Materials for organic electroluminescent devices

Abstract

The present invention relates to compounds of formula (1). The compounds are suitable for use in electronic devices, in particular organic electroluminescent devices, comprising these compounds. In some embodiments, the compounds are used as matrix materials for phosphorescent or fluorescent emitters as well as a hole-blocking or electron-transport materials. ##STR00001##

Claims

1. A crosslinked compound obtained by crosslinking groups Q of a compound of the formula (2) or (3), ##STR00143## where Ar.sup.3, Ar.sup.4, Ar.sup.5 are selected on each occurrence, identically or differently, from the group consisting of an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R; Q is on each occurrence, identically or differently, a crosslinkable group bonded to the adjacent phenyl group via a single bond, or Q is a crosslinkable mono- or polycyclic group condensed on the adjacent phenyl group; R is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, N(Ar).sub.2, C(═O)Ar, P(═O)(Ar).sub.2, S(═O)Ar, S(═O).sub.2Ar, (R)C═C(R)Ar, CN, NO.sub.2, Si(R.sup.1)3, B(OR.sup.1).sub.2, B(R.sup.1).sub.2, B(N(R.sup.1).sub.2).sub.2, OSO.sub.2R.sup.1, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.1, where one or more, non-adjacent CH.sub.2 groups may be replaced by (R.sup.1)C═C(R.sup.1), C≡C, Si(R.sup.1).sub.2, Ge(R.sup.1).sub.2, Sn(R.sup.1).sub.2, C═O, C═S, C═Se, P(═O)(R.sup.1), SO, SO.sub.2, N(R.sup.1), O, S or CON(R.sup.1) and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, or 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 an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.1, where optionally two adjacent substituents R can form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; Ar is an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.1; R.sup.1 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, N(R.sup.2).sub.2, C(═O)R.sup.2, P(═O)(R.sup.2).sub.2, S(═O)R.sup.2, S(═O).sub.2R.sup.2, (R.sup.2)C═C(R.sup.2).sub.2, CN, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, B(R.sup.2).sub.2, B(N(R.sup.2).sub.2).sub.2, OSO.sub.2R.sup.2, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.2, where one or more, non-adjacent CH.sub.2 groups may be replaced by (R.sup.2)C═C(R.sup.2), C≡C, Si(R.sup.2).sub.2, Ge(R.sup.2).sub.2, Sn(R.sup.2).sub.2, C═O, C═S, C═Se, P(═O)(R.sup.2), SO, SO.sub.2, N(R.sup.2), O, S or CON(R.sup.2) and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, or 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.2, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.2, where optionally two adjacent substituents R.sup.1 can form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; R.sup.2 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, CN, NO.sub.2, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 20 C atoms or a straightchain alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms; where optionally two adjacent substituents R.sup.2 can form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; m is on each occurrence, identically or differently, 1 or 2; n is on each occurrence, identically or differently, 0 or 1; with the proviso that m+n=2 in the amino moiety comprising a group Ar.sup.3 and an aromatic or heteroaromatic ring system containing Y, and m+n=2 in the amino moiety comprising a group Ar.sup.5 and an aromatic or heteroaromatic ring system containing Y; p is 1; s is on each occurrence, identically or differently, 0, 1, 2, 3 or 4; and t is on each occurrence, identically or differently, 0, 1, 2 or 3.

2. The compound according to claim 1, with the proviso that s≤3 and t≤2 when the corresponding phenyl ring is substituted by a group Q which corresponds to a mono- or polycyclic group condensed on this phenyl ring.

3. The compound according to claim 1, characterized in that Q is on each occurrence, identically or differently, a crosslinkable group selected from terminal or cyclic alkenyl groups, terminal dienyl groups, terminal alkynyl groups, alkenyloxy groups, dienyloxy groups, alkynyloxy groups, acrylic acid derivatives, oxetane groups, oxirane groups, silanes groups and cyclobutane groups.

4. The compound according to claim 1, characterized in that Q is selected from groups of the following formulae Q1 to Q24, ##STR00144## ##STR00145## ##STR00146## where the dashed bond in the formulae Q1 to Q11, Q13 to Q24 and the dashed bonds in the formula Q12 represent the linking of the crosslinkable group to; the adjacent phenyl group of the formula (2) or (3); and where R.sup.11, R.sup.12 and R.sup.13 are on each occurrence, identically or differently, H, a straight-chain or branched alkyl group having 1 to 6 C atoms; Ar.sup.10 is on each occurrence, in each case identically or differently, a mono- or polycyclic, aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R, where R is as defined in claim 1; u is an integer from 0 to 8; and v is an integer from 1 to 8.

