U.S. patent application number 14/450708 was filed with the patent office on 2015-03-19 for luminescent cyclometallated iridium (iii) complexes having acetylide ligands.
The applicant listed for this patent is The University of Southern California. Invention is credited to Alberto Bossi, Peter ivan Djurovich, Mark E. Thompson.
Application Number | 20150076470 14/450708 |
Document ID | / |
Family ID | 45437943 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150076470 |
Kind Code |
A1 |
Thompson; Mark E. ; et
al. |
March 19, 2015 |
Luminescent Cyclometallated Iridium (III) Complexes Having
Acetylide Ligands
Abstract
The present invention relates to phosphorescent
(triplet-emitting) organometallic materials. The phosphorescent
materials of the present invention comprise Ir(III)cyclometallated
alkynyl complexes for use as triplet light-emitting materials. The
Ir(III)cyclometallated alkynyl complexes comprise at least one
cyclometallating ligand and at least one alkynyl ligand bonded to
the iridium. Also provided is an organic light emitting device
comprising an anode, a cathode and an emissive layer between the
anode and the cathode, wherein the emissive layer comprises a
Ir(III)cyclometallated alkynyl complex as a triplet emitting
material.
Inventors: |
Thompson; Mark E.; (Anaheim,
CA) ; Bossi; Alberto; (Gallarate, IT) ;
Djurovich; Peter ivan; (Los Angeles, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The University of Southern California |
Los Angeles |
CA |
US |
|
|
Family ID: |
45437943 |
Appl. No.: |
14/450708 |
Filed: |
August 4, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13161296 |
Jun 15, 2011 |
8822042 |
|
|
14450708 |
|
|
|
|
61359118 |
Jun 28, 2010 |
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Current U.S.
Class: |
257/40 ; 546/4;
548/103 |
Current CPC
Class: |
C09K 2211/1029 20130101;
H01L 51/5016 20130101; H01L 51/0085 20130101; Y10S 428/917
20130101; C07F 15/0033 20130101; C09K 2211/1044 20130101; C09K
2211/185 20130101 |
Class at
Publication: |
257/40 ; 548/103;
546/4 |
International
Class: |
H01L 51/00 20060101
H01L051/00 |
Goverment Interests
GOVERNMENT RIGHTS
[0002] The present invention was made under Department of Energy
Grant No. DE-FC26-08NT01585. The government may have certain rights
to the subject invention.
Claims
1. A compound having the formula I: ##STR00169## wherein: X.sup.1
X.sup.2 is a substituted or unsubstituted bidentate cyclometallated
aromatic ligand; X.sup.1 and X.sup.2 are independently selected
from C and N; Z is an acetylide ligand having the structure:
--C.ident.C--R.sup.1, --C.ident.C--(C.ident.C).sub.x--R.sup.1, or
--C.ident.C-(A-C.ident.C).sub.y--R.sup.1, each R.sup.1 is
independently selected from the group consisting of H, alkyl,
cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl,
Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic group, each of
which may be substituted or unsubstituted; each x is independently
selected from 0-5; each y is independently selected from 0-5; each
R.sup.2 is independently selected from H, alkyl, cycloalkyl,
alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group;
M is a metal atom; L is a mono-, bi- or tridentate ligand; z is
0-5; A is aryl or heteroaryl; Y is a monodentate ancillary ligand;
a is 1, 2, 3, or 4; b is 0, 1, 2, or 3; n is 1 or 2; the sum of
a+b+n is 4 or 5; and Cat is an optional cation the charge of which
provides a net neutral charge for formula I.
2. The compound of claim 1, wherein n is 2, a is 1 and b is 1.
3. The compound of claim 1, wherein n is 2, a is 2.
4. The compound of claim 1, having the formula II: ##STR00170##
wherein C N is a substituted or unsubstituted cyclometallated
ligand; each R.sup.1 is independently selected from the group
consisting of H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, awl,
heteroaryl, Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic
group, each of which may be substituted or unsubstituted; each
R.sup.2 is independently selected from H, alkyl, cycloalkyl,
alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group;
M is a metal atom; L is a mono-, bi- or tridentate ligand; z is
0-5; Y is a monodentate ancillary ligand; and Cat is an optional
cation the charge of which provides a net neutral charge for
formula II.
5. The compound of claims 1 or 2, wherein each R.sup.1 is
independently selected from: ##STR00171## ##STR00172## ##STR00173##
wherein each X is independently selected from C(R').sub.d,
N(R').sub.e, S, O, SO, SO.sub.2 and Si(R').sub.d; d is 1 or 2; e is
0 or 1; n is 1 to 5; each R is independently selected from H, halo,
CN, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, heteroaryl; OR',
NR'.sub.2, CO.sub.2R', COR', CONR'.sub.2, and Si(R').sub.3; each R'
is independently selected from H, alkyl, cycloalkyl, alkenyl, aryl,
aralkyl, and heteroaryl; M is a metal atom; L is a mono-, bi- or
tridentate ligand; and j is 0 to 5.
6. The compound of claim 2, wherein Y has the formula
--C.dbd.N--R.sup.3; and R.sup.3 is selected from the group
consisting of alkyl, cycloalkyl, alkenyl, aryl, aralkyl, and
heteroaryl.
7. The compound of claim 1, having the formula III: ##STR00174##
wherein C N is a substituted or unsubstituted cyclometallated
ligand; R.sup.1a and R.sup.1b are independently selected from the
group consisting of H, alkyl, cycloalkyl, alkenyl, cycloalkenyl,
aryl, heteroaryl, Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic
group, each of which may be substituted or unsubstituted; each
R.sup.2 is independently selected from H, alkyl, cycloalkyl,
alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group;
M is a metal atom; L is a mono-, bi- or tridentate ligand; z is
0-5; and Cat is an optional cation the charge of which provides a
net neutral charge for formula III.
8. The compound of claim 1, wherein the triplet energy of the
acetylide ligand Z is lower than that of the C N cyclometallating
ligands.
9. The compound of claim 1 having the structure selected from the
group consisting of: ##STR00175## ##STR00176##
10. An organic light emitting device comprising an anode, a cathode
and an emissive layer between the anode and the cathode, wherein
the emissive layer comprises the compound of the claim 1.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/359,118, filed Jun. 28, 2010, the content of
which is incorporated herein by reference in its entirety.
RESEARCH AGREEMENTS
[0003] 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: Regents of the
University of Michigan, 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.
FIELD OF THE INVENTION
[0004] The present invention relates to phosphorescent
(triplet-emitting) organometallic materials. The phosphorescent
materials of the present invention comprise Ir(III)cyclometallated
alkynyl systems for use as triplet emitting dopants in organic
light emitting diodes (OLEDs), contrast agent, oxygen sensing and
related applications.
BACKGROUND
[0005] Opto-electronic devices that make use of organic materials
are becoming increasingly desirable for a number of reasons. Many
of the materials used to make such devices are relatively
inexpensive, so organic opto-electronic devices have the potential
for cost advantages over inorganic devices. In addition, the
inherent properties of organic materials, such as their
flexibility, may make them well suited for particular applications
such as fabrication on a flexible substrate. Examples of organic
opto-electronic devices include organic light emitting devices
(OLEDs), organic phototransistors, organic photovoltaic cells, and
organic photodetectors. For OLEDs, the organic materials may have
performance advantages over conventional materials. For example,
the wavelength at which an organic emissive layer emits light may
generally be readily tuned with appropriate dopants.
[0006] OLEDs make use of thin organic films that emit light when
voltage is applied across the device. OLEDs are becoming an
increasingly interesting technology for use in applications such as
flat panel displays, illumination, and backlighting. Several OLED
materials and configurations are described in U.S. Pat. Nos.
5,844,363, 6,303,238, and 5,707,745, which are incorporated herein
by reference in their entirety.
[0007] One application for phosphorescent emissive molecules is a
full color display. Industry standards for such a display call for
pixels adapted to emit particular colors, referred to as
"saturated" colors. In particular, these standards call for
saturated red, green, and blue pixels. Color may be measured using
CIE coordinates, which are well known to the art.
[0008] One example of a green emissive molecule is
tris(2-phenylpyridine) iridium, denoted Ir(ppy).sub.3, which has
the structure:
##STR00001##
[0009] In this, and later figures herein, we depict the dative bond
from nitrogen to metal (here, Ir) as a straight line.
