U.S. patent application number 16/563311 was filed with the patent office on 2020-02-06 for organic electroluminescent materials and devices.
This patent application is currently assigned to Universal Display Corporation. The applicant listed for this patent is Universal Display Corporation. Invention is credited to Yi-Tzu HUNG, Raymond KWONG, Ken-Tsung WONG, Chuanjun XIA.
Application Number | 20200044163 16/563311 |
Document ID | / |
Family ID | 54702811 |
Filed Date | 2020-02-06 |
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United States Patent
Application |
20200044163 |
Kind Code |
A1 |
HUNG; Yi-Tzu ; et
al. |
February 6, 2020 |
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES
Abstract
A luminescent materials including donor-acceptor compounds with
a nitrogen containing donor connected to the 1-position of a
carbazole and triazene acceptor connected at the 9-position is
disclosed.
Inventors: |
HUNG; Yi-Tzu; (Taipei,
TW) ; WONG; Ken-Tsung; (Taipei, TW) ; KWONG;
Raymond; (Shatin, HK) ; XIA; Chuanjun;
(Lawrenceville, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Universal Display Corporation |
Ewing |
NJ |
US |
|
|
Assignee: |
Universal Display
Corporation
Ewing
NJ
|
Family ID: |
54702811 |
Appl. No.: |
16/563311 |
Filed: |
September 6, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14294336 |
Jun 3, 2014 |
10461260 |
|
|
16563311 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 51/0067 20130101;
C07D 409/14 20130101; H01L 51/5012 20130101; H01L 51/0072 20130101;
H01L 51/5036 20130101; H01L 2251/308 20130101; C07D 403/14
20130101; H01L 51/0061 20130101; H01L 51/5016 20130101; H01L
2251/5376 20130101; C07D 401/14 20130101; C09K 11/06 20130101; C07D
403/04 20130101; C07D 487/06 20130101; C07D 403/10 20130101; C07D
405/14 20130101; H01L 51/0073 20130101; H01L 51/0074 20130101 |
International
Class: |
H01L 51/00 20060101
H01L051/00; C07D 403/04 20060101 C07D403/04; C07D 403/10 20060101
C07D403/10; C07D 405/14 20060101 C07D405/14; C07D 409/14 20060101
C07D409/14; C07D 487/06 20060101 C07D487/06; C07D 401/14 20060101
C07D401/14 |
Claims
1. A compound having a structure according to Formula 1:
##STR00203## wherein R.sup.a to R.sup.g, R.sup.1 and R.sup.2 are
independently selected from the group consisting of hydrogen,
deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,
alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,
heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,
carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,
sulfonyl, phosphino, and combinations thereof; and wherein Ar.sup.1
to Ar.sup.3 are independently substituted or unsubstituted aryl or
heteroaryl and can connect to one another to form fused ring(s)
and, wherein L is a direct bond or a linker.
2. The compound of claim 1, wherein R.sup.a to R.sup.g are H.
3. The compound of claim 1, wherein Ar.sup.1 is ##STR00204##
4. The compound of claim 3, wherein Ar.sup.2 and Ar.sup.3 are
phenyl.
5. The compound of claim 4, wherein L is a direct bond.
6. The compound of claim 1, wherein Ar.sup.1 and L are ##STR00205##
and Ar.sup.2 and Ar.sup.3 are phenyl.
7. The compound of claim 1, wherein said compound is selected from
the group consisting of ##STR00206##
8. The compound of claim 1, wherein Ar.sup.1 and Ar.sup.2 are
connected to form a carbazole moiety.
9. The compound of claim 8, wherein said compound is selected from
the group consisting of ##STR00207##
10. The compound of claim 1, wherein Ar.sup.2 and Ar.sup.3 are
connected to form a carbazole moiety.
11. The compound of claim 10, wherein said compound is selected
from the group consisting of ##STR00208##
12. The compound of claim 1, wherein said compound is selected from
the group consisting of ##STR00209## ##STR00210## ##STR00211##
##STR00212## ##STR00213## ##STR00214## ##STR00215## ##STR00216##
##STR00217## ##STR00218## ##STR00219## ##STR00220##
13. A first device comprising a first organic light emitting
device, the first organic light emitting device comprising: an
anode; a cathode; and an emissive layer, disposed between the anode
and the cathode, wherein the emissive layer comprises a first
emitting compound having a structure according to Formula 1:
##STR00221## wherein R.sup.a to R.sup.g, R.sup.1 and R.sup.2 are
independently selected from the group consisting of hydrogen,
deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,
alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,
heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,
carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,
sulfonyl, phosphino, and combinations thereof; and wherein Ar.sup.1
to Ar.sup.3 are independently substituted or unsubstituted aryl or
heteroaryl and can connect to one another to form fused ring(s)
and, wherein L is a direct bond or a linker.
14. The first device of claim 13, wherein the first emitting
compound is selected from the group consisting of ##STR00222##
##STR00223## ##STR00224## ##STR00225## ##STR00226## ##STR00227##
##STR00228## ##STR00229##
15. The first device of claim 13, wherein the first device emits a
luminescent radiation at room temperature when a voltage is applied
across the organic light emitting device; wherein the luminescent
radiation comprises a delayed fluorescence process.
16. The first device of claim 13, wherein the emissive layer
further comprises a first phosphorescent emitting material.
