Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2000-07-05
2002-07-16
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S704000, C428S917000, C313S504000, C313S506000, C257S040000, C257S103000, C252S301160, C252S301260
Reexamination Certificate
active
06420057
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a material of organic electroluminescent element and an organic electroluminescent element (hereinafter referred to an organic EL), particularly relates to a material of organic EL element and an organic electroluminescent element excellent in the luminance of the light emitted thereby.
BACKGROUND OF THE INVENTION
An inorganic electroluminescent element has been used for a plane-shaped light source, and a high voltage alternating current has been required to drive such the element.
An organic electroluminescent element recently developed is constituted by a thin layer containing a fluorescent organic compound arranged between a cathode and an anode, and an electron and a positive hole were injected into the thin layer to form an exciton by recombination of the electron and the positive hole. The element emits light utilizing the generation of light, fluorescent light or phosphorescent light, by the inactivation of the exciton. The element can emit light by applying a relatively low voltage such as from several to several decade volts, the element is excellent in the dependency of viewing angle and in the visuality since the element is self light emission type, and the element is a complete solid element. Accordingly, such the element is noted from the viewpoint of the space saving and portability.
Various organic EL elements have been reported. For example, Appl. Phys. Lett. Vol. 51, p. 913, and Japanese Patent Publication to Open Inspection (hereinafter referred to JP O.P.I.) No. 59-194393 disclose an element having a combination of a positive hole injection layer and an organic fluorescent layer, JP O.P.I. No. 63-295695 discloses one having a combination of a positive hole injection layer and an electron injection and transportation layer, and Jpn. Journal of Applied Physics, Vol. 127, No. 2, p.p. 269-271 discloses one having a combination of a positive hole transportation layer, a light emission layer and an electron transportation layer.
However, further raising in the energy conversion efficiency and the light emission quantum efficiency are required and a problem of short lifetime of light emission is pointed out. Factors such as decomposition of the organic compound constituting the thin layer and crystallization of the organic compound in the thin layer which are caused by the organic compound used for the material of the organic EL element are pointed out as the reason of lowering of the luminance in the period of time even though the reason is not completely elucidated yet.
SUMMARY OF THE INVENTION
The object of the invention is to provide a material of organic electroluminescent element and an organic electroluminescent element excellent in the light emission efficiency and is capable of emitting high luminance light.
The object can be attained by the following constitution.
(1) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains an organic metal complex having both of an ionic coordinate bond formed between a nitrogen anion and a metal cation and a coordinate bond formed by a nitrogen atom or a chalcogen and a metal.
(2) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains an organic metal complex having both of an ionic coordinate bond formed by a nitrogen anion included in an aromatic heterocyclic ring and a metal cation and a coordinate bond formed between a nitrogen atom or a chalcogen and a metal.
(3) The organic electroluminescent element described in (2) in which a substituent of the nitrogen anion-containing aromatic heterocyclic ring forming the ionic coordinate bond with the metal cation has a Hammett's &sgr;p value of from −1.00 to 0.65.
(4) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains a salt of the anion of a compound represented by Formula I and a metal cation,
wherein R
1
, R
2
and R
3
are each a hydrogen atom or a substituent having a Hammett's value of from −1.00 to 0.65, R
2
and R
3
may be bonded with each other to form a ring condensed with the imidazole ring, and at least one of R
1
, R
2
and R
3
has a nitrogen atom or a chalcogen atom at a position far from 2 or 3 atoms from the nitrogen atom forming an ionic coordinate bond with a metal cation.
(5) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains a salt of the anion of a compound represented by Formula II and a metal cation,
wherein R
4
, R
5
and R
6
are each a hydrogen atom or a substituent, R
4
and R
5
or R
5
and R
6
may be bonded with each other to a ring condensed with the pyrazole ring, and at least one of R
4
, R
5
and R
6
has a nitrogen atom or a chalcogen atom at a position far from 2 or 3 atoms from the nitrogen atom forming an ionic coordinate bond with a metal cation.
(6) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains a salt of the anion of a compound represented by Formula III and a metal cation,
wherein L
1
is an —N(R
9
)— group or a —C(R
10
)(R
11
)— group, L
2
is a nitrogen atom or a —C(R
12
)═ group, L
3
is a nitrogen atom or a ═C(R
13
)— group, R
7
, R
8
, R
9
, R
10
, R
11
, R
12
and R
13
are each a hydrogen atom or a substituent, R
7
and R
8
may be bonded with each other to form a ring condensed with the pyrazole ring, and at least one of R
7
through R
13
has a nitrogen atom or a chalcogen atom at a position far from 2 or 3 atoms from the nitrogen atom forming an ionic coordinate bond with a metal cation.
(7) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains a salt of the anion of a compound represented by Formula IV and a metal cation,
wherein L
4
is an —N(R
16
)— group or a —C(R
17
)(R
18
)— group, L
5
is a nitrogen atom or a —C(R
19
)═ group, L
6
is a nitrogen atom or a ═C(R
20
)— group, R
14
, R
15
, R
16
, R
17
, R
18
, R
19
and R
20
are each a hydrogen atom or a substituent, and at least one of R
14
through R
20
has a nitrogen atom or a chalcogen atom at a position far from 2 or 3 atoms from the nitrogen atom forming an ionic coordinate bond with a metal cation.
(8) An organic electroluminescent element comprising a light emission layer comprised of single or plural thin layers of an organic compound put between an anode and a cathode facing to each other, in which at least one of the thin layer of the organic compound contains a salt of the anion of a compound represented by Formula V and a metal cation,
wherein L
7
is an —N(R
23
)— group or a —C(R
24
)(R
25
)— group, L
8
is a nitrogen atom or a —C(R
26
)═ group, L
9
is a nitrogen atom or a ═C(R
27
)— group, R
21
, R
22
, R
23
, R
24
, R
25
, R
26
and R
27
are each a hydrogen atom or a substituent, R
21
and R
22
may be bonded with each other to form a ring condensed with the pyrazole ring, and at least one of R
21
through R
27
has a nitrogen atom or a chalcogen atom at a position far from 2 or 3
Kita Hiroshi
Suzuri Yoshiyuki
Ueda Noriko
Yamada Taketoshi
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Kelly Cynthia H.
Konica Corporation
Xu Ling
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