Nitrogen-containing polymers as electroluminescent materials

Details Nitrogen-containing polymers as electroluminescent materials Nitrogen-containing polymers as electroluminescent materials

1997-03-28

1999-02-23

Cooney, Jr., John M.

Stock material or miscellaneous articles

Composite

Of inorganic material

313504, 313506, 428917, 528230, 528247, 528248, 528249, 528266, 528269, C08G 1002, H05B 3314

Patent

active

058741798

DESCRIPTION:

BRIEF SUMMARY
There is a high industrial demand for large-area solid-state light sources for a number of applications, chiefly in the field of display elements, display screen technology and illumination. The requirements imposed on these light sources cannot currently be met entirely satisfactorily by any of the existing technologies.
As an alternative to conventional display and illumination elements such as incandescent lamps, gas discharge lamps and non-luminous liquid-crystal display elements use has been made for some time now of electroluminescent (EL) materials and devices such as light-emitting diodes (LED).
DE-A 25 45 784 (corresponds to U.S. Pat. No. 3,995,299) describes an electroluminescence device with a radiation source, which comprises a layer of an amorphous or predominantly amorphous polymer material having appreciable electrical charge mobility and low ionization potential, a strong electron donor, a strong electron acceptor and preferably at least one luminescent additive, electrical connections being provided through which an electric current can be passed through the thickness of the layer to excite radiation therefrom.
Polymer materials used include conjugated polymers such as poly(p-phenylenevinylene) (see e.g. WO-A 90/13148), as well as nonconjugated polymers (see e.g. I. Sokolik et al., J. Appl. Phys, 1993, 74, 3584), conjugated materials generally having the advantage of higher charge carrier mobility and consequently better efficiency and lower threshold voltages.
In addition to polymer-based devices, low molecular-weight organic electroluminescence devices have also been known for some time. Saito et al. (Appl. Phys. Lett. 1990, 56, 799) describe such devices containing triarylamine stilbenes as light-emitting layers.
Although good results have been achieved with these materials, the characteristic profile of these compounds still leaves substantial room for improvement.
Since, furthermore, the development of electroluminescent materials, especially those based on polymers, cannot yet in any way be regarded as complete, the manufacturers of illumination and display devices are interested in the most diverse electroluminescent materials for such devices.
One of the reasons for this is that only the interaction of the electroluminescent materials with the other components of the devices permits inferences regarding the quality, including that of the electroluminescent materials.
It was therefore an object of the present invention to provide novel electroluminescent materials which, when used in illumination or display devices, are suitable for improving the characteristic profile of these devices.
Surprisingly it has now been found that certain nitrogen-containing polymers are particularly suitable as electroluminescent materials.
Polymers containing triaryl units are known to some extent as photosensitive components for electrophotographic processes and as sensitizers for electrically photosensitive dyes (U.S. Pat. No. 4,323,203), but it is not possible to deduce therefrom that the novel polymers having a different structure might be suitable as electroluminescent materials.
The invention therefore relates to a polymer containing structural units of formula (I), ##STR2## where the symbols and indices have the following meanings: Ar.sup.1, Ar.sup.2, Ar.sup.3 are, identically or differently, mono- and/or polynuclear and/or condensed aryl and/or heteroaryl groups which may or may not be linked via one or more bridges, preferably having from 4 to 400, particularly preferably from 4 to 100, especially preferably from 4 to 20 carbon atoms, which may or may not be substituted; R.sup.5 --, --CO--, --CR.sup.6 .dbd.CR.sup.7, CR.sup.8 R.sup.9 --CR.sup.10 R.sup.11 or SiR.sup.12 R1.sup.13 ; which may or may not be substituted and may also contain hetero atoms, preferably O and/or F, having from 1 to 22 carbon atoms or Ar.sup.4, where Ar.sup.4, identical with or different from Ar.sup.1, has the same meanings as Ar.sup.1 ;
Preference is given to polymers which consist of structural units of formula (I). The

REFERENCES:
patent: 3418261 (1968-12-01), Idelson et al.
patent: 4952667 (1990-08-01), Shikatani et al.
patent: 5227252 (1993-07-01), Murayama et al.
Chem. Abstracts, vol. 112, No. 18 (1990), p. 64.

Affiliated with

Also associated with

Rating

Nitrogen-containing polymers as electroluminescent materials does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Nitrogen-containing polymers as electroluminescent materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nitrogen-containing polymers as electroluminescent materials will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-305080