U.S. patent application number 10/532794 was filed with the patent office on 2006-03-09 for material for organic electroluminescent device and organic electroluminescent device using same.
Invention is credited to Masakazu Funahashi.
Application Number | 20060052641 10/532794 |
Document ID | / |
Family ID | 32310532 |
Filed Date | 2006-03-09 |
United States Patent
Application |
20060052641 |
Kind Code |
A1 |
Funahashi; Masakazu |
March 9, 2006 |
Material for organic electroluminescent device and organic
electroluminescent device using same
Abstract
The present invention provides an organic electroluminescent
device material composed of an aromatic amine derivative having a
specific structure in which amine moieties are linked to a chrysene
moiety; and an organic electroluminescent device having a cathode,
an anode, and one or more organic thin-film layers interposed
between the cathode and the anode, the organic thin-layers
including at least a light-emitting layer, wherein at least one of
the organic thin-film layers contains the organic
electroluminescent device material in the form of single component
material or a mixture of a plurality of components. The organic
electroluminescent device material and the organic
electroluminescent device containing the material attains a long
service life and can emit blue light of high color purity at high
emission efficiency.
Inventors: |
Funahashi; Masakazu; (Chiba,
JP) |
Correspondence
Address: |
STEPTOE & JOHNSON LLP
1330 CONNECTICUT AVENUE, N.W.
WASHINGTON
DC
20036
US
|
Family ID: |
32310532 |
Appl. No.: |
10/532794 |
Filed: |
October 20, 2003 |
PCT Filed: |
October 20, 2003 |
PCT NO: |
PCT/JP03/13366 |
371 Date: |
April 25, 2005 |
Current U.S.
Class: |
564/426 ;
313/504; 313/506; 428/690; 428/917; 564/433; 564/434 |
Current CPC
Class: |
H05B 33/14 20130101;
H01L 51/0054 20130101; Y10S 428/917 20130101; H01L 51/5012
20130101; C09K 11/06 20130101; C09K 2211/1011 20130101; H01L
51/0058 20130101; H01L 51/0071 20130101; C09K 2211/1014 20130101;
H01L 51/006 20130101 |
Class at
Publication: |
564/426 ;
564/433; 564/434; 428/690; 428/917; 313/504; 313/506 |
International
Class: |
C07C 211/43 20060101
C07C211/43; C09K 11/06 20060101 C09K011/06; H05B 33/14 20060101
H05B033/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2002 |
JP |
2002-327956 |
Claims
1. An organic electroluminescent device material comprising an
aromatic amine derivative represented by any of the following
formulas (I) to (IV): ##STR6## (wherein each of A.sub.1 to A.sub.12
represents a hydrogen atom, a substituted or unsubstituted alkyl
group having 1 to 50 carbon atoms, a substituted or unsubstituted
aryl group having 5 to 50 ring carbon atoms, a substituted or
unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a
substituted or unsubstituted alkoxyl group having 1 to 50 carbon
atoms, a substituted or unsubstituted aryloxy group having 5 to 50
ring carbon atoms, a substituted or unsubstituted arylamino group
having 5 to 50 ring carbon atoms, a substituted or unsubstituted
alkylamino group having 1 to 20 carbon atoms, or a halogen atom; m
is an integer of 0 to 5, and when m is 2 or more, groups
represented by any of A.sub.1 to A.sub.12 may be identical to or
different from one another, or may be linked together to form a
saturated or unsaturated ring; each pair of A.sub.1 and A.sub.2,
A.sub.3 and A.sub.4, A.sub.5 and A.sub.6, A.sub.7 and A.sub.8,
A.sub.9 and A.sub.10, and A.sub.11 and A.sub.12 is such that the
members thereof may be linked together to form a saturated or
unsaturated ring; with the proviso that in formula (I), at least
one of A.sub.1 to A.sub.4 does not represent a hydrogen atom, that
in formula (II), at least one of A.sub.5 to A.sub.8 does not
represent a hydrogen atom; that in formula (III), at least one of
A.sub.9 and A.sub.10 does not represent a hydrogen atom, and that
in formula (IV), at least one of A.sub.11 and A.sub.12 does not
represent a hydrogen atom; each of R.sub.1 to R.sub.42 represents a
hydrogen atom, a substituted or unsubstituted alkyl group having 1
to 20 carbon atoms, a substituted or unsubstituted aryl group
having 6 to 20 ring carbon atoms, or a cyano group; and each of
X.sub.1 to X.sub.3 represents a substituted or unsubstituted
arylene group having 6 to 20 ring carbon atoms).
2. An organic electroluminescent device material as described in
claim 1, which is a light-emitting material for use in an organic
electroluminescent device.
3. An organic electroluminescent device comprising a cathode, an
anode, and one or more organic thin-film layers interposed between
the cathode and the anode, the organic thin-layers including at
least a light-emitting layer, wherein at least one of the organic
thin-film layers contains the organic electroluminescent device
material as recited in claim 1 in the form of single component
material or a mixture of a plurality of components.
4. An organic electroluminescent device comprising a cathode, an
anode, and one or more organic thin-film layers interposed between
the cathode and the anode, the organic thin-layers including at
least a light-emitting layer, wherein the light-emitting layer
contains the organic electroluminescent device material as recited
in claim 1 in an amount of 0.1 to 20 wt. %.
5. An organic electroluminescent device as described in claim 3,
which further includes a layer containing an aromatic tertiary
amine derivative and/or a phthalocyanine derivative, the layer
being provided between the light-emitting layer and the anode.
6. An organic electroluminescent device as described in claim 4,
which further includes a layer containing an aromatic tertiary
amine derivative and/or a phthalocyanine derivative, the layer
being provided between the light-emitting layer and the anode.
7. An organic electroluminescent device as described in claim 1,
which emits blue light.
