Electronic device comprising an organic semiconductor, an organic semiconductor, and an intermediate buffer layer made of a polymer that is cationically polymerizable and contains no photoacid
The present invention describes a novel design principle for organic electronic elements by inserting at least one additional crosslinkable layer. The properties of the electronic devices are thereby improved. Structured construction of these devices is furthermore facilitated.
1 . An electronic device containing at least one layer of a conductive doped polymer and at least one layer of an organic semiconductor, characterized in that at least one conducting or semiconducting organic buffer layer which is cationically polymerizable, and to which less than 0.5% of a photoacid is added, is introduced between these layers.
2 . The electronic device as claimed in claim 1 , characterized in that no photoacid is added to the buffer layer.
3 . The electronic device as claimed in claim 1 , characterized in that the crosslinking of the organic buffer layer is thermally initiated.
4 . The electronic device as claimed in claim 1 , wherein the electronic device comprises organic or polymeric light-emitting diodes (OLEDs, PLEDs), organic solar cells (O-SCs), organic field effect transistors (O-FETs), organic circuit elements (O-ICs), organic field quench devices (O-FQDs), organic optical amplifiers or organic laser diodes (O-lasers).
5 . The electronic device as claimed in claim 1 , wherein the electronic device contains the following elements: substrate, electrode, interlayer of a conductive doped polymer, conducting or semiconducting organic cationically crosslinkable buffer layer, organic semiconductor layer and back electrode.
6 . The electronic device as claimed in claim 5 , characterized in that an interlayer of a material with a high dielectric constant is introduced between a metal cathode and the organic semiconductor.
7 . The electronic device as claimed in claim 1 , characterized in that anode materials with a potential of more than 4.5 eV vs. vacuum are used.
8 . The electronic device as claimed in claim 1 , characterized in that the conductive doped polymer has a conductivity of >10 −8 S/cm and a potential of 4-6 eV vs. vacuum.
9 . The electronic device as claimed in claim 8 , characterized in that derivatives of polythiophene or polyaniline are used as the conductive polymer, and the doping is carried out via polymer-bound Brönsted acids.
10 . The electronic device as claimed in claim 5 , wherein said organic semiconductor is a low molecular weight oligomeric, dendritic or polymeric semiconducting material.
11 . The electronic device as claimed in claim 10 , characterized in that the organic semiconductor is a conjugated polymer.
12 . The electronic device as claimed in claim 10 , characterized in that the organic semiconductor is a cationically crosslinkable compound.
13 . The electronic device as claimed in claim 12 , characterized in that the cationic crosslinking takes place via ring-opening cationic polymerization of a heterocycle.
14 . The electronic device as claimed in claim 13 , characterized in that the cationic crosslinking takes place via oxetane groups which can be crosslinked via radiation by adding a photoacid.
15 . The electronic device as claimed in claim 1 , characterized in that the crosslinkable buffer layer is low molecular weight oligomeric, dendritic or polymeric before the crosslinking.
16 . The electronic device as claimed in claim 1 , characterized in that the layer thickness of the buffer layer lies in the range of 5-300 nm.
17 . The electronic device as claimed in claim 1 , characterized in that the potential of the buffer layer lies between the potential of the conductive doped polymer and that of the organic semiconductor.
18 . The electronic device as claimed in claim 1 , characterized in that cationically crosslinkable hole-conductive materials are used for the buffer layer.
19 . The electronic device as claimed in claim 18 , characterized in that cationically crosslinkable triarylamine-based, thiophene-based or triarylphosphine-based materials are used for the buffer layer.
20 . The electronic device as claimed in claim 1 , characterized in that materials in which at least one H atom is replaced by a heterocyclic group, reacting by cationic ring-opening polymerization, are used as materials for the buffer layer.
21 . The electronic device as claimed in claim 20 , characterized in that the cationically polymerizable heterocycle is a group of the formula (I), (II) or (III),
in which
R 1 in each occurrence is identically or differently hydrogen, a straight-chained, branched or cyclic alkyl, alkoxy or thioalkoxy group having from 1 to 20 C atoms, an aromatic or heteroaromatic ring system having from 4 to 24 aromatic ring atoms or an alkenyl group having from 2 to 10 C atoms, wherein one or more hydrogen atoms may be replaced by halogen or by CN and one or more non-neighboring C atoms may be replaced by —O—, —S—, —CO—, —COO— or —O—CO—; a plurality of R 1 radicals may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another or with R 2 , R 3 and/or R 4 ;
R 2 in each occurrence is identically or differently hydrogen, a straight-chained, branched or cyclic alkyl group having from 1 to 20 C atoms, an aromatic or heteroaromatic ring system having from 4 to 24 aromatic ring atoms or an alkenyl group having from 2 to 10 C atoms, wherein one or more hydrogen atoms may be replaced by halogen or by CN and one or more non-neighboring C atoms may be replaced by —O—, —S—, —CO—, —COO— or —O—CO—; a plurality of R 2 radicals may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another or with R 1 , R 3 and/or R 4 ;
X in each occurrence is identically or differently —O—, —S—, —CO—, —COO—, —O—CO— or a bivalent —(CR 3 R 4 ) n — group;
Z in each occurrence is identically or differently a bivalent —(CR 3 R 4 ) n — group;
R 3 , R 4 in each occurrence is identically or differently hydrogen, a straight-chained, branched or cyclic alkyl, alkoxy or thioalkoxy group having from 1 to 20 C atoms, an aromatic or heteroaromatic ring system having from 4 to 24 aromatic ring atoms or an alkenyl group having from 2 to 10 C atoms, wherein one or more hydrogen atoms may be replaced by halogen or by CN; two or more R 3 or R 4 radicals may also form a ring system with one another or with R 1 , R 2 ;
n in each occurrence is identically or differently an integer between 0 and 20;
with the proviso that the number of these groups according to formula (I) and/or formula (II) and/or formula (III) is limited by the maximally available, i.e. substitutable H atoms.
22 . The electronic device as claimed in claim 21 , characterized in that the crosslinking of these units is carried out by thermal treatment of the device.
23 . The electronic device as claimed in claim 22 , characterized in that the crosslinking takes place at a temperature of from 80 to 200° C. and for a duration of from 0.1 to 120 minutes in an inert atmosphere.