17. The first device of claim 16, wherein the emissive layer
further comprises a second phosphorescent emitting material.
18. The first device of claim 13, wherein the emissive layer
further comprises a host material.
19. The first device of claim 16, wherein the first device emits a
white light at room temperature when a voltage is applied across
the organic light emitting device.
20. A formulation comprising a compound having a structure
according to Formula 1: ##STR00230## wherein R.sup.a to R.sup.g,
R.sup.1 and R.sup.2 are independently selected from the group
consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,
heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,
cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,
carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,
sulfinyl, sulfonyl, phosphino, and combinations thereof; and
wherein Ar.sup.1 to Ar.sup.3 are independently substituted or
unsubstituted aryl or heteroaryl and can connect to one another to
form fused ring(s) and, wherein L is a direct bond or a linker.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of the co-pending U.S.
patent application Ser. No. 14/294,336, filed on Jun. 3, 2014, the
disclosure of which is incorporated herein by reference in its
entirety.
PARTIES TO A JOINT RESEARCH AGREEMENT
[0002] 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, 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
[0003] The present invention relates to organic light emitting
devices. More specifically, the present disclosure pertains to
luminescent materials comprising donor-acceptor compounds with a
nitrogen containing donor connected to the 1-position of a
carbazole and triazene as the acceptor for use as emitters in
organic light emitting diodes.
BACKGROUND
[0004] 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.
[0005] 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.
[0006] 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.
[0007] One example of a green emissive molecule is
tris(2-phenylpyridine) iridium, denoted Ir(ppy).sub.3, which has
the following structure:
##STR00001##
[0008] In this, and later figures herein, we depict the dative bond
from nitrogen to metal (here, Ir) as a straight line.
[0009] 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 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. The core moiety of a dendrimer may
be a fluorescent or phosphorescent small molecule emitter. A
dendrimer may be a "small molecule," and it is believed that all
dendrimers currently used in the field of OLEDs are small
molecules.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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
[0016] According to an embodiment of the present disclosure, a
compound having a structure according to the following Formula 1 is
disclosed:
##STR00002##
In Formula 1, R.sup.a to R.sup.g, R.sup.1 and R.sup.2 are
independently selected from the group consisting of hydrogen,
deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,
alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,
heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,
carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,
sulfonyl, phosphino, and combinations thereof. Ar.sup.1 to Ar.sup.3
are independently substituted or unsubstituted aryl or heteroaryl
and can connect to one another to form fused ring(s). L is a direct
bond or a linker.
[0017] According to another embodiment, a first device comprising a
first organic light emitting device is disclosed. The first organic
light emitting device comprising: an anode; a cathode; and an
emissive layer, disposed between the anode and the cathode, wherein
the emissive layer comprises a first emitting compound having a
structure according to Formula 1:
##STR00003##
In Formula 1, R.sup.a to R.sup.g, R.sup.1 and R.sup.2 are
independently selected from the group consisting of hydrogen,
deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,
alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,
heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,
carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,
sulfonyl, phosphino, and combinations thereof. Ar.sup.1 to Ar.sup.3
are independently substituted or unsubstituted aryl or heteroaryl
and can connect to one another to form fused ring(s). L is a direct
bond or a linker.
[0018] According to yet another embodiment, a formulation
comprising a compound having a structure according to Formula 1 is
also disclosed.
[0019] The compound of the present disclosure can be used in OLEDs
as emitters, hosts, charge transport materials, in both single
color or multiple color devices. The compound can be easily
utilized in fabrication of OLEDs because the compound can be
vapor-evaporated or solution processed. The compound is useful as
emitters because it provides high efficiency OLEDs without using
organometallic compounds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows an organic light emitting device that can
incorporate the inventive host material disclosed herein.
[0021] FIG. 2 shows an inverted organic light emitting device that
can incorporate the inventive host material disclosed herein.
[0022] FIG. 3 shows Formula 1 as disclosed herein.
DETAILED DESCRIPTION
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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, a
cathode 160, and a barrier layer 170. 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.
[0027] 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 F4-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
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.
[0028] 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.
[0029] 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.
[0030] 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
outcoupling, 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.
[0031] 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. Pat. No. 7,431,968,
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 OVID. 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.
[0032] Devices fabricated in accordance with embodiments of the
present invention may further optionally comprise a barrier layer.
One purpose of the barrier layer is to protect the electrodes and
organic layers from damaging exposure to harmful species in the
environment including moisture, vapor and/or gases, etc. The
barrier layer may be deposited over, under or next to a substrate,
an electrode, or over any other parts of a device including an
edge. The barrier layer may comprise a single layer, or multiple
layers. The barrier layer may be formed by various known chemical
vapor deposition techniques and may include compositions having a
single phase as well as compositions having multiple phases. Any
suitable material or combination of materials may be used for the
barrier layer. The barrier layer may incorporate an inorganic or an
organic compound or both. The preferred barrier layer comprises a
mixture of a polymeric material and a non-polymeric material as
described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.
