Materials for organic electroluminescent devices

Abstract

The present invention relates to compounds of the formula (1) which are suitable for use in electronic devices, in particular organic electroluminescent devices, and to electronic devices which comprise these compounds.

Claims

1. Compound of the formula (1), ##STR00417## where the following applies to the symbols and indices used: Ar.sup.S is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may in each case also be substituted by one or more radicals R.sup.1; Ar.sup.1, Ar.sup.2, Ar.sup.3, Ar.sup.4 stand on each occurrence, identically or differently, for: an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.1; or a group Ar.sup.L; Ar.sup.L stands on each occurrence, identically or differently, for a group of formula (ArL-1), ##STR00418## where the dashed bond in formula (ArL-1) indicates the bonding to the structure of formula (1); X stands for CR.sup.2 or X stands for C, if it is bonded to Ar.sup.5, Ar.sup.6, R.sup.3 or to an adjacent fluorene-type derivative unit; Y stands on each occurrence, identically or differently, for BR.sup.0, C(R.sup.0).sub.2, C(R.sup.0).sub.2C(R.sup.0).sub.2, C(R.sup.0).sub.2O, C(R.sup.0).sub.2S, R.sup.0C?CR.sup.0, R.sup.0C?N, Si(R.sup.0).sub.2, Si(R.sup.0).sub.2Si(R.sup.0).sub.2, C(?O), C(?NR.sup.0), C(?C(R.sup.0).sub.2), O, S, S(?O), SO.sub.2, N(R.sup.0), P(R.sup.0) and P((?O)R.sup.0; Ar.sup.5, Ar.sup.6 stand on each occurrence, identically or differently, for an aryl or heteroaryl group having 6 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.3; G is selected from the group consisting of formulae (G-1-1) to (G-1-23), ##STR00419## ##STR00420## ##STR00421## ##STR00422## where the dashed bonds indicate the bonding to the adjacent groups as depicted in formula (1); the groups of formulae (G-1-1) to (G-1-23) may be substituted by one or more radicals R.sup.4 or one or more groups Ar.sup.L at any free positions; E.sup.2 stands, on each occurrence, identically or differently, for C(R.sup.E).sub.2, O or S; Ar.sup.7 stands on each occurrence, identically or differently, for an aryl or heteroaryl group having 6 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.4, wherein at least one of the group Ar.sup.7 in formulae (G-1) and (G-2) has 10 or more aromatic ring atoms; Ar.sup.8 stands on each occurrence, identically or differently, for an aryl or heteroaryl group having 6 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.4 or one or more groups Ar.sup.L; E is identically or differently on each occurrence, selected from BR.sup.E, C(R.sup.E).sub.2, C(R.sup.E).sub.2C(R.sup.E).sub.2, C(R.sup.E).sub.2O, C(R.sup.E).sub.2S, R.sup.EC?CR.sup.E, R.sup.EC?N, Si(R.sup.E).sub.2, Si(R.sup.E).sub.2Si(R.sup.E).sub.2, C(?O), C(?NR.sup.E), C(?C(R.sup.E).sub.2), O, S, S(?O), SO.sub.2, N(R.sup.E), P(R.sup.E) and P((?O)R.sup.E); or E is a group of formula (E-1), ##STR00423## where the symbol * in formula (E-1) indicates the corresponding group E in formula (G-1) or (G-2); and where two groups E may be in a cis- or trans-position relative to each other; E.sup.0 is identically or differently on each occurrence, selected from the group consisting of a single bond, BR.sup.4, C(R.sup.4).sub.2, C(R.sup.4).sub.2C(R.sup.4).sub.2, C(R.sup.4).sub.2O, C(R.sup.4).sub.2S, R.sup.4C?CR.sup.4, R.sup.4C?N, Si(R.sup.4).sub.2, Si(R.sup.4).sub.2Si(R.sup.4).sub.2, C(?O), C(?NR.sup.4), C(?C(R.sup.4).sub.2), O, S, S(?O), SO.sub.2, N(R.sup.4), P(R.sup.4) and P((?O)R.sup.4); R.sup.E stands on each occurrence, identically or differently, for: H, D, F, Cl, Br, I, a straight-chain alkyl having 1 to 40 C atoms or branched or a cyclic alkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.5, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by R.sup.5C?CR.sup.5, C?C, Si(R.sup.5).sub.2, Ge(R.sup.5).sub.2, Sn(R.sup.5).sub.2, C?O, C?S, C?Se, P(?O)(R.sup.5), SO, SO.sub.2, O, S or CONR.sup.5 and where one or more H atoms may be replaced by D, F, Cl, Br, I or CN, an aromatic or heteroaromatic ring systems having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.5, where two adjacent substituents R.sup.E may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R.sup.5; or R.sup.E stands for a group Ar.sup.L; R.sup.0, R.sup.1, R.sup.2, R.sup.3, R.sup.4 stand on each occurrence, identically or differently, for: a group selected from H, D, F, Cl, Br, I, CHO, CN, N(Ar).sub.2, C(?O)Ar, P(?O)(Ar).sub.2, S(?O)Ar, S(?O).sub.2Ar, NO.sub.2, Si(R.sup.5).sub.3, B(OR.sup.5).sub.2, OSO.sub.2R.sup.5, a straight-chain alkyl, alkoxy or thioalkyl groups having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl groups having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.5, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by R.sup.5C?CR.sup.5, C?C, Si(R.sup.5).sub.2, Ge(R.sup.5).sub.2, Sn(R.sup.5).sub.2, CO?O, C?S, C?Se, P(?O)(R.sup.5), SO, SO.sub.2, O, S or CONR.sup.5 and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, an aromatic or heteroaromatic ring systems having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.5, or an aryloxy groups having 5 to 40 aromatic ring atoms, which may be substituted by one or more radicals R.sup.5; or R.sup.0, R.sup.1, R.sup.2, R.sup.3 and/or R.sup.4 stands for a group Ar.sup.L; where two adjacent substituents R.sup.0, two adjacent substituents R.sup.1, two adjacent substituents R.sup.2, two adjacent substituents R.sup.3 and/or two adjacent substituents R.sup.4, may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R.sup.5; R.sup.5 stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, N(Ar).sub.2, C(?O)Ar, P(?O)(Ar).sub.2, S(?O)Ar, S(?O).sub.2Ar, NO.sub.2, Si(R.sup.6).sub.3, B(OR.sup.6).sub.2, OSO.sub.2R.sup.6, a straight-chain alkyl, alkoxy or thioalkyl groups having 1 to 40 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl groups having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.6, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by R.sup.6C?CR.sup.6, C?C, Si(R.sup.6).sub.2, Ge(R.sup.6).sub.2, Sn(R.sup.6).sub.2, CO?O, C?S, C?Se, P(?O)(R.sup.6), SO, SO.sub.2, O, S or CONR.sup.6 and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, an aromatic or heteroaromatic ring systems having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.6, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.6, where two adjacent substituents R.sup.5 may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R.sup.6; Ar is an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which may in each case also be substituted by one or more radicals R.sup.6; R.sup.6 stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkyl groups having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl groups having 3 to 20 C atoms, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by SO, SO.sub.2, O, S and where one or more H atoms may be replaced by D, F, Cl, Br or I, or an aromatic or heteroaromatic ring system having 5 to 24 C atoms; n is equal to 1; i is equal to 0, 1 or 2; q, r are on each occurrence, identically or differently, an integer selected from 1 to 10; p, s, t are on each occurrence, identically or differently, an integer selected from 0 to 10; and where the compounds of formula (1) comprise at least one group Ar.sup.1, Ar.sup.2, Ar.sup.3, Ar.sup.4, R.sup.E, R.sup.0, R.sup.1, R.sup.2, R.sup.3 or R.sup.4, which stands for a group Ar.sup.L.

