Organic electroluminescent device with chromophore dopants

• US 20050221116A1
• Filed: 03/28/2003
• Published: 10/06/2005
• Est. Priority Date: 03/29/2002
• Status: Abandoned Application

• Current Assignee: Consiglio Nazionale Delle Ricerche (Repubblica Italiana)
• Original Assignee: Consiglio Nazionale Delle Ricerche (Repubblica Italiana)
• Inventors: Cocchi, Massimo, Virgili, Dalia, Stampor, Waldemar, Giro, Gabriele, Di Marco, Piergiulio, Fattori, Valeria, Kalinowski, Jan
• Application Number:
  US10/509,111
• Publication Number:
  US 20050221116A1
• Time in Patent Office: Days
• 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 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: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

An organic electroluminescent device having an anode, a cathode, and an intermediate element, which is set between the anode and the cathode and contains hole-transporting organic material, electron-transporting organic material, and luminophore material; the electron-transporting organic material and the hole-transporting organic material being designed to form between them molecular complexes in an excited state (exciplexes or electroplexes); the luminophore material being designed to emit electromagnetic radiation and being supplied, in use, for transfer of energy from the molecular complexes in the excited state.

Claims

1. An organic electroluminescent device having an anode (2), a cathode (3), and an intermediate element (7), which is set between the anode (2) and the cathode (3) and comprises at least one hole-transporting organic material, and at least one electron-transporting organic material;

the electron-transporting organic material and the hole-transporting organic material being designed to form between them exciplexes or electroplexes;

the device (1) being characterized in that said intermediate element (7) comprises at least one luminophore material;

the luminophore material being designed to emit electromagnetic radiation;

the luminophore material being supplied, in use, for transfer of energy from said exciplexes or electroplexes.

2. The device of claim 1, wherein said intermediate element (7) essentially includes a first layer (4), which comprises the hole-transporting organic material and is set in contact with the anode (2), and a second layer (6), which comprises the electron-transporting organic material and is set in contact with said cathode (3) and said first layer (4).

3. The device of claim 2, wherein said first layer (4) comprises the luminophore material.

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

5. The device of claim 2, wherein said first layer (4) comprises polycarbonate (PC).

6. The device of claim 1, wherein said electron-transporting organic material has a first ionization potential and said hole-transporting organic material has a second ionization potential;

the first ionization potential being higher by at least 0.7 eV than the second ionization potential.

7. The device of claim 1, wherein said electron-transporting organic material has a first electronic affinity and said hole-transporting organic material has a second electronic affinity;

the first electronic affinity being higher by at least 0.4 eV than the second electronic affinity.

8. The device of claim 1, wherein said luminophore material comprises at least one metallocyclic compound, which satisfies the structural formula M L L′

L″

, in which M represents a transition metal, L, L′ and

L″

represent, each independently of the others, a chelating ligand, which satisfies the structural formula;

in which Y represents an electron-donor heteroatom.

9. The device of claim 8, wherein M represents iridium (Ir).

10. The device of claim 8, wherein M is positively formally charged.

11. The device of claim 1, wherein said luminophore material comprises at least one metallocyclic compound, which satisfies the structural formula M′

L L′

, in which M′

represents a transition metal, L and L′

represent, each independently of the other, a chelating ligand, which satisfies the structural formula;

in which Y represents an electron-donor heteroatom;

M′

representing a transition metal chosen in the group consisting of;

platinum (Pt); and

palladium (Pd).

12. The device of claim 11, wherein M′

is positively formally charged.

13. The device of claim 8, wherein the chelating ligands L, L′

and L″

satisfy, each independently of the others, a structural formula chosen in the group consisting of;

in which R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ represent, each independently of the others, one chosen from among;

an alkyl group,

an aryl group,

a condensate ring, or

a hydrogen atom;

L, L′ and

L″

being negatively formally charged.

14. The device of claim 8, wherein said metallocyclic compound is iridium tris (2-phenylpyridine) (Ir(ppy)₃).

15. The device of claim 11, wherein said metallocyclic compound is chosen in the group consisting of:

platinum bis (2-thienylpyridine); and

platinum bis (2-phenylpyridine).

16. The device of claim 1, wherein said luminophore material comprises at least one organometallic complex which satisfies the structural formula:

M″

Q_n A_3-n,

in which n is comprised between 1 and 3, each Q is, independently of the other Qs, a quinoline derivative, and each A is, independently of the other As, a phenol derivative, and in which M″

is a metal, having a positive formal charge, chosen in the group consisting of;

aluminium (Al), and

gallium (Ga).

17. The device of claim 16, wherein the organometallic complex is alumino bis (phenol)(8-hydroxyquinaldine) (Alqfen₂).

18. The device of claim 1, wherein said luminophore material comprises at least one organometallic complex, which satisfies the structural formula:

M′

″

Q_m A_2-m,

in which m is 1 or 2, each Q is, independently of the other Qs, a quinoline derivative, and each A is, independently of the other As, a phenol derivative, and in which M′

″

is a metal, having a positive formal charge, chosen in the group consisting of;

zinc (Zn), and

beryllium (Be).

