Heterocyclic compounds and their use in electro-optical or opto-electronic devices
Compounds exhibiting high hole mobility and/or high glass transition temperatures are provided which are of the formula [Ar 1 ] m [Ar 2 ] n wherein: m is an integer from 1-3 and n is an integer and may be 1 or 2; Ar 1 represents a thianthrene residue having a linkage to Ar 2 at one or two positions selected from ring positions 1-4 and 5-8 and optionally mono-, bi- or poly-substituted with C 1 -C 4 -alkyl-, C 1 -C 4 -alkoxy-, fluoro, phenyl or biphenyl which in the case of phenyl or biphenyl may be further substituted with C 1 -C 4 -alkyl-, C 1 -C 4 -alkoxy- or fluoro; Ar 2 represents a residue derived from an arylamine in which the aryl rings are phenyl, naphthyl or anthracenyl optionally substituted with C 1 -C 4 -alkyl-, C 1 -C 4 -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 C 1 -C 4 -alkyl-, C 1 -C 4 -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.
1. Bis [3-(phenylvinyl-1-thianthrenyl)]-4,4′-biphenyl
2. 2-(4′-Diphenylamino)phenyl-8-(1′-thianthrenyl)-dibenzothiophene.
3. Either compound of the following structure:
(a) bis [3-(phenylvinyl-1-thianthrenyl)]-4,4′-biphenyl
(b) 2-(4′-Diphenylamino)phenyl-8-(1′-thianthrenyl)-dibenzothiophene.
4. A hole transport material comprising a compound according to claim 3 and a p-dopant which is an acceptor-type organic molecule.
5. The material of claim 4 , wherein the dopant is present in an amount such that when the material is deposited to form a layer the dopant contributes about 10-40% to layer thickness.
6. The material of claim 5 , wherein:
(a) the dopant comprises tetracyanoquinodimethane or tetrafluorotetracyano-quinodimethane;
(b) the dopant comprises a compound of any of the general formulae (i)-(vii) below:
wherein the groups R in any of the formulae in (i) to (vii) can be the same or different and are selected from hydrogen; substituted and unsubstituted aliphatic groups; substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures; halogens; and thiophenyl groups; and wherein
in formula (i) the methyl groups may be replaced by C 1 -C 4 alkyl or monocyclic or polyclic aryl or heteroraryl which may be further substituted e.g. with alkyl, aryl or arylamino, or of the formula viii or ix
wherein the groups R 1 -R 4 when appearing in either of the above formulae can be the same or different and are selected from hydrogen; substituted and unsubstituted aliphatic groups; substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures; halogens; and thiophenyl groups;
(c) the dopant comprises a teritiary amine which is α-NPB or β-NBP.
7. An optical light-emitting diode having first and second electrodes and between said electrodes a layer comprising a compound as claimed in claim 3 .
8. The diode of claim 7 , wherein said layer is a hole transport layer or a hole injection layer.
9. The diode of claim 7 , having an emissive layer comprising an emitter selected from:
(a) a fluorescent emitter;
(b) a phosphorescent emitter;
(c) an ion fluorescent (rare earth based) emitter;
(d) quantum dots; and
(e) thermally activated fluorescent (TADF) materials.
10. The diode of claim 7 , having a hole injection layer comprising CuPC, ZnTpTP, 2-TNATA or
11. The diode of claim 7 , which forms part of a flat panel display, a lighting panel, r an organic photovoltaic device.
12. An imaging member for forming an electrostatic latent image, an organic thin film transistor, a dye-sensitised solar cell, a printed device or a quantum dot based electroluminescent device comprising a compound as claimed in claim 3 .
13. An OLED device used as a light source to print conductive, resistive, dielectric, piezoelectric or pyroelectric films or lines or grids said device comprising a compound as claimed in claim 3 .
14. An OLED lighting panel comprising a compound as claimed in claim 3 .