2. Compound according to claim 1, wherein the compound of formula (1) bears at least one group R.sup.0, R.sup.1, R.sup.2, R.sup.3, R.sup.4 or R.sup.E, which stands for a straight-chain alkyl group having 1 to 40 C atoms or a branched or a cyclic alkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.6.

3. Compound according to claim 1, selected from compounds of formulae (2) to (10), ##STR00424## where the symbols and indices have the same meaning as in claim 1.

4. Compound according to claim 1, wherein the group Ar.sup.L is a group of formula (ArL-2), ##STR00425## where the symbols and indices have the same meaning as in claim 1.

5. Compound according to claim 1, wherein Ar.sup.5 and Ar.sup.6 are selected, identically or differently, from the group consisting of the groups of formulae (Ar5-1) to (Ar5-26), ##STR00426## ##STR00427## ##STR00428## ##STR00429## where the dashed bonds indicate the bonding to the adjacent groups depicted in formula (1), where the groups of formulae (Ar5-1) to (Ar5-26) may be substituted at each free position by a group R.sup.3, which has the same meaning as in claim 1 and where E.sup.1 is selected from B(R.sup.0-), C(R.sup.0).sub.2, C(R.sup.0).sub.2C(R.sup.0).sub.2, Si(R.sup.0).sub.2, C(?O), C(?NR.sup.0), C?(C(R.sup.0)).sub.2, O, S, S(?O), SO.sub.2, N(R.sup.0), P(R.sup.0) and P((?O)R.sup.0, where the substituent R.sup.0 has the same meaning as in claim 1.

6. Compound according to claim 1, wherein Ar.sup.5 and Ar.sup.6 are selected, identically or differently, from the group consisting of the groups of formulae (Ar5-27) to (Ar5-37), ##STR00430## ##STR00431## where the dashed bonds indicate the bonding to the adjacent groups depicted in formula (1) and the groups of formulae (Ar5-26) to (Ar5-32) may be substituted at each free position by a group R.sup.3, which has the same meaning as in claim 1 and where the substituent the group E.sup.1 in formulae (Ar5-30) to (Ar5-32) has the same meaning as in claim 1.

7. Compound according to claim 1, wherein the group Ar.sup.L is selected from the groups of formulae (ArL-3) to (ArL-8), ##STR00432## ##STR00433## where the dashed bond indicates the bonding to the structure of formula (1) and where the symbols and indices X, R.sup.0, R.sup.3, Ar.sup.6, E.sup.1, r, p, q and t have the same meaning as in claim 1.

8. Compound according to claim 1, wherein r and q are on each occurrence, identically or differently, equal to 1, 2, 3, 4 or 5.

9. Compound according to claim 1, wherein Ar.sup.6 stands on each occurrence, identically or differently, for an aryl group having 6 to 14 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.3.

10. Compound according to claim 1, wherein Ar.sup.6 stands on each occurrence, identically or differently, for a benzene, naphthalene, biphenyl or fluorene group, which may in each case be substituted by one or more radicals R.sup.3.

11. Compound according to claim 1, wherein the group R.sup.0 stands on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl having 1 to 20 C atoms or branched or a cyclic alkyl group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R.sup.5, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by R.sup.5C?CR.sup.5, O or S, and where one or more H atoms may be replaced by D or F, an aromatic or heteroaromatic ring systems having 5 to 40 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.5, where two adjacent substituents R.sup.0 may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R.sup.5.

12. Compound according to claim 1, wherein the group E is, identically or differently, on each occurrence, selected from C(R.sup.E).sub.2, Si(R.sup.E).sub.2, and the group of formula (E-1), ##STR00434## where the symbol * in formula (E-1) indicates the corresponding group E in formula (G-1) or (G-2) and where E.sup.0 and R.sup.4 have the same meaning as in claim 1.

13. Formulation comprising at least one compound according to claim 1 and at least one solvent.

14. Electronic device comprising at least one compound according to claim 1, selected from the group consisting of organic electroluminescent devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic solar cells, dye-sensitised organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells, organic laser diodes and organic plasmon emitting devices.

15. Electronic device according to claim 14, which is an organic electroluminescent device, wherein the compound according to claim 1 is a fluorescent emitter or a matrix material for fluorescent emitters.

16. Compound according to claim 11, wherein R.sup.0 stands on each occurrence, identically or differently, for a straight-chain alkyl having 1 to 10 C atoms or a cyclic alkyl group having 3 to 10 C atoms.

Description

A) SYNTHESIS EXAMPLES

(1) A-1) Indenofluorene and Benzofluorene Derivatives

(2) ##STR00286##
Synthesis of Compound Int1.1

(3) ##STR00287##

(4) 30 g (97.5 mmol) 2-Bromo-7-Chloro-9,9-dimethyl-9H-fluorene (see JP 2003277305 A), 25.5 g (107.3 mmol) (9,9-dimethylfluoren-2-yl)boronic acid 90 g (390 mmol), 0.9 g (4 mmol) palladium(II)acetate and 3.6 g (11.7 mmol) tri(o-tolyl)-phosphine are dissolved in 1 liter of a toluene, dioxane, water mixture (1:1:1) and stirred at reflux overnight. After cooling down to room temperature 200 mL toluene are added and the organic phase is separated and washed with water (2?200 ml) the combined organic phases are concentrated under reduced pressure. The residue is purified by recrystallization from toluene/heptane.