Description
TECHNICAL FIELD
[0001] The present invention relates to a material for use in an
organic electroluminescent device (hereinafter may be referred to
as "organic electroluminescent device material") which is employed
as a flat light-emitting device for use in a wall-mounted,
flat-panel television set or as a light source such as a backside
light of a display device; which has a long service life; and which
can emit blue light of high color purity at high emission
efficiency. The invention also relates to an organic
electroluminescent device including the material.
BACKGROUND ART
[0002] Electroluminescent (EL) devices including an organic
substance have been promising candidates for wide-area, full-color,
and inexpensive display devices based on solid-state emission, and
development of a variety of such devices is under way. Generally,
an EL device is composed of a pair of electrodes, and a
light-emitting layer interposed between the electrodes. Light
emission is a phenomenon occurring through the following mechanism.
When an electric field is applied between electrodes, electrons are
injected from the cathode and holes are injected from the anode,
both to the light-emitting layer. In the light-emitting layer, the
injected electrons are recombined with holes, thereby creating an
excited state. During transition from the excited state to the
ground state, energy is released as light.
[0003] As compared with inorganic light-emitting diodes,
conventional organic EL devices are operated at higher operation
voltage and exhibit lower emission luminance and emission
efficiency. In addition, organic EL devices are not actually used
in practice, because of considerable impairment in characteristics.
Recently, organic EL devices have been improved step by step.
However, further improvement in emission efficiency and service
life is demanded.
[0004] One disclosed technique is based on employment of a single
monoanthracene compound serving as an organic light-emitting
material (Japanese Patent Application Laid-Open (kokai) No.
11-3782). However, this technique is not practically employed,
since luminance at a current density of 165 mA/cm.sup.2 is as low
as 1,650 cd/m.sup.2, and emission efficiency is as considerably low
as 1 cd/A. Another disclosed technique is based on employment of a
single bisanthracene compound serving as an organic light-emitting
material (Japanese Patent Application Laid-Open (kokai) No.
8-12600). However, emission efficiency attained by the technique is
as low as about 1 to 3 cd/A, which remains to be improved before
the technique is put into practice. Meanwhile, a long-life organic
EL device has been proposed (WO 94/06157). The EL device includes a
distyryl compound serving as an organic light-emitting material in
combination with an additive such as styrylamine. However, the
proposed EL device has an insufficient half-life, which is to be
further improved.
[0005] Still another disclosed technique is based on employment of
an organic light-emitting medium layer containing a mono- or a
bis-anthracene compound and a distyryl compound (Japanese Patent
Application Laid-Open (kokai) No. 2001-284050). According to the
technique, a peak in an emission spectrum is red-shifted because of
a conjugation structure of the styryl compound, thereby impairing
color purity.
DISCLOSURE OF THE INVENTION
[0006] The present invention has been conceived in order to solve
the aforementioned problems. Thus, an object of the present
invention is to provide a material for use in an organic EL device
material which has a long service life and which can emit blue
light of high color purity at high emission efficiency. Another
object of the invention is to provide an organic EL device
including the material.
[0007] The present inventors have carried out extensive studies
with an aim toward developing a material for use in an organic EL
device exhibiting the aforementioned desirable properties and an
organic EL device including the material, and have found that the
aforementioned objects can be attained through employment of an
aromatic amine derivative in which amine moieties are linked to a
chrysene moiety and which is represented by any of the following
formulas (I) to (IV). The present invention has been accomplished
on the basis of this finding.
[0008] Accordingly, the present invention provides an organic EL
device material comprising an aromatic amine derivative represented
by any of the following formulas (I) to (IV): ##STR1## (wherein
each of A.sub.1 to A.sub.12 represents a hydrogen atom, a
substituted or unsubstituted alkyl group having 1 to 50 carbon
atoms, a substituted or unsubstituted aryl group having 5 to 50
ring carbon atoms, a substituted or unsubstituted cycloalkyl group
having 3 to 50 ring carbon atoms, a substituted or unsubstituted
alkoxyl group having 1 to 50 carbon atoms, a substituted or
unsubstituted aryloxy group having 5 to 50 ring carbon atoms, a
substituted or unsubstituted arylamino group having 5 to 50 ring
carbon atoms, a substituted or unsubstituted alkylamino group
having 1 to 20 carbon atoms, or a halogen atom; m is an integer of
0 to 5, and when m is 2 or more, groups represented by any of
A.sub.1 to A.sub.12 may be identical to or different from one
another, or may be linked together to form a saturated or
unsaturated ring; each pair of A.sub.1 and A.sub.2, A.sub.3 and
A.sub.4, A.sub.5 and A.sub.6, A.sub.7 and A.sub.8, A.sub.9 and
A.sub.10, and A.sub.11 and A.sub.12 is such that the members
thereof may be linked together to form a saturated or unsaturated
ring;
[0009] with the proviso that in formula (I), at least one of
A.sub.1 to A.sub.4 does not represent a hydrogen atom, that in
formula (II), at least one of A.sub.5 to A.sub.8 does not represent
a hydrogen atom, that in formula (III), at least one of A.sub.9 and
A.sub.10 does not represent a hydrogen atom, and that in formula
(IV), at least one of A.sub.11 and A.sub.12 does not represent a
hydrogen atom;
[0010] each of R.sub.1 to R.sub.42 represents a hydrogen atom, a
substituted or unsubstituted alkyl group having 1 to 20 carbon
atoms, a substituted or unsubstituted aryl group having 6 to 20
ring carbon atoms, or a cyano group; and
[0011] each of X.sub.1 to X.sub.3 represents a substituted or
unsubstituted arylene group having 6 to 20 ring carbon atoms).
[0012] The present invention also provides an organic EL device
comprising a cathode, an anode, and one or more organic thin-film
layers interposed between the cathode and the anode, the organic
thin-layers including at least a light-emitting layer, wherein at
least one of the organic thin-film layers contains the organic EL
device material in the form of single component material or a
mixture of a plurality of components. The present invention also
provides such an organic EL device, wherein the light-emitting
layer contains the organic EL device material in an amount of 0.1
to 20 wt. %.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an NMR spectrum of compound (1) synthesized in
Synthesis Example 1 and serving an organic EL device material
according to the present invention.
[0014] FIG. 2 is an NMR spectrum of compound (2) synthesized in
Synthesis Example 2 and serving an organic EL device material
according to the present invention.
[0015] FIG. 3 is an NMR spectrum of compound (5) synthesized in
Synthesis Example 3 and serving an organic EL device material
according to the present invention.
[0016] FIG. 4 is an NMR spectrum of compound (6) synthesized in
Synthesis Example 4 and serving an organic EL device material
according to the present invention.
[0017] FIG. 5 is an NMR spectrum of compound (8) synthesized in
Synthesis Example 5 and serving an organic EL device material
according to the present invention.
[0018] FIG. 6 is an NMR spectrum of compound (9) synthesized in
Synthesis Example 6 and serving an organic EL device material
according to the present invention.
[0019] FIG. 7 is an NMR spectrum of compound (10) synthesized in
Synthesis Example 7 and serving an organic EL device material
according to the present invention.
[0020] FIG. 8 is an NMR spectrum of compound (11) synthesized in
Synthesis Example 8 and serving an organic EL device material
according to the present invention.
[0021] FIG. 9 is an NMR spectrum of compound (12) synthesized in
Synthesis Example 9 and serving an organic EL device material
according to the present invention.
[0022] FIG. 10 is an NMR spectrum of compound (14) synthesized in
Synthesis Example 10 and serving an organic EL device material
according to the present invention.
[0023] FIG. 11 is an NMR spectrum of compound (19) synthesized in
Synthesis Example 11 and serving an organic EL device material
according to the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0024] The organic EL device material of the present invention
comprises an aromatic amine derivative represented by any of the
aforementioned formulas (I) to (IV).
[0025] In formulas (I) to (IV), each of A.sub.1 to A.sub.12
represents a hydrogen atom, a substituted or unsubstituted alkyl
group having 1 to 50 (preferably 1 to 20) carbon atoms, a
substituted or unsubstituted aryl group having 5 to 50 (preferably
5 to 20) ring carbon atoms, a substituted or unsubstituted
cycloalkyl group having 3 to 50 (preferably 5 to 12) ring carbon
atoms, a substituted or unsubstituted alkoxyl group having 1 to 50
(preferably 1 to 6) carbon atoms, a substituted or unsubstituted
aryloxy group having 5 to 50 (preferably 5 to 18) ring carbon
atoms, a substituted or unsubstituted arylamino group having 5 to
50 (preferably 5 to 18) ring carbon atoms, a substituted or
unsubstituted alkylamino group having 1 to 20 carbon atoms
(preferably 1 to 6), or a halogen atom.
[0026] Examples of the substituted or unsubstituted alkyl group
represented by any of A.sub.1 to A.sub.12 include methyl, ethyl,
propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl,
heptyl, octyl, stearyl, 2-phenylisopropyl, trichloromethyl,
trifluoromethyl, benzyl, .alpha.-phenoxybenzyl,
.alpha.,.alpha.-dimethylbenzyl, .alpha.,.alpha.-methylphenylbenzyl,
.alpha.,.alpha.-ditrifluoromethylbenzyl, triphenylmethyl, and
.alpha.-benzyloxybenzyl.
[0027] Examples of the substituted or unsubstituted aryl group
represented by any of A.sub.1 to A.sub.12 include phenyl,
2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl,
biphenyl, 4-methylbiphenyl, 4-ethylbiphenyl, 4-cyclohexylbiphenyl,
terphenyl, 3,5-dichlorophenyl, naphthyl, 5-methylnaphthyl, anthryl,
and pyrenyl.
[0028] Examples of the substituted or unsubstituted cycloalkyl
group represented by any of A.sub.1 to A.sub.12 include
cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.
[0029] Examples of the substituted or unsubstituted alkoxyl group
represented by any of A.sub.1 to A.sub.12 include methoxy, ethoxy,
propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy,
pentyloxy groups, and hexyloxy groups.
[0030] Examples of the substituted or unsubstituted aryloxy group
represented by any of A.sub.1 to A.sub.12 include phenoxy,
tolyloxy, and naphthyloxy.
[0031] Examples of the substituted or unsubstituted arylamino group
represented by any of A.sub.1 to A.sub.12 include diphenylamino,
ditolylamino, dinaphthylamino, and naphthylphenylamino.
[0032] Examples of the substituted or unsubstituted alkylamino
group represented by any of A.sub.1 to A.sub.12 include
dimethylamino, diethylamino, and dihexylamino.
[0033] Examples of the halogen atom represented by any of A.sub.1
to A.sub.12 include fluorine, chlorine, and bromine.
[0034] In formula (I), at least one of A.sub.1 to A.sub.4 does not
represent a hydrogen atom. In formula (II), at least one of A.sub.5
to A.sub.8 does not represent a hydrogen atom. In formula (III), at
least one of A.sub.9 and A.sub.10 does not represent a hydrogen
atom. In formula (IV), at least one of A.sub.11 and A.sub.12 does
not represent a hydrogen atom.
[0035] The "m" is an integer of 0 to 5, preferably 0 to 2. When m
is 2 or more, groups represented by any of A.sub.1 to A.sub.12 may
be identical to or different from one another, or may be linked
together to form a saturated or unsaturated ring. Each pair of
A.sub.1 and A.sub.2, A.sub.3 and A.sub.4, A.sub.5 and A.sub.6,
A.sub.7 and A.sub.8, A.sub.9 and A.sub.10, and A.sub.11 and
A.sub.12, is such that the members thereof may be linked together
to form a saturated or unsaturated ring.
[0036] Each of R.sub.1 to R.sub.42 represents a hydrogen atom, a
substituted or unsubstituted alkyl group having 1 to 20 ring carbon
atoms, a substituted or unsubstituted aryl group having 6 to 20
ring carbon atoms, or a cyano group.
[0037] Examples of the substituted or unsubstituted alkyl group and
aryl group represented by any of R.sub.1 to R.sub.42 include the
same groups as mentioned in relation to the A.sub.1 to
A.sub.12.
[0038] Each of X.sub.1 to X.sub.3 represents a substituted or
unsubstituted arylene group having 6 to 20 ring carbon atoms.
[0039] Examples of the substituted or unsubstituted arylene group
represented by any of X.sub.1 to X.sub.3 include phenyl, biphenyl,
terphenyl, divalent groups derived from naphthalene, fluorene, or a
similar compound, and divalent groups formed by linking a plurality
of the compounds.
[0040] Specific examples of the aromatic amine derivative
represented by any of formulas (I) to (IV) include, but are not
limited to, the following. The symbol "Me" denotes a methyl group.
##STR2## ##STR3## ##STR4## ##STR5##
[0041] The compound of the present invention represented by any of
the formulas (I) to (IV) has a structure in which amine moieties
substituted by a substituent-containing benzene ring are linked to
a chrysene moiety. Therefore, association of molecules of the
compound is prevented, thereby prolonging the life time. The
compound of the present invention exhibits highly fluorescent
properties in the solid state and excellent electric-field-induced
emission characteristics, and attains a fluorescence quantum
efficiency of 0.3 or more. In addition, the compound exhibits
excellent hole-injectability and hole-transportability from a
metallic electrode or an organic thin-film layer, as well as
excellent electron-injectability and electron-transportability from
a metallic electrode or an organic thin-film layer. Thus, the
compound of the present invention is effectively used as an organic
EL device material. The compound may be used in combination with
another hole-transporting material, another electron-transporting
material, or a doping material.
[0042] The organic EL device of the present invention is composed
of a cathode, an anode, and one or more organic thin films
interposed between the cathode and the anode. When a single organic
thin film is used, a light-emitting layer is interposed between the
cathode and the anode. The light-emitting layer contains a
light-emitting material and may further contain a hole-injecting
material for transporting, to the light-emitting material, holes
injected from the anode, or an electron-injecting material for
transporting, to the light-emitting material, electrons injected
from the cathode. By virtue of excellent emission characteristics,
hole-injectability, hole-transportability, electron-injectability,
and electron-transportability, the compound represented by any of
formulas (I) to (IV) can be used as a light-emitting material in
the light-emitting layer.
[0043] In the organic EL device of the present invention, the
light-emitting layer preferably contains the organic EL device
material in an amount of 0.1 to 20 wt. %, more preferably 1 to 10
wt. %. Since the organic EL device material exhibits remarkably
high fluorescence quantum efficiency and high hole- and
electron-transportability and can provide uniform thin film, the
light-emitting layer can be formed solely from the light-emitting
material of the present invention.
[0044] Examples of the multi-layer structure of the organic EL
device include (anode/hole-injecting layer/light-emitting
layer/cathode), (anode/light-emitting layer/electron-injecting
layer/cathode), and (anode/hole-injecting layer/light-emitting
layer/electron-injecting layer/cathode).
[0045] In addition to the compound of the present invention
represented by any of formulas (I) to (IV), the light-emitting
layer may further contain, in accordance with needs, a known
light-emitting material, doping material, hole-injecting material,
or electron-injecting material. When the organic EL device has a
multi-layer structure, decrease in luminance and life time due to
quenching can be prevented. If required, a light-emitting material
can be used in combination with a doping material, a hole-injecting
material, or an electron-injecting material. When a doping material
is used, emission luminance and emission efficiency can be
elevated, and red-light-emission or blue-light-emission can be
attained. Each of the hole-injecting layer, light-emitting layer,
and electron-injecting layer may be composed of two or more layers.
In the case of the hole-injecting layer, a layer to which holes are
injected from an electrode is referred to as "hole-injecting
layer," and a layer for receiving holes from the hole-injecting
layer and transporting the holes to the light-emitting layer is
referred to as "hole-transporting layer." Similarly, in the case of
the electron-injecting layer, a layer to which electrons are
injected from an electrode is referred to as "electron-injecting
layer," and a layer for receiving electrons from the
electron-injecting layer and transporting the electrons to the
light-emitting layer is referred to as "electron-transporting
layer." These layers may be employed in accordance with energy
level of the material, heat resistance, adhesion with respect to an
organic layer or a metallic electrode, or other factors.
[0046] No particular limitation is imposed on the light-emitting
material or the doping material which may be used in the
light-emitting layer in combination with the compound represented
by any of formulas (I) to (IV). Examples include anthracene,
naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene,
fluoresceine, perylene, phthaloperylene, naphthaloperylene,
perynone, phthaloperynone, naphthaloperynone, diphenylbutadiene,
tetraphenylbutadiene, coumarin, oxadiazole, aldazine,
bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline
metal complexes, aminoquinoline metal complexes, benzoquinoline
metal complexes, imines, diphenylethylene, vinylanthracene,
diaminocarbazole, pyrane, thiopyrane, polymethine, merocyanine,
imidazole-chelated oxinoid compounds, quinacridone, rubrene, and
fluorescent dyes.
[0047] Preferably, the hole-injecting material is a compound which
can transfer holes, which exhibits hole-injecting effect (from an
anode) and excellent hole-injecting effect to a light-emitting
layer or a light-emitting material, which prevents transfer of
excitons generated in the light-emitting layer to an
electron-injecting layer or an electron-injecting material, and
which has excellent thin-film-formability. No particular limitation
is imposed on the hole-injecting material, and specific examples
include phthalocyanine derivatives, naphthalocyanine derivatives,
porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole,
imidazolone, imidazolethione, pyrazoline, pyrazolone,
tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone,
polyarylalkanes, stilbene, butadiene, benzidine-type
triphenylamines, styrylamine-type triphenylamines, diamine-type
triphenylamines, derivatives thereof, and polymer materials such as
polyvinylcarbazole, polysilane, and conductive polymers.