PCT/US2007/023098 and PCT/US2009/042829, which are herein
incorporated by reference in their entireties. To be considered a
"mixture", the aforesaid polymeric and non-polymeric materials
comprising the barrier layer should be deposited under the same
reaction conditions and/or at the same time. The weight ratio of
polymeric to non-polymeric material may be in the range of 95:5 to
5:95. The polymeric material and the non-polymeric material may be
created from the same precursor material. In one example, the
mixture of a polymeric material and a non-polymeric material
consists essentially of polymeric silicon and inorganic
silicon.
[0033] 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, medical
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, 3-D
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.), but could be used outside this
temperature range, for example, from -40 degree C. to +80 degree
C.
[0034] 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.
[0035] The term "halo" or "halogen" as used herein includes
fluorine, chlorine, bromine, and iodine.
[0036] The term "alkyl" as used herein contemplates both straight
and branched chain alkyl radicals. Preferred alkyl groups are those
containing from one to fifteen carbon atoms and includes methyl,
ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and the
like. Additionally, the alkyl group may be optionally
substituted.
[0037] The term "cycloalkyl" as used herein contemplates cyclic
alkyl radicals. Preferred cycloalkyl groups are those containing 3
to 7 carbon atoms and includes cyclopropyl, cyclopentyl,
cyclohexyl, and the like. Additionally, the cycloalkyl group may be
optionally substituted.
[0038] The term "alkenyl" as used herein contemplates both straight
and branched chain alkene radicals. Preferred alkenyl groups are
those containing two to fifteen carbon atoms. Additionally, the
alkenyl group may be optionally substituted.
[0039] The term "alkynyl" as used herein contemplates both straight
and branched chain alkyne radicals. Preferred alkyl groups are
those containing two to fifteen carbon atoms. Additionally, the
alkynyl group may be optionally substituted.
[0040] The terms "aralkyl" or "arylalkyl" as used herein are used
interchangeably and contemplate an alkyl group that has as a
substituent an aromatic group. Additionally, the aralkyl group may
be optionally substituted.
[0041] The term "heterocyclic group" as used herein contemplates
aromatic and non-aromatic cyclic radicals. Hetero-aromatic cyclic
radicals also refer to heteroaryl. Preferred hetero-non-aromatic
cyclic groups are those containing 3 or 7 ring atoms which includes
at least one hetero atom, and includes cyclic amines such as
morpholino, piperdino, pyrrolidino, and the like, and cyclic
ethers, such as tetrahydrofuran, tetrahydropyran, and the like.
Additionally, the heterocyclic group may be optionally
substituted.
[0042] The term "aryl" or "aromatic group" as used herein
contemplates single-ring groups and polycyclic ring systems. The
polycyclic rings may have two or more rings in which two carbons
are common to two adjoining rings (the rings are "fused") wherein
at least one of the rings is aromatic, e.g., the other rings can be
cycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls.
Additionally, the aryl group may be optionally substituted.
[0043] The term "heteroaryl" as used herein contemplates
single-ring hetero-aromatic groups that may include from one to
three heteroatoms, for example, pyrrole, furan, thiophene,
imidazole, oxazole, thiazole, triazole, pyrazole, pyridine,
pyrazine and pyrimidine, and the like. The term heteroaryl also
includes polycyclic hetero-aromatic systems having two or more
rings in which two atoms are common to two adjoining rings (the
rings are "fused") wherein at least one of the rings is a
heteroaryl, e.g., the other rings can be cycloalkyls,
cycloalkenyls, aryl, heterocycles, and/or heteroaryls.
Additionally, the heteroaryl group may be optionally
substituted.
[0044] The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl,
heterocyclic group, aryl, and heteroaryl may be optionally
substituted with one or more substituents selected from the group
consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,
heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, cyclic amino,
silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,
heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile,
isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and
combinations thereof.
[0045] As used herein, "substituted" indicates that a substituent
other than H is bonded to the relevant position, such as carbon.
Thus, for example, where R.sup.1 is mono-substituted, then one
R.sup.1 must be other than H. Similarly, where R.sup.1 is
di-substituted, then two of R.sup.1 must be other than H.
Similarly, where R.sup.1 is unsubstituted, R.sup.1 is hydrogen for
all available positions.
[0046] The "aza" designation in the fragments described herein,
i.e. aza-dibenzofuran, aza-dibenzonethiophene, etc. means that one
or more of the C--H groups in the respective fragment can be
replaced by a nitrogen atom, for example, and without any
limitation, azatriphenylene encompasses both
dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. One of ordinary
skill in the art can readily envision other nitrogen analogs of the
aza-derivatives described above, and all such analogs are intended
to be encompassed by the terms as set forth herein.
[0047] It is to be understood that when a molecular fragment is
described as being a substituent or otherwise attached to another
moiety, its name may be written as if it were a fragment (e.g.
naphthyl, dibenzofuryl) or as if it were the whole molecule (e.g.
naphthalene, dibenzofuran). As used herein, these different ways of
designating a substituent or attached fragment are considered to be
equivalent.
[0048] As used herein, the phrase "electron acceptor" or "acceptor"
means a fragment that can accept electron density from an aromatic
system, and the phrase "electron donor" or "donor" means a fragment
that donates electron density into an aromatic system.
[0049] It is believed that the internal quantum efficiency (IQE) of
fluorescent OLEDs can exceed the 25% spin statistics limit through
delayed fluorescence. As used herein, there are two types of
delayed fluorescence, i.e. P-type delayed fluorescence and E-type
delayed fluorescence. P-type delayed fluorescence is generated from
triplet-triplet annihilation (TTA).