19. The device of claim 16, wherein each Q represents, independently of the other Qs, a quinoline derivative, which satisfies a structural formula chosen in the group consisting of:

in which R⁹, R¹⁰, R¹¹, R¹² and R¹³ represent, each independently of the others, one chosen from among;

an alkyl group,

a hydrogen atom, or

an aryl group.

20. The device of claim 16, wherein each A is a phenol derivative, which satisfies, independently of the other As, a structural formula chosen in the group consisting of:

in which R¹⁴, R¹⁵ and R¹⁶ represent, each independently of the others, one chosen from among;

an alkyl group,

a hydrogen atom, or

an aryl group.

21. The device of claim 1, wherein said luminophore material comprises at least one aromatic hydrocarbon with condensate rings, which satisfies a structural formula chosen in the group consisting of:

in which R¹⁷, R¹⁸, R¹⁹, R²⁰, R²¹, R²², R²³, R³² and R³³ represent, each independently of the others, one chosen from among;

an alkyl group,

a hydrogen atom, or

an aryl group.

22. The device of claim 21, wherein said aromatic hydrocarbon with condensate rings is rubrene.

23. The device of claim 1, wherein said luminophore material comprises at least one thiophene derivative which satisfies a structural formula chosen in the group consisting of:

in which n¹ is an integer comprised between 3 and 7, m¹ and m² are, each independently of the other, integers comprised between 1 and 3, in which R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R²⁹, R³⁰ and R³¹ represent, each independently of the others, one chosen from among;

an alkyl group,

a hydrogen atom, or

an aryl group.

24. The device of claim 1, wherein said hole-transporting organic material is substantially represented by a tertiary aromatic amine;

the tertiary aromatic amine satisfying the structural formula;

in which T¹ and T² represent, each independently of the other, a tertiary amine; and

in which A represents an aryl group.

25. The device of claim 24, wherein T¹ and T² represent, each independently of the other, a tertiary amine which satisfies a structural formula chosen in the group consisting of:

in which Z¹ and Z², represent, each independently of the other, one chosen from among;

an alkyl group,

an alcohol group, or

a hydrogen atom;

in which Ar¹ and Ar² represent, each independently of the other, an aryl group.

26. The device of claim 24, wherein said hole-transporting organic material comprises 4,4′

,4″

-tris (N-3-methylphenyl-N-phenylamino)-triphenylamine (m-MTDATA).

27. The device of claim 1, wherein said electron-transporting organic material is substantially constituted by a heterocyclic compound which satisfies a structural formula chosen in the group consisting of:

in which E¹, E², E³, E⁴ and E⁵ represent, each independently of the others, an aryl group.

28. The device of claim 1, wherein said electron-transporting organic material comprises 2-(4-biphenyl)-5-phenyl-1,3,4-oxadiazole (PBD).

34. The device of claim 11, wherein the chelating ligands L, L′

and L″

satisfy, each independently of the others, a structural formula chosen in the group consisting of;

in which R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ represent, each independently of the others, one chosen from among;

an alkyl group,

an aryl group,

a condensate ring, or

a hydrogen atom;

L, L′ and

L″

being negatively formally charged.

35. The device of claim 18, wherein each Q represents, independently of the other Qs, a quinoline derivative, which satisfies a structural formula chosen in the group consisting of:

in which R⁹, R¹⁰, R¹¹, R¹² and R¹³ represent, each independently of the others, one chosen from among;

an alkyl group,

a hydrogen atom, or

an aryl group.

36. The device of claim 18, wherein each A is a phenol derivative, which satisfies, independently of the other As, a structural formula chosen in the group consisting of:

in which R¹⁴, R¹⁵ and R¹⁶ represent, each independently of the others, one chosen from among;

an alkyl group,

a hydrogen atom, or

an aryl group.

29. A method for producing an organic electroluminescent device;

the method comprising a depositing step for depositing an intermediate element (7) on an anode (2); and

an apposition step for positioning a cathode (3) on said intermediate element (7);

the intermediate element (7) comprising at least one luminophore material;

the luminophore material being designed to emit electromagnetic radiation;

the method being characterized in that said intermediate element (7) comprises at least one hole-transporting organic material and at least one electron-transporting organic material;

the electron-transporting organic material and the hole-transporting organic material being designed to form between them exciplexes or electroplexes;

the luminophore material being supplied, in use, for transfer of energy from said exciplexes or electroplexes.

30. The method of claim 29, wherein said luminophore material is chosen so that said electromagnetic radiation is of a given wavelength.

31. The method of claim 29, wherein said depositing step comprises a first depositing substep for depositing said first layer (4) on an anode (2);

and a second depositing substep for depositing the second layer (6) on the first layer (4);

of positioning a cathode (3) on said second layer (6).

32. The method of claim 31, wherein, during said first depositing substep, said luminophore material is deposited.

33. The method of claim 31, wherein, during said first depositing substep polycarbonate, is deposited.