[0010] As used herein, the term "organic" includes polymeric
materials as well as small molecule organic materials that may be
used to fabricate organic opto-electronic devices. "Small molecule"
refers to any organic material or organometallic material that is
not a polymer, and "small molecules" may actually be quite large.
Small molecules may include repeat units in some circumstances. For
example, using a long chain alkyl group as a substituent does not
remove a molecule from the "small molecule" class. Small molecules
may also be incorporated into polymers, for example as a pendent
group on a polymer backbone or as a part of the backbone. Small
molecules may also serve as the core moiety of a dendrimer, which
consists of a series of chemical shells built on the core moiety. A
dendrimer may be a "small molecule," and it is believed that all
dendrimers currently used in the field of OLEDs are small
molecules.
[0011] As used herein, "top" means furthest away from the
substrate, while "bottom" means closest to the substrate. Where a
first layer is described as "disposed over" a second layer, the
first layer is disposed further away from substrate. There may be
other layers between the first and second layer, unless it is
specified that the first layer is "in contact with" the second
layer. For example, a cathode may be described as "disposed over"
an anode, even though there are various organic layers in
between.
[0012] As used herein, "solution processible" means capable of
being dissolved, dispersed, or transported in and/or deposited from
a liquid medium, either in solution or suspension form.
[0013] A ligand may be referred to as "photoactive" when it is
believed that the ligand directly contributes to the photoactive
properties of an emissive material. A ligand may be referred to as
"ancillary" when it is believed that the ligand does not contribute
to the photoactive properties of an emissive material, although an
ancillary ligand may alter the properties of a photoactive
ligand.
[0014] As used herein, and as would be generally understood by one
skilled in the art, a first "Highest Occupied Molecular Orbital"
(HOMO) or "Lowest Unoccupied Molecular Orbital" (LUMO) energy level
is "greater than" or "higher than" a second HOMO or LUMO energy
level if the first energy level is closer to the vacuum energy
level. Since ionization potentials (IP) are measured as a negative
energy relative to a vacuum level, a higher HOMO energy level
corresponds to an IP having a smaller absolute value (an IP that is
less negative). Similarly, a higher LUMO energy level corresponds
to an electron affinity (EA) having a smaller absolute value (an EA
that is less negative). On a conventional energy level diagram,
with the vacuum level at the top, the LUMO energy level of a
material is higher than the HOMO energy level of the same material.
A "higher" HOMO or LUMO energy level appears closer to the top of
such a diagram than a "lower" HOMO or LUMO energy level.
[0015] As used herein, and as would be generally understood by one
skilled in the art, a first work function is "greater than" or
"higher than" a second work function if the first work function has
a higher absolute value. Because work functions are generally
measured as negative numbers relative to vacuum level, this means
that a "higher" work function is more negative. On a conventional
energy level diagram, with the vacuum level at the top, a "higher"
work function is illustrated as further away from the vacuum level
in the downward direction. Thus, the definitions of HOMO and LUMO
energy levels follow a different convention than work
functions.
[0016] More details on OLEDs, and the definitions described above,
can be found in U.S. Pat. No. 7,279,704, which is incorporated
herein by reference in its entirety.
SUMMARY OF THE INVENTION
[0017] Phosphorescent (triplet-emitting) organometallic materials
are provided. The phosphorescent materials of the present invention
comprise Ir(III)cyclometallated alkynyl systems for use as triplet
emitting dopants in organic light emitting diodes (OLEDs), contrast
agent, oxygen sensing and related applications.
[0018] In preferred aspects of the invention, the triplet-emitting
material is a compound having the formula I:
##STR00002##
wherein: X.sup.1 X.sup.2 is a substituted or unsubstituted
bidentate cyclometallated aromatic ligand; X.sup.1 and X.sup.2 are
independently selected from C and N; Z is an acetylide ligand
having the structure: [0019] --C.ident.C--R.sup.1,
--C.ident.C--(C.ident.C).sub.x--R.sup.1,
--C.ident.C-(A-C.ident.C).sub.y--R.sup.1, each R.sup.1 is
independently selected from the group consisting of H, alkyl,
cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl,
Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic group, each of
which may be substituted or unsubstituted; each x is independently
selected from 0-5; each y is independently selected from 0-5; each
R.sup.2 is independently selected from H, alkyl, cycloalkyl,
alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group;
M is a metal atom; L is a mono-, bi- or tridentate ligand; z is
0-5; A is aryl or heteroaryl; Y is a monodentate ancillary ligand;
additionally or alternatively, X and Y, two X ligands, and/or two Y
ligands may be connected by a bridging moiety; a is 1, 2, 3, or 4;
b is 0, 1, 2, or 3; n is 1 or 2; the sum of a+b+n is 4 or 5; and
Cat is an optional cation the charge of which provides a net
neutral charge for formula I.
[0020] Also provided is an organic light emitting device comprising
an anode, a cathode and an emissive layer between the anode and the
cathode, wherein the emissive layer comprises a compound of the
formula I.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows an organic light emitting device.
[0022] FIG. 2 shows an inverted organic light emitting device that
does not have a separate electron transport layer.
[0023] FIG. 3 shows the chemical structures of Iridium (III)
complexes with labels.
[0024] FIG. 4 shows the X-ray crystal structure of
Ir(ppy).sub.2(CNtBu)(CCPheneatr) (ORTEP view).
[0025] FIG. 5 shows the X-ray crystal structure of
Ir(ppz).sub.2(CNtBu)(CCPh) (ORTEP view).
[0026] FIG. 6 shows the .sup.1H NMR (400 MHz, CDCl.sub.3, ppm) for
Ir(ppz).sub.2(CNtBu)Cl.
[0027] FIG. 7 shows the .sup.1H NMR (400 MHz, CD.sub.3CN, ppm) (A)
and the .sup.19F NMR (376 MHz, CD.sub.3CN, ppm) (B) for
Ir(ppz).sub.2(CNtBu)OTf.
[0028] FIG. 8 shows the .sup.1H NMR (400 MHz, CDCl.sub.3, ppm) for
Ir(ppy).sub.2(CNtBu)Cl.
[0029] FIG. 9 shows the .sup.1H NMR (400 MHz, CD.sub.3CN, ppm) (A)
and the .sup.19F NMR (376 MHz, CD.sub.3CN, ppm) for
Ir(ppy).sub.2(CNtBu)OTf.
[0030] FIG. 10 shows absorption (acetonitrile), excitation and
emission (2MeTHF, 77K) spectra of Ir(ppz).sub.2(CNtBu)(CCPh).
[0031] FIG. 11 shows the LCMS (C18, acetonitrile:H.sub.2O, 80:20 to
90:10; ESI+) for Ir(ppz).sub.2(CNtBu)(CCPh).
[0032] FIG. 12 shows the absorption (acetonitrile) and emission
(toluene, room temperature; 2MeTHF, 77K) spectra of
Ir(ppz).sub.2(CNtBu)(CCPh).
[0033] FIG. 13 shows the LCMS (C18, acetonitrile:H.sub.2O, 80:20 to
90:10; ESI+) for Ir(ppy).sub.2(CNtBu)(CCPh).
[0034] FIG. 14 shows absorption (acetonitrile), excitation and
emission (2MeTHF, 77K) spectra of
Ir(ppy).sub.2(CNtBu)(CCPheneatr).
[0035] FIG. 15 shows the LCMS (C18, acetonitrile:H.sub.2O, 80:20 to
90:10; ESI+) of Ir(ppy).sub.2(CNtBu)(CCPheneatr).
[0036] FIG. 16 shows the LCMS (C18, acetonitrile:H.sub.2O, 80:20 to
90:10; ESI+,-) for Ir(ppy).sub.2(CCPh).sub.2Li.
[0037] FIG. 17 shows the UV Absorption (Acetonitrile) of
Ir(ppy).sub.2(CCPh).sub.2Li.
[0038] FIG. 18 shows the absorption (acetonitrile) and emission
(2MeTHF, 77K; toluene, room temp.) spectra of
Ir(ppz).sub.2(CNtBu)(CCPheneatr).
[0039] FIG. 19 shows the LCMS (C8, acetonitrile:H.sub.2O, 80:20;
ESI+) for Ir(ppz).sub.2(CNtBu)(CCPheneatr).
[0040] FIG. 20 shows the brightness vs. voltage for devices having
the structure ITO/PVK/CBP(Ir complex 8% w/w)/BCP(400 .ANG.)/LiF(10
.ANG.)/Al in which the Ir complex is
Ir(ppy).sub.2(CNtBu)(CCPheneatr), Ir(ppz).sub.2(CNtBu)(CCPheneatr)
or Ir(ppy).sub.3.
