Organic electroluminescent device based upon emission of exciplexes or electroplexes, and a method for its fabrication

• US 20050048310A1
• Filed: 07/12/2002
• Published: 03/03/2005
• Est. Priority Date: 07/13/2001
• Status: Abandoned Application

• Current Assignee: Consiglio Nazionale Delle Ricerche (Repubblica Italiana)
• Original Assignee: Consiglio Nazionale Delle Ricerche (Repubblica Italiana)
• Inventors: Marco, Piergiulio Di, Kalinowski, Jan, Giro, Gabriele, Cocchi, Massimo, Fattori, Valeria
• Application Number:
  US10/483,893
• Publication Number:
  US 20050048310A1
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/636 comprising heteroaromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

An organic electroluminescent device (1) based upon emission of exciplexes or electroplexes, the device basically including an anode (2), a cathode (3), a first layer (4), which comprises organic material for transporting positive charges (5), and a second layer (6), which comprises organic material for transporting negative charges (7), said organic material for transporting negative charges (7) and said organic material for transporting positive charges (5) being capable to form between them exciplexes or electroplexes.

Claims

1. An organic electroluminescent device (1) based upon emission of exciplexes or electroplexes, said organic electroluminescent device (1) basically including an anode (2), a cathode (3), a first layer (4), which comprises at least one organic material for transporting positive charges (5) and is set in contact with the anode (2), and a second layer (6), which comprises at least one organic material for transporting negative charges (7) and is set in contact with said cathode (3) and with said first layer (4), said organic material for transporting negative charges (7) and said organic material for transporting positive charges (5) being capable to form between them exciplexes or electroplexes.

2. The device of claim 1, wherein said anode (2) is substantially transparent.

3. The device of claim 2, and comprising a transparent substrate (9) set in contact with said anode (2).

4. The device of claim 2, wherein said anode (2) comprises indium and tin oxides (ITOs).

5. The device of claim 3, wherein said transparent substrate (9) is a sheet of glass.

6. The device of claim 1, wherein said organic material for transporting negative charges (7) has a first ionization potential, and said organic material for transporting positive charges (8) has a second ionization potential, said first ionization potential being higher by at least 0.7 electronvolts than the second ionization potential.

7. The device of claim 1, wherein said organic material for transporting negative charges (7) has a first electronic affinity, and said organic material for transporting positive charges (5) has a second electronic affinity, said first electronic affinity being higher by at least 0.4 electronvolts than said second electronic affinity.

8. The device of claim 1, wherein said material for transporting positive charges (5) is substantially made up of a tertiary aromatic amine for transporting positive charges, said tertiary aromatic amine satisfying the structural formula:

11. The device of claim 8, wherein A represents an aryl group that satisfies a structural formula chosen in the group consisting of:

12. The device of claim 8, wherein said tertiary aromatic amine is chosen in the group consisting of

4,4′

,4″

-tri(N-3-methylphenyl-N-phenyl-amino)-triphenylamine (M-TDATA),

4,4′

,4″

-tri(N,N-diphenyl-amino)-triphenylamine (TDATA), or

4,4′

,4″

-tri(carbazol-9-yl)-triphenylamine (TCTA).

13. The device of claim 1, wherein said material for transporting negative charges (7) is essentially made up of a heterocyclic compound that satisfies one chosen from among the structural formulas:

14. The device of claim 13, wherein E¹, E², E³, E⁴ and E⁵ represent, each independently of the others, a substituent that satisfies one chosen from among the following structural formulas:

15. The device of claim 13, wherein said heterocyclic compound is chosen in the group consisting of:

3,5-bi(4-ter-butyl-phenyl)-4-phenyl-triazole (TAZ), or

3-(4-diphenylyl)-4-phenyl-5-ter-butylphenyl-1,2,4-triazole (PBD).

16. The device of claim 1, in which said cathode (3) comprises a metal chosen in the group consisting of:

alkaline metals, or

alkaline-earth metals.

9. The device of claim, wherein T¹ and T² represent, each independently of the other, a tertiary amine that satisfies a structural formula chosen in the group consisting of:

10. The device of claim, wherein Ar¹ and Ar² represent, each independently of the other, a functionality that satisfies a structural formula chosen in the group consisting of:

17. A method for the fabrication of an organic electroluminescent device (1) based upon emission of exciplexes or electroplexes, said method including basically the steps of:

depositing on an anode (2) a first layer (4) comprising at least one organic material for transporting positive charges (5);

depositing on said first layer (4) a second layer (6) comprising an organic material for transporting negative charges (7);

positioning on said second layer (6) a cathode (3), said organic material for transporting negative charges (7) and said organic material for transporting positive charges (5) being capable to form between them exciplexes or electroplexes.

18. The device of claim 17, wherein said organic material for transporting positive charge (5) and of said organic material for transporting negative charge (7) are chosen so as to obtain selectively a pre-set wavelength of the emission of exciplexes or electroplexes.

19. The device of claim 17, and comprising the step of positioning said anode (2) on a transparent substrate (9).

20. The device of claim 17, wherein said organic material for transporting negative charges (7) has a first ionization potential and said organic material for transporting positive charges (5) has a second ionization potential, said first ionization potential being higher by at least 0.7 electronvolts than said second ionization potential.

21. The device of claim 17, wherein said organic material for transporting negative charges (7) has a first electronic affinity and said organic material for transporting positive charges (5) has a second electronic affinity, said first electronic affinity being higher by at least 0.4 electronvolts than said second electronic affinity.

22. The device of claim 17, wherein said material for transporting positive charges (5) is substantially made up of a tertiary aromatic amine for transporting positive charges, said tertiary aromatic amine satisfying the structural formula:

23. The device of claim 17, wherein said material for transporting negative charges (7) is substantially made up of a heterocyclic compound that satisfies one chosen from among the structural formulas: