Materials for electronic devices

Abstract

The present invention relates to polymers comprising structural units having partially fluorinated substituents, to mixtures and formulations comprising the polymers according to the invention, to a process for the preparation of the polymers according to the invention, and to the use of the polymers according to the invention as functional materials in electronic devices.

Claims

1. A polymer comprising 30 to 60 mol % of one or more structural elements of the formula (I), ##STR00024## wherein M on each occurrence, identically or differently, represents a benzene, naphthalene, anthracene, benzanthracene, benzofluorene, dibenzofluorene, cis- or trans-indenofluorene, benzindenofluorene, dibenzindenofluorene, spirobifluorene, phenanthrene, benzophenanthrene or dihydrophenanthrene derivative, where the substituents R.sub.F defined below and are identical or different on each occurrence, with the proviso that the following applies to the indices a and b:
1a10,000
1b10 and the dashed lines represent bonds to adjacent structural units, where, in addition, more than the two bonds shown may occur, and the polymer optionally comprise further identical or different structural elements M which are not substituted by partially fluorinated radicals R.sub.F, with the proviso that the sum of the structural units M is between 2 and 10,000, and furthermore R.sub.F represents, identically or differently, a partially fluorinated non-aromatic substituent having 1 to 20 C atoms, which is optionally saturated or unsaturated, linear, cyclic or branched and in which one CH.sub.2 groups is optionally replaced by O, S, Si(R.sup.2).sub.2, BR.sup.2, NR.sup.2, PR.sup.2, CO, CS, CNR.sup.2, PO(R.sup.2), PS(R.sup.2), R.sup.2CCR.sup.2,CC, SO, SO.sub.2, O(CO)O or CONR.sup.2, and R.sup.2 on each occurrence, identically or differently, represents H, F or an aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, in which one or more H atoms is optionally replaced by F and (i) units which are used as polymer backbone wherein the units which are used as polymer backbone are selected from 4,5-dihydropyrene derivatives, 4,5,9,10-tetrahydropyrene derivatives, fluorene derivatives, 9,9-spirobifluorene derivatives, phenanthrene derivatives, 9,10-dihydrophenanthrene derivatives, 5,7-dihydrodibenzoxepine derivatives and cis- and trans-indenofluorene derivatives.

2. The polymer according to claim 1, wherein the structural element M represents a benzene, naphthalene, anthracene, benzanthracene, cis- or trans-indenofluorene, benzindenofluorene, dibenzindenofluorene, spirobifluorene, phenanthrene, benzophenanthrene or dihydrophenanthrene derivative.

3. The polymer according to claim 1, wherein the polymer comprises one or more structural elements M selected from one or more of the following formulae (IV) to (XXXIV): ##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029## where the structural elements, as defined in claim 1, may optionally be substituted at all H-substituted positions of the skeleton instead by one or more identical or different radicals R.sup.1.

4. The polymer according to claim 1, wherein R.sub.F represents a partially fluorinated saturated linear, branched or cyclic alkyl group which contains 1 to 12 C atoms and in which one CH.sub.2 groups may optionally be replaced by O, S, NR.sup.2, CO or CONR.sup.2.

5. The polymer according to claim 1, wherein R.sub.F comprises one or more structural elements selected from the groups OCF.sub.3, SCF.sub.3, N(CF.sub.3).sub.2 and terminal aliphatic trifluoromethyl.

6. The polymer according to claim 1, wherein the polymer has a molecular weight of 100,000 to 2,000,000 g/mol.

7. The polymer according to claim 1 comprising structural elements which fulfil one or more of the following functions: charge transport, charge injection, hole transport, hole injection, emission, charge blocking, or morphology, rheology or processability improvement.

8. The polymer according to claim 1, wherein the polymer has a molecular weight of 200,000 to 1,000,000 g/mol.

9. A polymer comprising (i) 30 to 60 mol % of one or more structural elements of the formula (I), ##STR00030## wherein M on each occurrence, identically or differently, represents an aromatic, heteroaromatic or aliphatically bridged aromatic ring system, which is optionally substituted by one or more radicals R.sup.1, where the substituents R.sub.F and R.sup.1 defined below and are identical or different on each occurrence, with the proviso that the following applies to the indices a and b:
1a10,000
1b10 and the dashed lines represent bonds to adjacent structural units, where, in addition, more than the two bonds shown may occur, and the polymer optionally comprise further identical or different structural elements M which are not substituted by partially fluorinated radicals R.sub.F, with the proviso that the sum of the structural units M is between 2 and 10,000, and furthermore R.sub.F represents, identically or differently, a partially fluorinated non-aromatic substituent having 1 to 20 C atoms, which is optionally saturated or unsaturated, linear, cyclic or branched and in which one CH.sub.2 groups is optionally replaced by O, S, Si(R.sup.2).sub.2, BR.sup.2,NR.sup.2,PR.sup.2,CO, CS, CNR.sup.2, PO(R.sup.2), PS(R.sup.2), R.sup.2CCR.sup.2, CC, SO, SO.sub.2, COO, O(CO)O or CONR.sup.2, and R.sup.1on each occurrence, identically or differently, represents H, F or an aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, in which, in addition, one or more H atoms may be replaced by F and in which, in addition, one or more adjacent or non-adjacent CH.sub.2 groups is optionally replaced by O, S, Se, Te, Si(R.sup.2).sub.2, Ge(R.sup.2).sub.2, BR.sup.2, NR.sup.2, PR.sup.2, CO, CS, CSe, CNR.sup.2, PO(R.sup.2), PS(R.sup.2), R.sup.2CCR.sup.2, CC, SO, SO.sub.2,COO, O(CO)O or CONR.sup.2, with the proviso that two or more substituents R.sup.1 which are bonded to one group M or to two or more different adjacent or non-adjacent groups M optionally faun an aliphatic, unsaturated or aromatic ring system, and R.sup.2 on each occurrence, identically or differently, represents H, F or an aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, in which one or more H atoms is optionally replaced by F and the polymer comprises further structural units which influence the hole-injection and/or hole-transport properties of the polymer and which are selected from the group consisting of triarylamine, benzidine, tetraaryl-paraphenylenediamine, triarylphosphine, phenothiazine, phenoxazine, dihydrophenazine, thianthrene, dibenzo-para-dioxin, phenoxathiyne, carbazole, azulene, thiophene, pyrrole and furan derivatives and (ii) 0.5 to 50 mol % of units of group 1 which influence the hole-injection and/or hole-transport properties of the polymer and/or units of group 2 which influence the electron-injection and/or electron-transport of the polymer, (iii) units which are typically used as polymer backbone, (iv) wherein the units which influence the hole-injection and/or hole-transport properties are selected from triarylamine, benzidine, tetraaryl-para-phenylenediamine, triarylphosphine, phenothiazine, phenoxazine, dihydrophenazine, thianthrene, dibenzo-para-dioxin, phenoxathiyne, carbazole, azulene, thiophene, pyrrole and furan derivatives, (v) wherein the units which influence the electron-injection and/or electron-transport of the polymer are selected from pyridine, pyrimidine, pyridazine, pyrazine, oxadiazole, quinoline, quinoxaline, anthracene, benzanthracene, pyrene, perylene, benzimidazole, triazine, ketone, phosphine oxide and phenazine derivatives, and (vi) wherein the units which are typically used as polymer backbone are selected from 4,5-dihydropyrene derivatives, 4,5,9,10-tetrahydropyrene derivatives, fluorene derivatives, 9,9-spirobifluorene derivatives, phenanthrene derivatives, 9,10-dihydrophenanthrene derivatives, 5,7-dihydrodibenzoxepine derivatives and cis- and trans-indenofluorene derivatives.

10. The polymer according to claim 9, wherein the polymer has a molecular weight of 100,000 to 2,000,000 g/mol.

11. The polymer according to claim 9, wherein the polymer has a molecular weight of 200,000 to 1,000,000 g/mol.

12. The polymer according to claim 9, wherein the further structural units are triarylamine.

13. The polymer according to claim 9, wherein the structural element M represents an aromatic ring system having 6 to 40 C atoms.

