Electroluminescent materials

• US 6,717,354 B1
• Filed: 07/30/2001
• Issued: 04/06/2004
• Est. Priority Date: 02/01/1999
• Status: Expired due to Fees

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: South Bank University Enterprises Limited (London South Bank University)
• Inventors: Kathirgamanathan, Poopathy
• Primary Examiner(s): Patel, Ashok
• Assistant Examiner(s): Phinney, Jason
• Application Number:
  US09/890,431
• Time in Patent Office: 981 Days
• Field of Search: 313/503, 313/504, 428/690, 428/917
• US Class Current: 313/503
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/351 Metal complexes comprising lanthanides or actinides, e.g. comprising europium
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

An electroluminescent material which can form electroluminescent devices which emit light in the ultra-violet region of the spectrum which comprises an organic metallic complex of a transition metal, lanthanide or actinide and a polyamine ligand particularly gadolinium ethylenediaminetetraacetate sodium salt, Na[Gd(EDTA)] and gadolinium europium ethylenediaminetetraacetate salts Gd[Eu(EDTA)]₃.

Claims

1. An electroluminescent material which emits light in the ultra-violet region of the spectrum which comprises an organic metallic complex having a formula Ln*[Ln(polyamine)]₃ wherein Ln and Ln* are the same or different and are selected from the group consisting of transition metals, lanthanides and actinide, and wherein the polyamine is selected from the group consisting of ethylene diamine tetramine, DCTA, DTPA and TTHA.

2. An electroluminescent material as claimed in claim 1 in which Ln and Ln* are selected from the group consisting of Gd, Sm, Eu, Tb and Dy.

3. An electroluminescent material as claimed in claim 1 wherein the complex is Gd[Eu(EDTA)]₃.

14. An electroluminescent material as claimed in claim 1 wherein the organic metallic complex comprises gadolinium in the III state.

4. An electroluminescent device which comprises sequentially (i) a first electrode comprising a transparent conductive substrate (ii) a layer of an electroluminescent material which emits light in the ultra-violet region of the spectrum and which comprises an organic metallic complex selected from the group consisting of Gd[Ln(polyamine)]₃ and M[Gd(polyamine)] wherein M is an alkali metal and wherein Ln is selected from the group consisting of a transition metal, lanthanide and actinide and (iv) a metal electrode.

5. An electroluminescent device as claimed in claim 4 in which the transparent substrate is a conductive glass or plastic material which acts as the anode.

6. An electroluminescent device as claimed in claim 4 in which there is a hole transporting material mixed with the electroluminescent material in a ratio of 5 to 95% of the electroluminescent material to 95 to 5% of the hole transporting material.

7. An electroluminescent device as claimed in claim 4 in which the hole transporting material is an aromatic amine complex.

8. An electroluminescent device as claimed in claim 4 in which the hole transporting material is selected from the group consisting of poly(vinylcarbazole), N,N′

diphenyl-N,N′

-bis(3-methylphenyl)-1,1′

-biphenyl-4,4′

-diamine (TPD) and polyaniline.

9. An electroluminescent device as claimed in claim 4 in which an electron injecting material is mixed with the electroluminescent material and co-deposited with it.

10. An electroluminescent device as claimed in claim 9 in which the electron injecting material is selected from the group consisting of a metal complex oxadiazole and an oxadiazole derivative.

11. An electroluminescent device as claimed in claim 10 in which the electron injecting material is selected from the group consisting of an aluminum quinolate and 2-(4biphenyl)-5-(4-tert-butylphenyl)-1,3,4 oxadiazole.

12. An electroluminescent device as in claim 4 in which the metal electrode includes at least one selected from the group consisting of aluminum alloy, magnesium alloy, lithium alloy, calcium alloy and magnesium silver alloy.

13. An electroluminescent device as claimed in claim 4 in which there is at least one layer which incorporates a dye which fluoresces in ultra-violet light to give emitted light in the color spectrum.

15. An electroluminescent device as claimed in claim 4 wherein the organic metallic complex comprises gadolinium in the III state.

16. An electroluminescent device as claimed in claim 15 in which the complex is in the form of a salt.

17. An electroluminescent device as claimed in claim 15 in which the complex is in the form of an alkali metal salt.

18. An electroluminescent device as claimed in claim 4 in which the electroluminescent material is in the form of the salt of formula Gd[Ln(EDTA)]₃.

19. An electroluminescent device as claimed in claim 18 in which Ln is selected from the group consisting of Gd, Sm, Eu, Tb and Dy.

20. An electroluminescent device as claimed in claim 4 in which the complex is Gd[Eu(EDTA)]₃.