[0041] FIG. 21 shows current density vs. voltage for devices having
the structure ITO/PVK/CBP(Ir complex 8% w/w)/BCP(400 .ANG.)/LiF(10
.ANG.)/Al in which the Ir complex is
Ir(ppy).sub.2(CNtBu)(CCPheneatr), Ir(ppz).sub.2(CNtBu)(CCPheneatr)
or Ir(ppy).sub.3.
[0042] FIG. 22 shows the quantum efficiency vs. current density for
devices having the structure ITO/PVK/CBP(Ir complex 8% w/w)/BCP(400
.ANG.)/LiF(10 .ANG.)/Al in which the Ir complex is
Ir(ppy).sub.2(CNtBu)(CCPheneatr), Ir(ppz).sub.2(CNtBu)(CCPheneatr)
or Ir(ppy).sub.3.
[0043] FIG. 23 shows the electroluminescent emission at 30V for
devices having the structure ITO/PVK/CBP(Ir complex 8% w/w)/BCP(400
.ANG.)/LiF(10 .ANG.)/Al in which the Ir complex is
Ir(ppy).sub.2(CNtBu)(CCPheneatr), Ir(ppz).sub.2(CNtBu)(CCPheneatr)
or Ir(ppy).sub.3.
DETAILED DESCRIPTION
[0044] Generally, an OLED comprises at least one organic layer
disposed between and electrically connected to an anode and a
cathode. When a current is applied, the anode injects holes and the
cathode injects electrons into the organic layer(s). The injected
holes and electrons each migrate toward the oppositely charged
electrode. When an electron and hole localize on the same molecule,
an "exciton," which is a localized electron-hole pair having an
excited energy state, is formed. Light is emitted when the exciton
relaxes via a photoemissive mechanism. In some cases, the exciton
may be localized on an excimer or an exciplex. Non-radiative
mechanisms, such as thermal relaxation, may also occur, but are
generally considered undesirable.
[0045] The initial OLEDs used emissive molecules that emitted light
from their singlet states ("fluorescence") as disclosed, for
example, in U.S. Pat. No. 4,769,292, which is incorporated by
reference in its entirety. Fluorescent emission generally occurs in
a time frame of less than 10 nanoseconds.
[0046] More recently, OLEDs having emissive materials that emit
light from triplet states ("phosphorescence") have been
demonstrated. Baldo et al., "Highly Efficient Phosphorescent
Emission from Organic Electroluminescent Devices," Nature, vol.
395, 151-154, 1998; ("Baldo-I") and Baldo et al., "Very
high-efficiency green organic light-emitting devices based on
electrophosphorescence," Appl. Phys. Lett., vol. 75, No. 3, 4-6
(1999) ("Baldo-II"), which are incorporated by reference in their
entireties. Phosphorescence is described in more detail in U.S.
Pat. No. 7,279,704 at cols. 5-6, which are incorporated by
reference.
[0047] FIG. 1 shows an organic light emitting device 100. The
figures are not necessarily drawn to scale. Device 100 may include
a substrate 110, an anode 115, a hole injection layer 120, a hole
transport layer 125, an electron blocking layer 130, an emissive
layer 135, a hole blocking layer 140, an electron transport layer
145, an electron injection layer 150, a protective layer 155, and a
cathode 160. Cathode 160 is a compound cathode having a first
conductive layer 162 and a second conductive layer 164. Device 100
may be fabricated by depositing the layers described, in order. The
properties and functions of these various layers, as well as
example materials, are described in more detail in U.S. Pat. No.
7,279,704 at cols. 6-10, which are incorporated by reference.
[0048] More examples for each of these layers are available. For
example, a flexible and transparent substrate-anode combination is
disclosed in U.S. Pat. No. 5,844,363, which is incorporated by
reference in its entirety. An example of a p-doped hole transport
layer is m-MTDATA doped with F.sub.4-TCNQ at a molar ratio of 50:1,
as disclosed in U.S. Patent Application Publication No.
2003/0230980, which is incorporated by reference in its entirety.
Examples of emissive and host materials are disclosed in U.S. Pat.
No. 6,303,238 to Thompson et al., which is incorporated by
reference in its entirety. An example of an n-doped electron
transport layer is BPhen doped with Li at a molar ratio of 1:1, as
disclosed in U.S. Patent Application Publication No. 2003/0230980,
which is incorporated by reference in its entirety. U.S. Pat. Nos.
5,703,436 and 5,707,745, which are incorporated by reference in
their entireties, disclose examples of cathodes including compound
cathodes having a thin layer of metal such as Mg:Ag with an
overlying transparent, electrically-conductive, sputter-deposited
ITO layer. The theory and use of blocking layers is described in
more detail in U.S. Pat. No. 6,097,147 and U.S. Patent Application
Publication No. 2003/0230980, which are incorporated by reference
in their entireties. Examples of injection layers are provided in
U.S. Patent Application Publication No. 2004/0174116, which is
incorporated by reference in its entirety. A description of
protective layers may be found in U.S. Patent Application
Publication No. 2004/0174116, which is incorporated by reference in
its entirety.
[0049] FIG. 2 shows an inverted OLED 200. The device includes a
substrate 210, a cathode 215, an emissive layer 220, a hole
transport layer 225, and an anode 230. Device 200 may be fabricated
by depositing the layers described, in order. Because the most
common OLED configuration has a cathode disposed over the anode,
and device 200 has cathode 215 disposed under anode 230, device 200
may be referred to as an "inverted" OLED. Materials similar to
those described with respect to device 100 may be used in the
corresponding layers of device 200. FIG. 2 provides one example of
how some layers may be omitted from the structure of device
100.
[0050] The simple layered structure illustrated in FIGS. 1 and 2 is
provided by way of non-limiting example, and it is understood that
embodiments of the invention may be used in connection with a wide
variety of other structures. The specific materials and structures
described are exemplary in nature, and other materials and
structures may be used. Functional OLEDs may be achieved by
combining the various layers described in different ways, or layers
may be omitted entirely, based on design, performance, and cost
factors. Other layers not specifically described may also be
included. Materials other than those specifically described may be
used. Although many of the examples provided herein describe
various layers as comprising a single material, it is understood
that combinations of materials, such as a mixture of host and
dopant, or more generally a mixture, may be used. Also, the layers
may have various sublayers. The names given to the various layers
herein are not intended to be strictly limiting. For example, in
device 200, hole transport layer 225 transports holes and injects
holes into emissive layer 220, and may be described as a hole
transport layer or a hole injection layer. In one embodiment, an
OLED may be described as having an "organic layer" disposed between
a cathode and an anode. This organic layer may comprise a single
layer, or may further comprise multiple layers of different organic
materials as described, for example, with respect to FIGS. 1 and
2.
[0051] Structures and materials not specifically described may also
be used, such as OLEDs comprised of polymeric materials (PLEDs)
such as disclosed in U.S. Pat. No. 5,247,190 to Friend et al.,
which is incorporated by reference in its entirety. By way of
further example, OLEDs having a single organic layer may be used.
OLEDs may be stacked, for example as described in U.S. Pat. No.
5,707,745 to Forrest et al, which is incorporated by reference in
its entirety. The OLED structure may deviate from the simple
layered structure illustrated in FIGS. 1 and 2. For example, the
substrate may include an angled reflective surface to improve
out-coupling, such as a mesa structure as described in U.S. Pat.
No. 6,091,195 to Forrest et al., and/or a pit structure as
described in U.S. Pat. No. 5,834,893 to Bulovic et al., which are
incorporated by reference in their entireties.
[0052] Unless otherwise specified, any of the layers of the various
embodiments may be deposited by any suitable method. For the
organic layers, preferred methods include thermal evaporation,
ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and
6,087,196, which are incorporated by reference in their entireties,
organic vapor phase deposition (OVPD), such as described in U.S.
Pat. No. 6,337,102 to Forrest et al., which is incorporated by
reference in its entirety, and deposition by organic vapor jet
printing (OVJP), such as described in U.S. patent application Ser.
No. 10/233,470, which is incorporated by reference in its entirety.