[0048] Among the hole-injecting materials which may be used in the
organic EL device of the present invention, an aromatic tertiary
amine derivative and a phthalocyanine derivative serve as a more
effective hole-injecting material.
[0049] No particular limitation is imposed on the type of the
aromatic tertiary amine derivative, and examples include
triphenylamine, tritolylamine, tolyldiphenylamine,
N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine,
N,N,N',N'-(4-methylphenyl)-1,1'-phenyl-4,4'-diamine,
N,N,N',N'-(4-methylphenyl)-1,1'-biphenyl-4,4'-diamine,
N,N'-diphenyl-N,N'-dinaphthyl-1,1'-biphenyl-4,4'-diamine,
N,N'-(methylphenyl)-N,N'-(4-n-butylphenyl)-phenanthrene-9,10-diamine,
N,N-bis(4-di-4-tolylaminophenyl)-4-phenyl-cyclohexane, and
oligomers and polymers having a skeletal structure of any of these
aromatic tertiary amines.
[0050] No particular limitation is imposed on the type of the
phthalocyanine (Pc) derivative, and examples include phthalocyanine
derivatives such as H.sub.2Pc, CuPc, CoPc, NiPc, ZnPc, PdPc, FePc,
MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl.sub.2SiPc, (HO)AlPc,
(HO)GaPc, VOPc, TiOPc, MoOPc, GaPc-O-GaPc, and naphthalocyanine
derivatives.
[0051] The organic EL device of the present invention preferably
includes, between the light-emitting layer and the anode, a layer
containing any of these aromatic tertiary amine derivatives and/or
phthalocyanine derivatives, for example, the aforementioned
hole-transporting layer or a hole-injecting layer.
[0052] Preferably, the electron-injecting material is a compound
which can transfer electrons, which exhibits electron-injecting
effect (from a cathode) and excellent electron-injecting effect to
a light-emitting layer or a light-emitting material, which prevents
transfer of excitons generated in the light-emitting layer to a
hole-injecting layer, and which has excellent
thin-film-formability. No particular limitation is imposed on the
electron-injecting material, and specific examples include
fluorenone, anthraquinodimethane, diphenoquinone, thiopyrane
dioxide, oxazole, oxadiazole, triazole, imidazole,
perylenetetracarboxylic acid, fluorenylidenemethane,
anthraquinodimethane, anthrone, and derivatives thereof. The
hole-injecting material may be sensitized through addition of an
electron-acceptor thereto, and the electron-injecting material may
be sensitized through addition of an electron-donor thereto.
[0053] Among the electron-injecting materials which may be used in
the organic EL device of the present invention, a metal complex
compound and a nitrogen-containing five-membered ring derivative
serve as a more effective electron-injecting material.
[0054] No particular limitation is imposed on the type of the metal
complex compound, and examples include 8-hydroxyquinolinatolithium,
bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper,
bis(8-hydroxyquinolinato)manganese,
tris(8-hydroxyquinolinato)aluminum,
tris(2-methyl-8-hydroxyquinolinato)aluminum,
tris(8-hydroxyquinolinato)gallium,
bis(10-hydroxybenzo[h]quinolinato)beryllium,
bis(10-hydroxybenzo[h]quinolinato)zinc,
bis(2-methyl-8-quinolinato)chlorogallium,
bis(2-methyl-8-quinolinato)(o-cresolato)gallium,
bis(2-methyl-8-quinolinato)(1-naphtholato)aluminum, and
bis(2-methyl-8-quinolinato)(2-naphtholato)gallium.
[0055] The nitrogen-containing five-membered-ring derivative is
preferably an oxazole derivative, a thiazole derivative, an
oxadiazole derivative, a thiadiazole derivative, and a triazole
derivative. Specific examples of the derivative include
2,5-bis(1-phenyl)-1,3,4-oxazole, dimethyl-POPOP,
2,5-bis(1-phenyl)-1,3,4-thiazole,
2,5-bis(1-phenyl)-1,3,4-oxadiazole,
2-(4'-tert-butylphenyl)-5-(4''-biphenyl)-1,3,4-oxadiazole,
2,5-bis(1-naphthyl)-1,3,4-oxadiazole,
1,4-bis[2-(5-phenyloxadiazolyl)]benzene,
1,4-bis[2-(5-phenyloxadiazolyl)-4-tert-butylbenzene],
2-(4'-tert-butylphenyl)-5-(4''-biphenyl)-1,3,4-thiadiazole,
2,5-bis(1-naphthyl)-1,3,4-thiadiazole,
1,4-bis[2-(5-phenylthiadiazolyl)]benzene,
2-(4'-tert-butylphenyl)-5-(4''-biphenyl)-1,3,4-triazole,
2,5-bis(1-naphthyl)-1,3,4-triazole, and
1,4-bis[2-(5-phenyltriazolyl)]benzene.
[0056] In the organic EL device of the present invention, the
light-emitting layer may contain, in addition to the compound
represented by any of formulas (I) to (IV), at least one species
selected from among a light-emitting material, a doping material, a
hole-injecting material, and an electron-injecting material. In
order to enhance stability of the organic EL device fabricated
according to the present invention, with respect to temperature,
humidity, atmosphere, and other conditions, the surface of the
device may be coated with a protective layer. Alternatively, the
entirety of the device may be protected with silicone oil, resin,
or a similar material.