(5) Yield: 39.1 g (93 mmol; 96%)

(6) Following compounds can be synthesized in an analogous manner in similar yields:

(7) TABLE-US-00003 Com- Starting Starting pound material A material B Product Int1.2 0 Int1.3 Int1.4
Synthesis of EG1

(8) ##STR00297##

(9) 40 g (95 mmol) Int1.1, 38.6 g (152 mmol) bis-(pinacolato)-diboron, 4.2 g (5.7 mmol) trans-dichloro(tricyclohexylphosphine)palladium(II) and 28 g (285 mmol) potassium acetate are dissolved in 400 ml dioxane and stirred for 16 h at reflux. The reaction mixture is allowed to cool to room temperature and 400 ml toluene are added. The organic phase is separated, washed with water (2?200 mL) and filtered through Celite. The solution is concentrated to dryness under reduced pressure. The residue is purified by recrystallization from toluene/heptane.

(10) Yield: 36 g (70 mmol; 74%)

(11) Following compounds can be synthesized in an analogous manner in similar yields:

(12) TABLE-US-00004 Compound Starting material Product EG2 Int1.2 EG3 Int1.3
Synthesis of Int2.4

(13) ##STR00300##

(14) 5.5 g (17.8 mmol) 2-Bromo-5-iodo-1,3-dimethylbenzene, 6.5 g (12.7 mmol) EG1, 366 mg (0.3 mmol) tetrakis(triphenylphosphin)-palladium(0) and 2.7 g (13 mmol) sodium carbonate are dissolved in 200 ml toluene, ethanol and water (2:1:1) and stirred for 16 hours at 90? C. After cooling down to room temperature 100 ml toluene are added, the organic phase is separated and washed with water (2?50 ml). The organic phase is concentrated to dryness under reduced pressure. The residue is purified by recrystallization from toluene/heptane.

(15) Yield: 6.2 g (11 mmol; 86%)

(16) The following compounds can be synthesized in an analogous manner in similar yields:

(17) TABLE-US-00005 Starting Starting Compound material A material B Product Int2.5 EG2 CAS 106-93-8 01 Int2.6 EG2 02 03 Int2.7 CAS 1679-18-1 Int2.4 04
Synthesis of EG4 to EG6:

(18) Compounds EG3 to EG5 can be synthesized in an analogous manner to EG1 in similar yields:

(19) TABLE-US-00006 Starting Compound material Product EG4 Int2.8 05 EG5 Int2.7 06 EG6 Int2.5 07
Synthesis of the Amine (EA.1):

(20) ##STR00308##

(21) 12.2 g (37.3 mmol)bis-(4-bromo-phenyl)-amine, 55.5 g (78.4 mmol) EG.2, 37.8 g (164.2 mmol) potassium phosphate monohydrate and 1.2 g (1.5 mmol) XPhos Pd Gen 3 (GAS 1445085-55-1) are added to 600 mL THF/water (2:1) and stirred at 65? C. After 16 h the mixture is cooled to room temperature diluted with toluene and H2O. The organic phase is collected, the aqueous phase is extracted further with toluene. The combined organics are washed with brine, collected, dried with Na.sub.2SO.sub.4, filtered and concentrated. The resulting residue is deposited in 1 L EtOH and stirred vigorously until free flowing precipitate is formed. The precipitate is collected by filtration and washing with EtOH. The material is taken up in DCM and filtered through SiO.sub.2. The filtrate is concentrated to dryness.

(22) Yield: 44.7 g (33.6 mmol; 90%)

(23) The following compounds EA.2 to EA.6 can be synthesized in analogous manner and similar yields:

(24) TABLE-US-00007 Comp. SM1 SM2 Product EA.2 EG1 09 0 EA.3 EG1 EA.4 EG4 EA.5 EG3 EA.6 EG.2
Compounds A1.1

(25) ##STR00319## ##STR00320##

(26) 10.0 g (7.4 mmol) EA.1, 3.6 g (8.2 mmol) Core 1, 0.74 ml (0.74 mmol) tri-tertbutylphosphine (1M in toluene), 2.14 g (22.3 mmol) sodium-tert-butylate and 83.5 mg (0.37 mmol)palladium(II)diacetate were added to 250 ml toluene and stirred at 100? C. After 16 h the reaction mixture was allowed to room temperature, diluted with toluene and H2O. The organic phase was collected, the aqueous phase extracted further with toluene. The combined organic phases were washed with brine, collected, dried with Na2SO4, filtered and concentrated. The resulting residue was dissolved in toluene and filtered through silica and concentrated. The precipitate was further purified by recrystallisation from toluene/heptane and tempering (250? C., <10.sup.?4 mbar).