Other suitable deposition methods include spin coating and other
solution based processes. Solution based processes are preferably
carried out in nitrogen or an inert atmosphere. For the other
layers, preferred methods include thermal evaporation. Preferred
patterning methods include deposition through a mask, cold welding
such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which
are incorporated by reference in their entireties, and patterning
associated with some of the deposition methods such as ink-jet and
OVJD. Other methods may also be used. The materials to be deposited
may be modified to make them compatible with a particular
deposition method. For example, substituents such as alkyl and aryl
groups, branched or unbranched, and preferably containing at least
3 carbons, may be used in small molecules to enhance their ability
to undergo solution processing. Substituents having 20 carbons or
more may be used, and 3-20 carbons is a preferred range. Materials
with asymmetric structures may have better solution processibility
than those having symmetric structures, because asymmetric
materials may have a lower tendency to recrystallize. Dendrimer
substituents may be used to enhance the ability of small molecules
to undergo solution processing.
[0053] Devices fabricated in accordance with embodiments of the
invention may be incorporated into a wide variety of consumer
products, including flat panel displays, computer monitors,
televisions, billboards, lights for interior or exterior
illumination and/or signaling, heads up displays, fully transparent
displays, flexible displays, laser printers, telephones, cell
phones, personal digital assistants (PDAs), laptop computers,
digital cameras, camcorders, viewfinders, micro-displays, vehicles,
a large area wall, theater or stadium screen, or a sign. Various
control mechanisms may be used to control devices fabricated in
accordance with the present invention, including passive matrix and
active matrix. Many of the devices are intended for use in a
temperature range comfortable to humans, such as 18 degrees C. to
30 degrees C., and more preferably at room temperature (20-25
degrees C.).
[0054] The materials and structures described herein may have
applications in devices other than OLEDs. For example, other
optoelectronic devices such as organic solar cells and organic
photodetectors may employ the materials and structures. More
generally, organic devices, such as organic transistors, may employ
the materials and structures.
[0055] The terms halo, halogen, alkyl, cycloalkyl, alkenyl,
alkynyl, aralkyl, heterocyclic group, aryl, aromatic group, and
heteroaryl are known to the art, and are defined in U.S. Pat. No.
7,279,704 at cols. 31-32, which are incorporated herein by
reference.
[0056] The devices of the invention have an emissive layer
comprising a phosphorescent (triplet-emitting) organometallic
material. At least one of the phosphorescent materials in the
emissive layer is an Ir(III)cyclometallated alkynyl system. The
Ir(III)cyclometallated alkynyl complexes comprise at least one
cyclometallating ligand. The cyclometallating ligand is preferably
aromatic, with the bonds between the iridium directly to one or
more aromatic rings of which the cyclometallating ligand is
comprised. The cyclometallating ligand also is preferably
bidentate. In preferred embodiments, at least one of the bonds to
the cyclometallating ligand is a carbon-iridium bond. The second
bond to the cyclometallating ligand may be through a second
carbon-iridium bond or through a bond between a heteroatom and the
iridium. In particularly preferred embodiments the heteroatom is
nitrogen. Thus, in some preferred embodiments, the iridium is
bonded to the cyclometallating ligand through a carbon-iridium bond
and a nitrogen-iridium bond. The substructure may be represented
as:
##STR00003##
In the above figure, X.sup.1 X.sup.2 is a substituted or
unsubstituted bidentate cyclometallating ligand. It is preferred
that X.sup.1, X.sup.2, or most preferably both, are a member of an
aromatic ring. In preferred embodiments, X.sup.1 and X.sup.2 are
independently selected from C and N.
[0057] The bidentate cyclometallating ligand may have the following
structure:
##STR00004##
Rings A and B are independently aromatic rings or a fused aromatic
rings that bond to the iridium through X.sup.1 and X.sup.2. X.sup.1
and X.sup.2 are independently selected from C and N. W is selected
from nitrogen and carbon. The dotted lines represent optional
double bonds. The rings can be optionally substituted. Optional
substituents on the rings include alkyl, alkenyl, alkynyl, aralkyl,
CN, CF.sub.3, NR.sub.2, NO.sub.2, OR, halo, and aryl, wherein R is
H, alkyl or aryl.
[0058] In certain embodiments in which the cyclometallating ligand
is a bidentate ligand that is bound to the iridium through a
carbon-metal bond and a nitrogen-metal bond to form a
cyclometallated ring, cyclometallating ligand may have the
following structure:
##STR00005##
Ring A' is an aromatic heterocyclic ring or a fused aromatic
heterocyclic ring with at least one nitrogen atom that coordinates
to iridium. W is selected from carbon or nitrogen. Ring B' is a
phenyl group that is bonded to the iridium through a carbon atom,
and which may additionally be a member of a fused aromatic ring
system. The rings can be optionally substituted. Optional
substituents on the rings include alkyl, alkenyl, alkynyl, aralkyl,
CN, CF.sub.3, NR.sub.2, NO.sub.2, OR, halo, and aryl, wherein R is
H, alkyl or aryl.
[0059] Representative cyclometallating ligands include:
##STR00006##
The above cyclometallating ligands may be optionally substituted.
Optional substituents on the rings include of alkyl, alkenyl,
alkynyl, aralkyl, CN, CF.sub.3, NR.sub.2, NO.sub.2, OR, halo, and
aryl. X is NR, SiR.sub.2, S and O. R is H, alkyl or aryl.
[0060] The Ir(III)cyclometallated alkynyl complexes also comprise
at least one bond to an acetylide ligand. The acetylide ligand is
bonded to the iridium in the Ir(III)cyclometallated alkynyl complex
through an acetylide carbon to provide the substructure
Ir--C.ident.C--R.sup.1.
[0061] The Ir(III)cyclometallated alkynyl complexes may also
comprise an ancillary ligand to fill the coordination sphere of the
iridium center. These ligands are referred to as "ancillary"
because it is believed that they may modify the photoactive
properties of the molecule, as opposed to directly contributing to
the photoactive properties. The definitions of photoactive and
ancillary are intended as non-limiting theories. The ancillary
ligands may be selected from those disclosed in the following
references:
U.S. Pat. Application Publ. No. 2002-0034656 (K&K 10020/15303),
FIGS. 11-50, U.S. Pat. Application Publ. No. 2003-0072964 (Thompson
et al.), paragraphs 7-132; and FIGS. 1-8; U.S. Pat. Application
Publ. No. 2002-0182441 (Lamansky et al.), paragraphs 13-165,
including FIGS. 1-9(g); U.S. Pat. No. 6,420,057 B1 (Ueda et al.),
col. 1, line 57, through col. 88, line 17, including each compound
I-1 through XXIV-12; U.S. Pat. No. 6,383,666 B1 (Kim et al.), col.
2, line 9, through col. 21, lin3 67; U.S. Pat. Application Publ.
No. 2001-0015432 A1 (Igarashi et al.), paragraphs 2-57, including
compounds (1-1) through (1-30); U.S. Pat. Application Publ. No.
2001-0019782 A1 (Igarashi et al.), paragraphs 13-126, including
compounds (1-1) through (1-70), and (2-1) through (2-20); U.S. Pat.
Application Publ. No. 2002-0024293 (Igarashi et al.), paragraphs
7-95, including general formulas K-I through K-VI, and example
compounds (K-1) through (K-25); U.S. Pat. Application Publ. No.
2002-0048689 A1 (Igarashi et al.), paragraphs 5-134, including
compounds 1-81, and example compounds (1-1) through (1-81); U.S.
Pat. Application Publ. No. 2002-0063516 (Tsuboyama et al.),
paragraphs 31-161, including each compound 1-16; U.S. Pat.
Application Publ. No. 2003-0068536 (Tsuboyama et al.), paragraphs
31-168, including each compound in Tables 1-17, corresponds to
EP-1-239-526-A2; U.S. Pat. Application Publ. No. 2003-0091862
(Tokito et al.), paragraphs 10-190, including each compound in
Tables 1-17, corresponds to EP-1-239-526-A2; U.S. Pat. Application
Publ. No. 2003-0096138 (Lecloux et al.), paragraphs 8-124,
including FIGS. 1-5; U.S. Pat. Application Publ. No. 2002-0190250
(Grushin et al.), paragraphs 9-191; U.S. Pat. Application Publ. No.
2002-0121638 (Grushin et al.), paragraphs 8-125; U.S. Pat.
Application Publ. No. 2003-0068526 (Kamatani et al.), paragraphs
33-572, including each compound in Tables 1-23; U.S. Pat.
