Heterocyclic compounds and their use in electro-optical or opto-electronic devices

Abstract

Compounds exhibiting high hole mobility and / or high glass transition temperatures are provided which are of the formula [Ar1]m[Ar2]n wherein:m is an integer from 1-3 and n is an integer and may be 1 or 2;Ar1 represents a thianthrene residue having a linkage to Ar2 at one or two positions selected from ring positions 1-4 and 5-8 and optionally mono-, bi- or poly-substituted with C1-C4-alkyl-, C1-C4-alkoxy-, fluoro, phenyl or biphenyl which in the case of phenyl or biphenyl may be further substituted with C1-C4-alkyl-, C1-C4-alkoxy- or fluoro;Ar2 represents a residue derived from an arylamine in which the aryl rings are phenyl, naphthyl or anthracenyl optionally substituted with C1-C4-alkyl-, C1-C4-alkoxy- or fluoro, a polycyclic fused or chain aromatic ring system optionally containing nitrogen or sulphur and in a chain aromatic ring system optionally containing one or more chain oxygen or sulphur atoms, a triarylphosphine oxide or an arylsilane the rings of any of which are optionally substituted with C1-C4-alkyl-, C1-C4-alkoxy- or fluoro.Certain of the compounds may be used in electron transport layers and may be doped with p-type dopants. They may be incorporated into OLEDs, organic photovoltaic devices, imaging members and thin film transistors.In further embodiments there are provided OLEDs or other devices e.g. electrostatic latent image forming members in which improved efficiency is obtained by using as electron transport layers, electron injectors, hosts and emitters (dopants) ambipolar or electron-transmitting compounds in which thianthrene is bonded to aryl e.g. 1-anthracenyl-9-yl-thianthrene, 1-biphenyl-4-yl-thianthrene and 9,10-Bis(1-thianthrenyl) anthracene.

Description

CLAIM OF PRIORITY[0001]This application is a continuation-in-part of and claims the benefit of priority under 35 U.S.C. §120 to International Patent Application No. PCT / GB2014 / 050970, filed on Mar. 27, 2014, and which claims the benefit of priority under 35 U.S.C. §119 to United Kingdom Patent Application No. 1306365.6, filed on Apr. 9, 2013, each of which are incorporated by reference herein in its entirety.FIELD OF THE INVENTION[0002]This invention relates to novel compounds and to their use in electro-optical or opto-electronic devices, inters alia optical light emitting devices, for example in a hole transport layer. It also relates to a second class of compounds having ambipolar properties. It further relates to novel compounds and to their use in electro-optical or opto-electronic devices, inter alia optical light emitting devices, for example in an electroluminescent device in the field of flat panel displays and lighting in an electron transport layer, hole blocking layer, h...

AI Technical Summary

Benefits of technology

[0041]Embodiments of the present compounds exhibit a surprisingly favourable combination of hole mobility and high glass transition temperature or melting point, and the compounds also find utility in a hole injection layer and / or in an electron blocking layer. Since they are in general small molecules, many of them are purifiable by sublimation, which is desirable for the production of compounds of the purity required for OLEDs and other device applications. Embodiments of these compounds exhibit ambipolarity i.e they can be doped to form either electron or hole transport layers depending upon whether they are doped with p-type or n-type dopants. Such molecules are sought-after by device manufacturers because in some embodiments the number of different materials in different layers that have to be used is reduced.

Problems solved by technology

However, the fused carbazole ring structures of the Duksan compounds exhibit relatively low hole mobility so that these compounds would be expected to exhibit poorbried performance if used as hole transporters.

113-114° C., all of which are undesirably low for device applications.

Although the compounds were investigated by cyclic voltammetry, DPV spectroscopy, UV-Visible spectroscopy and fluorescence—were alleged to have band gaps in a range appropriate for semiconductors, no hole mobility measurements were made, and the compounds were not tested in OLEDs or other practical devices.

However these suffer from the disadvantages of high energy consumption, high cost of manufacture, low quantum efficiency and the inability to make flat panel displays.

Organic polymers have been proposed as useful in electroluminescent devices, but it is not possible to obtain pure colours; they are expensive to make and have a relatively low efficiency.

Another electroluminescent compound which has been proposed is aluminium quinolate, but it requires dopants to be used to obtain a range of colours and has a relatively low efficiency.

However, there is no disclosure or suggestion of the suitability of incorporating such compounds into an electron transport layer of such a device, and in exemplified cells the electron transport layer used was of well-known materials such as aluminium quinolate.

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