Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2002-06-13
2004-05-04
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S704000, C428S917000, C313S504000, C313S506000, C252S301160, C252S301260, C257S040000, C257S103000, C546S112000, C546S134000, C546S135000, C546S268100
Reexamination Certificate
active
06730418
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an organic compound useful as a light emitting material for an organic electroluminescence element (hereinafter referred to as an “organic EL element”) and a light emitting material for other electronic device materials or the like, and to an element employing such organic compound.
BACKGROUND ART
Organic EL elements are constructed by layering, on a transparent glass substrate, a transparent first electrode (for example, ITO), an organic compound layer which includes an organic compound having strong fluorescence, and a metal (for example, Mg) second electrode in that order.
The organic layer has, for example, a three-layer structure in which a layer of molecules having a hole transport function, a layer of molecules having an emissive function, and a layer of molecules having an electron transport function are layered in that order, and emits light when an electric field is applied to the pair of electrodes. In other words, when holes are injected from the first electrode and electrons are injected from the second electrode, the injected holes and electrons move through the hole transport functional molecule layer, the emissive functional molecule layer, and the electron transport functional molecule layer of the organic layer, such that the holes and electrons collide, recombine, and disappear. The energy generated by there combination is used for producing exited states of the emissive molecules and fluorescence is emitted from the organic EL element.
In such an organic EL element, an aluminum quinolinol complex (Alq
3
) represented by a chemical formula (3),
is well known as a light emitting material having a quinoline ring. This compound is obtained by substituting a hydroxy group into the quinoline ring to form a complex with aluminum and emits a green light.
As a red light emitting material for an organic EL element, a phthalocyanine derivative as disclosed in Japanese Patent Laid-Open Publication No. Hei 7-288184 and a porphyrin derivative as disclosed in Japanese Patent Laid-Open Publication No. Hei 9-296166 are known.
Because all of the known light emitting materials having the quinoline ring such as Alq
3
have a short conjugate system, light emitting function has so far been obtained only in the blue~green range. To realize a color organic EL element, it is necessary to obtain a compound which emits light with sufficient characteristics for other colors, specifically those in the yellow~red range.
On the other hand, although the phthalocyanine derivative and porphyrin derivative as described above have a red light emitting function, they do not have sufficient luminance nor sufficient endurance, and, thus, do not satisfy all the requirements desired for applications such as in an organic EL element.
The present invention was conceived to solve the problem described above, and one object of the present invention is to provide a novel organic compound having superior stability and light emitting luminance characteristic and having light emitting function in yellow~red range, and an organic EL element which employs such organic compound.
DISCLOSURE OF INVENTION
In order to achieve at least the object described above, according to the present invention, there is provided a quinoline derivative compound represented by a chemical formula (1),
wherein at least two of the substituents R
1
~R
7
in the chemical formula (1) have a structure represented by a chemical formula (2),
where Q in the chemical formula (2) is an arbitrary functional group.
In the novel organic compound, at least two substituents having a double bond in the structural formula (chemical formula (2)) are introduced as substituents for the quinoline ring (chemical formula (1)). Because of this, the compound has a structure in which the conjugate system is long and the energy difference between the excited state and the ground state of the compound is small and, thus, light emission function in the yellow~red range can be obtained.
According to another aspect of the present invention, it is preferable that, in the organic compound represented by the chemical formula (1), at least one of the substituents R
1
~R
7
other than the substituents having a structure represented by the chemical formula (2) is an electron attracting substituent.
By introducing an electron attracting substituent as a substituent in the quinoline ring, the fluorescence quantum yield of the compound can be improved and, as a result, a light emitting material which can emit light at higher luminance and higher efficiency can be obtained.
According to another aspect of the present invention, it is preferable that, in the organic compound, Q in chemical formula (2) is an aromatic group having carbon or aheteroatomin the skeleton of the ring and at least one of the substituents R
Q
of the aromatic group Q is an electron donating substituent.
By using a stable aromatic group as Q, it is possible to prevent reactions of the double bonds in the chemical formula (2) and thereby improve the stability as a compound. Furthermore, by using at least one electron donating substituent for the substituents R
Q
, the fluorescence quantum yield of the overall compound represented by the chemical formula (1) can be improved. In particular, it is preferable that an electron attracting group is introduced to at least one of the substituents R
1
~R
7
of the quinoline ring and an electron donating group is introduced as the substituent R
Q
of Q. More preferably, a cyano group is used for the subsituent R
3
and a p-aminophenyl group is used for the substituent Q. With such a structure, the fluorescence quantum yield of the compound is further improved, and a light emitting material having even higher luminance and higher efficiency can be obtained.
According to another aspect of the present invention, it is preferable that, in the organic compound, the number n of the double bonds in the chemical formula (2) be, for example, at least 2 or no more than 5, or it is also preferable that the number n of the double bonds in the chemical formula (2) be in the range of 1~3.
When the value of n is in the range of 1~3 or 2 or greater, a highly stable compound can be obtained which allows for improvements in the endurance of an element when the compound is used, for example, in an organic compound layer of an organic EL element, as will be described below.
According to another aspect of the present invention, it is preferable that the substituents R
n
and R′
n
in the chemical formula (2) are cyclized. Through the cyclization, free rotation which is normally generated in a vinyl group represented by the chemical formula (2) can be blocked, and the link in the conjugated system can be maintained. Moreover, separation of the n-bonds within the molecule and alteration of the molecular shape can also be prevented, allowing for improvement in the endurance or the like of the molecule.
According to another aspect of the present invention, there is provided an organic electroluminescence element wherein an organic compound layer which includes an emissive layer is formed between two electrodes, and the organic compound described above, that is, an organic compound represented by the chemical formula (1) and having at least two of the substituents R
1
~R
7
substituted by a substituent represented by the chemical formula (2), is used for the organic compound layer.
As described above, because the organic compound according to the present invention has a light emitting characteristic in the yellow~red range, by using the organic compound as the material for the organic compound layer, in particular, for the emissive layer, of the organic EL element, an organic EL element having high luminance, high efficiency, and high stability can be obtained.
According to another aspect of the present invention, it is preferable that, in the organic electroluminescence element, the organic compound layer comprises a hole transport layer and an emissive layer, and any one of the quinoline derivative compounds described above i
Ishii Masahiko
Mori Tomohiko
Mouri Makoto
Noda Koji
Takeuchi Hisato
Jones Deborah
Kabushiki Kaisha Toyota Chuo Kenkyusho
Xu Ling
LandOfFree
Quinoline derivatives and organic electroluminescent devices does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Quinoline derivatives and organic electroluminescent devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quinoline derivatives and organic electroluminescent devices will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3206266