Application Publ. No. 2003-0141809 (Furugori et al.), paragraphs
29-207; U.S. Pat. Application Publ. No. 2003-0162299 A1 (Hsieh et
al.), paragraphs 8-42; WO 03/084972, (Stossel et al.), Examples
1-33; WO 02/02714 A2 ((Petrov et al.), pages 2-30, including each
compound in Tables 1-5; EP 1-191-613 A1 (Takiguchi et al.),
paragraphs 26-87, including each compound in Tables 1-8,
(corresponding to U.S. Pat. Application Publ. No. 2002-0064681);
and EP 1-191-614 A2 (Tsuboyama et al.), paragraphs 25-86, including
each compound in Tables 1-7; which are incorporated herein by
reference in their entirety.
[0062] In certain embodiments, the ancillary ligand is selected to
have the formula --C.ident.N--R.sup.3; wherein R.sup.3 is selected
from the group consisting of alkyl, cycloalkyl, alkenyl, aryl,
aralkyl, and heteroaryl.
[0063] In preferred aspects of the invention, the triplet-emitting
material is a compound having the formula I:
##STR00007##
wherein: X.sup.1 X.sup.2 is a substituted or unsubstituted
bidentate cyclometallated aromatic ligand; X.sup.1 and X.sup.2 are
independently selected front C and N; Z is an acetylide ligand
having the structure: [0064] --C.ident.C--R.sup.1,
--C.ident.C--(C.ident.C).sub.x--R.sup.1,
--C.ident.C-(A-C.ident.C).sub.y--R.sup.1, each R.sup.1 is
independently selected from the group consisting of H, alkyl,
cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl,
Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic group, each of
which may be substituted or unsubstituted; each x is independently
selected from 0-5; each y is independently selected from 0-5; each
R.sup.2 is independently selected from H, alkyl, cycloalkyl,
alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group;
M is a metal atom; L is a mono-, bi- or tridentate ligand; z is
0-5; A is aryl or heteroaryl; Y is a monodentate ancillary ligand;
a is 1, 2, 3, or 4; b is 0, 1, 2, or 3; n is 1 or 2; the sum of
a+b+n is 4 or 5; and Cat is an optional cation the charge of which
provides a net neutral charge for formula I.
[0065] In certain preferred embodiments, n is 2, a is 1 and b is 1.
In other preferred embodiments, n is 2, a is 2, and b is 0.
[0066] In other aspects of the invention, the triplet-emitting
material is a compound having the formula II:
##STR00008##
wherein C N is a substituted or unsubstituted cyclometallated
ligand; each R.sup.1 is independently selected from the group
consisting of H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl,
heteroaryl, Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic
group, each of which may be substituted or unsubstituted; each
R.sup.2 is independently selected from H, alkyl, cycloalkyl,
alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group;
M is a metal atom; L is a mono-, bi- or tridentate ligand; z is
0-5; Y is a monodentate ancillary ligand; and Cat is an optional
cation the charge of which provides a net neutral charge for
formula II.
[0067] In other aspects of the invention, the triplet-emitting
material is a compound having the formula III:
##STR00009##
wherein C N is a substituted or unsubstituted cyclometallated
ligand;
[0068] R.sup.1a and R.sup.1b are independently selected from the
group consisting of
H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl,
Si(R.sup.2).sub.3, M(L).sub.z, and a heterocyclic group, each of
which may be substituted or unsubstituted; each R.sup.2 is
independently selected from H, alkyl, cycloalkyl, alkenyl,
cycloalkenyl, aryl, heteroaryl, and a heterocyclic group; M is a
metal atom; L is a mono-, bi- or tridentate ligand; z is 0-5; and
Cat is an optional cation the charge of which provides a net
neutral charge for formula III. In each embodiment that may
comprise the cation Cat, the cation may be selected from any
appropriate species having a positive charge, including metal
cations (such as alkali metal cations) and quaternary ammonium
cations.
[0069] The acetylide ligand (Z) may accommodate a wide variety of
substituent groups (designated R.sup.1, R.sup.1a or R.sup.1b in the
above structure). In preferred embodiments, each R.sup.1, R.sup.1a
or R.sup.1b is independently selected from:
##STR00010## ##STR00011## ##STR00012##
wherein each X is independently selected from C(R').sub.d,
N(R').sub.e, S, O, SO, SO.sub.2 and Si(R').sub.d; d is 1 or 2; e is
0 or 1; n is 1 to 5; each R is independently selected from H, halo,
CN, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, heteroaryl; OR',
NR'.sub.2, CO.sub.2R', COR', CONR'.sub.2, and Si(R').sub.3; each R'
is independently selected from H, alkyl, cycloalkyl, alkenyl, aryl,
aralkyl, and heteroaryl; M is a metal atom; L is a mono-, bi- or
tridentate ligand; and j is 0 to 5. Also, each of the above groups
depicted as preferred embodiments of R.sup.1, R.sup.1a or R.sup.1b
may be further optionally substituted at any available carbon atom
by a substituent selected from halo, CN, alkyl, cycloalkyl,
alkenyl, aryl, aralkyl, heteroaryl; OR', NR'.sub.2, CO.sub.2R',
COR', CONR'.sub.2, and Si(R').sub.3.
[0070] In certain embodiments of the invention, the relative
triplet energy of the acetylide ligands and the cyclometallated
ligands, allow the tuning of the emission of the claimed complexes,
such as that if the triplet energy of the acetylides is lower than
the cyclometallating ligands, the emission may be driven by the
former group.
[0071] An organic light emitting device is also provided. The
device may include an anode, a cathode, and an organic emissive
layer disposed between the anode and the cathode. The organic
emissive layer may include a host and a phosphorescent dopant.
Combination with Other Materials
[0072] The materials described herein as useful for a particular
layer in an organic light emitting device may be used in
combination with a wide variety of other materials present in the
device. For example, emissive dopants disclosed herein may be used
in conjunction with a wide variety of hosts, transport layers,
blocking layers, injection layers, electrodes and other layers that
may be present. The materials described or referred to below are
non-limiting examples of materials that may be useful in
combination with the compounds disclosed herein, and one of skill
in the art can readily consult the literature to identify other
materials that may be useful in combination.
[0073] In addition to and/or in combination with the materials
disclosed herein, many hole injection materials, hole transporting
materials, host materials, dopant materials, exciton/hole blocking
layer materials, electron transporting and electron injecting
materials may be used in an OLED. Non-limiting examples of the
materials that may be used in an OLED in combination with materials
disclosed herein are listed in Table 1 below. Table 1 lists
non-limiting classes of materials, non-limiting examples of
compounds for each class, and references that disclose the
materials.
TABLE-US-00001 TABLE 1 MATERIAL EXAMPLES OF MATERIAL PUBLICATIONS
Hole injection materials Phthalo- cyanine and porphryin compounds
##STR00013## Appl. Phys. Lett. 69, 2160 (1996) Starburst
triarylamines ##STR00014## J. Lumin. 72-74, 985 (1997) CF.sub.x
Fluoro- hydrocarbon polymer ##STR00015## Appl. Phys. Lett. 78, 673
(2001) Conducting polymers (e.g., PEDOT:PSS, polyaniline, poly-
thiophene) ##STR00016## Synth. Met. 87, 171 (1997) WO2007002683
Phosphonic acid and sliane SAMs ##STR00017## US20030162053 Triaryl-
amine or poly- thiophene polymers with conducitivity dopants
##STR00018## EA01725079A1 and ##STR00019## ##STR00020## Arylamines
complexed with metal oxides such as molybdenum and tungsten oxides
##STR00021## SID Symposium Digest, 37, 923 (2006) WO2009018009
p-type semi- conducting organic complexes ##STR00022##
US20020158242 Metal organo- metallic complexes ##STR00023##
US20060240279 Cross- linkable compounds ##STR00024## US20080220265
Hole transporting materials Triarylamines (e.g., TPD, .alpha.-NPD)
##STR00025## Appl. Phys. Lett. 51, 913 (1987) ##STR00026##
US5061569 ##STR00027## EP650955 ##STR00028## J. Mater. Chem. 3, 319
(1993) ##STR00029## Appl. Phys. Lett. 90, 183503 (2007)
##STR00030## Appl. Phys. Lett. 90, 183503 (2007) Triaylamine on
spirofluorene core ##STR00031## Synth. Met. 91, 209 (1997)
Arylamine carbazole compounds ##STR00032## Adv. Mater. 6, 677
(1994), US20080124572 Triarylamine with (di)benzo- thiophene/ (di)-
benzofuran ##STR00033## US20070278938, US20080106190 Indolo-
carbazoles ##STR00034## Synth. Met. 111, 421 (2000) Isoindole
compounds ##STR00035## Chem. Mater. 15, 3148 (2003) Metal carbene
complexes ##STR00036## US20080018221 Phosphorescent OLED host
materials Red hosts Aryl- carbazoles ##STR00037## Appl. Phys. Lett.