[0050] On the other hand, E-type delayed fluorescence does not rely
on the collision of two triplets, but rather on the thermal
population between the triplet states and the singlet excited
states. Compounds that are capable of generating E-type delayed
fluorescence are required to have very small singlet-triplet gaps.
Thermal energy can activate the transition from the triplet state
back to the singlet state. This type of delayed fluorescence is
also known as thermally activated delayed fluorescence (TADF). A
distinctive feature of TADF is that the delayed component increases
as temperature rises due to the increased thermal energy. If the
reverse intersystem crossing rate is fast enough to minimize the
non-radiative decay from the triplet state, the fraction of back
populated singlet excited states can potentially reach 75%. The
total singlet fraction can be 100%, far exceeding the spin
statistics limit for electrically generated excitons.
[0051] E-type delayed fluorescence characteristics can be found in
an exciplex system or in a single compound. Without being bound by
theory, it is believed that E-type delayed fluorescence requires
the luminescent material to have a small singlet-triplet energy gap
(.DELTA.E.sub.S-T). Organic, non-metal containing, donor-acceptor
luminescent materials may be able to achieve this. The emission in
these materials is often characterized as a donor-acceptor
charge-transfer (CT) type emission. The spatial separation of the
HOMO and LUMO in these donor-acceptor type compounds often results
in small .DELTA.E.sub.S-T. These states may involve CT states.
Often, donor-acceptor luminescent materials are constructed by
connecting an electron donor moiety such as amino- or
carbazole-derivatives and an electron acceptor moiety such as
N-containing six-membered aromatic rings.
[0052] The present disclosure provides compounds with
multiple-nitrogen donors and triazine acceptors which may show
strong CT emission. The inventors discovered that donor-acceptor
compounds with a nitrogen containing donor connected to the
1-position of a carbazole and triazene acceptor connected at the
9-position may be more efficient emitters with emission originated
from the charge transfer (CT) state. Substitution at the 1 position
of the carbazole causes a significant steric hindrance between the
substitutents at the 1 position and the 9-position. This steric
hindrance was expected to result in a disruption of the
through-bond conjugation of the donor and the acceptor.
Unexpectedly, however, the donor-acceptor compounds exhibited
efficient emission. This appears to be the result of a
through-space interaction between the donor and the acceptor
enabled by the donor and acceptor being adjacent to each other.
This may be an effective mechanism of charge transfer emission
without lowering the emission energy due to through-bond
7c-conjugation. The emission can be tuned by varying the strength
of the donor-acceptor interaction and the resulting energy of the
CT state. The compounds may be used as emitters in OLED.
[0053] According to an embodiment, the donor-acceptor compound with
a nitrogen containing donor connected to the 1-position of a
carbazole and triazene as the acceptor has a structure according to
Formula 1:
##STR00004##
wherein R.sup.a to R.sup.g, R.sup.1 and R.sup.2 are independently
selected from the group consisting of hydrogen, deuterium, halide,
alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,
silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,
heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,
isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and
combinations thereof; and wherein Ar.sup.1 to Ar.sup.3 are
independently substituted or unsubstituted aryl or heteroaryl and
can connect to one another to form fused ring(s) and, wherein L is
a direct bond or a linker.
[0054] According to one embodiment, the alkyl and cycloalkyl in
Formula 1 can be selected from the group consisting of methyl,
ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl,
2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl,
3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,
2,2-dimethylpropyl, cyclopentyl, cyclohexyl, partially or fully
deuterated variants thereof, and combinations thereof. The aryl and
heteroaryl in Formula 1 can be selected from the group consisting
of phenyl, biphenyl, terphenyl, tetraphenyl, pentaphenyl, pyridine,
phenyl pyridine, pyridyl phenyl, triphenylene, carbazole, fluorene,
dibenzofuran, dibenzothiophene, dibenzoselenophene,
aza-triphenylene, aza-carbazole, aza-fluorene, aza-dibenzofuran,
aza-dibenzothiophene, aza-dibenzoselenophene and combinations
thereof.
[0055] In one embodiment, R.sup.a to R.sup.g in Formula 1 are H. In
one embodiment, Ar.sup.1 is
##STR00005##
In one embodiment, Ar.sup.1 is
##STR00006##
and Ar.sup.2 and Ar.sup.3 are phenyl. In one embodiment, Ar.sup.1
is
##STR00007##
Ar.sup.2 and Ar.sup.3 are phenyl, and L is a direct bond. In one
embodiment, Ar.sup.1 and L are
##STR00008##
and Ar.sup.2 and Ar.sup.3 are phenyl.
