White light emitting organic electroluminescent device and method for fabricating the same

• US 6,759,145 B2
• Filed: 11/27/2001
• Issued: 07/06/2004
• Est. Priority Date: 10/18/2001
• Status: Expired due to Fees

• Current Assignee: Opto Tech Corporation (OptoTech Corp.)
• Original Assignee: Opto Tech Corporation (OptoTech Corp.)
• Inventors: Lin, San Bao, Lin, Ming-Der, Chuang, Feng-Ju
• Primary Examiner(s): Garrett, Dawn L.
• Application Number:
  US09/993,682
• Publication Number:
  US 20030099860A1
• Time in Patent Office: 952 Days
• Field of Search: 428/690, 428/917, 428/66, 428/212, 313/502, 313/504, 313/506, 427/66
• 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 50/14 Carrier transporting layers
• CPC Class Codes: H10K 85/146 poly N-vinylcarbazol; Derivatives thereof
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/341 Transition metal complexes, e.g. Ru(II)polypyridine complexes H10K85/331 takes precedence
• 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 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

The present invention discloses a white light emitting organic electroluminescent (EL) device and a method for fabricating the same. The device comprises: a substrate; an anode formed on the substrate; at least one hole transporting layer formed on the anode; at least one luminescent layer (DPVBi) formed on the hole transporting layer, wherein a first dopant (DCM₂) is doped into the luminescent layer; at least one electron transporting layer formed on the luminescent layer, wherein a second dopant (C₆) is doped into the electron transporting layer; and a cathode formed on the electron transporting layer; wherein a first light (red) is emitted by the first dopant, a second light (green) is emitted by the second dopant, and a third light (blue) is emitted by the luminescent layer when the device is applied with a bias voltage.

Claims

1. A white light emitting organic electroluminescent organic (EL) device comprising:

a substrate;

an anode formed on said substrate;

at least one hole transporting layer formed on said anode;

at least one luminescent layer formed on said hole transporting layer, wherein a first dopant is doped into said luminescent layer;

at least one electron transporting layer formed on said luminescent layer, wherein a second dopant is doped into said electron transporting layer; and

,

a cathode formed on said electron transporting layer;

wherein a first light is emitted by said first dopant, a second light is emitted by said second dopant, and a third light is emitted by said luminescent layer when the device is applied with a bias voltage; and

,

wherein the luminescence intensity of said second light and said third light is proportional to the volume ratio of said first dopant to said luminescent layer.

2. The organic EL device as recited in claim 1, wherein the volume ratio of said first dopant to said luminescent layer is in the range from 0.04% to 0.01%.

3. The organic EL device as recited in claim 2, wherein the volume ratio of said first dopant to said luminescent layer is preferably 0.025%.

4. A white light emitting organic electroluminescent organic (EL) device comprising:

a substrate;

an anode formed on said substrate;

at least one hole transporting layer formed on said anode;

at least one luminescent layer formed on said hole transporting layer, wherein a first dopant is doped into said luminescent layer;

at least one electron transporting layer formed on said luminescent layer, wherein a second dopant is doped into said electron transporting layer; and

,

a cathode formed on said electron transporting layer;

wherein a first light is emitted by said first dopant, a second light is emitted by said second dopant, and a third light is emitted by said luminescent layer when the device is applied with a bias voltage; and

,

wherein the luminescence intensity of said third light is proportional to the thickness of said luminescent layer and the luminescence intensity of said second light is in inverse proportion to the thickness of said luminescent layer.

5. A white light, organic electroluminescent (EL) device, comprising:

a substrate;

an anode formed on said substrate;

at least one hole transporting layer formed on said anode;

at least one luminescent layer formed on said hole transporting layer, wherein a first dopant is doped into said luminescent layer;

at least one electron transporting layer formed on said luminescent layer, wherein a second dopant is doped into said electron transporting layer; and

a cathode formed on said electron transporting layer;

wherein a first light is emitted by said first dopant, a second light different in color from said first light is emitted by said second dopant, and a third light different in color from said second light is emitted by said luminescent layer when the device is applied with a bias voltage, said first light being red light, said second light being green light, and said third light being blue light.

6. A white light organic electroluminescent (EL) device, comprising:

a substrate;

an anode formed on said substrate;

at least one hole transporting layer formed on said anode;

at least one luminescent layer formed on said hole transporting layer, wherein a first dopant is doped into said luminescent layer, said luminescent layer being selected from the group consisting of;

DPVBi, Balq, PVK, Zn(ODZ)₂, and a combination thereof;

at least one electron transporting layer formed on said luminescent layer, wherein a second dopant is doped into said electron transporting layer; and

a cathode formed on said electron transporting layer;

wherein a first light is emitted by said first dopant, a second light different in color from said first light is emitted by said second dopant, and a third light different in color from said second light is emitted by said luminescent layer when the device is applied with a bias voltage, said third light being blue light.

7. A method for fabricating a white light emitting organic electroluminescent (EL) device, comprising the steps of:

providing a substrate;

forming, in sequence from substrate up, an anode, at least one hole transporting layer, at least one luminescent layer, at least one electron transporting layer, and a cathode;

doping a first dopant into said luminescent layer; and

doping a second dopant into said electron transporting layer;

wherein a first light is emitted by said first dopant, a second light is emitted by said second dopant, and a third light is emitted by said luminescent layer when the device is applied with a bias voltage; and

,

wherein said luminescent layer is DPVBi for emitting blue light, said first dopant is DCM₂ for emitting red light, said second dopant includes a coumarin 6 dye material for emitting green light.

8. The method as recited in claim 7, wherein the luminescence intensity of green light and blue light depends on the ratio of DCM₃ to DPVBi.

9. A method for fabricating a white light emitting organic electroluminescent (EL) device, comprising the steps of:

providing a substrate;

forming, in sequence from substrate up, an anode, at least one hole transporting layer, at least one luminescent layer, at least one electron transporting layer, and a cathode;

doping a first dopant into said luminescent layer; and

doping a second dopant into said electron transporting layer;

wherein a first light is emitted by said first dopant, a second light is emitted by said second dopant, and a third light is emitted by said luminescent layer when the device is applied with a bias voltage; and

,

wherein the luminescence intensity of said second light and said third light depends on the thickness of said luminescence layer, wherein the luminescence intensity of said second light gets weaker and the luminescence intensity of said third light gets stronger as the thickness of said luminescent layer increases.