78, 1622 (2001) Metal 8- hydroxy- quinolates (e.g., Alq.sub.3,
BAlq) ##STR00038## Nature 395, 151 (1998) ##STR00039##
US20060202194 ##STR00040## WO2005014551 ##STR00041## WO2006072002
Metal phenoxy- benzo- thiazole compounds ##STR00042## Appl. Phys.
Lett. 90, 123509 (2007) Conjugated oligomers and polymers (e.g.,
poly- fluorene) ##STR00043## Org. Electron. 1, 15 (2000) Aromatic
fused rings ##STR00044## WO2009066779, WO2009066778, WO2009063833,
US20090045731, US20090045730, WO2009008311, US20090008605,
US20090009065 Zinc complexes ##STR00045## WO2009062578 Green hosts
Aryl- carbazoles ##STR00046## Appl. Phys. Lett. 78, 1622 (2001)
##STR00047## US20030175553 ##STR00048## WO2001039234 Aryl-
triphenylene compounds ##STR00049## US20060280965 ##STR00050##
US20060280965 ##STR00051## WO2009021126 Donor acceptor type
molecules ##STR00052## WO2008056746 Aza- carbazole/ DBT/DBF
##STR00053## JP2008074939 Polymers (e.g., PVK) ##STR00054## Appl.
Phys. Lett. 77, 2280 (2000) Spiro- fluorene compounds ##STR00055##
WO2004093207 Metal phenoxy- benzo- oxazole compounds ##STR00056##
WO2005089025 ##STR00057## WO2006132173 ##STR00058## JP200511610
Spiro- fluorene- carbazole compounds ##STR00059## JP2007254297
##STR00060## JP2007254297 Indolo- cabazoles ##STR00061##
WO2007063796 ##STR00062## WO2007063754 5-member ring electron
deficient heterocycles (e.g., triazole, oxadiazole) ##STR00063## J.
Appl. Phys. 90, 5048 (2001) ##STR00064## WO2004107822 Tetra-
phenylene complexes ##STR00065## US20050112407 Metal phenoxy-
pyridine compounds ##STR00066## WO2005030900 Metal coordination
complexes (e.g., Zn, Al with N{circumflex over ( )}N ligands)
##STR00067## US20040137268, US20040137267 Blue hosts Aryl-
carbazoles ##STR00068## Appl. Phys. Lett, 82, 2422 (2003)
##STR00069## US20070190359 Dibenzo- thiophene/ Dibenzo- furan-
carbazole compounds ##STR00070## WO2006114966, US20090167162
##STR00071## US20090167162 ##STR00072## WO2009086028 ##STR00073##
US20090030202, US20090017330 Silicon aryl compounds ##STR00074##
US20050238919 ##STR00075## WO2009003898 Silicon/ Germanium aryl
compounds ##STR00076## EP2034538A Aryl benzoyl ester ##STR00077##
WO2006100298 High triplet metal organo- metallic complex
##STR00078## US7154114 Phosphorescent dopants Red dopants Heavy
metal porphyrins (e.g., PtOEP) ##STR00079## Nature 395, 151 (1998)
Iridium (III) organo- metallic complexes ##STR00080## Appl. Phys.
Lett. 78, 1622 (2001) ##STR00081## US2006835469 ##STR00082##
US2006835469 ##STR00083## US20060202194 ##STR00084## US20060202914
##STR00085## US20070087321 ##STR00086## US20070087321 ##STR00087##
Adv. Mater. 19, 739 (2007) ##STR00088## WO2009100991 ##STR00089##
WO2008101842 Platinum (II) organo- metallic complexes ##STR00090##
WO2003040257 Osminum (III) complexes ##STR00091## Chem. Mater. 17,
3532 (2005) Ruthenium (II) complexes ##STR00092## Adv. Mater. 17,
1059 (2005) Rhenium (I), (II), and (III) complexes ##STR00093##
US20050244673 Green dopants Iridium (III) organo- metallic
complexes ##STR00094## Inorg. Chem. 40, 1704 (2001) ##STR00095##
US20020034656 ##STR00096## US7332232 ##STR00097## US20090108737
##STR00098## US20090039776 ##STR00099## US6921915 ##STR00100##
US6687266 ##STR00101## Chem. Mater. 16, 2480 (2004) ##STR00102##
US20070190359 ##STR00103## US 20060008670 JP2007123392 ##STR00104##
Adv. Mater. 16, 2003 (2004) ##STR00105## Angew. Chem. Int. Ed.
2006, 45, 7800 ##STR00106## WO2009050290 ##STR00107## US20090165846
##STR00108## US20080015355 Monomer for polymeric metal organo-
metallic compounds ##STR00109## US7250226, US7396598 Pt (II)
organo- metallic complexes, including polydentated ligands
##STR00110## Appl. Phys. Lett. 86, 153505 (2005) ##STR00111## Appl.
Phys. Lett. 86, 153505 (2005) ##STR00112## Chem. Lett. 34, 592
(2005) ##STR00113## WO2002015645 ##STR00114## US20060263635 Cu
complexes ##STR00115## WO2009000673 Gold complexes ##STR00116##
Chem. Commun. 2906 (2005) Rhenium (III) complexes ##STR00117##
Inorg. Chem. 42, 1248 (2003) Deuterated organo- metallic complexes
##STR00118## US20030138657
Organo- metallic complexes with two or more metal centers
##STR00119## US20030152802 ##STR00120## US7090928 Blue dopants
Iridium (III) organo- metallic complexes ##STR00121## WO2002002714
##STR00122## WO2006009024 ##STR00123## US20060251923 ##STR00124##
US7393599, WO2006056418, US20050260441, WO2005019373 ##STR00125##
US7534505 ##STR00126## US7445855 ##STR00127## US20070190359,
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##STR00133## WO2005123873 ##STR00134## WO2005123873 ##STR00135##
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BCP, BPhen) ##STR00141## Appl. Phys. Lett. 75, 4 (1999)
##STR00142## Appl. Phys. Lett. 79, 449 (2001) Metal 8- hydroxy-
quinolates (e.g., BAlq) ##STR00143## Appl. Phys. Lett. 81, 162
(2002) 5-member ring electron deficient heterocycles such as
triazole, oxadiazole, imidazole, benzo- imidazole ##STR00144##
Appl. Lett. 81, 162 (2002) Triphenylene compounds ##STR00145##
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WO2008132085 Electron transporting materials Anthracene- benzo-
imidazole compounds ##STR00148## WO2003060956 ##STR00149##
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US20090115316 Anthracene- benzothiazole compounds ##STR00151##
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[0074] It is understood that the various embodiments described
herein are by way of example only, and are not intended to limit
the scope of the invention. For example, many of the materials and
structures described herein may be substituted with other materials
and structures without deviating from the spirit of the invention.
The present invention as claimed may therefore includes variations
from the particular examples and preferred embodiments described
herein, as will be apparent to one of skill in the art. It is
understood that various theories as to why the invention works are
not intended to be limiting.
EXPERIMENTAL
Iridium Complex Synthesis/Absorption/Emission
[0075] The general reactions follow the procedure reported in
literature by Fornies et al. Dalton trans. 2003, 822-830; W. Weng,
et al. J. Am. Chem. Soc. 1995, 117, 11922-11931 and modified by
disclosed below. The general synthesis was performed as
follows:
Example 1
a) Synthesis of the (C N).sub.2Ir(CNtBu)OTf (Scheme 1)
[0076] 1 equivalent of ((C N).sub.2Ir .mu.Cl).sub.2, synthesized by
the Nonoyama's procedure (M. Nonoyama, Bull. Chem. Soc. Jap. 1974,
47, 767), is reacted with and 2.05 equivalents of
tert-butylisocyanide in CH.sub.2Cl.sub.2 at room temperature for 1
hour. The mixture is flash chromatographed through Silica with
CH.sub.2Cl.sub.2 to remove less polar impurities; the product is
collected using CH.sub.2Cl.sub.2/MeOH 95/5; removing the solvent
and washing the residue with MeOH to afford the clean (C N).sub.2Ir
(CNtBu)Cl.
