Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2000-07-06
2002-07-02
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S704000, C428S917000, C313S504000, C313S506000, C257S040000, C257S103000
Reexamination Certificate
active
06413658
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to polymers having high electric conductivity, materials for luminescent devices capable of exhibiting luminescence by converting electric energy into light, and luminescent devices. In particular, the invention is concerned with luminescent devices suitably used in the fields of indication devices, display, back light, electrophotography, illumination light sources, recording light sources, reader light sources, beacons, billboards and interior decoration.
BACKGROUND OF THE INVENTION
Nowadays, there are lively researches and developments of various display devices. In particular, organic luminescent devices attract attention as promising display devices because they can exhibit luminescence of high luminance under a low voltage. For instance, luminescent devices comprising organic thin films formed by evaporation of organic compounds are known (
Applied Physics Letters,
vol. 51, p. 913 (1987). However, the luminescent device production accompanied by the evaporating operation of organic compounds has a problem with productivity. Therefore, the device production utilizing coating methods is preferable from the viewpoints of simplification of production steps, processing efficiency and expansion of image sizes.
As luminescent device materials used for producing luminescent devices in accordance with coating methods favorable for productivity, there are known the polymers having &pgr;-conjugated systems represented by paraphenylenevinylene (PPV). In view of color tone, luminous intensity and durability, however, they have many problems with their practical use.
As another luminescent device produced using coating methods, there is known the device containing a low molecular fluorescent compound dispersed in poly(N-vinylcarbazole) (JP-A-4-212286, wherein the term “JP-A” as used herein means an “unexamined published Japanese patent application”). According to this method, the species of the fluorescent compound used in the device can be arbitrarily changed, so that the color tone and the luminous intensity can be adjusted with relatively ease. However, such a device requires a high operating voltage, and besides, it tends to cause a lowering of luminous intensity when its operation is resumed after a long-term lapse or continues for a long time, namely it has a rawback of being inferior in durability.
The cause of such drawbacks is attributed, in part, to shortages of electron injection property and electron transporting property, and so it has been attempted to develop various electron injection and electron transporting polymers.
However, no polymers having satisfactory physical properties as well as those abilities have been developed yet. For instance, polyacetylene well-known as an electron-transporting (electrically conductive) polymer has a problem with its solubility and film formability, and so it is unsuitable for device production using a coating process. And even the polymers reported in
J. Phys.: condens. Matter,
10(1998) 5171-5178, such as poly(2,5-pyridinediyl) , cannot be solutions to the pending problems, because they have various drawbacks of having no suitability for blue luminescent devices and green luminescent devices because of their narrow band gaps, lacking electron affinity (receptivity to injected electrons), having poor conductivity, and being soluble in special solvents, such as formic acid, but sparingly soluble in general organic solvents.
SUMMARY OF THE INVENTION
Therefore, objects of the invention are to provide a material for luminescent device use which not only has excellent ability to transport electrons and suitability for luminescent device production using a coating process but also ensures for the luminescent device the operability at low voltage, satisfactory luminous characteristics and high stability under repeated use, and further to provide a luminescent device comprising such a material.
The aforementioned objects are attained with the following means:
[1] A luminescent device material comprising a polymer having at least one partial structure represented by the following formula (I):
wherein R
1
and R
2
, which may be the same or different, each represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl 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, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted aliphatic heterocyclic group; and R
1
and R
2
may combine with each other to complete a ring.
[2] A polymer represented by the following formula (II):
wherein R
3
and R
4
, which may be the same or different, each represent a substituted or unsubstituted aryl group except for an unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group which has a condensed ring (hereinafter sometimes referred to as a substituted or unsubstituted ring-condensed aryl 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, a substituted or unsubstituted nitrogen-containing heteroaryl group, a substituted or unsubstituted oxygen-containing heteroaryl group, or a substituted or unsubstituted aliphatic heterocyclic group, and R
3
and R
4
may combine with each other to complete a ring; X
1
and X
2
, which may be the same or different, each represent a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group or an aromatic heterocyclic group, and X
1
and X
2
may combine with each other to complete a ring; and n is an integer of at least 2.
[3] A luminescent device having a luminescent layer or at least two thin organic compound layers, inclusive of a luminescent layer, between a pair of electrodes; at least one of the layers comprising at least one polymer as described in the means [1] or [2].
[4] A luminescent device having a luminescent layer or at least two thin organic compound layers, inclusive of a luminescent layer, between a pair of electrodes; at least one of the layers being a filmy layer formed by coating at least one polymer as described in the means [1] or [2].
DETAILED DESCRIPTION OF THE INVENTION
The invention is illustrated below in detail.
The present polymer is a polymer having a partial structure represented by formula (I) in its main chain and/or side chains, preferably a compound containing at least one repeating unit represented by formula (I).
The polymer having a partial structure represented by formula (I) has a low band gap, high electron affinity and good solubility in organic solvents, and works well for injection of electrons, transportation of electrons and luminescent device production using a coating process.
In formula (1), it is desirable for R
1
and R
2
each to be a hydrogen atom, a substituted or unsubstituted alkyl group containing up to 20 carbon atoms in all, a substituted or unsubstituted aryl group containing up to 20 carbon atoms in all, a substituted or unsubstituted alkoxy group containing up to 20 carbon atoms in all, a substituted or unsubstituted aryloxy group containing up to 20 carbon atoms in all, a substituted or unsubstituted alkylthio group containing up to carbon atoms in all, a substituted or unsubstituted arylthio group containing up to 20 carbon atoms in all, a substituted or unsubstituted amino group containing up to 40 carbon atoms in all, a substituted or unsubstituted heteroaryl group containing up to 20 carbon atoms in all, or a substituted or unsubstituted aliphatic heterocyclic group containing up to 20 carbon atoms in all. Of these groups, the groups preferred as R
1
and R
2
each include alkyl groups containing 3 to 16 carbon atoms, alkoxy groups containing
Fuji Photo Film Co. , Ltd.
Yamnitzky Marie
LandOfFree
Polymers, luminescent device materials, and luminescent... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polymers, luminescent device materials, and luminescent..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polymers, luminescent device materials, and luminescent... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2889120