Phosphorescent compounds and devices comprising the same

Details Phosphorescent compounds and devices comprising the same Phosphorescent compounds and devices comprising the same

2001-10-17

2004-12-28

Yamnitzky, Marie (Department: 1774)

Stock material or miscellaneous articles

Composite

Of inorganic material

C428S917000, C313S504000, C546S004000, C546S010000

Reexamination Certificate

active

06835469

ABSTRACT:

FIELD OF THE INVENTION
The present invention pertains to organometallic compounds and efficient organic light emitting devices comprising the same.
BACKGROUND OF THE INVENTION
Research Agreements
The claimed invention was made by, on behalf of, and/or in connection with one or more of the following parties to a joint university-corporation research agreement: Princeton University, The University of Southern California, and the Universal Display Corporation. The agreement was in effect on and before the date the claimed invention was made, and the claimed invention was made as a result of activities undertaken within the scope of the agreement.
Electronic display currently is a primary means for rapid delivery of information. Television sets, computer monitors, instrument display panels, calculators, printers, wireless phones, handheld computers, etc. aptly illustrate the speed, versatility, and interactivity that is characteristic of this medium. Of the known electronic display technologies, organic light emitting devices (OLEDs) are of considerable interest for their potential role in the development of full color, flat-panel display systems that may render obsolete the bulky cathode ray tubes still currently used in many television sets and computer monitors.
Generally, OLEDs are comprised of several organic layers in which at least one of the layers can be made to electroluminesce by applying a voltage across the device (see, e.g., Tang, et al.,
Appl. Phys. Lett
. 1987, 51, 913 and Burroughes, et al.,
Nature
, 1990, 347, 359). When a voltage is applied across a device, the cathode effectively reduces the adjacent organic layers (i.e., injects electrons) and the anode effectively oxidizes the adjacent organic layers (i.e., injects holes). Holes and electrons migrate across the device toward their respective oppositely charged electrodes. When a hole and electron meet on the same molecule, recombination is said to occur and an exciton is formed. Recombination of the hole and electron in luminescent compounds is accompanied by radiative emission, thereby producing electroluminescence.
Depending on the spin states of the hole and electron, the exciton which results from hole and electron recombination can have either a triplet or singlet spin state. Luminescence from a singlet exciton results in fluorescence whereas luminescence from a triplet exciton results in phosphorescence. Statistically, for organic materials typically used in OLEDs, one quarter of the excitons are singlets and the remaining three quarters are triplets (see, e.g., Baldo, et al.,
Phys. Rev. B
, 1999, 60,14422). Until the discovery that there were certain phosphorescent materials that could be used to fabricate practical electro-phosphorescent OLEDs (U.S. Pat. No. 6,303,238) and, subsequently, demonstration such that electro-phosphorescent OLEDs could have a theoretical quantum efficiency of up to 100% (i.e., harvesting all of both triplets and singlets), the most efficient OLEDs were typically based on materials that fluoresced. Fluorescent materials luminesce with a maximum theoretical quantum efficiency of only 25% (where quantum efficiency of an OLED refers to the efficiency with which holes and electrons recombine to produce luminescence), since the triplet to ground state transition of phosphorescent emission is formally a spin forbidden process. Electro-phosphorescent OLEDs have now been shown to have superior overall device efficiencies as compared with electro-fluorescent OLEDs (see, e.g., Baldo, et al.,
Nature
, 1998, 395, 151 and Baldo, e.g.,
Appl. Phys. Lett
. 1999, 75(3), 4).
Due to strong spin-orbit coupling that leads to singlet-triplet state mixing, heavy metal complexes often display efficient phosphorescent emission from such triplets at room temperature. Accordingly, OLEDs comprising such complexes have been shown to have internal quantum efficiencies of more than 75% (Adachi, et al.,
Appl. Phys. Lett