[0056] In one preferred embodiment the donor-acceptor compound with
a nitrogen containing donor connected to the 1-position of a
carbazole and triazene as the acceptor is selected from the group
consisting of
##STR00009##
[0057] In one embodiment, Ar.sup.1 and Ar.sup.2 in Formula 1 are
connected to form a carbazole moiety. In another preferred
embodiment, Ar.sup.1 and Ar.sup.2 are connected to form a carbazole
moiety and the compound is selected from the group consisting
of
##STR00010##
[0058] In one embodiment, Ar.sup.2 and Ar.sup.3 in Formula 1 are
connected to form a carbazole moiety. In another preferred
embodiment, Ar.sup.2 and Ar.sup.3 are connected to form a carbazole
moiety and the compound is selected from the group consisting
of
##STR00011##
[0059] In another preferred embodiment, the compound is selected
from the group consisting of
##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016##
##STR00017## ##STR00018##
[0060] According to another aspect of the present disclosure, a
first device comprising a first organic light emitting device is
disclosed. The first organic light emitting device comprises an
anode; a cathode; and an emissive layer, disposed between the anode
and the cathode, wherein the emissive layer comprises a first
emitting compound having a structure according to Formula 1:
##STR00019##
wherein R.sup.a to R.sup.g, R.sup.1 and R.sup.2 are independently
selected from the group consisting of hydrogen, deuterium, halide,
alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,
silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,
heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,
isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and
combinations thereof; and wherein Ar.sup.1 to Ar.sup.3 are
independently substituted or unsubstituted aryl or heteroaryl and
can connect to one another to form fused ring(s) and, wherein L is
a direct bond or a linker.
[0061] In one embodiment of the first device, the first emitting
compound is selected from the group consisting of Compound 1
through Compound 53 disclosed herein.
[0062] In one embodiment, the first device emits a luminescent
radiation at room temperature when a voltage is applied across the
organic light emitting device, wherein the luminescent radiation
comprises a delayed fluorescence process.
[0063] In one embodiment of the first device, the emissive layer
further comprises a first phosphorescent emitting material. In
another embodiment, the emissive layer further comprises a second
phosphorescent emitting material. In another embodiment, the
emissive layer further comprises a host material.
[0064] In one embodiment of the first device, the emissive layer
further comprises a first phosphorescent emitting material and the
first device emits a white light at room temperature when a voltage
is applied across the organic light emitting device.
[0065] In another embodiment of the first device, the emissive
layer further comprises a first phosphorescent emitting material
and the first device emits a white light at room temperature when a
voltage is applied across the organic light emitting device, and
the first emitting compound emits a blue light with a peak
wavelength of about 400 nm to about 500 nm.
[0066] In another embodiment of the first device, the emissive
layer further comprises a first phosphorescent emitting material
and the first device emits a white light at room temperature when a
voltage is applied across the organic light emitting device, and
the first emitting compound emits a yellow light with a peak
wavelength of about 530 nm to about 580 nm.
[0067] In another embodiment of the first device, the first device
comprises a second organic light emitting device, wherein the
second organic light emitting device is stacked on the first
organic light emitting device.
[0068] In one embodiment of the first device, the first device is a
consumer product. In another embodiment of the first device, the
first device is a lighting panel.
[0069] According to another aspect, a formulation comprising a
compound having a structure according to Formula 1 is also
disclosed.
Synthesis of Compound 1
##STR00020##
[0071] 1-bromo-9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole
(0.50 g, 1.05 mmol), (4-(diphenylamino)phenyl)boronic acid (0.46 g,
1.26 mmol) and Pd.sub.2(dba).sub.3 (0.03 g) were mixed in a 25 mL
two-neck flask. The whole system was evacuated and purged with
argon gas. The mixture was dissolved in dry toluene (10 mL).
.sup.tBu.sub.3P (2.51 mL, 0.05 M in toluene) and degassed
K.sub.2CO.sub.3 (1.26 mL, 2.5 M in H.sub.2O) were added. The
mixture was refluxed under argon for 14 hours. After completion of
the reaction, it was cooled to room temperature and the mixture was
extracted with dichloromethane. The combined organic layer was
washed with brine and dried over MgSO.sub.4 after which the solvent
was removed by rotary evaporation. The crude product was purified
by column chromatography on silica gel using
hexane:dichloromethane=5:1 and then with
hexane:dichloromethane:toluene=3:1:0.1 to obtained the pure
product, Compound 1, (0.60 g, 90%) as a yellow solid.
Synthesis of Compound 2
##STR00021##
[0073] 1-bromo-9H-carbazole (0.50 g, 2.03 mmol),
4-(diphenylamino)phenylboronic acid (0.71 g, 2.44 mmol), and
Pd.sub.2(dba).sub.3 (0.06 g) were mixed in a 25 mL two-neck bottle.
The whole system was evacuated and purged with argon gas. Dry
toluene (10 mL), t-Bu.sub.3P (4.88 mL of 0.05 M in toluene and
degassed K.sub.2CO.sub.3 (3.66 mL, 2.5 M in H.sub.2O) were added.
The system was refluxed for 14 hours under an inert atmosphere.
Upon completion of the reaction, the mixture was cooled to room
temperature and then extracted with ethyl ether. The combined
organic layer was washed with brine, dried with MgSO.sub.4 and
finally the solvent was removed by rotary evaporation. The crude
product was purified by column chromatography on silica gel using
hexane:dichloromethane=3:1 as the eluent to obtain the desired
product, 4-(9H-carbazol-1-yl)-N,N-diphenylaniline, (0.75 g, 90%) as
a white solid.