14. A polymer comprising (i) 30 to 60 mol % of one or more structural elements of the formula (I), ##STR00031## wherein M on each occurrence, identically or differently, represents a benzene, naphthalene, anthracene, benzanthracene, benzofluorene, dibenzofluorene, cis- or trans-indenofluorene, benzindenofluorene, dibenzindenofluorene, spirobifluorene, phenanthrene, benzophenanthrene or dihydrophenanthrene derivative, where the substituents R.sub.F defined below and are identical or different on each occurrence, with the proviso that the following applies to the indices a and b:
1a10,000
1b10 and the dashed lines represent bonds to adjacent structural units, where, in addition, more than the two bonds shown may occur, and the polymer optionally comprise further identical or different structural elements M which are not substituted by partially fluorinated radicals R.sub.F, with the proviso that the sum of the structural units M is between 2 and 10,000, and furthermore R.sub.F represents, identically or differently, a partially fluorinated non-aromatic substituent having 1 to 20 C atoms, which is optionally saturated or unsaturated, linear, cyclic or branched and in which one CH.sub.2 groups is optionally replaced by O, S, Si(R.sup.2).sub.2, BR.sup.2, NR.sup.2, PR.sup.2, CO, CS, CNR.sup.2, PO(R.sup.2), PS(R.sup.2), R.sup.2CCR.sup.2, CC, SO, SO.sub.2, COO, O(CO)O or CONR.sup.2, and R.sup.1 on each occurrence, identically or differently, represents H, F or an aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, in which, in addition, one or more H atoms may be replaced by F and in which, in addition, one or more adjacent or non-adjacent CH.sub.2 groups is optionally replaced by O, S, Se, Te, Si(R.sup.2).sub.2, Ge(R.sup.2).sub.2, BR.sup.2, NR.sup.2,PR.sup.2, CO, CS, CSe, CNR.sup.2,PO(R.sup.2), PS(R.sup.2), R.sup.2CCR.sup.2, CC, SO, SO.sub.2,COO, O(CO)O or CONR.sup.2, with the proviso that two or more substituents R.sup.1 which are bonded to one group M or to two or more different adjacent or non-adjacent groups M optionally form an aliphatic, unsaturated or aromatic ring system, and R.sup.2 on each occurrence, identically or differently, represents H, F or an aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, in which one or more H atoms is optionally replaced by F and (ii) 0.5 to 50 mol % of units of group 1 which influence the hole-injection and/or hole-transport properties of the polymer and/or units of group 2 which influence the electron-injection and/or electron-transport of the polymer, (iii) units which are typically used as polymer backbone, (iv) wherein the units which influence the hole-injection and/or hole-transport properties are selected from triarylamine, benzidine, tetraaryl-para-phenylenediamine, triarylphosphine, phenothiazine, phenoxazine, dihydrophenazine, thianthrene, dibenzo-para-dioxin, phenoxathiyne, carbazole, azulene, thiophene, pyrrole and furan derivatives, (v) wherein the units which influence the electron-injection and/or electron-transport of the polymer are selected from pyridine, pyrimidine, pyridazine, pyrazine, oxadiazole, quinoline, quinoxaline, anthracene, benzanthracene, pyrene, perylene, benzimidazole, triazine, ketone, phosphine oxide and phenazine derivatives, and (vi) wherein the units which are typically used as polymer backbone are selected from 4,5-dihydropyrene derivatives, 4,5,9,10-tetrahydropyrene derivatives, fluorene derivatives, 9,9-spirobifluorene derivatives, phenanthrene derivatives, 9,10-dihydrophenanthrene derivatives, 5,7-dihydrodibenzoxepine derivatives and cis- and trans-indenofluorene derivatives.

Description

WORKING EXAMPLES

(1) Preparation of the Polymers

(2) The monomeric compounds for the synthesis of the polymers according to the invention can be prepared by methods described in the prior art, where the person skilled in the art will be able to apply the methods to the specific case in question without being inventive. Processes for the synthesis of indenofluorene derivatives which are substituted by alkyl groups in the 9-positions are disclosed, for example, in WO 04/113412.

(3) Processes for the synthesis of the partially fluorinated side chains according to the invention, especially those containing OCF.sub.3, SCF.sub.3 and N(CF.sub.3).sub.2 groups, are disclosed in detail in WO 06/072401 and WO 08/003447.

(4) Preparation of the Polymers

(5) Polymers P1 to P6 according to the invention are synthesised using the following monomers (per cent data=mol %) by SUZUKI coupling in accordance with the general procedure from WO 03/048225 A2.

