U.S. patent application number 09/818846 was filed with the patent office on 2002-04-25 for anthracene derivative and organic electroluminescence device using the derivative.
This patent application is currently assigned to Idemitsu Kosan Co., Ltd.. Invention is credited to Funahashi, Masakazu, Hosokawa, Chishio, Ikeda, Hidetsugu.
Application Number | 20020048687 09/818846 |
Document ID | / |
Family ID | 26588674 |
Filed Date | 2002-04-25 |
United States Patent
Application |
20020048687 |
Kind Code |
A1 |
Hosokawa, Chishio ; et
al. |
April 25, 2002 |
Anthracene derivative and organic electroluminescence device using
the derivative
Abstract
An anthracene derivative represented by general formula (I): 1
wherein X and Y represent a trifunctional aromatic ring group or
the like, (1) A.sup.1 to A.sup.4 represent an aryl group or a
monovalent heterocyclic group or (2) A.sup.1 and A.sup.3 represent
hydrogen atom and A.sup.2 and A.sup.4 represent a styryl group in
which the phenyl portion may be substituted and the
.alpha.-position or the .beta.-position of the vinyl portion may be
substituted with an alkyl group, R.sup.1 to R.sup.16 represent
hydrogen atom, a halogen atom, cyano group, nitro group, alkyl
group or the like, Q represents an arylene group or the like and p
represents 0, 1 or 2; and an organic electroluminescence device
which comprises at least an organic light emitting layer disposed
between a pair of electrodes and the above anthracene derivative.
The novel anthracene derivative exhibits a high efficiency of light
emission and excellent heat resistance when the derivative is used
as a material constituting an organic electroluminescence
device.
Inventors: |
Hosokawa, Chishio; (Chiba,
JP) ; Ikeda, Hidetsugu; (Chiba, JP) ;
Funahashi, Masakazu; (Chiba, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
Idemitsu Kosan Co., Ltd.
Chiyoda-ku
JP
|
Family ID: |
26588674 |
Appl. No.: |
09/818846 |
Filed: |
March 28, 2001 |
Current U.S.
Class: |
428/690 ;
252/301.16; 313/504; 313/506; 428/917 |
Current CPC
Class: |
C09K 2211/1048 20130101;
C09K 11/06 20130101; C07C 2603/24 20170501; C07D 209/86 20130101;
C07D 285/12 20130101; C07D 333/18 20130101; H01L 51/0068 20130101;
C07D 223/22 20130101; C07D 241/42 20130101; H01L 51/5012 20130101;
C09K 2211/1044 20130101; C07C 15/52 20130101; H01L 51/0053
20130101; C07C 255/51 20130101; C07D 249/08 20130101; H01L 51/0054
20130101; C07D 207/323 20130101; C09K 2211/1059 20130101; H01L
51/0069 20130101; C07D 213/16 20130101; C07D 213/38 20130101; C07D
215/12 20130101; C07D 213/06 20130101; H01L 51/0058 20130101; H01L
51/007 20130101; C09K 2211/1051 20130101; H01L 51/005 20130101;
H01L 51/0067 20130101; C09K 2211/1029 20130101; C07D 215/06
20130101; H01L 51/0052 20130101; C09K 2211/1007 20130101; C07D
333/08 20130101; H01L 51/0065 20130101; C07C 15/28 20130101; C09K
2211/1092 20130101 |
Class at
Publication: |
428/690 ;
428/917; 313/504; 313/506; 252/301.16 |
International
Class: |
H05B 033/14; C09K
011/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2000 |
JP |
090644/2000 |
Oct 19, 2000 |
JP |
319297/2000 |
Claims
1. An anthracene derivative represented by general formula (I):
29wherein X and Y each independently represent a substituted or
unsubstituted trifunctional aromatic ring group having 6 to 30
carbon atoms or a substituted or unsubstituted trifunctional
heterocyclic group having 4 to 30 carbon atoms; (1) A.sup.1 to
A.sup.4 each independently represent a substituted or unsubstituted
aryl group having 6 to 30 carbon atoms or a substituted or
unsubstituted monovalent heterocyclic group having 4 to 30 carbon
atoms or (2) A.sup.1 represents hydrogen atom, A.sup.2 represents a
styryl group in which a phenyl portion may be substituted and an
.alpha.-position or a .beta.-position of a vinyl portion may be
substituted with an alkyl group having 1 to 30 carbon atoms,
A.sup.3 represents hydrogen atom and A.sup.4 represents a styryl
group in which a phenyl portion may be substituted and an
.alpha.-position or a .beta.-position of a vinyl portion may be
substituted with an alkyl group having 1 to 30 carbon atoms;
R.sup.1 to R.sup.16 each independently represent hydrogen atom, a
halogen atom, cyano group, nitro group, a substituted or
unsubstituted alkyl group, a substituted or unsubstituted alkoxy
group, a substituted or unsubstituted aryloxy group, a substituted
or unsubstituted alkylthio group, a substituted or unsubstituted
arylthio group, a substituted or unsubstituted amino group or a
substituted or unsubstituted aryl group; adjacent groups
represented by R.sup.1 to R.sup.16 may for rings by forming bonds
between each other; Q represents a substituted or unsubstituted
cycloalkylene group having 5 to 30 carbon atoms, a substituted or
unsubstituted arylene group having 6 to 30 carbon atoms or a
substituted or unsubstituted divalent heterocyclic group having 4
to 30 carbon atoms; and p represents a number selected from 0, 1
and 2.
2. An anthracene derivative represented by general formula (II):
30wherein (1) A.sup.1 to A.sup.4 each independently represent a
substituted or unsubstituted aryl group having 6 to 30 carbon atoms
or a substituted or unsubstituted monovalent heterocyclic group
having 4 to 30 carbon atoms or (2) A.sup.1 represents hydrogen
atom, A.sup.2 represents a styryl group in which a phenyl portion
may be substituted and an .alpha.-position or a .beta.-position of
a vinyl portion may be substituted with an alkyl group having 1 to
30 carbon atoms, A.sup.3 represents hydrogen atom and A.sup.4
represents a styryl group in which a phenyl portion may be
substituted and an .alpha.-position or a .beta.-position of a vinyl
portion may be substituted with an alkyl group having 1 to 30
carbon atoms; R.sup.1 to R.sup.16 each independently represent
hydrogen atom, a halogen atom, cyano group, nitro group, a
substituted or unsubstituted alkyl group, a substituted or
unsubstituted alkoxy group, a substituted or unsubstituted aryloxy
group, a substituted or unsubstituted alkylthio group, a
substituted or unsubstituted arylthio group, a substituted or
unsubstituted amino group or a substituted or unsubstituted aryl
group; adjacent groups represented by R.sup.1 to R.sup.16 may for
rings by forming bonds between each other; Q represents a
substituted or unsubstituted cycloalkylene group having 5 to 30
carbon atoms, a substituted or unsubstituted arylene group having 6
to 30 carbon atoms or a substituted or unsubstituted divalent
heterocyclic group having 4 to 30 carbon atoms; and p represents a
number selected from 0, 1 and 2.
3. An anthracene derivative represented by general formula (II'):
31wherein (1) A.sup.1 to A.sup.4 each independently represent a
substituted or unsubstituted aryl group having 6 to 30 carbon atoms
or a substituted or unsubstituted monovalent heterocyclic group
having 4 to 30 carbon atoms or (2) A.sup.1 represents hydrogen
atom, A.sup.2 represents a styryl group in which a phenyl portion
may be substituted and an .alpha.-position or a .beta.-position of
a vinyl portion may be substituted with an alkyl group having 1 to
30 carbon atoms, A.sup.3 represents hydrogen atom and A.sup.4
represents a styryl group in which a phenyl portion may be
substituted and an .alpha.-position or a .beta.-position of a vinyl
portion may be substituted with an alkyl group having 1 to 30
carbon atoms; R.sup.1 to R.sup.16 each independently represent
hydrogen atom, a halogen atom, cyano group, nitro group, a
substituted or unsubstituted alkyl group, a substituted or
unsubstituted alkoxy group, a substituted or unsubstituted aryloxy
group, a substituted or unsubstituted alkylthio group, a
substituted or unsubstituted arylthio group, a substituted or
unsubstituted amino group or a substituted or unsubstituted aryl
group; adjacent groups represented by R.sup.1 to R.sup.16 may for
rings by forming bonds between each other; Q represents a
substituted or unsubstituted cycloalkylene group having 5 to 30
carbon atoms, a substituted or unsubstituted arylene group having 6
to 30 carbon atoms or a substituted or unsubstituted divalent
heterocyclic group having 4 to 30 carbon atoms; and p represents a
number selected from 0, 1 and 2.
4. An anthracene derivative represented by general formula (III):
32wherein X and Y each independently represent a substituted or
unsubstituted trifunctional aromatic ring group having 6 to 30
carbon atoms or a substituted or unsubstituted trifunctional
heterocyclic group having 4 to 30 carbon atoms; R.sup.1 to R.sup.20
each independently represent hydrogen atom, a halogen atom, cyano
group, nitro group, a substituted or unsubstituted alkyl group, a
substituted or unsubstituted alkoxy group, a substituted or
unsubstituted aryloxy group, a substituted or unsubstituted
alkylthio group, a substituted or unsubstituted arylthio group, a
substituted or unsubstituted amino group or a substituted or
unsubstituted aryl group; adjacent groups represented by R.sup.1 to
R.sup.20 may for rings by forming bonds between each other; Q
represents a substituted or unsubstituted cycloalkylene group
having 5 to 30 carbon atoms, a substituted or unsubstituted arylene
group having 6 to 30 carbon atoms or a substituted or unsubstituted
divalent heterocyclic group having 4 to 30 carbon atoms; and p
represents a number selected from 0, 1 and 2.
5. An organic electroluminescence device which comprises a light
emitting area comprising an anthracene derivative described in
claim 1.
6. An organic electroluminescence device which comprises an organic
light emitting layer comprising an anthracene derivative described
in claim 1.
7. An organic electroluminescence device according to claim 5,
wherein the organic light emitting layer further comprises a
substance forming a recombination site.
8. An organic electroluminescence device according to claim 6,
wherein the organic light emitting layer further comprises a
substance forming a recombination site.
9. An organic electroluminescence device according to claim 7,
wherein the substance forming a recombination site is a fluorescent
substance having a quantum yield of fluorescence of 0.3 to 1.0.
10. An organic electroluminescence device according to claim 8,
wherein the substance forming a recombination site is a fluorescent
substance having a quantum yield of fluorescence of 0.3 to 1.0.
11. An organic electroluminescence device according to claim 7,
wherein the substance forming a recombination site is at least one
compound selected from styrylamine compounds, quinacridone
derivatives, rubrene derivatives, coumarine derivatives, perylene
derivatives, pyrane derivatives and fluoranthene derivatives.
12. An organic electroluminescence device according to claim 8,
wherein the substance forming a recombination site is at least one
compound selected from styrylamine compounds, quinacridone
derivatives, rubrene derivatives, coumarine derivatives, perylene
derivatives, pyrane derivatives and fluoranthene derivatives.
13. An organic electroluminescence device according to claim 5,
wherein a layer of a chalcogenide, a layer of a metal halide or a
layer of a metal oxide is formed between the organic light emitting
layer and a cathode or an anode.
14. An organic electroluminescence device according to claim 6,
wherein a layer of a chalcogenide, a layer of a metal halide or a
layer of a metal oxide is formed between the organic light emitting
layer and a cathode or an anode.
Description
TECHNICAL FIELD
[0001] The present invention relates to a novel organic compound
and an organic electroluminescence (electroluminescence will be
referred to as EL, hereinafter) device using the organic compound.
More particularly, the present invention relates to an anthracene
derivative used as a material constituting an organic EL device and
an organic EL device which uses the anthracene derivative and
exhibits a high efficiency of light emission and excellent heat
resistance.
BACKGROUND ART
[0002] Electroluminescence devices which utilize light emission in
the electric field show high self-distinguishability because of the
self-emission and are excellent in impact resistance because they
are completely solid devices. Therefore, organic EL devices are
used in the field of the back light of thin film display devices
and liquid crystal displays and the planar light source.
[0003] EL devices practically used at present are EL devices of the
dispersion type. Since EL devices of the dispersion type require an
alternating voltage of several tens volts or higher and 10 kiloHerz
or higher, driving circuits of the EL devices are complicated.
[0004] Therefore, organic EL devices which can be driven at a
voltage of 10 volts or lower and can achieve light emission of a
high degree are actively studied. For example, organic EL devices
having a laminate structure of a transparent electrode/a hole
injection layer/a light emitting layer/a back face electrode are
proposed (Appl. Phys. Lett., Volume 51, Pages 913 to 915 (1987) and
Japanese Patent Application Laid-Open No. Showa 63(1988)-264629).
In these organic EL devices, holes are efficiently injected into
the light emitting layer through the hole injecting layer disposed
in the organic EL devices. The light emitting layer used in the
organic EL devices may be a single layer. However, an excellent
balance between the electron transporting property and the hole
transporting property cannot be achieved by the single layer
structure. Improvement in the properties of the organic EL devices
has been made by using a multi-layer laminate structure.
[0005] Forming a laminate structure causes problems in that the
process for producing the organic EL devices is complicated and the
time required for the production increases and that restrictions
such as the necessity for forming each layer into a sufficiently
thin film arise. Moreover, in recent years, a lower driving voltage
is required since information instruments are required to have a
decrease size and to be portable. Therefore, development of a light
emitting material and a hole transporting material which contribute
to a decrease in the weight and a decrease in the driving voltage
has been conducted. It is known that anthracene can be used as the
light emitting material. However, forming a uniform thin film of
anthracene is not easy. Therefore, introduction of various
substituents into anthracene has been attempted. For example,
condensed multi-ring aromatic hydrocarbons are proposed for the
light emitting material of organic EL devices (Japanese Patent
Application Laid-Open Nos. Heisei 4(1992)-178488, Heisei
6(1994)-228544, Heisei 6(1994)-228545, Heisei 6(1994)-228546,
Heisei 6(1994)-228547, Heisei 6(1994)-228548, Heisei
6(1994)-228549, Heisei 8(1996)-311442, Heisei 8(1996)-12600, Heisei
8(1996)-12969 and Heisei 10(1998)-72579).
[0006] However, organic EL devices using the above compounds have a
problem in that the efficiency of light emission and heat
resistance are not sufficient.
DISCLOSURE OF THE INVENTION
[0007] The present invention has been made under the above
circumstances and has objects of providing a novel compound which
exhibits a high efficiency of light emission and excellent heat
resistance when the compound is used as a material constituting an
organic EL device and an organic EL device using the compound.
[0008] As the result of extensive studies by the present inventors
to achieve the above objects, it was found that the objects can be
achieved by anthracene derivatives having specific structures. The
present invention has been completed based on the knowledge.
[0009] The present invention can be summarized as follows.
[0010] [1] An anthracene derivative represented by general formula
(I): 2
[0011] wherein X and Y each independently represent a substituted
or unsubstituted trifunctional aromatic ring group having 6 to 30
carbon atoms or a substituted or unsubstituted trifunctional
heterocyclic group having 4 to 30 carbon atoms; (1) A.sup.1 to
A.sup.4 each independently represent a substituted or unsubstituted
aryl group having 6 to 30 carbon atoms or a substituted or
unsubstituted monovalent heterocyclic group having 4 to 30 carbon
atoms or (2) A.sup.1 represents hydrogen atom, A.sup.2 represents a
styryl group in which a phenyl portion may be substituted and an
.alpha.-position or a .beta.-position of a vinyl portion may be
substituted with an alkyl group having 1 to 30 carbon atoms,
A.sup.3 represents hydrogen atom and A.sup.4 represents a styryl
group in which a phenyl portion may be substituted and an
.alpha.-position or a .beta.-position of a vinyl portion may be
substituted with an alkyl group having 1 to 30 carbon atoms;
R.sup.1 to R.sup.16 each independently represent hydrogen atom, a
halogen atom, cyano group, nitro group, a substituted or
unsubstituted alkyl group, a substituted or unsubstituted alkoxy
group, a substituted or unsubstituted aryloxy group, a substituted
or unsubstituted alkylthio group, a substituted or unsubstituted
arylthio group, a substituted or unsubstituted amino group or a
substituted or unsubstituted aryl group; adjacent groups
represented by R.sup.1 to R.sup.16 may form rings by forming bonds
between each other; Q represents a substituted or unsubstituted
cycloalkylene group having 5 to 30 carbon atoms, a substituted or
unsubstituted arylene group having 6 to 30 carbon atoms or a
substituted or unsubstituted divalent heterocyclic group having 4
to 30 carbon atoms; and p represents a number selected from 0, 1
and 2.
[0012] [2] An anthracene derivative represented by general formula
(II): 3
[0013] wherein (1) A.sup.1 to A.sup.4 each independently represent
a substituted or unsubstituted aryl group having 6 to 30 carbon
atoms or a substituted or unsubstituted monovalent heterocyclic
group having 4 to 30 carbon atoms or (2) A.sup.1 represents
hydrogen atom, A.sup.2 represents a styryl group in which a phenyl
portion may be substituted and an .alpha.-position or a
.beta.-position of a vinyl portion may be substituted with an alkyl
group having 1 to 30 carbon atoms, A.sup.3 represents hydrogen atom
and A.sup.4 represents a styryl group in which a phenyl portion may
be substituted and an .alpha.-position or a .beta.-position of a
vinyl portion may be substituted with an alkyl group having 1 to 30
carbon atoms; R.sup.1 to R.sup.16 each independently represent
hydrogen atom, a halogen atom, cyano group, nitro group, a
substituted or unsubstituted alkyl group, a substituted or
unsubstituted alkoxy group, a substituted or unsubstituted aryloxy
group, a substituted or unsubstituted alkylthio group, a
substituted or unsubstituted arylthio group, a substituted or
unsubstituted amino group or a substituted or unsubstituted aryl
group; adjacent groups represented by R.sup.1 to R.sup.16 may for
rings by forming bonds between each other; Q represents a
substituted or unsubstituted cycloalkylene group having 5 to 30
carbon atoms, a substituted or unsubstituted arylene group having 6
to 30 carbon atoms or a substituted or unsubstituted divalent
heterocyclic group having 4 to 30 carbon atoms; and p represents a
number selected from 0, 1 and 2.
[0014] [3] An anthracene derivative represented by general formula
(II'): 4
[0015] wherein (1) A.sup.1 to A.sup.4 each independently represent
a substituted or unsubstituted aryl group having 6 to 30 carbon
atoms or a substituted or unsubstituted monovalent heterocyclic
group having 4 to 30 carbon atoms or (2) A.sup.1 represents
hydrogen atom, A.sup.2 represents a styryl group in which a phenyl
portion may be substituted and an .alpha.-position or a
.beta.-position of a vinyl portion may be substituted with an alkyl
group having 1 to 30 carbon atoms, A.sup.3 represents hydrogen atom
and A.sup.4 represents a styryl group in which a phenyl portion may
be substituted and an .alpha.-position or a .beta.-position of a
vinyl portion may be substituted with an alkyl group having 1 to 30
carbon atoms; R.sup.1 to R.sup.16 each independently represent
hydrogen atom, a halogen atom, cyano group, nitro group, a
substituted or unsubstituted alkyl group, a substituted or
unsubstituted alkoxy group, a substituted or unsubstituted aryloxy
group, a substituted or unsubstituted alkylthio group, a
substituted or unsubstituted arylthio group, a substituted or
unsubstituted amino group or a substituted or unsubstituted aryl
group; adjacent groups represented by R.sup.1 to R.sup.16 may for
rings by forming bonds between each other; Q represents a
substituted or unsubstituted cycloalkylene group having 5 to 30
carbon atoms, a substituted or unsubstituted arylene group having 6
to 30 carbon atoms or a substituted or unsubstituted divalent
heterocyclic group having 4 to 30 carbon atoms; and p represents a
number selected from 0, 1 and 2.
[0016] [4] An anthracene derivative represented by general formula
(III): 5
[0017] wherein X and Y each independently represent a substituted
or unsubstituted trifunctional aromatic ring group having 6 to 30
carbon atoms or a substituted or unsubstituted trifunctional
heterocyclic group having 4 to 30 carbon atoms; R.sup.1 to R.sup.20
each independently represent hydrogen atom, a halogen atom, cyano
group, nitro group, a substituted or unsubstituted alkyl group, a
substituted or unsubstituted alkoxy group, a substituted or
unsubstituted aryloxy group, a substituted or unsubstituted
alkylthio group, a substituted or unsubstituted arylthio group, a
substituted or unsubstituted amino group or a substituted or
unsubstituted aryl group; adjacent groups represented by R.sup.1 to
R.sup.20 may for rings by forming bonds between each other; Q
represents a substituted or unsubstituted cycloalkylene group
having 5 to 30 carbon atoms, a substituted or unsubstituted arylene
group having 6 to 30 carbon atoms or a substituted or unsubstituted
divalent heterocyclic group having 4 to 30 carbon atoms; and p
represents a number selected from 0, 1 and 2.
[0018] [5] An organic electroluminescence device which comprises a
light emitting area comprising an anthracene derivative described
in any of [1] to [4].
[0019] [6] An organic electroluminescence device which comprises an
organic light emitting layer comprising an anthracene derivative
described in any of [1] to [4].
[0020] [7] An organic electroluminescence device described in any
of [5] and [6], wherein the organic light emitting layer further
comprises a substance forming a recombination site.
[0021] [8] An organic electroluminescence device described in [7],
wherein the substance forming a recombination site is a fluorescent
substance having a quantum yield of fluorescence of 0.3 to 1.0.
[0022] [9] An organic electroluminescence device described in any
of [7] and [8], wherein the substance forming a recombination site
is at least one compound selected from styrylamine compounds,
quinacridone derivatives, rubrene derivatives, coumarine
derivatives, perylene derivatives, pyrane derivatives and
fluoranthene derivatives.
[0023] [10] An organic electroluminescence device described in any
of [5] to [9], wherein a layer of a chalcogenide, a layer of a
metal halide or a layer of a metal oxide is formed between the
organic light emitting layer and a cathode or an anode.
THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION
[0024] The organic compound of the present invention is a compound
represented by general formula (I): 6
[0025] In general formula (I), X and Y each independently represent
substituted or unsubstituted trivalent aromatic ring group having 6
to 30 carbon atoms or a substituted or unsubstituted trivalent
heterocyclic group having 4 to 30 carbon atoms.
[0026] Examples of the trivalent aromatic ring group having 6 to 30
carbon atoms include trivalent groups obtained by eliminating three
hydrogen atoms from aromatic compounds such as benzene,
naphthalene, biphenyl, terphenyl, triphenyl, chrysene, naphthacene,
picene, perylene, pentacene, coronene, rubicene, anthracene,
benzo[a]anthracene, benzo[a]pyrene, tetraphenylene and
bisanthracene. Examples of the trivalent heterocyclic group having
4 to 30 carbon atoms include trivalent groups obtained by
eliminating three hydrogen atoms from heterocyclic compounds such
as furan, thiophene, pyrrol, 2-hydroxypyrrol, benzofuran,
isobenzofuran, 1-benzothiophene, 2-benzothiophene, indole,
isoindole, indolidine, carbazole, 2-hydroxypyrane,
2-hydroxychromene, 1-hydroxy-2-benzopyrane, xanthene,
4-hydroxythiopyrane, pyridine, quinoline, isoquinoline,
4-hydroxyquinolidine, phenanthridine, acridine, oxazole, isoxazole,
thiazole, isothiazole, furazane, imidazole, pyrazole,
benzimidazole, 1-hydroxyimidazole, 1,8-naphthylidine, pyradine,
pyrimidine, pyridazine, quinoxaline, quinazoline, phthaladine,
purine, perimidine, 1,10-phenanthroline, thianthrene, phenoxithine,
phenoxazine, phenothiazine, phenazine, silacyclopentadiene,
silabenzene and dibenzo(b,f)azepine.
[0027] In the above general formula (I), (1) A.sup.1 to A.sup.4 may
each independently represent a substituted or unsubstituted aryl
group having 6 to 30 carbon atoms or a substituted or unsubstituted
monovalent heterocyclic group having 4 to 30 carbon atoms. Examples
of the aryl group having 6 to 30 carbon atoms include phenyl group,
naphthyl group, biphenyl group, anthranyl group, terphenyl group
and styryl group. Examples of the monovalent heterocyclic group
having 4 to 30 carbon atoms include monovalent groups corresponding
to the trivalent heterocyclic groups described as the examples of
the groups represented by X and Y.
[0028] In the above general formula (I), (2) A.sup.1 and A.sup.3
may each represent hydrogen atom and A.sup.2 and A.sup.4 may each
represent a styryl group. The phenyl portion of the styryl group
may be substituted and the .alpha.-position or the .beta.-position
of the vinyl portion of the styryl group may be substituted with an
alkyl group having 1 to 30 carbon atoms. When there are a plurality
of substituents, the substituents may form a ring structure by
forming a bond between each other. Examples of the styryl group
include phenylvinylene group, triphenylvinylene group,
naphthylvinylene group, biphenylvinylene group, terphenylvinylene
group and anthranylvinylene group.
[0029] In the above general formula (I), R.sup.1 to R.sup.16 each
independently represent hydrogen atom, a halogen atom, cyano group,
nitro group, a substituted or unsubstituted alkyl group having 1 to
6 carbon atoms, a substituted or unsubstituted alkoxy group having
1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group
having 5 to 18 carbon atoms, a substituted or unsubstituted
aralkyloxy group having 7 to 18 carbon atoms, a substituted or
unsubstituted alkylthio group having 1 to 20 carbon atoms, a
substituted or unsubstituted arylthio group having 6 to 18 carbon
atoms, a substituted or unsubstituted amino group, a substituted or
unsubstituted ester group having 1 to 6 carbon atoms or a
substituted or unsubstituted aryl group having 5 to 16 carbon
atoms.
[0030] Examples of the alkyl group having 1 to 6 carbon atoms
include methyl group, ethyl group, propyl group, isopropyl group,
butyl group, isobutyl group, sec-butyl group, tert-butyl group,
various types of pentyl groups and various types of hexyl groups.
Examples of the alkoxy group having 1 to 6 carbon atoms include
methoxy group, ethoxy group, propoxy group, isopropoxy group,
butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group,
various types of pentyloxy groups and various types of hexyloxy
groups. Examples of the aryloxy group having 5 to 18 carbon atoms
include phenoxy group, tolyloxy group and naphthyloxy group.
Examples of the aralkyloxy group having 7 to 18 carbon atoms
include benzyloxy group, phenetyloxy group and naphthylmethoxy
group. Examples of the alkylthio group having 1 to 20 carbon atoms
and the arylthio group having 6 to 18 carbon atoms include
methylthio group, ethylthio group, phenylthio group and tolylthio
group. Examples of the amino group substituted with an aryl group
having 5 to 16 carbon atoms include diphenylamino group,
dinaphthylamino group and naphthylphenylamio group. Examples of the
ester group having 1 to 6 carbon atoms include methoxycarbonyl
group, ethoxycarbonyl group, propoxycarbonyl group and
isopropoxycarbonyl group. Examples of the halogen atom include
fluorine atom, chlorine atom and bromine atom. Adjacent groups
represented by R.sup.1 to R.sup.16 may for rings by forming bonds
between each other.
[0031] In the above general formula (I), Q represents a substituted
or unsubstituted cycloalkylene group having 5 to 30 carbon atoms, a
substituted or unsubstituted arylene group having 6 to 30 carbon
atoms or a substituted or unsubstituted divalent heterocyclic group
having 4 to 30 carbon atoms. Examples of the cycloalkylene group
having 5 to 30 carbon atoms include cyclopentylene group,
cyclohexylene group and cycloheptylene group. Examples of the
arylene group having 6 to 30 carbon atoms include phenylene group,
naphthylene group, biphenylene group, anthranylene group and
terphenylene group. Examples of the divalent heterocyclic group
having 4 to 30 carbon atoms include divalent groups corresponding
to the trivalent groups described as the examples of the groups
represented by X and Y.
[0032] In the above general formula (I), p represents a number
selected from 0, 1 and 2. When p represents 0, groups at both sides
are bonded through a single bond.
[0033] When each group in the compounds represented by general
formulae (I) to (III) has substituents, examples of the
substituents include the groups described as the examples of the
groups represented by R.sup.1 to R.sup.16. Similarly to the groups
represented by R.sup.1 to R.sup.16, adjacent substituents may for
rings by forming bonds between each other.
[0034] The anthracene derivative represented by general formula (I)
is a compound selected from the compounds having the structures
described above. Among the above compounds, compounds having a
glass transition temperature of 100.degree. C. or higher are
preferable and compounds having a glass transition temperature of
120.degree. C. or higher are more preferable.
[0035] The preferred embodiments of the anthracene derivative
represented by general formula (I) include anthracene derivatives
represented by the following general formulae (II) and (II'): 7
[0036] In the above general formulae (II) and (II'), A.sup.1 to
A.sup.4, R.sup.1 to R.sup.16, Q and p are as defined in general
formula (I).
[0037] The preferred embodiments of the anthracene derivative
represented by general formula (I) further include anthracene
derivatives represented by the following general formula (III):
8
[0038] In the above general formula (III), X, Y, Q and p are as
defined in general formula (I) and R.sup.1 to R.sup.20 represent
the same atoms or groups as those represented by R.sup.1 to
R.sup.16.
[0039] Adjacent groups represented by R.sup.1 to R.sup.20 may form
rings by forming bonds between each other. Adjacent groups
represented by R.sup.1 to R.sup.16 frequently form rings by forming
bonds between each other.
[0040] Examples of the anthracene derivatives represented by
general formulae (I), (II), (II') and (III) include compounds E1 to
E44 shown in the following: 9
[0041] The process for producing the anthracene derivative
represented by general formula (I) is not particularly limited and
various processes may be used. For example, a desired anthracene
derivative can be efficiently produced in accordance with the
following process.
[0042] The process for producing a compound represented by general
formula (I) in which A.sup.1=A.sup.3, A.sup.2=A.sup.4 and X=Y will
be described. A halogen compound represented by general formula
(1-a): 10
[0043] wherein A.sup.1, A.sup.2 and X are as defined above and Z
represents a halogen atom, is reacted with an alkyllithium reagent
and converted into a lithium compound. The obtained lithium
compound is reacted with a bianthrone compound represented by
general formula (1-b): 11
[0044] wherein R.sup.1 to R.sup.16 are as defined above, and a
bisphenol derivative represented by general formula (1-c): 12
[0045] wherein A.sup.1, A.sup.2 and R.sup.1 to R.sup.16 are as
defined above, is obtained. By forming aromatic rings from the
bisphenol derivative in accordance with a conventional process, the
anthracene derivative represented by general formula (I) can be
obtained.
[0046] The organic EL device of the present invention is a device
having at least an organic light emitting layer disposed between a
pair of electrodes. Examples of the construction of the organic EL
device include the following constructions:
[0047] (1) An anode/a light emitting layer/a cathode;
[0048] (2) An anode/a hole injecting layer/a light emitting layer/a
cathode;
[0049] (3) An anode/a light emitting layer/an electron injecting
layer/a cathode;
[0050] (4) An anode/a hole injecting layer/a light emitting
layer/an electron injecting layer/a cathode;
[0051] (5) An anode/an organic semiconductor layer/a light emitting
layer/a cathode;
[0052] (6) An anode/an organic semiconductor layer/an electron
barrier layer/a light emitting layer/a cathode;
[0053] (7) An anode/an organic semiconductor layer/a light emitting
layer/an adhesion improving layer/a cathode; and
[0054] (8) An anode/a hole injecting layer/a hole transporting
layer/a light emitting layer/an electron injecting layer/a
cathode.
[0055] However, the construction of the organic EL device is not
limited to the above examples.
[0056] Among the above constructions, construction (8) is
preferably used. It is preferable that the anthracene derivative
represented by any of general formulae (I), (II), (II') and (III)
is comprises in the light emitting area such as the light emitting
layer, the hole transporting layer, the electron injection layer or
the hole injection layer (the layers other than the electrode
layers) in the above constructions. It is more preferable that the
anthracene derivative is comprised in the light emitting layer.
[0057] In general, the organic EL device is prepared on a substrate
which transmits light. The substrate which transmits light is the
substrate which supports the organic EL device. It is preferable
that the substrate which transmits light has a transmittance of
light of 50% or greater in the visible region of 400 to 700 nm. It
is also preferable that a flat and smooth substrate is used.
[0058] As the substrate which transmits light, glass plates and
synthetic resin plates are advantageously used. Specific examples
of the glass plates include plates made of soda ash glass, glass
containing barium and strontium, lead glass, aluminosilicate glass,
borosilicate glass, barium borosilicate glass and quartz. Specific
examples of the synthetic resin plates include plates made of
polycarbonate resins, acrylic resins, polyethylene terephthalate
resins, polyether sulfide resins and polysulfone resins.
[0059] As the anode, an electrode made of a material such as a
metal, an alloy, a conductive compound and a mixture of these
materials which has a great work function (4 eV or more) is
preferably used. Specific examples of the material for the anode
include metals such as Au and conductive materials such as CuIn,
ITO (indium tin oxide), SnO.sub.2, ZnO and In--Zn--O. The anode can
be prepared by forming a thin film of the electrode material
described above in accordance with a process such as the vapor
deposition process and the sputtering process. When the light
emitted from the light emitting medium layer is obtained through
the anode, it is preferable that the anode has a transmittance of
the emitted light greater than 10%. It is also preferable that the
sheet resistivity of the anode is several hundred
.OMEGA./.quadrature. or smaller. The thickness of the anode is, in
general, selected in the range of 10 nm to 1 .mu.m and preferably
in the range of 10 to 200 nm although the preferable range may be
different depending on the used material.
[0060] As the cathode, an electrode made of a material such as a
metal, an alloy, a conductive compound and a mixture of these
materials which has a small work function (4 eV or smaller) is
used. Specific examples of the material for the cathode include
sodium, sodium-potassium alloys, magnesium, lithium,
magnesium.silver mixtures, aluminum/aluminum oxide, Al/Li.sub.2O,
Al/LiO.sub.2, Al/LiF, aluminum.lithium alloys, indium and rare
earth metals.
[0061] The cathode can be prepared by forming a thin film of the
material described above in accordance with a process such as the
vapor deposition process and the sputtering process.
[0062] When the light emitted from the light emitting medium layer
is obtained through the cathode, it is preferable that the cathode
has a transmittance of the emitted light greater than 10%. It is
also preferable that the sheet resistivity of the cathode is
several hundred .OMEGA./.quadrature. or smaller. The thickness of
the cathode is, in general, selected in the range of 10 nm to 1
.mu.m and preferably in the range of 50 to 200 nm.
[0063] In the organic EL device of the present invention, it is
preferable that a layer of a chalcogenide, a metal halide or a
metal oxide is disposed on the surface of at least one of the pair
of electrodes prepared as described above. Specifically, it is
preferable that a layer of a chalcogenide (including an oxide) of a
metal such as silicon and aluminum is disposed on the surface of
the anode at the side of the light emitting medium layer and a
layer of a metal halide or a metal oxide is disposed on the surface
of the cathode at the side of the light emitting medium layer. Due
to the above layers, stability in driving can be improved.
[0064] Preferable examples of the chalcogenide include SiO.sub.x
(1.ltoreq.x.ltoreq.2), AlO.sub.x (1.ltoreq.x.ltoreq.1.52), SiON and
SiAlON. Preferable examples of the metal halide include CsF, LiF,
MgF.sub.2, CaF.sub.2 and fluorides of rare earth metals. Preferable
examples of the metal oxide include Cs.sub.2O, Li.sub.2O, MgO, SrO,
BaO and CaO.
[0065] As the light emitting layer in the organic EL of the present
invention, a layer having the combination of the following
functions is preferably used.
[0066] (1) The injecting function: the function of injecting holes
from the anode or the hole injecting layer or injecting electrons
from the cathode or the electron injecting layer when an electric
field is applied.
[0067] (2) The transporting function: the function of transporting
injected charges (electrons and holes) by the force of the electric
field.
[0068] (3) The light emitting function: the function of providing
the site for recombination of electrons and holes and emitting
light generated by the recombination.
