first host material has a triplet energy at least 0.2 eV and not more than 0.5 eV greater than the triplet energy of the first phosphorescent material.

7. The device of claim 1, wherein the hole transport layer consists essentially of NPD.

8. The device of claim 1 wherein the hole transport layer has a hole mobility of at least 5×

10<sup>−

4</sup> cm² V<sup>−

1</sup> s<sup>−

1</sup>.

9. The device of claim 1, wherein the anode consists essentially of indium zinc oxide.

10. The device of claim 1, wherein the voltage drop across the device at a luminance of 1000 cd/m² is 3.5 eV-4.1 eV.

11. The device of claim 1, wherein the voltage drop across the device at a luminance of 1000 cd/m² is less than 3.7 eV.

12. The device of claim 1, wherein the second phosphorescent material is compound B.

13. The device of claim 1, wherein the first organic emissive layer has a thickness of 4 nm to 10 nm.

14. The device of claim 1, wherein the blocking layer has a thickness of 12-37 nm and the hole transport layer has a thickness of 12-37 nm.

15. A consumer product, comprising a device, the device further comprising:

an anode;

a cathode;

a first organic emissive layer, further comprising;

first phosphorescent material having a concentration of 15-35 wt % in the first organic emissive layer, wherein the first phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 400 nm and 500 nm; and

a first host material having a triplet energy at least 0.2 eV and not more than 1.0 eV greater than the triplet energy of the first phosphorescent material;

wherein the first organic emissive layer is disposed between the anode and the cathode;

a second organic emissive layer further comprising;

a second phosphorescent material having a concentration of 15-35 wt % in the second organic emissive layer, wherein the second phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 500 nm and 600 nm;

a third phosphorescent material having a concentration of 0.1-3 wt % in the second organic emissive layer, wherein the third phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 600 nm and 700 nm;

a second host material having a triplet energy greater than that of the third phosphorescent emissive material;

wherein the second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer;

a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode, the blocking layer having a lowest unoccupied molecular orbital that is at least 0.1 eV greater than the lowest unoccupied molecular orbital of the second host material;

a hole transport layer disposed between the blocking layer and the anode;

wherein at least one of the anode and the cathode is transmissive.