Organic electroluminescent device and manufacturing method therefor

• US 20020039730A1
• Filed: 03/19/2001
• Published: 04/04/2002
• Est. Priority Date: 03/21/2000
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Morii, Katsuyuki
• Granted Patent: US 6,853,130 B2
• Time in Patent Office: Days
• US Class Current: 435/6
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H10K 50/826 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/844 Encapsulations

Abstract

An anode, a light-emitting layer, and a cathode, which has a structure formed by sequentially laminating from the light-emitting layer side a first cathode composed of a material having a work function of 3.0 eV or less and a second cathode composed of a material having a work function higher than that of the first cathode so that the total thickness of the first and the second cathodes is 100 angstroms or less, are stacked on a substrate 1, and light is emitted to the outside via at least the cathode.

Claims

1. An organic electroluminescent device comprising an anode, a light-emitting layer composed of an organic material, and a cathode having a structure in which a first cathode composed of a material having a work function of 3.0 eV or less and a second cathode composed of a material having a work function higher than that of the first cathode are sequentially stacked from the light-emitting layer side are stacked on a substrate, the total thickness of the first and the second cathodes being 100 angstroms or less, and light is emitted to the outside via at least the cathode.

2. An organic electroluminescent device according to claim 1, wherein the cathode side is sealed by a sealing layer composed of a light transmissive material.

3. An organic electroluminescent device according to claim 1, wherein the first cathode comprises Ca.

4. An organic electroluminescent device according to claim 1, wherein the thickness y (angstrom) of the first cathode is such that 50≦

y≦

80 holds.

5. An organic electroluminescent device according to claim 1, wherein the thickness y (angstrom) of the first cathode is such that 55≦

y≦

65 holds.

6. An organic electroluminescent device according to claim 1, wherein the second cathode comprises Al.

7. An organic electroluminescent device according to claim 1, wherein the thickness z (angstrom) of the second cathode is such that 10≦

z≦

20 holds.

8. An organic electroluminescent device according to one of claims 1 to 7, wherein the organic material forming the light-emitting layer is a polymeric material.

9. A method for manufacturing an organic electroluminescent device, comprising:

a step of forming an anode on a substrate;

a step of forming a light-emitting layer composed of an organic material above the anode; and

a step of forming a cathode above the light-emitting layer by laminating a first cathode composed of a material having a work function of 3.0 eV or less and a second cathode composed of a material having a work function higher than that of the first cathode from the light-emitting layer side so that the total thickness of the first and the second cathodes is 100 angstroms or less.

10. A method for manufacturing an organic electroluminescent device according to claim 9, wherein the step of forming the anode further comprises a step of performing an oxygen or an air plasma treatment after an electrode film is formed, and a current x and a time t in the treatment are set such that 10 (mA)≦

x≦

15 (mA) and 5 (minute)≦

t≦

7 (minute) hold.

11. A method for manufacturing an organic electroluminescent device according to claim 9, wherein the step of forming the anode further comprises a step of performing at oxygen or an air plasma treatment after an electrode film is formed, and a current x and a time t in the treatment are set such that 10 (mA)≦

x≦

12 (mA) and t=5 (minute) hold.