Light-emitting device with organic layer doped with photoluminescent material

• US 6,515,314 B1
• Filed: 11/16/2000
• Issued: 02/04/2003
• Est. Priority Date: 11/16/2000
• Status: Expired due to Term

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: General Electric Company
• Inventors: Srivastava, Alok Mani, Duclos, Steven Jude, Duggal, Anil Raj
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): Fordé , Remmon R.
• Application Number:
  US09/713,394
• Time in Patent Office: 810 Days
• Field of Search: 257/87, 257/89, 257/90, 257/96, 257/98, 257/100, 257/103, 257/184, 257/40, 257/13, 313/501, 313/503, 313/506, 313/507
• US Class Current: 257/184
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H10K 19/901 Assemblies of multiple devices comprising at least one organic element specially adapted for rectifying, amplifying, oscillating or switching
• CPC Class Codes: H10K 2102/331 Nanoparticles used in non-emissive layers, e.g. in packaging layer
• 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 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels

Abstract

A light-emitting device includes an anode, a cathode, and at least one organic electroluminescent (“EL”) material positioned between the anode and the cathode. Nanoparticles of at least one photoluminescent material are dispersed in the organic EL material. The organic EL material emits a first electromagnetic (“EM”) radiation having a first spectrum in response to an applied electrical field. The PL material absorbs a portion of the first EM radiation emitted by the organic EL material and emits a second EM radiation having a second spectrum. A plurality of the light-emitting devices are arranged on a transparent substrate to provide a panel display or a lighting source.

Claims

1. A light-emitting device comprising:

an anode;

a cathode; and

at least one organic electroluminescent (“

EL”

) material disposed between the anode and the cathode, the organic EL material having a plurality of nanoparticles of at least one inorganic photoluminescent (“

PL”

) material dispersed therein, the organic EL material being capable of emitting a first electromagnetic (“

EM”

) radiation having a first spectrum in response to an electrical voltage applied through the anode and the cathode, and the inorganic PL material being capable of absorbing a portion of the first EM radiation and emitting a second EM radiation having a second spectrum.

2. The light-emitting device of claim 1 wherein the anode, the cathode, and the organic EL material are formed as successive layers on a substantially transparent substrate.

3. The light-emitting device of claim 1 wherein the first spectrum has a range of shorter wavelengths than the second spectrum.

4. The light-emitting device of claim 1 wherein the first spectrum has a range of longer wavelengths than the second spectrum.

5. The light-emitting device of claim 3 wherein the first EM radiation has a wavelength in the range from about 100 nm to about 480 nm and the second EM radiation has a wavelength in the range from about 400 nm to about 770 nm.

6. The light-emitting device of claim 5 wherein the organic EL material is capable of emitting EM radiation having a wavelength range from about 100 nm to about 480 nm and comprises a material selected from the group consisting of poly(N-vinylcarbazole);

poly(alkylfluorene);

poly(paraphenylene);

polysilane;

1,3,5-tris[N-(4-diphenylaminophenyl)phenylamino] benzene;

anthracene;

phenylanthracene;

tetraarylethene;

coumarin;

rubrene;

tetraphenylbutadiene;

perylene;

coronene;

aluminum acetoacetonate;

gallium acetoacetonate;

indium acetoacetonate;

scandium acetoacetonate;

aluminum alkylphenoxide;

gallium alkylphenoxide;

indium alkylphenoxide;

scandium alkylphenoxide;

derivatives thereof; and

mixtures thereof.

7. The light-emitting device of claim 6 wherein the organic EL material comprises a material selected from the group consisting of poly(N-vinylcarbazole), poly(alkylfluorene) and polysilanes.

8. The light-emitting device of claim 5 wherein said at least one inorganic PL material is capable of absorbing EM radiation having a wavelength range from about 100 nm to about 480 nm and capable of emitting EM radiation having a wavelength range from about 400 nm to about 770 nm;

said at least one inorganic PL material is selected from the group consisting of yttrium aluminum oxide garnet Y₃Al₅O₁₂, (Y<sub>1−

x−

y</sub>Gd_xCe_y)₃Al₅O₁₂, (Y<sub>1−

x</sub>Ce_x)₃(Al<sub>1−

y</sub>Ga_y)O₁₂, (Y<sub>1−

x−

y</sub>Gd_xCe_y)(Al<sub>5−

z</sub>Ga_z)O₁₂, (Gd<sub>1−

x</sub>Ce_x)Sc₂Al₃O₁₂, wherein 0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