[0069] The easiness of injection of holes may be different from the
easiness of injection of electrons. The ability of transporting
holes expressed by the mobility of holes may be different from the
ability of transporting electrons expressed by the mobility of
electrons. It is preferable that either holes or electrons are
transported. The above anthracene derivative represented by any of
general formulae (I), (II), (II') and (III) satisfies the above
three conditions and the light emitting layer can be formed by
using the anthracene derivative as the main component.
[0070] As one of the materials constituting the light emitting
layer of the organic EL device, a substance forming a recombination
site can be used. The substance forming a recombination site is a
substance which positively provides a site for recombination of
electrons and holes injected from the both electrodes or a
substance which provides a site where a recombination energy is
transported and light is emitted although the recombination of
electrons and holes does not take place. Therefore, when the
substance forming a recombination site is used in combination,
electrons and holes are recombined at portions more concentrated
around the center of the light emitting layer and the luminance of
light emission can be increased in comparison with the single use
of the anthracene derivative.
[0071] From the standpoint of the above phenomenon, it is
preferable that a substance having a higher quantum yield of
fluorescence is used as the substance forming a recombination site
in the light emitting layer of the organic EL device of the present
invention. In particular, it is more preferable that the substance
has a quantum yield of fluorescence of 0.3 to 1.0. As the substance
forming a recombination site, a compound selected from styrylamine
compounds, quinacridone derivatives, rubrene derivatives, coumarine
derivatives, perylene derivatives, pyrane derivatives and
fluoranthene derivatives or a mixture of compounds selected from
these compounds is used. Further examples of the substance forming
a recombination site include conjugated macromolecular compounds
such as polyarylenevinylene derivatives and polyarylene and
vinylene derivatives substituted with alkyl groups and alkoxy
groups having 1 to 50 carbon atoms.
[0072] It is preferable that the substance forming a recombination
site is selected in accordance with the color of light emitted from
the light emitting layer. For example, when emission of blue light
is desired, it is preferable that perylene, a styrylamine
derivative or a distyrylarylene derivative substituted with an
amino group is used. When emission of green light is desired, it is
preferable that a quinacridone derivative or a coumarine derivative
is used. When emission of yellow light is desired, it is preferable
that a rubrene derivative is used. When emission of orange light or
reddish orange light is desired, it is preferable that a
dicyanomethylpyrane derivative is used.
[0073] In the present invention, it may be preferable that the
anthracene derivative represented by any of general formulae (I),
(II), (II) and (III) of the present invention is used as the
substance forming a recombination site.
[0074] In the organic EL device of the present invention, the
amount of the substance forming a recombination site used in the
device is decided in accordance with the luminance of light
emission and the color of emitted light of the light emitting
layer. It is preferable that the amount is in the range of 0.1 to
20 parts by mass per 100 parts by mass of the organic compound
described above. When the amount of the substance forming a
recombination site is less than 0.1 parts by mass, the luminance of
light emission tends to decrease. When the amount exceeds 20 parts
by mass, heat resistance tends to decrease. Therefore, to maintain
an excellent balance between the luminance of the light emission
and the heat resistance in the organic EL device, it is preferable
that the amount is 0.5 to 20 parts by mass and more preferably 1.0
to 10 parts by mass per 100 parts by mass of the organic compound
described above.
[0075] As the material constituting the organic light emitting
layer of the organic EL device, compounds shown in the following
are used in addition to the above compounds in accordance with the
desired hue. For example, to obtain light emission in the region of
ultraviolet region to purple, a compound represented by the
following general formula (IV) is preferably used: 13
[0076] wherein X represents a divalent group represented by the
following general formula: 14
[0077] a representing an integer of 2 to 5, and Y represents an
aryl group expressed by the following formula: 15
[0078] In the compound represented by general formula (IV), phenyl
group, phenylene group and naphthyl group may have a single or a
plurality of substituents selected from alkyl groups having 1 to 4
carbon atoms, alkoxy groups having 1 to 4 carbon atoms, hydroxyl
group, sulfonyl group, carbonyl group, amino group, dimethylamino
group and diphenylamino group. When there are a plurality of these
groups, the groups may be bonded to each other and form a saturated
five-membered or six-membered group. In the compound, it is
preferable that the bond is formed at the para-position of phenyl
group, phenylene group and naphthyl group since the bonding is
rigid and a smooth film is formed by vapor deposition without
chemical decomposition. Specific examples of the compound
represented by general formula (IV) include the compounds expressed
by the following formulae.
[0079] In the following formulae, Me represents methyl group, t-Bu
represents tertiary-butyl group and Ph represents phenyl group.
16
[0080] Among the compounds shown in the above, p-quarterphenyl
derivatives and p-quinquephenyl derivatives are preferable.
[0081] To obtain emission of blue to green light, for example, a
fluorescent whitening agent of benzothiazole, benzimidazole or
benzoxazole, a metal chelate compound of an oxinoid compound or a
styrylbenzene compound can be used. Examples of the above compounds
include compounds disclosed in Japanese Patent Application
Laid-Open No. Showa 59(1984)-194393. Further examples of the
compound useful as the above compounds include compounds listed in
Chemistry of Synthetic Dies, 1971, pages 628 to 637 and 640.
[0082] As the metal chelate compound of an oxinoid compound, for
example, compounds disclosed in Japanese Patent Application
Laid-Open No. Showa 63(1988)-295695 can be used. Typical examples
of the above compound include metal complexes of
8-hydroxyquinolines such as tris(8-quinolinol)aluminum and
dilithium-epintridione.
[0083] As the styrylbenzene compound, for example, compounds
disclosed in European Patent Nos. 0319881 and 0373582 can be used.
Distyrylpyrazine derivatives disclosed in Japanese Patent
Application Laid-Open No. Heisei 2(1990)-252793 can also be used as
the material of the light emitting layer. Polyphenyl compounds
disclosed in European Patent No. 0387715 can also be used as the
material of the light emitting layer.
[0084] Compounds other than the fluorescent whitening agents, metal
chelate compounds of oxinoid compounds and styrylbenzene compounds
can be used as the material of the light emitting layer. Examples
of such compounds include the following compounds:
12-phthaloperinone (J. Appl. Phys., Volume 27, L713 (1988));
1,4-diphenyl-1,3-butadiene and 1,1,4,4-tetraphenyl-1,3-butadiene
(Appl. Phys, Lett., Volume 56, L799 (1990)); naphthalimide
derivatives (Japanese Patent Application Laid-Open No. Heisei
2(1990)-305886); perylene derivatives (Japanese Patent Application
Laid-Open No. Heisei 2 (1990)-189890); oxadiazole derivatives
(Japanese Patent Application Laid-Open No. Heisei 2 (1990)-216791
and HAMADA et al., the 38th Associated Meeting of Applied Physics);
aldazine derivatives (Japanese Patent Application Laid-Open No.
Heisei 2 (1990)-220393); pyrazine derivatives (Japanese Patent
Application Laid-Open No. Heisei 2 (1990)-220394); cyclopentadiene
derivatives (Japanese Patent Application Laid-Open No. Heisei 2
(1990)-289675); pyrrolopyrrol derivatives (Japanese Patent
Application Laid-Open No. Heisei 2 (1990)-296891); styrylamine
derivatives (Appl. Phys. Lett., Volume 56, L799 (1990); coumarine
compounds (Japanese Patent Application Laid-Open No. Heisei 2
(1990)-191694); and macromolecular compounds described in
International Patent Application Publication WO90/13148 and Appl.
Phys. Lett., Vol. 158, 18, P1982 (1991).
[0085] In the present invention, it is preferable, in particular,
that aromatic dimethylidine compounds disclosed in European Patent
No. 0388768 and Japanese Patent Application Laid-Open No. Heisei 3
(1991)-231970 are used as the material of the light emitting layer.
Examples of the above compounds include
4,4'-bis(2,2-di-t-butylphenylvinyl)biphenyl,
4,4'-bis(2,2-diphenylvinyl)biphenyl and derivatives of these
compounds.
[0086] Further examples of the compounds which are used as the
material of the light emitting layer include compounds represented
by the general formula (Rs--Q).sub.2--Al--O--L which are described
in Japanese Patent Application Laid-Open No. Heisei 5(1993)-258862.
In the general formula, L represents a hydrocarbon group having 6
to 24 carbon atoms which comprises a phenyl portion, O--L
represents a phenolate ligand, Q represents a 8-quilinolate ligand
and Rs represents a substituent to the 8-quinolinolate ring which
is selected so as to inhibit coordination of more than two
8-quinolinolate ligands to the aluminum atom. Specific examples of
the above compound include bis(2-methyl-8-quinolinolato)(para-
-phenylphenolato)aluminum(III) and bis
(2-methyl-8-quinolinolato)(1-naphth- olato)aluminum(III).
[0087] Mixed emission of blue light and green light can be obtained
in a high efficiency in accordance with the doping method as
disclosed in Japanese Patent Application Laid-Open No. Heisei 6
(1994)-9953. In this method, the light emitting material described
above can be used as the host. As the dopant, a fluorescent die
having strong blue to green color such as a coumarine fluorescent
die and the same fluorescent die as that used for the host can be
used. Specifically, a light emitting material having a
distyrylarylene skeleton structure and preferably
4,4'-bis(2,2-diphenylvinyl)biphenyl is used as the host and a
perylene derivative and preferably, for example, a distyrylarylene
derivative is used as the dopant.
[0088] The light emitting layer for obtaining emission of white
light is not particularly limited. The following light emitting
layers may be used:
[0089] (1) A light emitting layer in which the energy level of each
layer in an organic EL laminate is specified and light is emitted
utilizing the tunnel injection (European Patent No. 0390551).
[0090] (2) A light emitting device emitting white light which is
described in an example of a device utilizing the tunnel injection
similarly to the device in (1) (Japanese Patent Application
Laid-Open No. Heisei 3(1991)-230584).
[0091] (3) A light emitting layer having a two-layer structure
(Japanese Patent Application Laid-Open Nos. Heisei 2(1990)-220390
and Heisei 2(1990)-216790).
[0092] (4) A light emitting layer divided into a plurality of
layers each of which is composed of a material having a different
wavelength of emitted light (Japanese Patent Application Laid-Open
No. Heisei 4(1992)-51491).
[0093] (5) A light emitting layer in which a light emitting
material emitting blue light (the peak wavelength of the
fluorescence: 380 to 480 nm) and a light emitting material emitting
green light (the peak wavelength of the fluorescence: 480 to 580
nm) are laminated and a fluorescent material emitting red light is
further contained (Japanese Patent Application Laid-Open No. Heisei
6(1994)-207170).
[0094] (6) A light emitting layer in which a light emitting layer
emitting blue light contains a fluorescent die emitting blue light,
a light emitting layer emitting green light has an area containing
a fluorescent die emitting red light and a fluorescent material
emitting green light is further contained (Japanese Patent
Application Laid-Open No. Heisei 7(1995)-142169).
[0095] Among these light emitting layers, the light emitting layer
having structure (5) is preferably used.
[0096] As the fluorescent material emitting red light, compounds
shown in the following are preferably used.
[0097] In the following formulae, Me represents methyl group, iPr
represents isopropyl group and Et represents ethyl group. 17
[0098] As the process for forming the light emitting layer using
the above materials, for example, a conventional process such as
the vapor deposition process, the spin coating process and the
Langmuir-Blodgett process (the LB process) can be used. In
particular, it is preferable that the light emitting layer is a
molecular deposition film. The molecular deposition film is a film
formed by deposition of a material compound in the gas phase or a
film formed by solidification of a material compound in a solution
or in the liquid state. The molecular deposition film can be
distinguished from a thin film formed by the LB process (a
molecular accumulation film) based on differences in the
aggregation structure and the higher order structures and
functional differences due to these structural differences.
[0099] As disclosed in Japanese Patent Application Laid-Open No.
Showa 57(1982)-51781, the light emitting layer can also be formed
by dissolving a binding material such as a resin and a material
compound into a solvent to prepare a solution, followed by forming
a thin film in accordance with the spin coating process.