[0057] The anode included in the organic EL device of the present
invention is preferably formed of a conductive material having a
work function higher than 4 eV. Examples of the conductive material
include carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten,
silver, gold, platinum, palladium, alloys thereof, metal oxides
such as tin oxide and indium oxide used in an ITO substrate or an
NESA substrate, and organic conductive resins such as polythiophene
and polypyrrole. The cathode included in the organic EL device of
the present invention is preferably formed of a conductive material
having a work function lower than 4 eV. No particular limitation is
imposed on the conductive material, and examples include magnesium,
calcium, tin, lead, titanium, yttrium, lithium, ruthenium,
manganese, aluminum, lithium fluoride, and alloys thereof. No
particular limitation is imposed on the type of alloys, and typical
examples of the alloys include magnesium/silver, magnesium/indium,
and lithium/aluminum. The alloy composition is appropriately
regulated in accordance with temperature of vapor-deposition
sources, atmosphere, vacuum degree, or other factors. In accordance
with needs, each of the anode and the cathode may be composed of
two or more layers.
[0058] In order to effectively emit light from the organic EL
device, at least one surface of the device is preferably
transparent sufficiently in a wavelength region of the emitted
light. Preferably, the substrate is also transparent. Such a
transparent electrode is produced from the aforementioned
conductive material through vapor deposition, sputtering, or a
similar method, such that a predetermined transparency is ensured.
The light-emission surface of the electrode preferably has a
light-transmittance of 10% or more. No particular limitation is
imposed on the material of the substrate so long as the substrate
has suitable mechanical and thermal strength and transparency.
Example of the substrate material include a glass substrate and
transparent resin film. Specific examples of the transparent resin
film include polyethylene, ethylene-vinyl acetate copolymer,
ethylene-vinyl alcohol copolymer, polypropylene, polystyrene,
poly(methyl methacrylate), poly(vinyl chloride), poly(vinyl
alcohol), poly(vinyl butyral), nylon, polyether-ether-ketones,
polysulfones, polyether sulfones,
tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer,
poly(vinyl fluoride), tetrafluoroethylene-ethylene copolymer,
tetrafluoroethylene-hexafluoropropylene copolymer,
poly(chlorotrifluoroethylene), poly(vinylidene fluoride),
polyesters, polycarbonates, polyurethanes, polyimides, polyether
imides, polyimides, and polypropylene.
[0059] Each component layer of the organic EL device of the present
invention may be formed through any of the dry film forming methods
such as vacuum vapor deposition, sputtering, and plasma-ion-plating
and the wet film formation methods such as spin-coating, dipping,
and flow coating. Although no particular limitation is imposed on
the film thickness, the film thickness must be controlled
appropriately. When the thickness excessively large, a large
voltage must be applied so as to gain a predetermined light output,
thereby lowering efficiency, whereas when the thickness is too
small, pinholes and other defects generate. In this case,
sufficient emission luminance cannot be attained even though
electric field is applied. In general, the thickness is preferably
5 nm to 10 .mu.m, more preferably 10 nm to 0.2 .mu.m.
[0060] In the case where the wet film formation method is employed,
materials for forming each layer is dissolved or dispersed in an
appropriate solvent such as ethanol, chloroform, tetrahydrofuran,
or dioxane, and a thin film is formed from the solution or
dispersion. Any appropriate solvents may be used. In order to
enhance film formability and prevent pinhole generation in the
film, an appropriate resin or additive may be incorporated into any
of the organic thin film layers. Examples of employable resins
include insulating resins such as polystyrene, polycarbonate,
polyarylate, polyester, polyamide, polyurethane, polysulfone,
poly(methyl methacrylate), poly(methyl acrylate), and cellulose;
copolymers thereof; photoconducting resins such as
poly-N-vinylcarbazole and polysilane; and conductive resins such as
polythiophene and polypyrrole. Examples of the additives include an
anti-oxidant, a UV-absorber, and a plasticizer.
[0061] As described above, by producing organic thin-film layers in
the organic EL device from the organic EL device material of the
present invention, the produced EL device exhibits a long service
life and can emit blue light of high color purity at high emission
efficiency.
[0062] The organic EL device of the present invention can be used
as a flat light-emitting device for use in a flat-panel display of
a wall-mounted, flat-panel television set; light sources for a
copying machine, a printer, a backside light of a liquid-crystal
display, indicators, etc.; display panels; signal lamps; etc., in
addition to organic EL devices, the material of the present
invention can be also used in an electrophotographic sensitizer, a
photoelectric conversion device, a solar cell, an image sensor,
etc.
[0063] The present invention will next be described in more detail
by of examples, which should not be construed as limiting the
invention thereto.
SYNTHESIS EXAMPLE 1
Synthesis of Compound (1)
[0064] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
N-phenyl-2-naphthylamine (5.4 g, 25 mmol), palladium acetate (0.03
g, 1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol. %),
t-butoxysodium (2.4 g, 25 mmol), and anhydrous toluene (100 mL)
were added to a 300-mL three-neck flask equipped with a condenser,
and the mixture was heated overnight at 100.degree. C. with
stirring. After completion of reaction, precipitated crystals were
collected through filtration, followed by washing with toluene (50
mL) and methanol (100 mL), to thereby yield 6.4 g of a pale yellow
powder. The powder was identified as compound (1) through an NMR
spectrum (see FIG. 1) and an FD-MS (field desorption mass spectrum)
(yield: 98%).
[0065] The NMR spectrum (solvent: CDCl.sub.3) was obtained by means
of a Fourier-transform NMR spectrometer (R-1900 (90 MHz), product
of Hitachi, Ltd.).
SYNTHESIS EXAMPLE 2
Synthesis of Compound (2)
[0066] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-methyldiphenylamine (4.5 g, 25 mmol), palladium acetate (0.03 g,
1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol %), t-butoxysodium
(2.4 g, 25 mmol), and anhydrous toluene (100 mL) were added to a
300-mL three-neck flask equipped with a condenser, and the mixture
was heated overnight at 100.degree. C. with stirring. After
completion of reaction, precipitated crystals were collected
through filtration, followed by washing with toluene (50 mL) and
methanol (100 mL), to thereby yield 5.4 g of a pale yellow powder.
