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

• US 20080309222A1
• Filed: 10/10/2007
• Published: 12/18/2008
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Jason Brooks, Mark Thompson, Raymond Kwong, Yeh-Jiun Tung
• Original Assignee: Jason Brooks, Mark Thompson, Raymond Kwong, Yeh-Jiun Tung
• Inventors: Thompson, Mark E., Kwong, Raymond, Tung, Yeh-Jiun, Brooks, Jason
• Granted Patent: US 8,105,700 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: C07C 13/567 with a fluorene or hydrogenated fluorene ring system
• CPC Class Codes: C07C 13/66 the condensed ring system contains only four rings
• CPC Class Codes: C07C 15/24 containing two rings
• CPC Class Codes: C07C 15/38 containing four rings
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1007 Non-condensed systems
• CPC Class Codes: C09K 2211/1011 Condensed systems
• 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 2102/103 comprising indium oxides, e.g. ITO
• 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 85/10 Organic polymers or oligomers
• CPC Class Codes: H10K 85/111 comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/115 Polyfluorene; Derivatives thereof
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/60 Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/622 containing four rings, e.g. pyrene
• CPC Class Codes: Y10S 428/917 : Electroluminescent

Abstract

A device is provided, having an anode, a cathode, and two adjacent organic layers disposed between the anode and the cathode. One organic layer is a phosphorescent emissive material. The other organic layer may comprise an aromatic hydrocarbon material, comprising an aromatic non-heterocyclic hydrocarbon core optionally substituted, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, substituted aryl, substituted heteroaryl and heterocyclic groups. The second organic layer may comprise a material having a molecular 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 luminance of about 100 to about 1000 cd m².

Claims

1. A device, comprising:

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

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 aromatic hydrocarbon material having the structure;

wherein;

R₁₄, R₁₉, and R₂₀-R₂₅ each represents no substitution, mono-, di-, or tri- or tetra-substitution, and R₁₅-R₁₈ each represent no substitution, mono-, di-, tri-substitution, and

each R substituent is the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl or the second organic layer comprises an aromatic hydrocarbon material has an unsubstituted structure selected from the group consisting of;

2. The device of claim 1, wherein the aromatic hydrocarbon material has a molecular dipole moment of less than about 2.0 debyes.

3. The device of claim 2, wherein the aromatic hydrocarbon material has a molecular dipole moment of zero.

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

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

6. The device of claim 1, wherein the aromatic hydrocarbon material has a highest occupied molecular orbital that is not more than 0.81 eV less than the highest occupied molecular orbital of the hole transporting material in the first organic layer.

7. The device of claim 6, wherein the aromatic hydrocarbon material has a molecular dipole moment less than about 2.0 debyes.

8. The device of claim 1, wherein 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 luminance of about 100 to about 1000 cd/m².

9. The device of claim 8, wherein the device has an unmodified external quantum efficiency of at least about 5% and a lifetime of at least about 1000 hours at an initial luminance of about 100 to about 1000 cd/m².

10. The device of claim 8, wherein the aromatic hydrocarbon material has a molecular dipole moment less than about 2.0 debyes.

11. The device of claim 8, wherein the aromatic hydrocarbon material has a zero molecular dipole moment.

12. The device of claim 8, wherein after 100 hours of operation at an initial luminance of 600 cd/m² at least about 90% of initial luminance is retained.

13. The device of claim 8, wherein after 1000 hours of operation at an initial luminance of 1000 cd/m² at least about 70% of initial luminance is retained.

14. A device, comprising:

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

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 aromatic material has the structure;

wherein;

R₁-R₁₀ each represent no substitution, mono-, di-, or tri-substitution, R₁₁-R₁₃, R₁₅-R₁₈, each represents no substitution, mono-, di-, or tri-substitution, and R₁₄, R₁₉, and R₂₀-R₂₅ each represents no substitution, mono-, di-, or tri- or tetra-substitution, and

and wherein R₁-R₂₅ are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, aryl, heteroalkyl, substituted aryl, substituted heteroaryl and heterocyclic groups;

or the unsubstituted structure;

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

16. The device of claim 14, wherein the aromatic material has a molecular dipole moment of less than about 2.0 debyes.

17. The device of claim 16, wherein the aromatic material has a molecular dipole moment of zero.

18. The device of claim 14, wherein the aromatic material includes only C and H atoms.

19. A device, comprising:

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

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 aromatic hydrocarbon material having an unsubstituted structure selected from the group consisting of;

20. The device of claim 19, wherein the second organic layer is in direct contact with the cathode.