[0100] The thickness of the light emitting layer thus formed is not
particularly limited and can be suitably selected in accordance
with the situation. It is preferable that the thickness is in the
range of 5 nm to 5 .mu.m. The light emitting layer may be
constituted with a single layer comprising one or more materials
selected from the above materials or may be a laminate of the above
light emitting layer with a light emitting layer comprising a
compound different from the compound comprised in the above light
emitting layer.
[0101] The hole injecting and transporting layer is a layer which
helps injection of holes into the light emitting layer and
transports holes to the light emitting area. This layer has a great
mobility of holes and the ionization energy is, in general, as
small as 5.5 eV or smaller. For the hole injecting and transporting
layer, a material transporting holes to the light emitting layer
under a small electric field strength is preferable. It is
preferable that the mobility of holes is, for example, at least
10.sup.-6 cm.sup.2/V.multidot.sec when an electric field of 104 to
106 V/cm is applied. The material which is mixed with the
distyrylarylene derivative of the present invention and forms the
hole injecting and transporting layer is not particularly limited
as long as the material has the desirable properties described
above. A material can be suitably selected from materials
conventionally used as the hole transporting material in optically
conductive materials and materials conventionally used for a hole
injecting layer in EL devices.
[0102] Examples of the material forming the hole injecting and
transporting layer are as follows: triazole derivatives (U.S. Pat.
No. 3,112,197); oxadiazole derivatives (U.S. Pat. No. 3,189,447);
imidazole derivatives (Japanese Patent Application Publication No.
Showa 37(1962)-16096); polyarylalkane derivatives (U.S. Pat. Nos.
3,615,402, 3,820,989 and 3,542,544, Japanese Patent Application
Publication Nos. Showa 45(1970)-555 and Showa 51(1976) -10983 and
Japanese Patent Application Laid-Open Nos. Showa 51(1976) -93224,
Showa 55(1980)-17105, Showa 56(1981)-4148, Showa 55(1980) -108667,
Showa 55(1980)-156953 and Showa 56(1981)-36656); pyrazoline
derivatives and pyrazolone derivatives (U.S. Pat. Nos. 3,180,729
and 4,278,746 and Japanese Patent Application Laid-Open Nos. Showa
55(1980)-88064, Showa 55(1980)-88065, Showa 49(1974)-105537, Showa
55(1980)-51086, Showa 56(1981)-80051, Showa 56(1981)-88141, Showa
57(1982)-45545, Showa 54(1979)-112637 and Showa 55(1980) -74546);
phenylenediamine derivatives (U.S. Pat. No. 3,615,404, Japanese
Patent Application Publication Nos. Showa 51(1976)-10105, Showa
46(1971)-3712 and Showa 47(1972)-25336 and Japanese Patent
Application Laid-Open Nos. Showa 54(1979)-53435, Showa 54(1979)
-110536 and Showa 54(1979)-119925); arylamine derivatives (U.S.
Pat. Nos. 3,567,450, 3,180,703, 3,240,597, 3,658,520, 4,232,103,
4,175,961 and 4,012,376, Japanese Patent Application Publication
Nos. Showa 49(1974)-35702 and Showa 39(1964)-27577, Japanese Patent
Application Laid-Open Nos. Showa 55(1980)-144250, Showa 56(1981)
-119132 and Showa 56(1981)-22437 and West German Patent No.
1,110,518); chalcone derivatives substituted with amines (U.S. Pat.
No. 3,526,501); oxazole derivatives (U.S. Pat. No. 3,257,203);
styrylanthracene derivatives (Japanese Patent Application Laid-Open
No. Showa 56(1981)-46234); fluorenone derivatives (Japanese Patent
Application Laid-Open No. Showa 54(1979)-110837); hydrazone
derivatives (U.S. Pat. No. 3,717,462 and Japanese Patent
Application Laid-Open Nos. Showa 54(1979)-59143, Showa
55(1980)-52063, Showa 55(1980)-52064, Showa 55(1980)-46760, Showa
55(1980)-85495, Showa 57(1982)-11350, Showa 57(1982)-148749 and
Heisei 2(1990) -311591); stilbene derivatives (Japanese Patent
Application Laid-Open Nos. Showa 61(1986)-210363, Showa
61(1986)-228451, Showa 61(1986)-14642, Showa 61(1986)-72255, Showa
62(1987)-47646, Showa 62(1987)-36674, Showa 62(1987)-10652, Showa
62(1987)-30255, Showa 60(1985)-93455, Showa 60(1985)-94462, Showa
60(1985)-174749 and Showa 60(1985)-175052); Silazane derivatives
(U.S. Pat. No. 4,950,950); polysilane compounds (Japanese Patent
Application Laid-Open No. Heisei 2(1990)-204996); aniline
copolymers (Japanese Patent Application Laid-Open No. Heisei
2(1990)-282263); and electrically conductive macromolecular
oligomers, in particular, thiophene oligomers (Japanese Patent
Application Laid-Open No. Heisei 1(1989)-211399).
[0103] As the material of the hole injecting layer, the above
materials can be used. The following materials can also be used as
the material of the hole injecting layer: porphyrin compounds
(Japanese Patent Application Laid-Open No. Showa 63(1988)-295695);
aromatic tertiary-amine compounds and styrylamine compounds (U.S.
Pat. No. 4,127,412 and Japanese Patent Application Laid-Open Nos.
Showa 53(1978)-27033, Showa 54(1979)-58445, Showa 54(1979)-149634,
Showa 54(1979)-64299, Showa 55(1980)-79450, Showa 55(1980)-144250,
Showa 56(1981)-119132, Showa 61(1986)-295558, Showa 61(1986)-98353
and Showa 63(1988)-295695).
[0104] Further examples include compounds having two condensed
aromatic rings in the molecule which are disclosed in U.S. Pat. No.
5,061,569, such as 4,4'-bis(N-(1-naphthyl)-N-phenylamino)biphenyl
and compounds having three triphenylamine units bonded in the star
burst form, which are disclosed in Japanese Patent Application
Laid-Open No. Heisei 4(1992)-308688, such as
4,4',4"-tris(N-(3-methylphenyl)-N-phenylamino)tri- phenylamine.
Aromatic dimethylidine compounds described above as the material of
the light emitting layer and inorganic compounds such as the p-type
Si and the p-type SiC can also be used as the material of the hole
injecting layer.
[0105] To form the hole injecting and transporting layer, a thin
film of the above compound is formed in accordance with a
conventional process such as the vacuum vapor deposition process,
the spin coating process, the casting process and the LB process.
The thickness of the hole injecting and transporting layer is not
particularly limited. The thickness is, in general, 5 nm to 5
.mu.m. As long as the compound of the present invention is
contained in the hole transporting area, the hole injecting and
transporting layer may be composed of a single layer comprising one
or more materials selected from the materials described above or
may be a laminate of the above hole injecting and transporting
layer with a hole injecting and transporting layer comprising a
compounds different from the compound comprised in the above hole
injecting and transporting layer.
[0106] The layer of an organic semiconductor is a layer for helping
injection of holes or electrons into the light emitting layer. It
is preferable that this layer has an electric conductivity of
10.sup.-10 S/cm or greater. As the material of the layer of an
organic semiconductor, electrically conductive oligomers such as
oligomers containing thiophene, oligomers containing arylamines
disclosed in Japanese Patent Application Laid-Open No. Heisei
8(1996)-193191 and electrically conductive dendrimers such as
dendrimers containing arylamines can be used.
[0107] The electron injecting layer is a layer for helping
injection of electrons into the light emitting layer and has a
great mobility of electrons. The layer for improving adhesion is
the electron injecting layer made of a material exhibiting
excellent adhesion with the cathode. As the material used for the
electron injecting layer, metal complexes of 8-hydroxyquinoline and
derivatives thereof are preferably used. Examples of the metal
complexes of 8-hydroxyquinoline and derivatives thereof which can
be used as the material for electron injecting layer include metal
chelate compounds of oxinoid compounds including chelate compounds
of oxine (in general, 8-quinolinol or 8-hydroxyquinoline) such as
tris(8-quinolinol) aluminum.
[0108] Examples of the oxadiazole derivative include electron
transferring compounds represented by the following general
formulae (V) to (VII): 18
[0109] wherein Ar.sup.1, Ar.sup.2, Ar.sup.3, Ar.sup.5, Ar.sup.6 and
Ar.sup.9 each represent an aryl group which may have substituents,
Ar.sup.1 and Ar.sup.2, Ar.sup.3 and Ar.sup.5, and Ar.sup.6 and
Ar.sup.9 may represent the same group or different groups,
Ar.sup.4, Ar.sup.7 and Ar.sup.8 each represent an arylene group
which may have substituents and Ar.sup.7 and Ar.sup.8 may represent
the same group or different groups.
[0110] Examples of the aryl group in the above general formulae (V)
to (VII) include phenyl group, biphenyl group, anthranyl group,
perylenyl group and pyrenyl group. Examples of the arylene group
include phenylene group, naphthylene group, biphenylene group,
anthranylene group, perylenylene group and pyrenylene group.
Examples of the substituent to the above groups include alkyl
groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10
carbon atoms and cyano group. As the electron transferring
compound, compounds having the excellent property to form a thin
layer are used.
[0111] Specific examples of the electron transferring compound
include the compounds expressed by the following formulae. In the
formulae, Me represents methyl group and t-Bu represents
tertiary-butyl group. 19
[0112] As for the process for preparing the organic EL device of
the present invention, the organic EL device can be prepared by
forming the anode, the light emitting layer and, where necessary,
the hole injecting layer and the electron injecting layer using the
above materials in accordance with the above process, followed by
forming the cathode. The organic EL device may be prepared in the
reverse order, i.e., by preparing the cathode first and the anode
last.
[0113] As an embodiment, preparation of an organic EL device having
the construction in which an anode, a hole injecting layer, a light
emitting layer, an electron injecting layer and a cathode are
formed on a substrate transmitting light in this order will be
described in the following.
[0114] The anode is formed first. A thin film of an anode material
is formed on the substrate transmitting light in accordance with a
process such as the vapor deposition process or the sputtering
process so that the formed thin film has a thickness of 1 .mu.m or
smaller and preferably in the range of 10 to 200 nm. The hole
injecting layer is then formed on the anode. As described above,
the hole injecting layer may be formed in accordance with a process
such as the vacuum vapor deposition process, the spin coating
process, the casting process and the LB process. The vacuum vapor
deposition process is preferable since a uniform film can be
obtained and the formation of pin holes can be suppressed. When the
hole injecting layer is formed in accordance with the vacuum vapor
deposition process, the conditions of the vacuum vapor deposition
process are different depending on the compound used (the material
of the hole injecting layer) and the crystal structure and the
recombination structure of the hole injecting layer to be formed.
In general, it is preferable that the temperature of the source of
the vapor deposition is selected in the range of 50 to 450.degree.
C., the degree of vacuum is selected in the range of 10.sup.-7 to
10.sup.-3 torr, the rate of vapor deposition is selected in the
range of 0.01 to 50 nm/second, the temperature of the substrate
plate is selected in the range of -50 to 300.degree. C. and the
thickness of the film is selected in the range of 5 nm to 5
.mu.m.
[0115] The light emitting layer is formed on the hole injecting
layer. Using a desired organic light emitting material, a thin film
of the organic light emitting material is formed in accordance with
a process such as the vacuum vapor deposition process, the
sputtering process, the spin coating process and the casting
process. The vacuum vapor deposition process is preferable since a
uniform film can be obtained and the formation of pin holes can be
suppressed. When the light emitting layer is formed in accordance
with the vacuum vapor deposition process, the conditions of the
vacuum vapor deposition process is different depending on the
compound used. In general, the conditions can be selected in the
same ranges as those described above in the formation of the hole
injecting layer.
[0116] The electron injecting layer is formed on the light emitting
layer formed above. Similarly to the formation of the hole
injecting layer and the light emitting layer, it is preferable that
the vacuum vapor deposition process is used since the formation of
a uniform film is necessary. The conditions of the vacuum vapor
deposition process can be selected in the same ranges as those
described in the formation of the hole injecting layer and the
light emitting layer.
[0117] The process for adding the anthracene derivative of the
present invention is different depending on the layer in which the
anthracene derivative is comprised. When the vacuum deposition
process is used, the anthracene derivative can be vacuum vapor
deposited simultaneously with other materials. When the spin
coating process is used, the anthracene derivative can be used as a
mixture with other materials.