The powder was identified as compound (2) through an NMR spectrum
(see FIG. 2) and an FD-MS (yield: 92%). The NMR spectrum was
obtained under the same conditions as employed in Synthesis Example
1.
SYNTHESIS EXAMPLE 3
Synthesis of Compound (5)
[0067] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
p,p'-ditolylamine (4.9 g, 25 mmol), palladium acetate (0.03 g, 1.5
mol %), tri-t-butylphosphine (0.06 g, 3 mol %), t-butoxysodium (2.4
g, 25 mmol), and anhydrous toluene (100 mL) were added to a 300-mL
three-neck flask equipped with a condenser, and the mixture was
heated overnight at 100.degree. C. with stirring. After completion
of reaction, precipitated crystals were collected through
filtration, followed by washing with toluene (50 mL) and methanol
(100 mL), to thereby yield 5.7 g of a pale yellow powder. The
powder was identified as compound (5) through an NMR spectrum (see
FIG. 3) and an FD-MS (yield: 93%). The NMR spectrum was obtained
under the same conditions as employed in Synthesis Example 1.
SYNTHESIS EXAMPLE 4
Synthesis of Compound (6)
[0068] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
m,m'-ditolylamine (4.9 g, 25 mmol), palladium acetate (0.03 g, 1.5
mol %), tri-t-butylphosphine (0.06 g, 3 mol %), t-butoxysodium (2.4
g, 25 mmol), and anhydrous toluene (100 mL) were added to a 300-mL
three-neck flask equipped with a condenser, and the mixture was
heated overnight at 100.degree. C. with stirring. After completion
of reaction, precipitated crystals were collected through
filtration, followed by washing with toluene (50 mL) and methanol
(100 mL), to thereby yield 5.5 g of a pale yellow powder. The
powder was identified as compound (6) through an NMR spectrum (see
FIG. 4) and an FD-MS (yield: 89%). The NMR spectrum was obtained
under the same conditions as employed in Synthesis Example 1.
SYNTHESIS EXAMPLE 5
Synthesis of Compound (8)
[0069] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-ethyldiphenylamine (4.9 g, 25 mmol), palladium acetate (0.03 g,
1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol %), t-butoxysodium
(2.4 g, 25 mmol), and anhydrous toluene (100 mL) were added to a
300-mL three-neck flask equipped with a condenser, and the mixture
was heated overnight at 100.degree. C. with stirring. After
completion of reaction, precipitated crystals were collected
through filtration, followed by washing with toluene (50 mL) and
methanol (100 mL), to thereby yield 5.7 g of a pale yellow powder.
The powder was identified as compound (8) through an NMR spectrum
(see FIG. 5) and an FD-MS (yield: 92%). The NMR spectrum was
obtained under the same conditions as employed in Synthesis Example
1.
SYNTHESIS EXAMPLE 6
Synthesis of Compound (9)
[0070] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-isopropyldiphenylamine (5.2 g, 25 mmol), palladium acetate (0.03
g, 1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol %),
t-butoxysodium (2.4 g, 25 mmol), and anhydrous toluene (100 mL)
were added to a 300-mL three-neck flask equipped with a condenser,
and the mixture was heated overnight at 100.degree. C. with
stirring. After completion of reaction, precipitated crystals were
collected through filtration, followed by washing with toluene (50
mL) and methanol (100 mL), to thereby yield 6.3 g of a pale yellow
powder. The powder was identified as compound (9) through an NMR
spectrum (see FIG. 6) and an FD-MS (yield: 98%). The NMR spectrum
was obtained under the same conditions as employed in Synthesis
Example 1.
SYNTHESIS EXAMPLE 7
Synthesis of Compound (10)
[0071] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-t-butyldiphenylamine (5.6 g, 25 mmol), palladium acetate (0.03 g,
1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol %), t-butoxysodium
(2.4 g, 25 mmol), and anhydrous toluene (100 mL) were added to a
300-mL three-neck flask equipped with a condenser, and the mixture
was heated overnight at 100.degree. C. with stirring. After
completion of reaction, precipitated crystals were collected
through filtration, followed by washing with toluene (50 mL) and
methanol (100 mL), to thereby yield 5.3 g of a pale yellow powder.
The powder was identified as compound (10) through an NMR spectrum
(see FIG. 7) and an FD-MS (yield: 79%). The NMR spectrum was
obtained under the same conditions as employed in Synthesis Example
1.
SYNTHESIS EXAMPLE 8
Synthesis of Compound (11)
[0072] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-isopropylphenyl-p-tolylamine (5.6 g, 25 mmol), palladium acetate
(0.03 g, 1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol %),
t-butoxysodium (2.4 g, 25 mmol), and anhydrous toluene (100 mL)
were added to a 300-mL three-neck flask equipped with a condenser,
and the mixture was heated overnight at 100.degree. C. with
stirring. After completion of reaction, precipitated crystals were
collected through filtration, followed by washing with toluene (50
mL) and methanol (100 mL), to thereby yield 6.0 g of a pale yellow
powder. The powder was identified as compound (11) through an NMR
spectrum (see FIG. 8) and an FD-MS (yield: 89%). The NMR spectrum
was obtained under the same conditions as employed in Synthesis
Example 1.
SYNTHESIS EXAMPLE 9
Synthesis of Compound (12)
[0073] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-diisopropylphenylamine (6.3 g, 25 mmol), palladium acetate (0.03
g, 1.5 mol %), tri-t-butylphosphine (0.06 g, 3 mol %),
t-butoxysodium (2.4 g, 25 mmol), and anhydrous toluene (100 mL)
were added to a 300-mL three-neck flask equipped with a condenser,
and the mixture was heated overnight at 100.degree. C. with
stirring. After completion of reaction, precipitated crystals were
collected through filtration, followed by washing with toluene (50
mL) and methanol (100 mL), to thereby yield 6.9 g of a pale yellow
powder. The powder was identified as compound (12) through an NMR
spectrum (see FIG. 9) and an FD-MS (yield: 95%). The NMR spectrum
was obtained under the same conditions as employed in Synthesis
Example 1.