(27) Yield: 4.4 g (2.6 mmol; 35%)

(28) The following compounds can be synthesized in analogous manner. For the synthesis of compounds D stoichiometry of the amine was doubled.

(29) TABLE-US-00008 Comp. SM1 Core Product A1.2 EA.2 1 A1.3 EA.3 1 A2.1 EA.4 2 A2.2 EA.1 2 A3.1 EA.1 4 A4.1 EA.1 3
Compound EA.7

(30) ##STR00327##

(31) Compound E can be done in analogous manner like compound C, using 1 eq. of EA.6 and one equivalent of CAS1134188-18-3

(32) Compounds A4.2, A2.3, A3.2

(33) ##STR00328##

(34) Compound A4.2 can be synthesized in analogous manner to compound A1.1. For the synthesis of compounds A2.3 and A3.2 stoichiometry of the amine was doubled.

(35) TABLE-US-00009 Compound SM1 SM2 A2.3 EA.7 Core 2 A3.2 EA.7 Core 3 0
B) Dibenzofurane Derivatives

(36) ##STR00331##
Synthesis Compound B:

(37) ##STR00332##

(38) In a 250-ml round-bottom flask reactor, 2-bromobiphenyl (8.4 g, 0.036 mol) and tetrahydrofuran (110 ml) are cooled down to ?78? C. At the same temperature, n-butyl lithium (19.3 ml, 0.031 mol) is dropwise added to the reaction solution and stirred for 2 hours. Thereafter, compound A (13.5 g, 0.026 mol) is added little by little to the reaction solution and stirred at room temperature. After full conversion of compound A the reaction is stopped with H2O (50 ml), extraction is conducted with ethyl acetate and water. The organic layer are separated, concentrated in a vacuum and recrystallized in acetonitrile to afford the intermediate as a solid. This is again dissolved in acetic acid (120 ml), and sulfuric acid (2 ml) and stirred for 5 hours under reflux. After full conversion of the intermediate the reaction mixture is then cooled to room temperature and filtered. Further purification is done by recrystalisation from toluene/heptane. (15.1 g, 0.023 88%)

(39) Following compounds can be obtained in analogous manner and similar yields:

(40) TABLE-US-00010 Compound Starting material A Starting material B Product B.1 B.2 B.3 0 B.4 B.5 B.6 0 B.7
Synthesis of Compound C.1

(41) ##STR00354##

(42) In a 250-ml round-bottom flask, a mixture of B.1 (6.2 g, 0.009 mol), bis(4-tert-butylphenyl)amine (6.0 g, 0.021 mol), palladium (II) acetate (0.08 g, 0.4 mmol), sodium tert-butoxide (3.4 g, 0.035 mol), tri-tertbutylphosphine (0.07 g, 0.4 mmol), and toluene (60 ml) is stirred for 2 hrs under reflux. After completion of the reaction, the reaction mixture is cooled to room temperature and then extracted with dichloromethane and water. The organic phase is separated, dried over magnesium sulfate, and concentrated in a vacuum. The concentrate is further purified by column chromatography and recrystallized in dichloromethane and acetone to yield the compound C1 as a solid (3.6 g, 37%).

(43) TABLE-US-00011 Starting material A Starting material B Product C.2 C.3 0 C.4 C.5 C.6 C.7 0
Synthesis of Compounds D

(44) The Synthesis of compound D.1 to D.7 is analog to the synthesis of EA.1. In case there is only one chloride attached to the starting material A only 1.1 equivalents of the boronate are used:

(45) TABLE-US-00012 Educt A B Product D.1 EG5 D.2 EG5 D.3 EG5 D.4 EG5 0 D.5 EG6 D.6 EG5 D.7 EG5
Synthesis of Compounds E and G:

(46) The Synthesis of compounds E and G is analog to the synthesis of C.1:

(47) TABLE-US-00013 Educt A Educt B Product G.1 EA.1 G.2 EA.5 0 G.3 EA.4 G.4 EA.1 G.5 EA.1 E.1 EA.3 E.2 EA.2 00 E.3 01 EA.1 02 E.4 03 EA.1 04
B) Fabrication of OLEDs

(48) The production of solution-based OLEDs has already been described many times in the literature, for example in WO2004/037887 and WO 2010/097155. The process is adapted to the circumstances described below (layer-thickness variation, materials).