[0118] The cathode is laminated in the final step and the organic
EL device can be obtained. The cathode is constituted with a metal
and the vacuum vapor deposition process or the sputtering process
can be used for the formation. The vacuum vapor deposition process
is preferable since formation of damages in the organic layers
formed in previous steps during the formation of the cathode can be
prevented.
[0119] It is preferable that the steps for preparing the organic EL
device from the formation of the anode to the formation of the
cathode are conducted after the pressure in the apparatus for the
preparation is reduced and while the pressure is maintained at the
reduced pressure.
[0120] When the organic EL device is used, the light emission can
be observed when the anode is connected to the positive electrode
(+) and the cathode is connected to the negative electrode (-) and
a voltage of 3 to 40 V is applied. When the anode is connected to
the negative electrode (-) and the cathode is connected to the
positive electrode (+), the light emission is not observed at all.
When an alternating voltage is applied, a uniform emission of light
is observed only when the anode is connected to the positive
electrode (+) and the cathode is connected to the negative
electrode (-). The wave form of the applied alternating voltage is
not limited.
[0121] The present invention will be described more specifically
with reference to examples in the following. However, the present
invention is not limited to the examples.
EXAMPLE 1 (SYNTHESIS OF COMPOUND E1)
[0122] Under the atmosphere of argon, 9.3 g (30 mmol) of
3,5-diphenylbromobenzene was dissolved into a mixed solvent
prepared from 50 ml of anhydrous toluene and 50 ml of anhydrous
tetrahydrofuran (THF) and the resultant solution was cooled at
-20.degree. C. in a methanol bath cooled with dry ice. To the
cooled solution, n-butyllithium (1.50 M in hexane; 21 ml; 32 mmol)
was added and the resultant mixture was stirred at -20.degree. C.
for 1 hour. Then, 3.8 g (10 mmol) of bianthrone was added and the
resultant mixture was stirred at -20.degree. C. for 1 hour and at
room temperature for 6 hours, successively, and left standing for
one night. The reaction mixture was quenched with 50 ml of a
saturated aqueous solution of ammonium chloride. The formed solid
substance was separated by filtration and washed with water,
methanol and acetone and 7.3 g (the yield: 87%) of a diol compound
was obtained as a white solid.
[0123] Under the atmosphere of argon, 7.3 g (8.6 mmol) of the diol
compound obtained above was suspended in 100 ml of acetic acid. To
the obtained suspension, a 57% hydroiodic acid (11 ml; 83 mmol; 10
eq) was added and the resultant mixture was stirred at 80.degree.
C. for 8 hours. The reaction product was quenched by adding 50 ml
of a 50% phosphorous acid. The formed solid substance was separated
by filtration and washed with water, methanol and acetone and 5.9 g
(the yield: 84%) of a white solid was obtained. The results of
measurements with the obtained product in accordance with the
elemental analysis and the field desorption mass spectroscopy
(FD-MS) were as follows:
[0124] Elemental analysis (%): C: 94.52; H: 5.38 (the calculated
value (%) as C.sub.64H.sub.42: C: 94.78; H: 5.22)
[0125] FD-MS: m/z=810 (M.sup.+, 100) (the molecular weight
calculated as C.sub.64H.sub.42=810)
EXAMPLE 2 (SYNTHESIS OF COMPOUND E7)
[0126] Under the atmosphere of argon, 20 g (64 mmol) of
1,3,5-tribromobenzene and 3.6 g (5.1 mmol; 4% Pd) of
dichlorobis(triphenylphosphine)palladium were dissolved into 500 ml
of anhydrous THF. To the resultant solution, a Grignard reagent
prepared from 27 g (0.13 mol) of 3-bromoquinoline and 3.7 g (0.16
mol) of magnesium was added dropwise and the resultant mixture was
heated under the refluxing condition for 4 hours. The reaction
product was quenched by adding water. The organic layer was
separated, washed with a saturated aqueous solution of sodium
chloride and dried with anhydrous magnesium sulfate. After the
solvent was removed by distillation, the product was purified in
accordance with the column chromatography (silica gel/hexane+10%
dichloromethane) and 8.4 g (the yield: 32%) of a white solid was
obtained.
[0127] Under the atmosphere of argon, 8.4 g (20 mmol) of the white
solid obtained above was dissolved into a mixed solvent prepared
from 50 ml of anhydrous toluene and 50 ml of anhydrous THF and the
resultant solution was cooled at -20.degree. C. in a methanol bath
cooled with dry ice. To the cooled solution, n-butyllithium (1.50 M
in hexane; 15 ml; 22 mmol) was added and the resultant mixture was
stirred at -20.degree. C. for 1 hour. Then, 2.6 g (6.8 mmol) of
bianthrone was added and the resultant mixture was stirred at
-20.degree. C. for 1 hour and at room temperature for 6 hours,
successively, and left standing for one night. The obtained
reaction product was quenched by adding 50 ml of a saturated
aqueous solution of ammonium chloride. The formed solid substance
was separated by filtration and washed with water, methanol and
acetone and 4.8 g (the yield: 67%) of a diol compound was obtained
as a white solid. Then, under the atmosphere of argon, 4.8 g (4.6
mmol) of the diol compound obtained above was suspended in 50 ml of
acetic acid. To the obtained suspension, a 57% hydroiodic acid (6
ml; 46 mmol; 10 eq) was added and the resultant mixture was stirred
at 80.degree. C. for 8 hours. The reaction product was quenched by
adding 30 ml of a 50% hypophosphorous acid. The formed solid
substance was separated by filtration and washed with water,
methanol and acetone and 3.8 g (the yield: 81%) of a white solid
was obtained. The results of measurements with the obtained product
in accordance with the elemental analysis and the field desorption
mass spectroscopy (FD-MS) were as follows:
[0128] Elemental analysis (%): C: 89.02; H: 4.22; N: 5.38 (the
calculated value (%) as C.sub.76H.sub.48N.sub.4: C: 89.91, H: 4.57;
N: 5.52)
[0129] FD-MS: m/z=1016 (M.sup.+, 100) (the molecular weight
calculated as C.sub.76H.sub.48N.sub.4=1016)
EXAMPLE 3 (SYNTHESIS OF COMPOUND E14)
[0130] Under the atmosphere of argon, 15 g (38 mmol) of
N-(3,5-dibromophenyl)carbazole and 1.1 g (1.5 mmol; 4% Pd) of
dichlorobis(triphenylphosphine)palladium were dissolved into 500 ml
of anhydrous THF. To the resultant solution, a Grignard reagent
prepared from 6.0 g (38 mmol) of bromobenzene and 1.1 g (46 mmol)
of magnesium was added dropwise and the resultant mixture was
heated under the refluxing condition for 4 hours. The reaction
product was quenched by adding 100 ml of water. The organic layer
was separated, washed with a saturated aqueous solution of sodium
chloride and dried with anhydrous magnesium sulfate. After the
solvent was removed by distillation, the product was purified in
accordance with the column chromatography (silica gel/hexane+10%
dichloromethane) and 8.0 g (the yield: 53%) of a white solid was
obtained.
[0131] Under the atmosphere of argon, 8.0 g (20 mmol) of the white
solid obtained above was dissolved into a mixed solvent prepared
from 50 ml of anhydrous toluene and 50 ml of anhydrous THF and the
resultant solution was cooled at -20.degree. C. in a methanol bath
cooled with dry ice. To the cooled solution, n-butyllithium (1.50 M
in hexane; 15 ml; 22 mmol) was added and the resultant mixture was
stirred at -20.degree. C. for 1 hour. Then, 2.6 g (6.8 mmol) of
bianthrone was added and the resultant mixture was stirred at
-20.degree. C. for 1 hour and at room temperature for 6 hours,
successively, and left standing for one night. The obtained
reaction product was quenched by adding 50 ml of a saturated
aqueous solution of ammonium chloride. The formed solid substance
was separated by filtration and washed with water, methanol and
acetone and 4.9 g (the yield: 71%) of a diol compound was obtained
as a white solid. Then, under the atmosphere of argon, 4.9 g (4.8
mmol) of the diol compound obtained above was suspended in 50 ml of
acetic acid. To the obtained suspension, a 57% hydroiodic acid (6
ml; 48 mmol; 10 eq) was added and the resultant mixture was stirred
at 80.degree. C. for 8 hours. The reaction product was quenched by
adding, 30 ml of a 50% hypophosphorous acid. The formed solid
substance was separated by filtration and washed with water,
methanol and acetone and 4.4 g (the yield: 92%) of a white solid
was obtained. The results of measurements with the obtained product
in accordance with the elemental analysis and the field desorption
mass spectroscopy (FD-MS) were as follows:
[0132] Elemental analysis (%): C: 91.98; H: 4.52; N: 2.64 (the
calculated value (%) as C.sub.76H.sub.48N.sub.2: C: 92.28, H: 4.89;
N: 2.83)
[0133] FD-MS: m/z=988 (M.sup.+, 100) (the molecular weight
calculated as C.sub.76H.sub.48N.sub.2=988)
EXAMPLE 4 (SYNTHESIS OF COMPOUND E31)
[0134] Under the atmosphere of argon, 20 g (64 mmol) of
1,3,5-tribromobenzene and 3.6 g (5.1 mmol; 4% Pd) of
dichlorobis(triphenylphosphine)palladium were dissolved into 500 ml
of anhydrous THF. To the resultant solution, a Grignard reagent
prepared from 23 g (0.13 mmol) of 2-bromo-5-methylthiophene and 3.7
g (0.16 mol) of magnesium was added dropwise and the resultant
mixture was heated under the refluxing condition for 4 hours. The
reaction product was quenched by adding 100 ml of water. The
organic layer was separated, washed with a saturated solution of
sodium chloride and dried with anhydrous magnesium sulfate. After
the solvent was removed by distillation, the product was purified
in accordance with the column chromatography (silica gel/hexane+10%
dichloromethane) and 7.8 g (the yield: 35%) of a white solid was
obtained.
[0135] Under the atmosphere of argon, 7.8 g (22 mmol) of the white
solid obtained above was dissolved into a mixed solvent prepared
from 50 ml of anhydrous toluene and 50 ml of anhydrous THF and the
resultant solution was cooled at -20.degree. C. in a methanol bath
cooled with dry ice. To the cooled solution, n-butyllithium (1.50 M
in hexane; 16 ml; 24 mmol) was added and the resultant mixture was
stirred at -20.degree. C. for 1 hour. Then, 2.8 g (7.3 mmol) of
bianthrone was added and the resultant mixture was stirred at
-20.degree. C. for 1 hour and at room temperature for 6 hours,
successively, and left standing for one night. The obtained
reaction product was quenched by adding 50 ml of a saturated
aqueous solution of ammonium chloride. The formed solid substance
was separated by filtration and washed with water, methanol and
acetone and 5.1 g (the yield: 76%) of a diol compound was obtained
as a white solid. Then, under the atmosphere of argon, 5.1 g (5.5
mmol) of the diol compound obtained above was suspended in 50 ml of
acetic acid. To the obtained suspension, a 57% hydroiodic acid (6
ml; 48 mmol; 10 eq) was added and the resultant mixture was stirred
at 80.degree. C. for 8 hours. The reaction product was quenched by
adding 30 ml of a 50% hypophosphorous acid. The formed solid
substance was separated by filtration and washed with water,
methanol and acetone and 4.5 g (the yield: 92%) of a white solid
was obtained. The results of measurements with the obtained product
in accordance with the elemental analysis and the field desorption
mass spectroscopy (FD-MS) were as follows:
[0136] Elemental analysis (%): C: 80.53; H: 4.49 (the calculated
value (%) as C.sub.60H.sub.42N.sub.2S.sub.4: C: 80.86, H: 4.75)
[0137] FD-MS: m/z=890 (M.sup.+, 100) (the molecular weight
calculated as C.sub.60H.sub.42N.sub.2S.sub.4=890)
EXAMPLE 5 (PREPARATION OF AN ORGANIC EL DEVICE)
[0138] A glass substrate of a size of 25 mm.times.75 mm.times.1.1
mm having a transparent electrode of indium tin oxide (manufactured
by GEOMATEC Company) was cleaned in isopropyl alcohol by ultrasonic
vibration for 5 minutes and then with ozone for 30 minutes under
irradiation by ultraviolet light and attached to a substrate holder
of a vacuum vapor deposition apparatus.