SYNTHESIS EXAMPLE 10
Synthesis of Compound (14)
[0074] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
di-2-naphthylamine (6.7 g, 25 mmol), palladium acetate (0.03 g, 1.5
mol %), tri-t-butylphosphine (0.06 g, 3 mol %), t-butoxysodium (2.4
g, 25 mmol), and anhydrous toluene (100 mL) were added to a 300-mL
three-neck flask equipped with a condenser, and the mixture was
heated overnight at 100.degree. C. with stirring. After completion
of reaction, precipitated crystals were collected through
filtration, followed by washing with toluene (50 mL) and methanol
(100 mL), to thereby yield 7.2 g of a pale yellow powder. The
powder was identified as compound (14) through an NMR spectrum (see
FIG. 10) and an FD-MS (yield: 94%). The NMR spectrum was obtained
under the same conditions as employed in Synthesis Example 1.
SYNTHESIS EXAMPLE 11
Synthesis of Compound (19)
[0075] Under argon flow, 6,12-dibromochrysene (3.8 g, 10 mmol),
4-(di-p-tolylamino)phenylboronic acid (7.9 g, 25 mmol),
tetrakistriphenylphosphine palladium (0.17 g, 1.5 mol %), aqueous
sodium carbonate (30 mL, 60 mmol, 2M), and toluene (60 mL) were
added to a 300-mL three-neck flask equipped with a condenser, and
the mixture was heated overnight at 100.degree. C. with stirring.
After completion of reaction, precipitated crystals were collected
through filtration, followed by washing with toluene (50 mL) and
methanol (100 mL), to thereby yield 7.3 g of a pale yellow powder.
The powder was identified as compound (19) through an NMR spectrum
(see FIG. 11) and an FD-MS (yield: 95%). The NMR spectrum was
obtained under the same conditions as employed in Synthesis Example
1.
EXAMPLE 1
[0076] An indium tin oxide transparent electrode (thickness: 120
nm) was formed on a glass substrate (25.times.75.times.1.1 mm). The
glass substrate was cleaned through irradiation with a UV ray in an
ozone atmosphere, and placed in a vacuum deposition apparatus.
[0077] On the transparent electrode,
N',N''-bis[4-(diphenylamino)phenyl]-N',N''-diphenylvinyl-4,4'-diamine
serving as a hole-injecting layer (thickness: 60 nm),
N,N,N',N'-tetrakis(4-biphenyl)-4,4'-benzidine serving as a
hole-transporting layer (thickness: 20 nm) were sequentially
vapor-deposited, followed by simultaneously vapor-depositing
10,10'-bis[1,1',4',1'']terphenyl-2-yl-9,9'-bianthracenyl and the
aforementioned compound (2) (40:2 by weight) thereon, to thereby
form a light-emitting layer (thickness: 40 nm).
[0078] Subsequently, tris(8-hydroxyquinolinato)aluminum serving as
an electron-injecting layer (thickness: 10 nm) was deposited,
followed by sequentially vapor-depositing lithium fluoride
(thickness: 1 nm) and aluminum (thickness: 150 nm). The lithium
fluoride/aluminum film served as a cathode. Thus, an organic EL
device was fabricated.
[0079] When the thus-fabricated organic EL device was tested under
application of voltage, a blue-light emission with an emission
luminance of 410 cd/m.sup.2 (maximum peak emission wavelength: 457
nm) was observed at a voltage of 6 V and a current density of 10
mA/cm.sup.2. When the EL device was continuously tested under
voltage application (DC) at an initial luminance of 500 cd/m.sup.2,
the half-life time was found to be 2,160 hours.
EXAMPLE 2
[0080] The procedure of Example 1 was repeated, except that
compound (5) was used instead of compound (2), to thereby fabricate
an organic EL device.
[0081] When the thus-fabricated organic EL device was tested under
application of voltage, a blue-light emission with an emission
luminance of 596 cd/m.sup.2 (maximum peak emission wavelength: 463
nm) was observed at a voltage of 6.5 V and a current density of 10
mA/cm.sup.2. When the EL device was continuously tested under
voltage application in a manner similar to that of Example 1, the
half-life time was found to be 3,880 hours.
EXAMPLE 3
[0082] The procedure of Example 1 was repeated, except that
compound (11) was used instead of compound (2), to thereby
fabricate an organic EL device.
[0083] When the thus-fabricated organic EL device was tested under
application of voltage, a blue-light emission with an emission
luminance of 594 cd/m.sup.2 (maximum peak emission wavelength: 462
nm) was observed at a voltage of 6.3 V and a current density of 10
mA/cm.sup.2. When the EL device was continuously tested under
voltage application in a manner similar to that of Example 1, the
half-life time was found to be 4,590 hours.
COMPARATIVE EXAMPLE 1
[0084] The procedure of Example 1 was repeated, except that
6,12-bis(diphenylamino)chrysene was used instead of compound (2),
to thereby fabricate an organic EL device.
[0085] When the thus-fabricated organic EL device was tested under
application of voltage, a blue-light emission with an emission
luminance of 311 cd/m.sup.2 (maximum peak emission wavelength: 451
nm) was observed at a voltage of 6.2 V and a current density of 10
mA/cm.sup.2. When the EL device was continuously tested under
voltage application in a manner similar to that of Example 1, the
half-life time was found to be as short as 1,000 hours.
INDUSTRIAL APPLICABILITY
[0086] The organic EL device including the organic EL device
material of the present invention serving as a light-emitting
material attains emission luminance sufficient for use in practice
through low applied voltage. The device also attains high emission
efficiency and has a long service life; i.e., does not severely
deteriorated during use for a long period of time.
* * * * *