Stacked organic light emitting device having high efficiency and high brightness

• US 8,951,645 B2
• Filed: 04/07/2005
• Issued: 02/10/2015
• Est. Priority Date: 04/09/2004
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Lee, Young Chul, Hahm, Yun Hye, Jeong, Dong Seob, Jang, Jun Gi, Jeong, Ji Weon, Noh, Jeoung Kwen
• Primary Examiner(s): CLARK, GREGORY D
• Application Number:
  US11/547,669
• Publication Number:
  US 20070221912A1
• Time in Patent Office: 3,596 Days
• Field of Search: 428/690, 428/917, 313/504, 313/505, 313/506, 257/40, 257/E51.05, 257/E51.026, 257/E51.032
• US Class Current: 428/690
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: H10K 85/731 Liquid crystalline materials
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

A stacked organic light emitting device that includes an anode connected to an external power source, a cathode connected to the external power source, at least two light emitting sections aligned between the anode and the cathode, including a light emitting layer, and an internal electrode aligned between the light emitting sections. The internal electrode is a single-layered internal electrode which is made from one selected from the group consisting of a metal, alloys of the metal, and metal oxides thereof, having a work function below 4.5 eV, each light emitting section includes an organic material layer containing an organic material having an electron affinity above 4 eV, and the organic material layer is formed between the light emitting layer of the light emitting section and the electrode facing the anode connected to the external power source in two electrodes which make contact with the light emitting section.

Claims

1. A stacked organic light emitting device comprising:

an anode connected to an external power source;

a cathode connected to the external power source;

at least two light emitting sections aligned between the anode and the cathode, each light emitting section including a light emitting layer; and

an internal electrode aligned between the light emitting sections, wherein

the internal electrode is a single-layered internal electrode consisting of a metal or a metal alloy, having a work function below 4.5 eV,

wherein one of the at least two light emitting sections includes an organic material layer containing an organic material having an electron affinity above 4 eV, and

wherein the organic material layer is formed between the light emitting layer of the one of the at least two light emitting sections and the internal electrode.

2. The stacked organic light emitting device as claimed in claim 1, wherein the organic material having the electron affinity above 4 eV is a compound having a chemical formula as shown below,

3. The stacked organic light emitting device as claimed in claim 2, wherein R₁ to R₆ are nitrile (—

CN).

4. The stacked organic light emitting device as claimed in claim 1, wherein the internal electrode is made from at least one selected from the group consisting of Al (4.28 eV), Ag (4.26 eV), Zn (4.33 eV), Nb (4.3 eV), Zr (4.05 eV), Sn (4.42 eV), Ta (4.25 eV), V (4.3 eV), Hg (4.49 eV), Ga (4.2 eV), In (4.12 eV), Cd (4.22 eV), B (4.4 eV), Hf (3.9 eV), La (3.5 eV), Ti (4.3 eV), Ca (2.87 eV), Mg (3.66 eV), Li (2.9 eV), Na (2.75 eV), K (2.3 eV), Cs, (2.14 eV), and alloys thereof.

5. The stacked organic light emitting device as claimed in claim 1, wherein each of the stacked light emitting sections has a light emission spectrum of a color selected from red, green, blue, and combination thereof, so that the stacked organic light emitting device is able to emit white light.

6. The stacked organic light emitting device as claimed in claim 1, wherein the stacked organic light emitting device is able to emit a white light of a wide range due to a micro-cavity effect.

7. The stacked organic light emitting device as claimed in claim 1, wherein the organic material having the electron affinity above 4 eV is one selected from the group consisting of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, fluoride 3,4,9,10-perylenetetracarboxylicdianhydride (PTCDA), cyano PTCDA, naphthalenetetracarboxylicdianhydride (NTCDA), fluoride NTCDA and cyano NTCDA.

8. The stacked organic light emitting device as claimed in claim 1 further comprising:

at least three light emitting sections, and

at least two internal electrodes.

9. The stacked organic light emitting device of claim 8,

wherein two of the at least three light emitting sections each includes a light emitting layer and an organic material layer, the organic material layer containing an organic material having an electron affinity above 4 eV, and

wherein each organic material layer is formed between the light emitting layer of the corresponding light emitting section and one of the at least two internal electrodes.

10. The stacked organic light emitting device of claim 1,

wherein all but one of the at least two light emitting sections each includes a light emitting layer and an organic material layer containing an organic material having an electron affinity above 4 eV, and

wherein each organic material layer is formed between the light emitting layer of the corresponding light emitting section and an internal electrode.

11. The stacked organic light emitting device of claim 1, wherein another of the at least two light emitting sections is located between the internal electrode and anode.

12. A display apparatus comprising a stacked organic light emitting device as claimed in claim 1.

13. The display apparatus as claimed in claim 12, wherein the internal electrode is made from at least one selected from the group consisting of AL (4.28 eV), Ag (4.26 eV), Zn (4.33 eV), Nb (4.3 eV), Zr (4.05 eV), Sn (4.42 Ev), Ta (4.25 eV) V (4.3 eV), Hg (4.49 eV), Ga (4.2 eV), In (4.12 eV) Cd (4.22 eC), B (4.4 eV), Hf (3.9 eV), La (3.5 eV), Ti (4.3 eV), Ca (2.87 eV), Mg (3.66 eV), Li (2.9 eV), Na (2.75 eV), K (2.3 eV), Cs, (2.14 eV), and alloys thereof.

14. The display apparatus as claimed in claim 12, wherein each of the stacked light emitting sections has a light emission spectrum of a color selected from red, green, blue, and combination thereof, so that the stacked organic light emitting device is able to emit white light.

15. The display apparatus as claim in claim 12, wherein the stacked organic light emitting device is able to emit a white light of a wide range due to a micro-cavity effect.

16. The display apparatus as claimed in claim 12, wherein the organic material having the electron affinity above 4 eV is a compound having a chemical formula as shown below,

17. The display of apparatus as claimed in claim 16, wherein R₁ to R₆ are nitrile (—

CN).

18. The display apparatus as claimed in claim 12, wherein the organic material having the electron affinity above 4 eV is one selected from the group consisting of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, fluoride 3,4,9,10-perylenetetracarboxylidianhydride (PTCDA), cyano PTCDA, naphthalenetetracarboxylicdianhydride (NTCDA), fluoride NTCDA and cyano NTCDA.