(49) The inventive material combinations are used in the following layer sequence: substrate, ITO (50 nm), hole-injection layer HIL (20 nm), hole-transport layer (HTL) (20 nm), emission layer (EML) (30 nm), hole-blocking layer (HBL) (10 nm) electron-transport layer (ETL) (40 nm), cathode (Al) (100 nm).

(50) Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm serve as substrate. The hole-injection layer is applied via spin coating in an inert atmosphere. For this, a hole-transporting, crosslinkable polymer and a p-dopant salt are dissolved in toluene. Corresponding materials are for example described in WO 2016/107668, WO 2013/081052 and EP 2325190. The solids content of such solutions is about 6 mg/ml if, as here, the layer thicknesses of 20 nm is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, and dried by heating at 200? C. for 30 minutes on a heating plate. The hole-transport and the emission layer are applied to these coated glass plates.

(51) The hole-transport layer is the polymer of the structure shown in Table 3, which was synthesised in accordance with WO2013156130. The polymer is dissolved in toluene, so that the solution typically has a solid content of approx. 5 g/l if, as here, the layer thickness of 20 nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, in the present case argon, and dried by heating at 220? C. for 30 min.

(52) The emission layer is composed of the matrix material (host material) H1 and the emitting dopant (emitter) D1. Both material are present in the emission layer in a proportion of 92% by weight H1 and 8% by weight D1. The mixture for the emission layer is dissolved in toluene. The solids content of such solutions is about 9 mg/ml if, as here, the layer thickness of 30 nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, and dried by heating at 170? C. for 10 minutes.

(53) The materials used in the present case are shown in Table 3.

(54) TABLE-US-00014 TABLE 3 Structures of the materials used 05 HTL1 06 H1 07 V-D1 08 V-D2 09 V-D3 0 D1 D2 D3 D4 D5

(55) The materials for the hole-blocking layer and electron-transport layer are likewise applied by thermal vapour deposition in a vacuum chamber and are shown in Table 4. The hole-blocking layer consists of ETM1. The electron-transport layer consists of the two materials ETM1 and ETM2, which are mixed with one another in a proportion by volume of 50% each by co-evaporation.

(56) TABLE-US-00015 TABLE 4 HBL and ETL materials used ETM1 ETM2

(57) The cathode is formed by the thermal evaporation of an aluminium layer with a thickness of 100 nm.

(58) The OLEDs are characterised by standard methods. For this purpose, the electroluminescence spectra are recorded, the current efficiency (measured in cd/A) and the external quantum efficiency (EQE, measured in percent) as a function of the luminous density assuming Lambert emission characteristics are calculated from current/voltage/luminous density characteristic lines (IUL characteristic lines). The electroluminescence spectra are recorded at a luminous density of 1000 cd/m.sup.2, and the CIE 1931 x and y colour coordinates are calculated from this data. The term EQE @1000 cd/m.sup.2 denotes the external quantum efficiency at an operating luminous density of 1000 cd/m.sup.2.

(59) The properties of the various OLEDs are summarised in Table 5. Example V01 is the comparative example, whereas E1 to E4 show properties of OLEDs containing materials of the present invention.

(60) TABLE-US-00016 TABLE 5 Properties of the OLEDs EQE EML EML [%] at Example host dopant 1000 cd/m.sup.2 CIE x/y V01 H1 V-D1 2.9 0.14/0.12 V02 H1 V-D2 3.5 0.14/0.14 V03 H1 V-D3 3.3 0.15/0.17 E01 H1 D1 4.0 0.14/0.13 E02 H1 D2 4.2 0.14/0.14 E03 H1 D3 4.9 0.14/0.14 E04 H1 D4 4.7 0.14/0.11 E05 H1 D5 5.2 0.15/0.17

(61) Table 5 shows, that use of materials according to the present invention gives rise to improvements over the prior art when used as fluorescent blue emitters, in particular with respect to efficiency.