##STR00022##
[0074] 4-(9H-carbazol-1-yl)-N,N-diphenylaniline (0.50 g, 1.22
mmol), 2-(4-bromophenyl)-4,6-diphenyl-1,3,5-triazine (0.57 g, 1.46
mmol), Pd.sub.2(dba).sub.3 (0.03 g), and NaO.sup.tBu (0.15 g, 1.58
mmol) were mixed in a 50 mL two neck round bottom flask and the
system was evacuated then purged with argon gas. The mixture was
dissolved in dry toluene (20 mL). .sup.tBu.sub.3P (2.44 mL, 0.05M
in toluene) was added and the mixture was refluxed under argon for
4 hour. After completion of the reaction, it was cooled to room
temperature, the salts were filtered. After removal of the solvent
by the rotary evaporation, about 10 mL of dichloromethane was added
to the crude product and heated to dissolve of the compound. Hexane
was added for crystallization to take place. The solid was filtered
and washed with hexane to afford the product, Compound 2, (0.71 g,
81%) as a yellow green solid.
Synthesis of Compound 3
##STR00023##
[0076] 1-bromo-9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole
(0.50 g, 1.05 mmol),
9-phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole
(0.46 g, 1.26 mmol), and Pd.sub.2(dba).sub.3 (0.03 g) were mixed in
a 25 mL two-neck flask, evacuated and then recharged with argon.
The mixture was dissolved in dry toluene (10 mL) and then
.sup.tBu.sub.3P (2.51 mL, 0.05 M in toluene, 12 mmol) and degassed
K.sub.2CO.sub.3 (1.26 mL, 2.5 M in H.sub.2O) were added. The
mixture was refluxed under argon for 14 hours. Upon completion of
the reaction, the mixture was cooled to room temperature and
extracted with dichloromethane. The combined organic layer was wash
with brine, dried over MgSO.sub.4 and the solvent was removed by
rotary evaporation. The crude product was purified by column
chromatography on silica gel using hexane:dichloromethane=5:1, and
then changed with hexane:dichloromethane:toluene=3:1:0.1 to
obtained pure product, Compound 3, (0.60 g, 90%) as a yellow
solid.
Synthesis of Compound 5
##STR00024##
[0078] A solution containing
9-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-9H-carbazole
(0.65 g, 1.8 mmol), Pd(PPh.sub.3).sub.4 (0.09 g, 0.08 mmol),
.sup.tBu.sub.3P (3.2 mL of 0.05M in toluene),
1-bromo-9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole (0.76 mg,
1.6 mmol) and Na.sub.2CO.sub.3 (2.9 mL, 2M in H.sub.2O) in toluene
(30 mL) was refluxed with vigorous stirring for 24 hours under an
argon atmosphere. The mixture was poured into water and extracted
with DCM. The organic extracts were washed with brine and dried
over MgSO.sub.4. The solvent was removed by rotary evaporation, and
washed with hot DCM to afford the pure product, Compound 5, (0.45
g, 39%).
[0079] Table 1 below summarizes the photoluminescence (PL),
photoluminescence quantum yield PLQY and solvatochromism data of
Compounds 1 and 2. It can be seen that in thin films (5% of emitter
by weight in PMMA, mCBP or mCP as host), PLQY's in the range of 50%
were obtained. Significant red shift in PL was observed as the
solvent polarity increased, indicating the charge transfer origin
of the luminescence.
TABLE-US-00001 TABLE 1 PL, PLQY and solvatochromism of Compound 1
and 2. Em.sub.max PLQY Compound Host (nm) (%) Solution Em.sub.max
(nm) Compound 1 PMMA 509 57 hexane 504 toluene 530 chloroform 572
Compound 2 PMMA 498 47 3- 490 methylpentane mCBP 496 55 toluene 520
mCP 499 57 2-methylTHF 552
Device Examples
[0080] In the OLED experiment, all device examples were fabricated
by high vacuum (<10.sup.-7 Torr) thermal evaporation. The anode
electrode is .about.800 .ANG. of indium tin oxide (ITO). The
cathode consisted of 10 .ANG. of LiF followed by 1,000 .ANG. of Al.
All devices were encapsulated with a glass lid sealed with an epoxy
resin in a nitrogen glove box (<1 ppm of H.sub.2O and O.sub.2)
and a moisture getter was incorporated inside the package.
Device Example 1
[0081] The organic stack of the Device Examples in Table 2 consists
of sequentially, from the ITO surface, 200 .ANG. of TAPC the hole
transporting layer (HTL), 300 .ANG. of Compound A doped with 5% of
the emitter Compound 1 as the emissive layer (EML) and 400 .ANG. of
TmPyPB as the ETL. Device Example 1 has an external quantum
efficiency (EQE) of 12% at 5 cd/m.sup.2 and 7.7% at 1000
cd/m.sup.2. The CIE is 0.249, 0.481, with an emission peak at 502
nm
[0082] The photoluminescence quantum yield (PLQY) of the neat film
of Compound 1 was measured to be 57% in Compound 1 in PMMA film (5%
by weight). For a standard fluorescent OLED with only prompt
singlet emission, the ratio of singlet excitons should be 25%. The
outcoupling efficiency of a bottom-emitting lambertian OLED is
considered to be around 20-25%. Therefore, for a fluorescent
emitter having a PLQY of 57% without additional radiative channels
such as delayed fluorescence, the highest EQE should not exceed
3.6% based on the statistical ratio of 25% electrically generated
singlet excitons and outcoupling efficiency of 25%. Thus devices
containing compounds of Formula I as the emitter, such as Compound
1, showed EQE far exceeding the theoretic limit.