[0139] On the surface of the substrate at the side having the
transparent electrode line, a film of
N,N'-bis(N,N'-diphenyl-4-aminophenyl)-N,N-diphe-
nyl-4,4'-diamino-1,1'-biphenyl (referred to as a TPD232 film,
hereinafter) having a thickness of 60 nm was formed. The formed
TPD232 film worked as the hole injecting layer.
[0140] On the formed TPD232 film, a film of
4,4'-bis[N-(1-naphthyl)-N-phen- yl]biphenyl (referred to as an NPD
film, hereinafter) having a thickness of 20 nm was formed. The
formed NPD film worked as the hole transporting film.
[0141] On the formed NPD film, a film of compound E1 having a
thickness of 40 nm was formed. The formed film worked as the light
emitting layer.
[0142] On the formed film of compound E1, a film of
tris(8-quinolinol)aluminum (referred to as an Alq film,
hereinafter) having a thickness of 20 nm was formed. The Alq film
worked as the electron injecting film.
[0143] On the formed Alq film, Li (manufactured by SAES GETTERS
Company) and Alq were binary vacuum vapor deposited and an Alq:Li
film was formed as the electron injecting layer (an anode).
[0144] On the formed Alq:Li film, metallic aluminum was vacuum
vapor deposited and a metallic anode was formed. Thus, an organic
EL device was formed.
[0145] When a voltage of 6 V was applied to the obtained device,
emission of blue light was obtained at a maximum luminance of
43,000 cd/m.sup.2 and 3.0 cd/A. The spectrum obtained by the device
had a peak wavelength at around 450 nm and excellent purity of
color having the chromaticity coordinates of (0.150, 0.131) was
obtained.
EXAMPLE 6 (PREPARATION OF AN ORGANIC EL DEVICE)
[0146] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E4 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
[0147] The test of heat resistance was conducted in accordance with
the following procedures:
[0148] [Test of Heat Resistance]
[0149] The luminance of the prepared device was measured and the
obtained value was used as the initial luminance (I.sub.0). Then,
the device was kept in a vessel thermostatted at 85.degree. C. for
500 hours. Then, the device was taken out of the vessel and left
standing until the temperature reached the room temperature. The
luminance (I.sub.500) after being kept for 500 hours under the
above condition was measured. The decrease in the luminance (%) was
obtained in accordance with the following equation and used for
evaluating the heat resistance.
Decrease in the luminance (%)=(I.sub.0-I.sub.500).times.100/Io
EXAMPLE 7 (PREPARATION OF AN ORGANIC EL DEVICE)
[0150] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E7 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
EXAMPLE 8 (PREPARATION OF AN ORGANIC EL DEVICE)
[0151] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E9 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
EXAMPLE 9 (PREPARATION OF AN ORGANIC EL DEVICE)
[0152] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E13 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
EXAMPLE 10 (PREPARATION OF AN ORGANIC EL DEVICE)
[0153] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E14 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
EXAMPLE 11 (PREPARATION OF AN ORGANIC EL DEVICE)
[0154] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E17 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
EXAMPLE 12 (PREPARATION OF AN ORGANIC EL DEVICE)
[0155] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using compound E31 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the test of heat resistance was conducted. The
results are shown in Table 1.
COMPARATIVE EXAMPLE 1 (PREPARATION OF AN ORGANIC EL DEVICE)
[0156] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was prepared by using an anthracene compound H1 expressed by
the following formula in place of compound E1. Using the prepared
device, the properties of light emission were confirmed and the
test of heat resistance was conducted. The results are shown in
Table 1. 20
EXAMPLE 13 (SYNTHESIS OF COMPOUND E32)
[0157] Compound E32 was synthesized in accordance with the
following process: 21
[0158] Synthesis of 4-bromostilbene
[0159] Into a 100 ml flask, 25 g (0.1 mol) of 4-bromobenzyl bromide
and 19 ml (0.11 mol) of triethyl phosphite were placed and the
resultant mixture was stirred under heating for 3 hours. After the
reaction was completed, the reaction solution was concentrated in
vacuo and a phosphite was obtained. The obtained phosphite was used
in the following reaction without purification.
[0160] In a 500 ml flask, the phosphite obtained above, 10 ml (0.1
mol) of benzaldehyde and 200 ml of dimethyl sulfoxide were placed
and cooled at 0.degree. C. with ice water. Then, 13.4 g (0.12 mol)
of potassium t-butoxide was slowly added and the resultant mixture
was kept being stirred at the room temperature for one night. After
the reaction was completed, the reaction solution was poured into
500 ml of water and the organic layer was treated by extraction
with ethyl acetate. After drying with magnesium sulfate, the
organic layer was concentrated in vacuo using a rotary evaporator
and yellow crystals were obtained. The obtained crystals were
purified by recrystallization (100 ml of isopropyl alcohol) and 15
g (the yield: 59%) of 4-bromostilbene as the object compound was
obtained.
[0161] Synthesis of Compound E32
[0162] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 1.6 g (66 mmol) of magnesium, a small
piece of iodine and 50 ml of THF were placed. After the resultant
mixture was stirred at the room temperature for 30 minutes, a
solution prepared by dissolving 7.8 g (30 mmol) of 4-bromostilbene
into 100 ml of THF was added dropwise. After the addition was
completed, the resultant mixture was stirred at 60.degree. C. for 1
hour and a Grignard reagent was prepared.
[0163] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 5.1 g (10 mmol) of
10,10'-dibromo-9,9'-bianthryl, 0.4 g (5% by mol) of
dichlorobis(triphenylphosphine)palladium, 1 ml (1 M; 1 mmol) of a
toluene solution of diisobutylaluminum hydride and 100 ml of THF
were placed. To the resultant mixture, the Grignard reagent
prepared above was added dropwise at the room temperature. Then,
the resultant mixture was heated and stirred under heating for one
night. After the reaction was completed, the reaction solution was
cooled with ice water. The formed crystals were separated by
filtration and washed with 50 ml of methanol and 50 ml of acetone,
successively, and 3.5 g of a yellow powder was obtained. The yellow
powder was identified to be compound E32 by measurements in
accordance with NMR, IR and FD-MS (the yield: 50%).
EXAMPLE 14 (SYNTHESIS OF COMPOUND E33)
[0164] Compound E33 was synthesized in accordance with the
following process: 22
[0165] Synthesis of 3-bromostilbene
[0166] Into a 100 ml flask, 25 g (0.1 mol) of 3-bromobenzyl bromide
and 19 ml (0.11 mol) of triethyl phosphite were placed and the
resultant mixture was stirred under heating for 3 hours. After the
reaction was completed, the reaction solution was concentrated in
vacuo and a phosphite was obtained. The obtained phosphite was used
in the following reaction without purification.
[0167] In a 500 ml flask, the phosphite obtained above, 10 ml (0.1
mol) of benzaldehyde and 200 ml of dimethyl sulfoxide were placed
and cooled at 0.degree. C. with ice water. Then, 13.4 g (0.12 mol)
of potassium t-butoxide was slowly added and the resultant mixture
was kept being stirred at the room temperature for one night. After
the reaction was completed, the reaction solution was poured into
500 ml of water and the organic layer was treated by extraction
with ethyl acetate. After drying with magnesium sulfate, the
organic layer was concentrated in vacuo using a rotary evaporator
and yellow crystals were obtained. The obtained crystals were
purified by recrystallization (100 ml of isopropyl alcohol) and 20
g (the yield: 77%) of 3-bromostilbene as the object compound was
obtained.
[0168] Synthesis of Compound E33
[0169] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 1.6 g (66 mmol) of magnesium, a small
piece of iodine and 50 ml of THF were placed. After the resultant
mixture was stirred at the room temperature for 30 minutes, a
solution prepared by dissolving 7.8 g (30 mmol) of 3-bromostilbene
into 100 ml of THF was added dropwise. After the addition was
completed, the resultant mixture was stirred at 60.degree. C. for 1
hour and a Grignard reagent was prepared.
[0170] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 5.1 g (10 mmol) of
10,10'-dibromo-9,9'-bianthryl, 0.4 g (5% by mol) of
dichlorobis(triphenylphosphine)palladium, 1 ml (1 M; 1 mmol) of a
toluene solution of diisobutylaluminum hydride and 100 ml of THF
were placed. To the resultant mixture, the Grignard reagent
prepared above was added dropwise at the room temperature. Then,
the resultant mixture was heated and stirred under heating for one
night. After the reaction was completed, the reaction solution was
cooled with ice water. The formed crystals were separated by
filtration and washed with 50 ml of methanol and 50 ml of acetone,
successively, and 1.4 g of a yellow powder was obtained. The yellow
powder was identified to be compound E33 by measurements in
accordance with NMR, IR and FD-MS (the yield: 20%).
EXAMPLE 15 (SYNTHESIS OF COMPOUND 35)
[0171] Compound E35 was synthesized in accordance with the
following process: 23
[0172] Synthesis of 2-bromostilbene
[0173] Into a 100 ml flask, 25 g (0.1 mol) of 2-bromobenzyl bromide
and 19 ml (0.11 mol) of triethyl phosphite were placed and the
resultant mixture was stirred under heating for 3 hours. After the
reaction was completed, the reaction solution was concentrated in
vacuo and a phosphite was obtained. The obtained phosphite was used
in the following reaction without purification.
[0174] In a 500 ml flask, the phosphite obtained above, 10 ml (0.1
mol) of benzaldehyde and 200 ml of dimethyl sulfoxide were placed
and cooled at 0.degree. C. with ice water. Then, 13.4 g (0.12 mol)
of potassium t-butoxide was slowly added and the resultant mixture
was kept being stirred at the room temperature for one night. After
the reaction was completed, the reaction solution was poured into
500 ml of water and the organic layer was treated by extraction
with ethyl acetate. After drying with magnesium sulfate, the
organic layer was concentrated in vacuo using a rotary evaporator
and yellow crystals were obtained. The obtained crystals were
purified in accordance with the column chromatography (silica gel;
the developing solvent: hexane) and 24 g (the yield: 92%) of
2-bromostilbene as the object compound was obtained.
[0175] Synthesis of Compound E35
[0176] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 1.6 g (66 mmol) of magnesium, a small
piece of iodine and 50 ml of THF were placed. After the resultant
mixture was stirred at the room temperature for 30 minutes, a
solution prepared by dissolving 7.8 g (30 mmol) of 2-bromostilbene
into 100 ml of THF was added dropwise. After the addition was
completed, the resultant mixture was stirred at 60.degree. C. for 1
hour and a Grignard reagent was prepared.
[0177] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 5.1 g (10 mmol) of
10,10'-dibromo-9,9'-bianthryl, 0.4 g (5% by mol) of
dichlorobis(triphenylphosphine)palladium, 1 ml (1 M; 1 mmol) of a
toluene solution of diisobutylaluminum hydride and 100 ml of THF
were placed. To the resultant mixture, the Grignard reagent
prepared above was added dropwise at the room temperature. Then,
the resultant mixture was heated and stirred under heating for one
night. After the reaction was completed, the reaction solution was
cooled with ice water. The formed crystals were separated by
filtration and washed with 50 ml of methanol and 50 ml of acetone,
successively, and 5.7 g of a yellow powder was obtained. The yellow
powder was identified to be compound E35 by measurements in
accordance with NMR, IR and FD-MS (the yield: 80%).
EXAMPLES 16 TO 18 (PREPARATION OF AN ORGANIC EL DEVICE)
[0178] Devices were prepared in accordance with the same procedures
as those conducted in Example 5 except that the compounds shown in
Table 1 were used in place of compound E1. Using the devices
prepared in Examples 16 to 18, the properties of light emission
were confirmed and the test of heat resistance was conducted. Using
the devices prepared in Examples 16 and 17, the chromaticity
coordinates were measured. The results are shown in Table 1.
