Organic light-emitting device comprising buffer layer and method for fabricating the same

• US 20060038484A1
• Filed: 08/19/2005
• Published: 02/23/2006
• Est. Priority Date: 12/31/1999
• Status: Active Grant

• Current Assignee: Jeoung Kwen Noh, Min Soo Kang, Se Hwan Son, Young Chul Lee, Yun Hye Hahm
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Kang, Min Soo, Son, Se Hwan, Lee, Young Chul, Hahm, Yun Hye, Noh, Jeoung Kwen
• Granted Patent: US 7,763,882 B2
• Time in Patent Office: Days
• US Class Current: 313/499
• CPC Class Codes: C07D 487/16 Peri-condensed systems
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1074 containing more than three nitrogen atoms as heteroatoms
• 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 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 85/311 Phthalocyanine
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/626 containing more than one polycyclic condensed aromatic rings, e.g. bis-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 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

Disclosed herein are an organic light-emitting device having a structure formed by the sequential deposition of a substrate, a first electrode, at least two organic layers and a second electrode, in which the organic layers include a light-emitting layer, and one of the organic layers, which is in contact with the second electrode, is a buffer layer comprising a compound represented by the following formula 1, as well as a fabrication method thereof:
wherein R¹ to R⁶ have the same meanings as defined in the specification. The buffer layer makes it possible to minimize or prevent damage to the organic layer, which can occur when forming the second electrode on the organic layer.

Claims

1. An organic light-emitting device comprising a substrate, a first electrode, at least two organic layers and a second electrode in the sequentially laminated form, in which the organic layers include a light-emitting layer, and one of the organic layers, which is in contact with the second electrode, is a buffer layer comprising a compound represented by the following formula 1:

wherein R¹ to R⁶ are each independently selected from the group consisting of hydrogen, halogen atoms, nitrile (—

CN), nitro (—

NO₂), sulfonyl (—

SO₂R), sulfoxide (—

SOR), sulfonamide (—

SO₂NR), sulfonate (—

SO₃R), trifluoromethyl (—

CF₃), ester (—

COOR), amide (—

CONHR or —

CONRR′

), substituted or unsubstituted straight or branched chain C₁-C₁₂ alkoxy, substituted or unsubstituted straight or branched C₁-C₁₂ alkyl, substituted or unsubstituted aromatic or non-aromatic heterocyclic rings, substituted or unsubstituted aryl, substituted or unsubstituted mono- or di-arylamine, and substituted or unsubstituted aralkylamine, and R and R′

are each independently selected from the group consisting of substituted or unsubstituted C₁-C₆₀ alkyl, substituted or unsubstituted aryl, and substituted or unsubstituted 5-7 membered heterocyclic rings.

2. The organic light-emitting device of claim 1, wherein the compound of formula 1 is selected from compounds represented by the following formulas 1-1 to 1-6:

3. The organic light-emitting device of claim 1, wherein the organic light-emitting device is a top emission type or both-side emission type light-emission device.

4. The organic light-emitting device of claim 1, wherein the second electrode is formed by thin-film formation technology capable of causing damage to the organic layer in the absence of the buffer layer comprising the compound of formula 1 by involving charges or particles with high kinetic energy.

5. The organic light-emitting device of claim 4, wherein the thin-film formation technology is selected from the group consisting of sputtering, physical vapor deposition (PVD) using a laser, and ion-beam assisted deposition.

6. The organic light-emitting device of claim 1, wherein the first electrode is a cathode, the second electrode is an anode, and the device is fabricated by forming the cathode on the substrate and then sequentially forming the organic layers and the anode on the cathode.

7. The organic light-emitting device of claim 1, wherein the second electrode is made of a conductive oxide film or metal having work function of 2-6 eV.

8. The organic light-emitting device of claim 7, wherein the second electrode is made of ITO (indium tin oxide).

9. The organic light-emitting device of claim 7, wherein the second electrode is made of IZO (indium zinc oxide).

10. The organic light-emitting device of claim 1, wherein an thin oxide film having an insulating property is additionally formed between the second electrode and the buffer layer.

11. The organic light-emitting device of claim 1, wherein the buffer layer also serves as a hole injection layer.

12. The organic light-emitting device of claim 1, wherein the buffer layer comprising the compound of formula 1 has a thickness of equal to or more than 20 nm.

13. The organic light-emitting device of claim 1, wherein the organic layers include an electron transport layer and the electron transport layer comprising a material having a group selected from the group consisting of imidazole, oxazole and thiazole.

14. The organic light-emitting device of claim 13, wherein the electron transport layer comprising a compound selected from the group consisting a compound of the formula 2 below and a compound of the formula 3 below:

wherein, R⁷ and R⁸ are each independently selected from the group consisting of hydrogen, aliphatic hydrocarbons of 1-20 carbon atoms, and aromatic heterocyclic rings or aromatic rings, provided that R⁷ and R⁸ is not hydrogen concurrently;

Ar is selected from the group consisting of aromatic heterocyclic rings or aromatic rings;

R⁹ is selected from the group consisting of hydrogen, aliphatic hydrocarbons having 1-6 carbon atoms, and aromatic heterocyclic rings or aromatic rings; and

X is selected from the group consisting of O, S and NR¹⁰ wherein R¹⁰ is selected from the group consisting of hydrogen, aliphatic hydrocarbons of 1-7 carbon atoms, and aromatic heterocyclic rings or aromatic rings.

wherein n is an integer of from 3 to 8;

Z is O, S or NR;

R and R′

are individually hydrogen;

alkyl of 1-24 carbon atoms;

aryl or hetero-atom substituted aryl of 5-20 carbon atoms;

or halo;

or atoms necessary to complete a fused aromatic ring;

B is a linkage unit consisting of alkyl, aryl, substituted alkyl, or substituted aryl, which conjugatedly or unconjugately connects the multiple benzazoles together.

15. The organic light-emitting device of claim 13, wherein an electron injection layer is formed between the first electrode and the electron transport layer.

16. The organic light-emitting device of claim 15, wherein the electron injection layer is a LiF layer.

17. A method for fabricating an organic light-emitting device, comprising the step of sequentially laminating a first electrode, at least two organic layers and a second electrode on a substrate, in which one of the organic layers is formed as a light-emitting layer, and one of the organic layers, which is in contact with the second electrode, is formed from a compound represented by the following formula 1:

wherein R¹ to R⁶ are each independently selected from the group consisting of hydrogen, halogen atoms, nitrile (—

CN), nitro (—

NO₂), sulfonyl (—

SO₂R), sulfoxide (—

SOR), sulfonamide (—

SO₂NR), sulfonate (—

SO₃R), trifluoromethyl (—

CF₃), ester (—

COOR), amide (—

CONHR or —

CONRR′

), substituted or unsubstituted straight or branched chain C₁-C₁₂ alkoxy, substituted or unsubstituted straight or branched C₁-C₁₂ alkyl, substituted or unsubstituted aromatic or non-aromatic heterocyclic rings, substituted or unsubstituted aryl, substituted or unsubstituted mono- or di-arylamine, and substituted or unsubstituted aralkylamine, and R and R′

are each independently selected from the group consisting of substituted or unsubstituted C₁-C₆₀ alkyl, substituted or unsubstituted aryl, and substituted or unsubstituted 5-7 membered heterocyclic rings.

18. The method of claim 17, wherein the second electrode is formed by thin-film formation technology capable of causing damage to the organic layer in no presence of the buffer layer comprising the compound of formula I by involving charges or particles having high kinetic energy.