Device Example 2
[0083] The organic stack of the Device Examples in Table 2 consists
of sequentially, from the ITO surface, 100 .ANG. of LG101
(purchased from LG Chem, Korea) as the hole injection layer (HIL),
300 .ANG. of Compound B the hole transporting layer (HTL), 300
.ANG. of mCBP doped with 6% of the emitter Compound 2 as the
emissive layer (EML), 50 .ANG. of Compound C as ETL1 and 400 .ANG.
of Compound D as ETL2. Device Example 2 has an EQE of 10% at 1
cd/m.sup.2 and 7.1% at 1000 cd/m.sup.2. The CIE is 0.240, 0.496,
with an emission peak at 510 nm. Again, the device EQE far exceeded
the conventional fluorescent device efficiency limit.
[0084] The chemical structure of the compounds used in the device
examples are shown below:
##STR00025##
Combination with Other Materials
[0085] 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.
HIL/HTL:
[0086] A hole injecting/transporting material to be used in the
present invention is not particularly limited, and any compound may
be used as long as the compound is typically used as a hole
injecting/transporting material. Examples of the material include,
but not limit to: a phthalocyanine or porphyrin derivative; an
aromatic amine derivative; an indolocarbazole derivative; a polymer
containing fluorohydrocarbon; a polymer with conductivity dopants;
a conducting polymer, such as PEDOT/PSS; a self-assembly monomer
derived from compounds such as phosphonic acid and silane
derivatives; a metal oxide derivative, such as MoO.sub.x; a p-type
semiconducting organic compound, such as
1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex,
and a cross-linkable compounds.
[0087] Examples of aromatic amine derivatives used in HIL or HTL
include, but not limit to the following general structures:
##STR00026##
[0088] Each of Ar.sup.1 to Ar.sup.9 is selected from the group
consisting aromatic hydrocarbon cyclic compounds such as benzene,
biphenyl, triphenyl, triphenylene, naphthalene, anthracene,
phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene,
azulene; group consisting aromatic heterocyclic compounds such as
dibenzothiophene, dibenzofuran, dibenzoselenophene, furan,
thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole,
indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole,
imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole,
dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine,
triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole,
indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole,
quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline,
naphthyridine, phthalazine, pteridine, xanthene, acridine,
phenazine, phenothiazine, phenoxazine, benzofuropyridine,
furodipyridine, benzothienopyridine, thienodipyridine,
benzoselenophenopyridine, and selenophenodipyridine; and group
consisting 2 to 10 cyclic structural units which are groups of the
same type or different types selected from the aromatic hydrocarbon
cyclic group and the aromatic heterocyclic group and are bonded to
each other directly or via at least one of oxygen atom, nitrogen
atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain
structural unit and the aliphatic cyclic group. Wherein each Ar is
further substituted by a substituent selected from the group
consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,
heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,
cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,
carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,
sulfinyl, sulfonyl, phosphino, and combinations thereof.
[0089] In one aspect, Ar.sup.1 to Ar.sup.g is independently
selected from the group consisting of:
##STR00027##
wherein k is an integer from 1 to 20; X.sup.101 to X.sup.108 is C
(including CH) or N; Z.sup.101 is NAr.sup.1, O, or S; Ar.sup.1 has
the same group defined above.
[0090] Examples of metal complexes used in HIL or HTL include, but
not limit to the following general formula:
##STR00028##
wherein Met is a metal, which can have an atomic weight greater
than 40; (Y.sup.101-Y.sup.102) is a bidentate ligand, Y.sup.101 and
Y.sup.102 are independently selected from C, N, O, P, and S;
L.sup.101 is an ancillary ligand; k' is an integer value from 1 to
the maximum number of ligands that may be attached to the metal;
and k'+k'' is the maximum number of ligands that may be attached to
the metal.
[0091] In one aspect, (Y.sup.101-Y.sup.102) is a 2-phenylpyridine
derivative. In another aspect, (Y.sup.101-Y.sup.102) is a carbene
ligand. In another aspect, Met is selected from Ir, Pt, Os, and Zn.
In a further aspect, the metal complex has a smallest oxidation
potential in solution vs. Fc.sup.+/Fc couple less than about 0.6
V.
Host:
[0092] The light emitting layer of the organic EL device of the
present invention preferably contains at least a metal complex as
light emitting material, and may contain a host material using the
metal complex as a dopant material. Examples of the host material
are not particularly limited, and any metal complexes or organic
compounds may be used as long as the triplet energy of the host is
larger than that of the dopant. While the Table below categorizes
host materials as preferred for devices that emit various colors,
any host material may be used with any dopant so long as the
triplet criteria is satisfied.
[0093] Examples of metal complexes used as host are preferred to
have the following general formula:
##STR00029##
wherein Met is a metal; (Y.sup.103-Y.sup.104) is a bidentate
ligand, Y.sup.103 and Y.sup.104 are independently selected from C,
N, O, P, and S; L.sup.101 is an another ligand; k' is an integer
value from 1 to the maximum number of ligands that may be attached
to the metal; and k'+k'' is the maximum number of ligands that may
be attached to the metal.
