Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Reexamination Certificate
2001-12-20
2003-12-30
Whitehead, Jr., Carl (Department: 2813)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
C257S040000, C438S026000, C438S069000, C438S082000, C438S099000, C556S137000, C428S690000
Reexamination Certificate
active
06670645
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to electroluminescent complexes of iridium(III) with fluorinated phenylpyridines, phenylpyrimidines, and phenylquinolines. It also relates to electronic devices in which the active layer includes an electroluminescent Ir(II) complex.
2. Description of the Related Art
Organic electronic devices that emit light, such as light-emitting diodes that make up displays, are present in many different kinds of electronic equipment. In all such devices, an organic active layer is sandwiched between two electrical contact layers. At least one of the electrical contact layers is light-transmitting so that light can pass through the electrical contact layer. The organic active layer emits light through the light-transmitting electrical contact layer upon application of electricity across the electrical contact layers.
It is well known to use organic electroluminescent compounds as the active component in light-emitting diodes. Simple organic molecules such as anthracene, thiadiazole derivatives, and coumarin derivatives are known to show electroluminescence. Semiconductive conjugated polymers have also been used as electroluminescent components, as has been disclosed in, for example, Friend et al., U.S. Pat. No. 5,247,190, Heeger et al., U.S. Pat. No. 5,408,109, and Nakano et al., Published European Patent Application 443 861. Complexes of 8-hydroxyquinolate with trivalent metal ions, particularly aluminum, have been extensively used as electroluminescent components, as has been disclosed in, for example, Tang et al., U.S. Pat. No. 5,552,678.
Burrows and Thompson have reported that fac-tris(2-phenylpyridine) iridium can be used as the active component in organic light-emitting devices. (
Appl. Phys. Lett.
1999, 75, 4.) The performance is maximized when the iridium compound is present in a host conductive material. Thompson has further reported devices in which the active layer is poly(N-vinyl carbazole) doped with fac-tris[2-(4′,5′-difluorophenyl)pyridine-C′
2
,N]iridium(III). (Polymer Preprints 2000, 41(1), 770.)
However, there is a continuing need for electroluminescent compounds having improved efficiency.
SUMMARY OF THE INVENTION
The present invention is directed to an iridium compound (generally referred as “Ir(III) compounds”) having at least two 2-phenylpyridine ligands in which there is at least one fluorine or fluorinated group on the ligand. The iridium compound has the following First Formula:
IrL
a
L
b
L
c
x
L′
y
L″
z
(First Formula)
where:
x=0 or 1, y=0, 1 or 2, and z=0 or 1, with the proviso that:
x=0 or y+z=0 and
when y=2 then z=0;
L′=a bidentate ligand or a monodentate ligand, and is not a phenylpyridine, phenylpyrimidine, or phenylquinoline; with the proviso that:
when L′ is a monodentate ligand, y+z=2, and
when L′ is a bidentate ligand, z=0;
L″=a monodentate ligand, and is not a phenylpyridine, and phenylpyrimidine, or phenylquinoline; and
L
a
, L
b
and L
c
are alike or different from each other and each of L
a
, L
b
and L
c
has structure (I) below:
wherein:
adjacent pairs of R
1
through R
4
and R
5
through R
8
can be joined to form a five- or six-membered ring,
at least one of R
1
through R
8
is selected from F, C
n
F
2n+1
,
OC
n
F
2n+1
, and OCF
2
X, where n is an integer from 1 through 6 and X=H, Cl, or Br, and
A=C or N, provided that when A=N, there is no R
1
.
In another embodiment, the present invention is directed to substituted 2-phenylpyridine, phenylpyrimidine, and phenylquinoline precursor compounds from which the above Ir(III) compounds are made. The precursor compounds have a structure (II) or (III) below:
where A and R
1
through R
8
are as defined in structure (I) above,
and R
9
is H.
where:
at least one of R
10
through R
19
is selected from F, C
n
F
2n+1
, OC
n
F
2n+1
, and OCF
2
X, where n=an integer between 1 and 6 and X is H, Cl, or Br, and R
20
is H.