EXAMPLE 19 (SYNTHESIS OF COMPOUND E42)
[0179] Compound E42 was synthesized in accordance with the
following process: 24
[0180] Synthesis of 4-bromo-.beta.-methylstilbene
[0181] Into a 100 ml flask, 25 g (0.1 mol) of 4-bromobenzyl bromide
and 19 ml (0.11 mol) of triethyl phosphite were placed and the
resultant mixture was stirred under heating for 3 hours. After the
reaction was completed, the reaction solution was concentrated in
vacuo and a phosphite was obtained. The obtained phosphite was used
in the following reaction without purification.
[0182] In a 500 ml flask, the phosphite obtained above, 12 g (0.1
mol) of acetophenone and 200 ml of dimethyl sulfoxide were placed
and cooled at 0.degree. C. with ice water. Then, 13.4 g (0.12 mol)
of potassium t-butoxide was slowly added and the resultant mixture
was kept being stirred at the room temperature for one night. After
the reaction was completed, the reaction solution was poured into
500 ml of water and the organic layer was treated by extraction
with ethyl acetate. After drying with magnesium sulfate, the
organic layer was concentrated in vacuo using a rotary evaporator
and yellow crystals were obtained. The obtained crystals were
purified by recrystallization (100 ml of isopropyl alcohol) and 12
g (the yield: 44%) of 4-bromo-.beta.-methylstilbene as the object
compound was obtained.
[0183] Synthesis of Compound E42
[0184] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 1.6 g (66 mmol) of magnesium, a small
piece of iodine and 50 ml of THF were placed. After the resultant
mixture was stirred at the room temperature for 30 minutes, a
solution prepared by dissolving 8.2 g (30 mmol) of
4-bromo-.beta.-methylstilbene into 100 ml of THF was added
dropwise. After the addition was completed, the resultant mixture
was stirred at 60.degree. C. for 1 hour and a Grignard reagent was
prepared.
[0185] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 5.1 g (10 mmol) of
10,10'-dibromo-9,9'-bianthryl, 0.4 g (5% by mol) of
dichlorobis(triphenylphosphine)palladium, 1 ml (1 M; 1 mmol) of a
toluene solution of diisobutylaluminum hydride and 100 ml of THF
were placed. To the resultant mixture, the Grignard reagent
prepared above was added dropwise at the room temperature. Then,
the resultant mixture was heated and stirred under heating for one
night. After the reaction was completed, the reaction solution was
cooled with ice water. The formed crystals were separated by
filtration and washed with 50 ml of methanol and 50 ml of acetone,
successively, and 4.4 g of a yellow powder was obtained. The yellow
powder was identified to be compound E42 by measurements in
accordance with NMR, IR and FD-MS (the yield: 60%).
EXAMPLE 20 (SYNTHESIS OF COMPOUND E43)
[0186] Compound E43 was synthesized in accordance with the
following process: 25
[0187] Synthesis of 3-bromo-.beta.-methylstilbene
[0188] Into a 100 ml flask, 25 g (0.1 mol) of 3-bromobenzyl bromide
and 19 ml (0.11 mol) of triethyl phosphite were placed and the
resultant mixture was stirred under heating for 3 hours. After the
reaction was completed, the reaction solution was concentrated in
vacuo and a phosphite was obtained. The obtained phosphite was used
in the following reaction without purification.
[0189] In a 500 ml flask, the phosphite obtained above, 12 g (0.1
mol) of acetophenone and 200 ml of dimethyl sulfoxide were placed
and cooled at 0.degree. C. with ice water. Then, 13.4 g (0.12 mol)
of potassium t-butoxide was slowly added and the resultant mixture
was kept being stirred at the room temperature for one night. After
the reaction was completed, the reaction solution was poured into
500 ml of water and the organic layer was treated by extraction
with ethyl acetate. After drying with magnesium sulfate, the
organic layer was concentrated in vacuo using a rotary evaporator
and yellow crystals were obtained. The obtained crystals were
purified by recrystallization (100 ml of isopropyl alcohol) and 17
g (the yield: 63%) of 3-bromo-.beta.-methylstilbene as the object
compound was obtained.
[0190] Synthesis of Compound E43
[0191] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 1.6 g (66 mmol) of magnesium, a small
piece of iodine and 50 ml of THF were placed. After the resultant
mixture was stirred at the room temperature for 30 minutes, a
solution prepared by dissolving 8.2 g (30 mmol) of
3-bromo-.beta.-methylstilbene into 100 ml of THF was added
dropwise. After the addition was completed, the resultant mixture
was stirred at 60.degree. C. for 1 hour and a Grignard reagent was
prepared.
[0192] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 5.1 g (10 mmol) of
10,10'-dibromo-9,9'-bianthryl, 0.4 g (5% by mol) of
dichlorobis(triphenylphosphine)palladium, 1 ml (1 M; 1 mmol) of a
toluene solution of diisobutylaluminum hydride and 100 ml of THF
were placed. To the resultant mixture, the Grignard reagent
prepared above was added dropwise at the room temperature. Then,
the resultant mixture was heated and stirred under heating for one
night. After the reaction was completed, the reaction solution was
cooled with ice water. The formed crystals were separated by
filtration and washed with 50 ml of methanol and 50 ml of acetone,
successively, and 5.3 g of a yellow powder was obtained. The yellow
powder was identified to be compound E43 by measurements in
accordance with NMR, IR and FD-MS (the yield: 72%).
EXAMPLE 21 (SYNTHESIS OF COMPOUND E44)
[0193] Compound E44 was synthesized in accordance with the
following process: 26
[0194] Synthesis of 3-bromo-.beta.-methylstilbene
[0195] In a 500 ml flask, 23 g(0.1 mol) of ethyl benzylphosphonate,
20 g (0.1 mol) of 4-bromoacetophenone and 200 ml of dimethyl
sulfoxide were placed and cooled at 0.degree. C. with ice water.
Then, 13.4 g (0.12 mol) of potassium t-butoxide was slowly added
and the resultant mixture was kept being stirred at the room
temperature for one night. After the reaction was completed, the
reaction solution was poured into 500 ml of water and the organic
layer was treated by extraction with ethyl acetate. After drying
with magnesium sulfate, the organic layer was concentrated in vacuo
using a rotary evaporator. The obtained product were purified in
accordance with the column chromatography (silica gel; the
developing solvent: hexane) and 26 g (the yield: 88%) of
3-bromo-.alpha.-methylstilb- ene as the object compound was
obtained.
[0196] Synthesis of Compound E44
[0197] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 1.6 g (66 mmol) of magnesium, a small
piece of iodine and 50 ml of THF were placed. After the resultant
mixture was stirred at the room temperature for 30 minutes, a
solution prepared by dissolving 8.2 g (30 mmol) of
3-bromo-.alpha.-methylstilbene into 100 ml of THF was added
dropwise. After the addition was completed, the resultant mixture
was stirred at 60.degree. C. for 1 hour and a Grignard reagent was
prepared.
[0198] Under a stream of argon, into a 500 ml three-necked flask
equipped with a condenser, 5.1 g (10 mmol) of
10,10'-dibromo-9,9'-bianthryl, 0.4 g (5% by mol) of
dichlorobis(triphenylphosphine)palladium, 1 ml (1 M; 1 mmol) of a
toluene solution of diisobutylaluminum hydride and 100 ml of THF
were placed. To the resultant mixture, the Grignard reagent
prepared above was added dropwise at the room temperature. Then,
the resultant mixture was heated and stirred under heating for one
night. After the reaction was completed, the reaction solution was
cooled with ice water. The formed crystals were separated by
filtration and washed with 50 ml of methanol and 50 ml of acetone,
successively, and 5.8 g of a yellow powder was obtained. The yellow
powder was identified to be compound E44 by measurements in
accordance with NMR, IR and FD-MS (the yield: 79%).
EXAMPLE 22 (MEASUREMENT OF THE GLASS TRANSITION TEMPERATURE)
[0199] To evaluate the heat resistance, the glass transition
temperatures (Tg) of compounds E1, E32, E33 and E42 were measured
in accordance with the differential scanning calorimetry (DSC) and
found to be 160.degree. C., 163.degree. C., 142.degree. C. and
140.degree. C., respectively. The transition temperatures were all
140.degree. C. or higher.
COMPARATIVE EXAMPLE 2 (MEASUREMENT OF THE GLASS TRANSITION
TEMPERATURE)
[0200] To evaluate the heat resistance, Tg of compound H1 used in
Comparative Example 1 was measured in accordance with DSC and found
to be as low as 96.degree. C.
EXAMPLE 23 (PREPARATION OF AN ORGANIC EL DEVICE)
[0201] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was formed by using compound E42 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the chromaticity coordinates were obtained. The
results are shown in Table 1. The maximum luminance of light
emission was 30,000 cd/m.sup.2.
EXAMPLE 24 (PREPARATION OF AN ORGANIC EL DEVICE)
[0202] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was formed by using compound E43 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the chromaticity coordinates were obtained. The
results are shown in Table 1.
EXAMPLE 25 (PREPARATION OF AN ORGANIC EL DEVICE)
[0203] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was formed by using compound E44 in place of compound E1.
Using the prepared device, the properties of light emission were
confirmed and the chromaticity coordinates were obtained. The
results are shown in Table
COMPARATIVE EXAMPLE 3 (PREPARATION OF AN ORGANIC EL DEVICE)
[0204] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was formed by using compound H2 expressed by the following
formula in place of compound E1. Using the prepared device, the
properties of light emission were confirmed and the chromaticity
coordinates were obtained. The results are shown in Table 1. 27
COMPARATIVE EXAMPLE 4 (PREPARATION OF AN ORGANIC EL DEVICE)
[0205] A device was prepared in accordance with the same procedures
as those conducted in Example 5 except that the light emitting
layer was formed by using compound H3 expressed by the following
formula in place of compound E1. Using the prepared device, the
properties of light emission were confirmed and the chromaticity
coordinates were obtained. The results are shown in Table 1.
1TABLE 1 (H3) 28 Heat resistance (decrease Chromat- Lumin- Color of
Effi- in icity Voltage ance emitted ciency luminance) coordi-
Compound (V) (nit) light (cd/A) (%) nates) Example 5 E1 6 95 blue
3.0 5 (0.150, 0.131) Example 6 E4 6 130 blue 3.5 7 -- Example 7 E7
6 161 blue 3.7 4 -- Example 8 E9 6 95 blue 2.7 3 -- Example 9 E13 6
210 yellowish 7.8 12 -- blue Example 10 E14 6 120 blue 3.7 6 --
Example 11 E17 6 60 bluish 4.0 5 -- green Example 12 E31 6 313 blue
4.8 8 -- Example 16 E32 6 210 blue 2.2 1 (0.150, 0.135) Example 17
E33 6 120 blue 4.3 2 (0.171, 0.130) Example 18 E35 6 170 blue 4.9 4
-- Example 23 E42 6 157 bluish 3.0 -- (0.170, 0.130) purple Example
24 E43 6 130 bluish 2.4 -- (0.155, 0.103) purple Example 25 E44 6
161 bluish 2.6 -- (0.155, 0.112) purple Comparative H1 6 120 bluish
1.7 45 (0.182, 0.288) Example 1 green Comparative H2 6 313 blue 1.6
-- (0.162, 0.160) Example 2 Comparative H3 6 120 bluish 2.0 --
(0.210, 0.320) Example 3 green
[0206] As shown in Table 1, the organic EL devices having the light
emitting layers formed by using the anthracene derivatives of the
present invention exhibited high efficiencies of light emission,
small decreases in the luminance and high heat resistances. These
properties were exhibited because these anthracene derivatives had
high glass transition temperatures of 140.degree. C. or higher and
the property of emitting strong fluorescence in the blue to green
region. It is also shown that the organic EL devices of the present
invention could emit blue light having more excellent purity of
color than the light emitted by the devices of the Comparative
Examples.
[0207] In contrast, the organic EL devices of Comparative Examples
1, 3 and 4 exhibited low efficiencies of light emission. Moreover,
the organic EL devices of Comparative Examples 1 and 4 exhibited
strongly greenish light and could not be used as a device emitting
blue light.
INDUSTRIAL APPLICABILITY
[0208] The anthracene derivative of the present invention is useful
as the material constituting organic EL devices. In particular,
when the anthracene derivative is used as a light emitting
material, an excellent efficiency of light emission and excellent
heat resistance (life) are exhibited and the obtained device is
used as the device having the property of emitting fluorescence in
the blue to green region.
* * * * *