[0094] In one aspect, the metal complexes are:
##STR00030##
wherein (O--N) is a bidentate ligand, having metal coordinated to
atoms O and N.
[0095] In another aspect, Met is selected from Ir and Pt. In a
further aspect, (Y.sup.103-Y.sup.104) is a carbene ligand.
[0096] Examples of organic compounds used as host are selected from
the group consisting aromatic hydrocarbon cyclic compounds such as
benzene, biphenyl, triphenyl, triphenylene, naphthalene,
anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene,
perylene, azulene; group consisting aromatic heterocyclic compounds
such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan,
thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole,
indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole,
imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole,
dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine,
triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole,
indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole,
quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline,
naphthyridine, phthalazine, pteridine, xanthene, acridine,
phenazine, phenothiazine, phenoxazine, benzofuropyridine,
furodipyridine, benzothienopyridine, thienodipyridine,
benzoselenophenopyridine, and selenophenodipyridine; and group
consisting 2 to 10 cyclic structural units which are groups of the
same type or different types selected from the aromatic hydrocarbon
cyclic group and the aromatic heterocyclic group and are bonded to
each other directly or via at least one of oxygen atom, nitrogen
atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain
structural unit and the aliphatic cyclic group. Wherein each group
is further substituted by a substituent selected from the group
consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,
heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,
cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,
carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,
sulfinyl, sulfonyl, phosphino, and combinations thereof.
[0097] In one aspect, host compound contains at least one of the
following groups in the molecule:
##STR00031## ##STR00032##
wherein R.sup.101 to R.sup.107 is independently selected from the
group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,
heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,
cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,
carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,
sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is
aryl or heteroaryl, it has the similar definition as Ar's mentioned
above. k is an integer from 0 to 20 or 1 to 20; k''' is an integer
from 0 to 20. X.sup.101 to X.sup.108 is selected from C (including
CH) or N. Z.sup.101 and Z.sup.102 is selected from NR.sup.101, O,
or S.
HBL:
[0098] A hole blocking layer (HBL) may be used to reduce the number
of holes and/or excitons that leave the emissive layer. The
presence of such a blocking layer in a device may result in
substantially higher efficiencies as compared to a similar device
lacking a blocking layer. Also, a blocking layer may be used to
confine emission to a desired region of an OLED.
[0099] In one aspect, compound used in HBL contains the same
molecule or the same functional groups used as host described
above.
[0100] In another aspect, compound used in HBL contains at least
one of the following groups in the molecule:
##STR00033##
wherein k is an integer from 1 to 20; L.sup.101 is an another
ligand, k' is an integer from 1 to 3.
ETL:
[0101] Electron transport layer (ETL) may include a material
capable of transporting electrons. Electron transport layer may be
intrinsic (undoped), or doped. Doping may be used to enhance
conductivity. Examples of the ETL material are not particularly
limited, and any metal complexes or organic compounds may be used
as long as they are typically used to transport electrons.
[0102] In one aspect, compound used in ETL contains at least one of
the following groups in the molecule:
##STR00034##
wherein R.sup.101 is selected from the group consisting of
hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,
arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,
heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,
carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,
sulfonyl, phosphino, and combinations thereof, when it is aryl or
heteroaryl, it has the similar definition as Ar's mentioned above.
Ar.sup.1 to Ar.sup.3 has the similar definition as Ar's mentioned
above. k is an integer from 1 to 20. X.sup.101 to X.sup.108 is
selected from C (including CH) or N.
[0103] In another aspect, the metal complexes used in ETL contains,
but not limit to the following general formula:
##STR00035##
wherein (O--N) or (N--N) is a bidentate ligand, having metal
coordinated to atoms O, N or N, N; L.sup.101 is another ligand; k'
is an integer value from 1 to the maximum number of ligands that
may be attached to the metal.
[0104] In any above-mentioned compounds used in each layer of the
OLED device, the hydrogen atoms can be partially or fully
deuterated. Thus, any specifically listed substituent, such as,
without limitation, methyl, phenyl, pyridyl, etc. encompasses
undeuterated, partially deuterated, and fully deuterated versions
thereof. Similarly, classes of substituents such as, without
limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc. also
encompass undeuterated, partially deuterated, and fully deuterated
versions thereof.
[0105] In addition to and/or in combination with the materials
disclosed herein, many hole injection materials, hole transporting
materials, host materials, dopant materials, exiton/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 A below. Table A lists
non-limiting classes of materials, non-limiting examples of
compounds for each class, and references that disclose the
materials.
TABLE-US-00002 TABLE A MATERIAL EXAMPLES OF MATERIAL PUBLICATIONS
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US20020158242 organic complexes Metal organometallic US20060240279
complexes Cross-linkable US20080220265 compounds Polythiophene
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677 (1994), US20080124572 Triarylamine with (di)benzothiophene/
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(2000) Isoindole compounds ##STR00056## Chem. Mater. 15, 3148
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Phosphorescent OLED host materials Red hosts Arylcarbazoles
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carbazole compounds ##STR00084## JP2007254297 ##STR00085##
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##STR00089## WO2004107822 Tetraphenylene complexes ##STR00090##
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##STR00098## US20090030202, US20090017330 ##STR00099##
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[0106] 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 include 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.
* * * * *