Materials and structures for enhancing the performance or organic light emitting devices

• US 6,902,833 B2
• Filed: 04/01/2003
• Issued: 06/07/2005
• Est. Priority Date: 04/01/2003
• Status: Expired due to Term

• Current Assignee: Universal Display Corporation, University of Southern California
• Original Assignee: Universal Display Corporation, University of Southern California
• Inventors: Thompson, Mark E., Kwong, Raymond, Brooks, Jason, Lu, Min-Hao Michael, Garon, Simona
• Primary Examiner(s): GARRETT, DAWN L
• Application Number:
  US10/405,009
• Publication Number:
  US 20040197601A1
• Time in Patent Office: 798 Days
• Field of Search: 428/690, 428/917, 428/212, 252/301.16, 313/504, 313/506
• US Class Current: 428/690
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/183 of the refractory metals, i.e. Ti, V, Cr, Zr, Nb, Mo, Hf, Ta or W
• CPC Class Codes: C09K 2211/188 of other metals not provided for in one of the previous groups
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 50/181 Electron blocking layers
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/311 Phthalocyanine
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/649 Aromatic compounds comprising a hetero atom
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

A device is provided, having an anode, a cathode, and a first organic layer disposed between the anode and the cathode. The first organic layer is capable of phosphorescent emissive when a voltage is applied between the anode and the cathode. A second organic layer disposed between the first organic layer and the cathode is also provided. The second organic layer is in direct contact with the first organic layer. The second organic layer may comprise a material having the structure:
M may be selected from the group Ti, Zr, Hf, Nb, Re, Sn and Ge. The substituents R1 through R10 may be selected from the group consisting of alkyl and aryl groups. Each of R1 through R10 may represent no substitution, mono-, di-, or tri-substitution. The second organic layer may comprise a material having a dipole moment less than about 2.0 debyes, such that the device has an unmodified external quantum efficiency of at least about 3% and a lifetime of at least about 1000 hours at an initial photon flux of about 10¹⁸ photons/sr-sec. The second organic layer may comprise a metal complex having a plurality of ligands, wherein each ligand makes the same contribution to the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the metal complex. The second organic layer may be in direct contact with the cathode, or there may be a separate organic layer between the second organic layer and the cathode. Other metal complexes having quinolate ligands may be used.

Claims

1. A device, comprising:

an anode;

a cathode;

an first organic layer disposed between the anode and the cathode, wherein the first organic layer is capable of phosphorescent emissive when a voltage is applied between the anode and the cathode;

a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises a material having the structure;

wherein;

M is a metal selected from the group consisting of Ti, Zr, Hf, Nb, Re, Sn and Ge;

R1, R2, R3, R4, R5, R6, R7 and R8 each represent no substitution, mono-, di-, or tri-substitution, and wherein the substituents are independently selected from the group consisting of;

alkyl and aryl groups.

2. The device of claim 1, wherein M is Zr.

3. The device of claim 1, wherein M is Hf.

4. The device of claim 1, wherein there is no substitution.

5. The device of claim 2, wherein there is no substitution.

6. The device of claim 1, wherein the second organic layer is in direct contact with the cathode.

7. The device of claim 1, further comprising a third organic layer disposed between the second organic layer and the cathode.

8. A device, comprising:

an anode;

a cathode;

an first organic layer disposed between the anode and the cathode, wherein the first organic layer is capable of phosphorescent emissive when a voltage is applied between the anode and the cathode;

a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises a material having the structure;

wherein;

x is an integer from 2 to 4, defining a number of quinolate ligands;

y is an integer from 0 to 3;

M is a metal selected from the group consisting of Ca, Sr, Ba, Ti, Zr, Hf, V, Nb, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Ni, Pd, Pt, Zn, Cd, Hg, Ge, Sn, and Pd;

i ranges from 1 to x;

Rai and Rbi each represent no substitution, mono-, di-, or tri-substitution, and wherein the substituents are independently selected from the group consisting of;

alkyl and aryl groups.

9. The device of claim 8, wherein Rai is the same on each ligand, and Rbi is the same on each ligand.

10. The device of claim 8, wherein the second organic layer is in direct contact with the cathode.

11. The device of claim 8, wherein the second organic layer comprises a

material having the structure:

wherein y=0 and 2≦

X≦

4.

12. The device of claim 11, wherein the second organic layer is in direct contact with the cathode.

13. A device, comprising:

an anode;

a cathode;

an first organic layer disposed between the anode and the cathode, wherein the first organic layer is capable of phosphorescent emissive when a voltage is applied between the anode and the cathode;

a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises a material having the structure;

14. The device of claim 13, wherein the second organic layer is in direct contact with the cathode.

15. A device, comprising:

an anode;

a cathode;

an first organic layer disposed between the anode and the cathode, wherein the first organic layer is capable of phosphorescent emissive when a voltage is applied between the anode and the cathode;

a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises a material having the structure

16. The device of claim 15, wherein the second organic layer is in direct contact with the cathode.

17. A device, comprising:

an anode;

a cathode;

an first organic layer disposed between the anode and the cathode, wherein the first organic layer is capable of phosphorescent emissive when a voltage is applied between the anode and the cathode;

a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises an organic material having a dipole moment less than about 2.0 debyes, and a highest occupied molecular orbital energy level that is not more than 0.7 eV less than the highest occupied molecular orbital energy level of the organic material in the first organic layer.

18. The device of claim 17, wherein the second organic material comprises a material having a highest occupied molecular orbital energy level that is not more than 0.3 eV less than the highest occupied molecular orbital energy level of the hole transporting material in the first organic layer.

19. The device of claim 17, wherein the second organic material comprises a material having a highest occupied molecular orbital energy level that is not more than 0.25 eV less than the highest occupied molecular orbital energy level of the hole transporting material in the first organic layer.

20. The device of claim 17, wherein the second organic material comprises a material having a highest occupied molecular orbital energy level that is greater than the highest occupied molecular orbital energy level of the hole transporting material in the first organic layer.