[0077] (C N).sub.2Ir (CNtBu)Cl is converted in the corresponding
trifluoromethanesulfonate (OTf) by reacting its solution in
CH.sub.2Cl.sub.2 with 1.1 equivalent of AgOTf dissolved in MeOH at
room temperature for 1 h. (J. Li et al., Polyhedron, 2004, 23(2-3),
419-428). The precipitate of AgCl was removed filtering the
suspension through celite. The solvent is removed affording the (C
N).sub.2Ir(CNtBu)OTf.
##STR00165##
b) Synthesis of the (C N).sub.2Ir(CNtBu)(CCAr)
[0078] To a solution of (C N).sub.2Ir (CNtBu)OTf in dry THF at
-78.degree. C., a solution of fresh LiC.ident.CAr (2-4 equivalents)
prepared from HC.ident.CAr (1.1 equivalents) and nBuLi (1
equivalent) in dry THF at -78.degree. C. was added drop wise via
cannula. The mixture is reacted for 1 h at -78.degree. C. and the
temperature allowed to reach RT over 2 hours.
[0079] The solvent is removed and the crude crystallized from ethyl
acetate/hexane or diethylether/hexane. The clean product is
obtained.
##STR00166##
Example 2
c) Synthesis of the (C N).sub.2Ir(MeOH).sub.2OTf
[0080] 1 equivalent of ((C N).sub.2Ir .mu.Cl).sub.2, prepared by
the Nonoyama's procedure (M. Nonoyama, Bull. Chem. Soc. Jap. 1974,
47, 767) is converted in the corresponding
trifluoromethanesulfonate (OTf) by treating its solution in
CH.sub.2Cl.sub.2 with 2.2 equivalent of AgOTf dissolved in MeOH at
room temperature for 1 h. (J. Li et al. Polyhedron, 2004, 23(2-3),
419-428). The precipitate of AgCl was removed by filtering the
suspension through celite. The solvent is removed affording the (C
N).sub.2Ir(MeOH).sub.2OTf
##STR00167##
d) Synthesis of the [(C N).sub.2Ir(CCAr).sub.2]Li
[0081] To a solution of (C N).sub.2Ir(MeOH).sub.2OTf in dry THF at
-78.degree. C. a solution of fresh LiC.ident.CAr (4-6 equivalents)
prepared from HC.ident.CAr (1.1 equivalents) and nBuLi (1
equivalent) in dry THF at -78.degree. C. was added drop wise via
cannula. The mixture is reacted for 1 h at -78.degree. C. and the
temperature allowed to reach RT over 2 hours.
##STR00168##
Example 3
Synthesis of the Ir(ppz).sub.2(CNtBu)OTf
[0082] 1.073 g of ((ppz).sub.2Ir.mu.Cl).sub.2 (1.043 mmol)
dissolved in 20 mL of CH.sub.2Cl.sub.2 at room temperature was
reacted with 0.25 mL of tert-butylisocyanide (2.08 mmol) for 1
hour. The mixture was flash chromatographed through silica with
CH.sub.2Cl.sub.2 to remove the less polar impurities and the
product was eluted using CH.sub.2Cl.sub.2/MeOH 95/5. Removing the
solvent and washing the residue with MeOH afforded 830 mg of clean
Ir(ppz).sub.2(CNtBu)Cl (71% yield).
[0083] .sup.1H NMR (400 MHz, CDCl.sub.3, ppm): 1.40 (9H, s); 6.15
(1H, dd, J=1.6, 7.2 Hz); 6.28 (1H, dd, J=1.2, 7.6 Hz); 6.61 (1H,
m); 6.66 (1H, dt, J=1.2, 7.6 Hz); 6.71 (1H, m); 6.74 (1H, dt,
J=1.2, 7.2 Hz); 6.85 (2H, m); 7.15 (2H, t, J=7.6 Hz); 7.90 (1H, d,
J=2.4 Hz); 8.02 (1H, d, J=2.8 Hz); 8.09 (1H, d, J=2.6 Hz); 8.37
(1H, d, J=2.6 Hz).
[0084] 500 mg of Ir(ppz).sub.2(CNtBu)Cl (0.84 mmol), dissolved in
50 mL of CH.sub.2Cl.sub.2, and 236 mg of AgOTf (0.92 mmol)
dissolved in 25 mL MeOH were added at room temperature. The mixture
was reacted for 2 h. The precipitate of AgCl was removed by
filtering the suspension through celite. The solvent was removed
affording 626 mg Ir(ppz).sub.2(CNtBu)OTf (>99% yield).
[0085] .sup.1H NMR (400 MHz, CD.sub.3CN, ppm): 1.40 (9H, s); 6.08
(2H, t, J=7.2 Hz); 6.71 (1H, dt, J=1.47, 7.9 Hz); 6.81 (2H, m);
6.87 (1H, t, J=2.64 Hz); 6.95 (1H, dt, J=1.17, 7.63 Hz); 7.00 (1H,
dt, J=1.17, 7.63 Hz); 7.38 (1H, dd, J=1.17, 7.63 Hz); 7.41 (1H, dd,
J=1.17, 7.92 Hz); 8.06 (1H, d, J=2.1 Hz); 8.11 (1H, d, J=2.3 Hz);
8.41 (1H, d, J=2.93 Hz); 8.43 (1H, d, J=2.93 Hz).
[0086] .sup.19F NMR (376 MHz, CD.sub.3CN, ppm): -79.3 (s).
Example 4
Synthesis of the Ir(ppy).sub.2(CNtBu)OTf
[0087] 482 mg of ((ppy).sub.2Ir .mu.Cl).sub.2 (0.45 mmol) suspended
in 10 mL of CH.sub.2Cl.sub.2 at room temperature was reacted with
0.11 mL of tertButylisocyanide (0.92 mmol) for 1 hour. The clear
solution was flash chromatographed through Silica with
CH.sub.2Cl.sub.2 to remove less polar impurities and the product
was eluted using CH.sub.2Cl.sub.2/MeOH 95/5. Removing the solvent
and washing the residue with MeOH afforded 405 mg of clean
Ir(ppy).sub.2(CNtBu)Cl (72% yield).
[0088] .sup.1H NMR (400 MHz, CDCl.sub.3, ppm): 1.323 (9H, s); 6.10
(1H, dd, J=1.6, 6.97 Hz); 6.33 (1H, dd, J=1.6, 7.5 Hz); 6.73 (1H,
dt, J=1.6, 7.78 Hz); 6.79 (1H, dt, J=1.3, 7.2 Hz); 6.85 (2H, tt,
1.34, 7.5 Hz); 7.13 (1H, m); 7.24 (1H, m); 7.56 (2H, m); 7.83 (4H,
m); 9.08 (1H, d, J=6.35 Hz); 9.91 (1H, d, J=6.35 Hz).
[0089] 400 mg of Ir(ppy).sub.2(CNtBu)Cl (0.646 mmol) dissolved in
40 mL of CH.sub.2Cl.sub.2 and 265 mg of AgOTf (1.03 mmol) dissolved
in 20 mL MeOH were added at room temperature, and the mixture was
reacted for 2 h. The precipitate of AgCl was removed by filtering
the suspension through celite. The solution was diluted with 20 mL
of ethyl ether and washed with water. The aqueous phase was back
extracted with CH.sub.2Cl.sub.2 and the organic phases combined.
The organic solvent was removed under reduced pressure affording
386 mg Ir(ppy).sub.2(CNtBu)OTf (78% yield).
[0090] .sup.1H NMR (400 MHz, CD.sub.3CN, ppm): 1.34 (9H, s); 6.05
(1H, d, J=7.63 Hz); 6.13 (1H, d, J=7.63 Hz); 6.78 (1H, t, J=7.05
Hz); 6.85 (1H, t, J=7.05 Hz); 6.95 (2H, m); 7.43 (2H, m); 7.69 (1H,
d, J=7.63 Hz); 7.72 (1H, d, J=7.63 Hz); 8.10 (4H, m); 9.03 (1H, d,
J=5.57 Hz); 9.08 (1H, d, J=5.87 Hz).
[0091] .sup.19F NMR (376 MHz, CD.sub.3CN, ppm): -79.3 (s).