It is understood that there is free rotation about the phenyl-pyridine, phenyl-pyrimidine and the phenyl-quinoline bonds. However, for the discussion herein, the compounds will be described in terms of one orientation.
In another embodiment, the present invention is directed to an organic electronic device having at least one emitting layer comprising the above Ir(III) compound, or combinations of the above Ir(III) compounds.
As used herein, the term “compound” is intended to mean an electrically uncharged substance made up of molecules that further consist of atoms, wherein the atoms cannot be separated by physical means. The term “ligand” is intended to mean a molecule, ion, or atom that is attached to the coordination sphere of a metallic ion. The term “complex”, when used as a noun, is intended to mean a compound having at least one metallic ion and at least one ligand. The term “group” is intended to mean a part of a compound, such a substituent in an organic compound or a ligand in a complex. The term “facial” is intended to mean one isomer of a complex, Ma
3
b
3
, having octahedral geometry, in which the three “a” groups are all adjacent, i.e. at the corners of one face of the octahedron. The term “meridional” is intended to mean one isomer of a complex, Ma
3
b
3
, having octahedral geometry, in which the three “a” groups occupy three positions such that two are trans to each other. The phrase “adjacent to,” when used to refer to layers in a device, does not necessarily mean that one layer is immediately next to another layer. On the other hand, the phrase “adjacent R groups,” is used to refer to R groups that are next to each other in a chemical formula (i.e., R groups that are on atoms joined by a bond). The term “photoactive” refers to any material that exhibits electroluminescence and/or photosensitivity. The term “(H+F)” is intended to mean all combinations of hydrogen and fluorine, including completely hydrogenated, partially fluorinated or perfluorinated substituents. By “emission maximum” is meant the wavelength, in nanometers, at which the maximum intensity of electroluminescence is obtained. Electroluminescence is generally measured in a diode structure, in which the material to be tested is sandwiched between two electrical contact layers and a voltage is applied. The light intensity and wavelength can be measured, for example, by a photodiode and a spectrograph, respectively.
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patent: 5552678 (1996-09-01), Tang et al.
patent: 2001/0019782 (2001-09-01), Igarashi et al.
patent: 2001/0053462 (2001-12-01), Mishima
patent: 1175128 (2002-01-01), None
patent: WO 96/03410 (1996-02-01), None
patent: WO 00/70655 (2000-11-01), None
Chatani, Naoto et al., Ru3(CO)12-Catalyzed Reaction of Pyridylbenzenes with Carbon Monoxide and Olefins. Carbonylation at a C-H Bond in the Benzene Ring, J. Org. Chem., 1997, 2604-2610, 62, American Chemical Society.
Gosmini, Corinne et al., Electrosynthesis of functionalized 2-arylpyridines from functionalized aryl and pyridine halides catalyzed by nickel bromide 2,2′-bipyridine complex, Tetrahedron Letters, 2000, 5039-5042, 41, Elsevier Science Ltd.
Cacchi, Sandro et al., The Palladium-Catalyzed Transfer Hydrogentation/Heterocyclization of B-(2-Aminophenyl-a,B-ynones. An Approach to 2-Aryl- and 2-Vinylquinolines, Synlett, 1999, 401-404, No. 4, Thieme Stuttgart, New York.
Wang, Yue et al., (Hydroxyphenyl)pyridine derivative, its metal complexes and application as electroluminscence material, Chemical Abstracts Service, Mar. 1, 2000, Database No. 133:315395.
U.S. patent application Ser. No. 60/347,910, Lecloux et al., filed Nov. 7, 2001.
U.S. patent application Ser. No. 60/347,911, Lecloux et al., filed Nov. 7, 2001.
Baldo, M.A. et al., High-efficiency fluorescent organic light-emitting devices using a phosphorescent sensitizer, Nature, Feb. 17, 2000, 750-753, vol. 403.
Djurovich, Peter I. et al., Ir(III) Cyclometalated Complexes as Efficient Ph
Grushin Vladimir
Lecloux Daniel D.
Petrov Viacheslav A.
Wang Ying
E. I. du Pont de Nemours and Company
Jr. Carl Whitehead
Kielin Erik
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