EXAMPLE 1

Polymer P1

(6) ##STR00018##

EXAMPLE 2

Polymer P2

(7) ##STR00019##

EXAMPLE 3

Polymer P3

(8) ##STR00020##

EXAMPLE 4

Polymer P4

(9) ##STR00021##

EXAMPLE 5

Polymer P5

(10) ##STR00022##

EXAMPLE 6

Polymer P6

(11) ##STR00023##

EXAMPLES 7 to 12

Production of PLEDs

(12) The production of a polymeric organic light-emitting diode (PLED) has already been described many times in the literature (for example in WO 2004/037887 A2). In order to explain the present invention in illustrative terms, PLEDs comprising polymers P1 to P6 according to the invention are produced by spin coating.

(13) To this end, especially manufactured substrates from Technoprint are used in a layout designed specifically for this purpose. The ITO structure (indium tin oxide, a transparent, conductive anode) is applied to soda-lime glass by sputtering in a pattern such that 4 pixels measuring 22 mm arise with the cathode applied by vapour deposition at the end of the production process.

(14) The substrates are cleaned with DI water and a detergent (Deconex 15 PF) in a clean room and then activated by UV/ozone plasma treatment. An 80 nm layer of PEDOT (PEDOT is a polythiophene derivative (Baytron P VAI 4083sp.) from H. C. Starck, Goslar, which is supplied as an aqueous dispersion) is then applied by spin coating, likewise in the clean room. The spin rate required depends on the degree of dilution and the specific spin-coater geometry (typical for 80 nm: 4500 rpm). In order to remove residual water from the layer, the substrates are dried by heating for 10 minutes at 180 C. on a hotplate. Then, under an inert-gas atmosphere (nitrogen or argon), firstly 20 nm of an interlayer (typically a hole-dominated polymer, here HIL-012 from Merck) and then 65 nm of the polymer layers are applied from toluene solutions (concentration of interlayer 5 g/l, for polymers P1 to P6 between 8 and 10 g/l). The two layers are dried by heating at 180 C. for at least 10 minutes. The Ba/Al cathode is then applied in the pattern indicated by vapour deposition through a vapour-deposition mask (high-purity metals from Aldrich, particularly barium 99.99% (Order No. 474711); vapour-deposition units from Lesker or others, typical vacuum level 510.sup.6 mbar). In order to protect, in particular, the cathode against air and atmospheric moisture, the device is finally encapsulated and then characterised.

(15) To this end, the devices are clamped into holders manufactured specifically for the substrate size and provided with spring contacts. A photodiode with eye response filter can be placed directly on the measurement holder in order to exclude influences from extraneous light.

(16) The voltages are typically increased from 0 to max. 20 V in 0.2 V steps and reduced again. For each measurement point, the current through the device and the photocurrent obtained are measured by the photodiode. In this way, the IUL data of the test devices are obtained. Important parameters are the maximum efficiency measured (max. eff. in cd/A) and the voltage required for 100 cd/m.sup.2.

(17) In order, in addition, to know the colour and the precise electroluminescence spectrum of the test devices, the voltage required for 100 cd/m.sup.2 is applied again after the first measurement, and the photodiode is replaced by a spectrum measurement head. This is connected to a spectrometer (Ocean Optics) by an optical fibre. The colour coordinates (CIE: Commission Internationale de lclairage, standard observer from 1931) can be derived from the measured spectrum.

(18) The results obtained on use of polymers P1 to P6 in PLEDs are shown in Table 1.

(19) TABLE-US-00001 TABLE 1 U @ U @ Max. eff. Max. eff. 100 cd/m.sup.2 1000 cd/m.sup.2 CIE Ex. Interlayer Polymer [cd/A] [lm/W] [V] [V] [x/y] 7 HIL-012 P1 5.97 2.8 4.08 5.48 0.15/0.18 8 HIL-012 P2 6.24 2.9 3.96 5.21 0.15/0.18 9 HIL-012 P3 6.11 3.1 3.72 4.98 0.15/0.18 10 HIL-012 P4 17.81 12.7 3.57 4.55 0.31/0.60 11 HIL-012 P5 19.21 12.8 3.76 4.72 0.31/0.59 12 HIL-012 P6 19.04 13.2 3.32 4.32 0.31/0.60