Example 5
Synthesis of the Ir(ppy).sub.2(MeOH).sub.2 OTf
[0092] 300 mg of ((ppy).sub.2Ir .mu.Cl).sub.2 (0.28 mmol) suspended
in 30 mL of CH.sub.2Cl.sub.2 at room temperature and 158 mg of
AgOTf (0.61 mmol) dissolved in 10 mL MeOH were added at room
temperature, and the mixture was reacted for 2 h. The precipitate
of AgCl was removed by filtering the suspension through celite. The
solvent was removed under reduced pressure and the crude product
was crystallized from CH.sub.2Cl.sub.2-hexane affording 420 mg
Ir(ppy).sub.2(MeOH).sub.2OTf (90% yield).
Example 6
Synthesis of the Ir(ppz).sub.2(CNtBu)(CCPh)
[0093] A solution of fresh LiC.ident.CPh, prepared by reacting
0.046 mL of phenylacetylene (0.42 mmol) and 0.51 mL of 1.5M hexane
nBuLi solution (0.34 mmol) in 20 mL of dry THF at -78.degree. C.
for 0.5 hour, was added drop-wise via cannula to a solution of 200
mg of Ir(ppz).sub.2(CNtBu)OTf (0.28 mmol) in 15 mL of dry THF at
-78.degree. C. The mixture was reacted for 1 h at -78.degree. C.
and the temperature was raised to RT over 2 hours.
[0094] 0.5 mL of isopropyl alcohol was added and 90% of the solvent
was removed under reduced pressure. The solution was diluted with
ethyl acetate and washed with water. The organic phase was dried
under reduced pressure. The crude material was dissolved in ethyl
acetate, filtered to remove insoluble material, and the water
precipitated with ethylic ether affording 60 mg of
Ir(ppz).sub.2(CNtBu)(CCPh) (32% yield).
[0095] LCMS, C18, acetonitrile:H.sub.2O, 80:20 to 90:10; ESI+,
[M+H].sup.+ 664.4
Example 7
Synthesis of the Ir(ppy).sub.2(CNtBu)(CCPh)
[0096] A solution of fresh LiC.ident.LCPh was prepared by reacting
0.057 mL of phenylacetylene (0.525 mmol) and 0.298 mL of 1.5M nBuLi
in hexane solution (0.462 mmol) in 15 mL of dry THF at -78.degree.
C. for 0.5 hour. The resulting solution was added drop wise via
cannula to a solution of 160 mg of Ir(ppy).sub.2(CNtBu)OTf (0.22
mmol) in 10 mL of dry THF at -78.degree. C. The mixture was reacted
for 1 h at -78.degree. C. and the temperature was raised to RT over
2 hours. The solvent was removed under reduced pressure and the
crude was extracted with diethylether. 67.8 mg of
Ir(ppy).sub.2(CNtBu)(CCPh) is obtained (45% yield).
[0097] LCMS, C18, acetonitrile:H.sub.2O, 80:20 to 90:10; ESI+,
[M+H].sup.+ 686.4.
Example 8
Synthesis of the Ir(ppy).sub.2(CNtBu)(CCPhenantr)
[0098] A solution of fresh LiC.ident.CPhenantrene was prepared by
reacting 35 mg of 9-ethinyl-phenantrene (0.173 mmol) and 0.125 mL
of 1.5M nBuLi hexane solution (0.173 mmol) in 10 mL of dry THF at
-78.degree. C. for 0.5 hour. The solution was added drop wise via
cannula to a solution of 60 mg of Ir(ppy).sub.2(CNtBu)OTf (0.0785
mmol) in 5 mL of dry THF at -78.degree. C. The mixture was reacted
for 1 h at -78.degree. C. and the temperature was raised to RT over
2 hours. The solvent was removed under reduced pressure and the
crude was dissolved in diethylether and precipitated with hexane
affording 77 mg of Ir(ppy).sub.2(CNtBu)(CCPheneatr) (77%
yield).
[0099] LCMS, C18, acetonitrile:H.sub.2O, 80:20 to 90:10; ESI+,
[M+H].sup.+ 786.5.
Example 9
Synthesis of the Ir(ppy).sub.2(CCPh).sub.2Li
[0100] A solution of fresh LiC.ident.CPh was prepared by reacting
0.118 mL of phenylacetylene (1.08 mmol) and 0.48 mL of 1.5M hexane
nBuLi solution (0.72 mmol) in 50 mL of dry THF at -78.degree. C.
for 0.5 hour. The solution was added drop wise via cannula to a
solution of 150 mg of Ir(ppy).sub.2(MeOH).sub.2OTf (0.18 mmol) in
10 mL of dry THF at -78.degree. C. The mixture was reacted for 1 h
at -78.degree. C. and the temperature was raised to RT over 2
hours. The solvent was removed under reduced pressure obtaining the
Ir(ppy).sub.2(CCPh).sub.2Li.
[0101] LCMS, C18, acetonitrile:H.sub.2O, 80:20 to 90:10; ESI+-,
[Ir(ppy).sub.2(CCPh).sub.2].sup.-=703
Example 10
Synthesis of the Ir(ppz).sub.2(CNtBu)(CCPhenantr)
[0102] A solution of fresh LiC.ident.CPhenantrene prepared by
reacting 102.7 mg of 9-Ethinyl-Phenantrene (0.508 mmol) and 0.303
mL of 1.6M hexane nBuLi solution (0.486 mmol) in 10 mL of dry THF
at -78.degree. C. for 0.5 hour was added drop wise, via cannula, to
a solution of 157 mg of Ir(ppz).sub.2(CNtBu)OTf (0.221 mmol) in 20
mL of dry THF at -78.degree. C. The mixture was reacted for 1 h at
-78.degree. C. and the temperature raised to RT over 2 hours.
[0103] The solvent was removed under reduced pressure, the crude
was dissolved in ethylacetate and the product precipitated with
diethylether. The precipitate was washed 3 times with
diethyleter/hexane 1/3 v/v obtaining. The organic solution was
dried and the solid was washed 3 times with diethyleter/hexane 1/3
v/v. The two precipitate accounts for 140 mg of
Ir(ppz).sub.2(CNtBu)(CCPheneatr) (83% yield).
[0104] LCMS, C8, acetonitrile:H.sub.2O, 80:20; ESI+: [M+H].sup.+
764.2; [M-(CCPhenantrene)+AcCN].sup.+ 603.2.
[0105] Table 1 provides the photophysical properties at room
temperature in toluene (tol) or CH.sub.2CL.sub.2 (DCM) and at 77K
in 2MeTHF (77K). Criteria for the reading of the emissions: peak
maxima of the shortest wavelength emission.
TABLE-US-00002 TABLE 2 Emission RT Emission 77 K Compound .lamda.
(nm) .PHI. PL .tau. .mu.s .lamda. (nm) .tau. .mu.s
Ir(ppz).sub.2(CNtBu)(CCPh) -- -- -- 420 1460
Ir(ppz).sub.2(CNtBu)(CCPhenantr) 548 0.07(tol) 442 531 1758
Ir(ppy).sub.2(CNtBu)(CCPh) 472 0.26(tol) 0.81(70%) 458 4.3(64%)
1.92(30%) 9.06(36%).sup.a .sup. 4.77.sup.b
Ir(ppy).sub.2(CNtBu)(CCPhenantr) 470 0.07(DCM) 0.52 and 530 1515
156 .sup.alifetime @ 500 nm; .sup.blifetime @ 460 nm;
Example 11
[0106] Devices having the following general devices structure were
prepared: [0107] ITO/PVK/CBP(Ir complex 8% w/w)/BCP(400
.ANG.)/LiF(10 .ANG.)/Al
[0108] The PVK layer was formed by spin coating on a ITO substrate
from a 20 mg/mL chlorobenzene solution at 3000 rpm for 40 seconds
and annealed at 150.degree. C. for 1 h. The emissive layer was
formed using a solution of CBP (with 8% w/w of the Ir complex) spin
coated on the PVK layer from a 15 mg/mL chloroform solution (with
the proper Ir complex co-dissolved at 8% w/w concentration) at 3000
rpm for 40 sec. No annealing performed was performed for this
layer. The BCP, LiF and Al were then vacuum deposited in
sequence.
[0109] The device data for devices prepared using
Ir(ppz).sub.2(CNtBu)(CCPhenantr), Ir(ppy).sub.2(CNtBu)(CCPhenantr),
and, as reference, fac-Ir(ppy).sub.3, as the Ir complex are
presented in FIGS. 20 to 23.
* * * * *