., 2000, 77,904). Certain organometallic iridium complexes have been reported as having intense phosphorescence (Lamansky, et al.,
Inorganic Chemistry
, 2001,40, 1704), and efficient OLEDs emitting in the green to red spectrum have been prepared with these complexes (Lamansky, et al.,
J. Am. Chem. Soc
., 2001, 123,4304). Red-emitting devices containing iridium complexes have been prepared according to U.S. Application Publication No. 2001/0019782. Phosphorescent heavy metal organometallic complexes and their respective devices have also been the subject of International Patent Application Publications WO 00/57676, WO 00/70655, and WO 01/41512; and U.S. Ser. Nos. 0/9274,609, now abandoned; 09/452,346, now abandoned; 09/637,766; 60/283,814; and U.S. Ser. No. 09/978,455, filed Oct. 16, 2001, entitled “Organometallic Compounds and Emission-Shifting Organic Electrophosphorescence” to Lamansky, et al.
Despite the recent discoveries of efficient heavy metal phosphors and the resulting advancements in OLED technology, there remains a need for even greater efficiency in devices. Fabrication of brighter devices that use less power and have longer lifetimes will contribute to the development of new display technologies and help realize the current goals toward full color electronic display on flat surfaces. The phosphorescent organometallic compounds, and the devices comprising them, described herein, help fulfill these and other needs.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides compounds of Formula I, II, or III:
wherein:
M is a metal atom;
each A
1
and A
2
is, independently, a monodentate ligand; or A
1
and A
2
are covalently joined together to form a bidentate ligand;
each R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, and R
10
is, independently, H, F, Cl, Br, I, R
11
, OR
11
, N(R
11
)
2
, P(R
11
)
2
, P(OR
11
)
2
, POR
11
, PO
2
R
11
, PO
3
R
11
, SR
11
, Si(R
11
)
3
, B(R
11
)
2
, B(OR
11
)
2
, C(O)R
11
, C(O)OR
11
, C(O)N(R
11
)
2
, CN, NO
2
, SO
2
, SOR
11
, SO
2
R
11
, SO
3
R
11
; and additionally, or alternatively, any one or more of R
1
and R
2
, or R
2
and R
3
, or R
3
and R
4
, or R
5
and R
6
, or R
6
and R
7
, or R
7
and R
8
, or R
9
and R
10
, together form, independently, a fused 4- to 7-member cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl, and wherein said cyclic group is optionally substituted by one or more substituents X;
each R
11
is, independently, H, C
1
-C
20
alkyl, C
2
-C
20
alkenyl, C
2
-C
20
alkynyl, C
1
-C
20
heteroalkyl, C
3
-C
40
aryl, C
3
-C
40
heteroaryl; wherein R
11
is optionally substituted by one or more substituents X;
each X is, independently, H, F, Cl, Br, I, R
12
, OR
12
, N(R
12
)
2
, P(R
12
)
2
, P(OR
12
)
2
, POR
12
, PO
2
R
12
, PO
3
R
12
, SR
12
, Si(R
12
)
3
, B(R
12
)
2
, B(OR
12
)
2
C(O)R
12
, C(O)OR
12
, C(O)N(R
12
)
2
, CN, NO
2
, SO
2
, SOR
12
, SO
2
R
12
, or SO
3
R
12
;
each R
12
is, independently, H, C
1
-C
20
alkyl, C
1
-C
20
perhaloalkyl C
2
-C
20
alkenyl, C
2
-C
20
alkynyl, C
1
-C
20
heteroalkyl, C
3
-C
40
aryl, or C
3
-C
40
heteroaryl;
m is the formal charge of metal atom M;
n is 1, 2 or 3; and
wherein at least one of R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, and R
10
is not H in compounds of Formula I.
In some embodiments, M can be a heavy metal. In further embodiments, M can be Ir, Os, Pt, Pb, Re, or Ru; or M can be Ir; or M can be Pt. In further embodiments, A
1
and A
2
can be monodentate ligands which, in turn, can have a combined charge of (−1). In yet further embodiments, A
1
or A
2
can be F, Cl, Br, I, CO, CN, CN(R
11
), SR
11
SCN, OCN, P(R
11
)
3
, P(OR
11
)
3
, N(R
11
)
3
, NO, N
3
, or a nitrogen-containing heterocycle optionally substituted by one or more substituents X. In further embodiments, A
1
and A
2
can be covalently joined together to form a bidentate ligand, which can be monoanionic. In some embodiments, the bidentate ligand can be
According to further embodiments, the bidentate ligand can coordinate through a carbon atom and a nitrogen atom. Further, the bidentate ligand can be a

Affiliated with

Also associated with

Rating

Phosphorescent compounds and devices comprising the same does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Phosphorescent compounds and devices comprising the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phosphorescent compounds and devices comprising the same will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3279916