5 and x+y≦

1;

Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺;

GdBO₃;

Ce³⁺, Tb³⁺;

CeMgAl₁₁O₁₉;

Y₂SiO₅;

Ce³⁺,Tb³⁺;

BaMg₂Al₁₆O₂₇;

Eu ²⁺,Mn²⁺;

Y₂O₃;

Bi³⁺,Eu³⁺;

SrMgP₂O₇;

Eu²⁺,Mn²⁺;

(Y,Gd)(V,B)O₄;

Eu³⁺;

3.5MgO.0.5MgF₂GeO₂;

Mn⁴⁺;

BaMg₂Al₁₆O₂₇;

Eu²⁺; and

Sr₅(PO₄)₁₀Cl₂;

Eu²⁺.

9. The light-emitting device of claim 5 wherein the anode is made of a material selected from the group consisting of indium tin oxide, tin oxide, indium oxide, zinc oxide, indium zinc oxide, and mixtures thereof.

10. The light-emitting device of claim 5 wherein the cathode is made of a material selected from the group consisting of K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn, Zr, alloys thereof, and mixtures thereof.

11. The light-emitting device of claim 1 further comprising a hole injection enhancement material disposed between the anode and the organic EL material.

12. The light-emitting device of claim 11 further comprising at least one PL material dispersed in the hole injection enhancement material.

13. The light-emitting device of claim 11 wherein the hole injection enhancement material is selected from the group consisting of 3,4,9,10-perylenetetra-carboxylic dianhydride;

bis(1,2,5-thiadiazolo)-p-quinobis(1,3-dithiole); and

mixtures thereof.

14. The light-emitting device of claim 13 further comprising a hole transport material disposed between the hole injection enhancement material and the organic EL material.

15. The light-emitting device of claim 14 further comprising at least one PL material dispersed in the hole transport material.

16. The light-emitting device of claim 14 wherein the hole transport material comprises a material selected from the group consisting of 3,4,9,10-perylenetetra-carboxylic dianhydride;

bis(1,2,5-thiadiazolo)-p-quinobis(1,3-dithiole); and

mixtures thereof.

17. The light-emitting device of claim 1 further comprising an electron injection enhancement and transport material disposed between the cathode and the organic EL layer.

18. The light-emitting device of claim 17 further comprising at least one PL material dispersed in the electron injection enhancement and transport material.

19. The light-emitting device of claim 15 wherein the electron injection enhancement and transport material comprises a material selected from the group consisting of tris(8-quinolinolato)aluminum, oxadiazole derives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, and mixtures thereof.

20. The light-emitting device of claim 1 wherein the organic EL material having the PL nanoparticles dispersed therein is applied on the anode by a method selected from the group consisting of spin coating, spray coating, dip coating, roller coating, and ink-jet printing.

21. The light-emitting device of claim 20 wherein the organic EL material having the PL nanoparticles dispersed therein is applied on the anode by ink-jet printing.

22. The light-emitting device of claim 11 wherein the hole injection enhancement material is applied on the anode by a method selected from the group consisting of spin coating, spray coating, dip coating, roller coating, ink-jet printing, and chemical vapor deposition.

23. The light-emitting device of claim 22 wherein the hole injection enhancement material is applied on the anode by ink-jet printing.

24. The light-emitting device of claim 14 wherein the hole transport material is applied on the hole injection enhancement material by a method selected from the group consisting of spin coating, spray coating, dip coating, roller coating, ink-jet printing, and chemical vapor deposition.

25. The light-emitting device of claim 24 wherein the hole transport material is applied on the hole injection enhancement material by ink-jet printing.

26. The light-emitting device of claim 17 wherein the electron injection enhancement and transport material is applied on the organic EL material by a method selected from the group consisting of spin coating, spray coating, dip coating, roller coating, ink-jet printing, and chemical vapor deposition.

27. The light-emitting device of claim 17 wherein the electron injection enhancement and transport material is applied on the organic EL material by ink-jet printing.

28. The light-emitting device of claim 2 wherein at least two organic EL materials, each having nanoparticles of at least one PL material dispersed therein, are disposed as distinct and adjacent layers between the anode layer and the cathode layer.