5. The compound according to claim 1, where Ar.sup.3, Ar.sup.4 and Ar.sup.5 are selected on each occurrence, identically or differently, from the group consisting of an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may be substituted by one or more radicals R.

6. The compound according to claim 1, where Ar.sup.3, Ar.sup.4 and Ar.sup.5 are selected on each occurrence, identically or differently, from the group consisting of benzene, naphthalene, anthracene, biphenyl, terphenyl, quaterphenyl, fluorene, dibenzofuran, dibenzothiophene, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, pyrazine, azacarbazole, benzocarboline, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, each of which may be substituted by one or more radicals R.

7. The compound according to claim 1, where m is equal to 1 and n is equal to 1.

8. The compound according to claim 1, where m is equal to 1.

9. A formulation comprising at least one compound according to claim 1 and at least one solvent.

10. An 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.

11. An organic electroluminescent device comprising a compound according to claim 1 wherein the compound is used in a hole-transport layer or in a hole-injection layer, where this layer may also be doped.

12. The compound according to claim 1, where Ar.sup.3 and Ar.sup.5 are selected on each occurrence, identically or differently, from the groups of the following formulae (A-1) to (A-51), ##STR00147## ##STR00148## ##STR00149## ##STR00150## ##STR00151## ##STR00152## ##STR00153## ##STR00154## ##STR00155## where the dashed bond indicates the bond to the nitrogen atom, where the groups of formulae (A-1) to (A-51) may further be substituted at each free position by a group R as defined in claim 1, and where R.sup.0, in formulae (A-18), (A-34) to (A-37), (A-44), (A-45) and (A-47), is selected on each occurrence, identically or differently, from the group consisting of H, D, F, CN, Si(R.sup.3).sub.3, a straight-chain alkyl group having 1 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R.sup.1, an aromatic or heteroaromatic ring system having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.1, where two adjacent substituents R.sup.0 may optionally form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R.sup.1.

13. The compound according to claim 12, where Ar.sup.4 is on each occurrence, identically or differently, selected from the groups of the following formulae (B-1) to (B-24), ##STR00156## ##STR00157## ##STR00158## ##STR00159## where the dashed bonds in (B-1) to (B-24) indicate the bonds to the nitrogen atoms of the arylamino groups depicted in formula (2) or (3); where the groups of formulae (B-1) to (B-24) may further be substituted at each free position by a group R, wherein R is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, N(Ar).sub.2, C(═O)Ar, P(═O)(Ar).sub.2, S(═O)Ar, S(═O).sub.2Ar, (R)C═C(R)Ar, CN, NO.sub.2, Si(R.sup.1).sub.3, B(OR.sup.1).sub.2, B(R.sup.1).sub.2, B(N(R.sup.1).sub.2).sub.2, OSO.sub.2R.sup.1, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.1, where one or more, non-adjacent CH.sub.2 groups may be replaced by (R.sup.1)C═C(R.sup.1), C≡C, Si(R.sup.1).sub.2, Ge(R.sup.1).sub.2, Sn(R.sup.1).sub.2, C═O, C═S, C═Se, P(═O)(R.sup.1), SO, SO.sub.2, N(R.sup.1), O, S or CON(R.sup.1) and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, or 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 an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.1, where optionally two adjacent substituents R can form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; Ar is an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.1; R.sup.1 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, N(R.sup.2).sub.2, C(═O)R.sup.2, P(═O)(R.sup.2).sub.2, S(═O)R.sup.2, S(═O).sub.2R.sup.2, (R.sup.2)C═C(R.sup.2).sub.2, CN, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, B(R.sup.2).sub.2, B(N(R.sup.2).sub.2).sub.2, OSO.sub.2R.sup.2, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R.sup.2, where one or more, non-adjacent CH.sub.2 groups may be replaced by (R.sup.2)C═C(R.sup.2), C≡C, Si(R.sup.2).sub.2, Ge(R.sup.2).sub.2, Sn(R.sup.2).sub.2, C═O, C═S, C═Se, P(═O)(R.sup.2), SO, SO.sub.2, N(R.sup.2), O, S or CON(R.sup.2) and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, or 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.2, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R.sup.2, where optionally two adjacent substituents R.sup.1 can form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; R.sup.2 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, CN, NO.sub.2, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 20 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms; where optionally two adjacent substituents R.sup.2 can form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; and where R.sup.0 has the same meaning as in claim 12.

Description

SYNTHESIS EXAMPLES

Synthesis Example 1

(1) ##STR00115## ##STR00116##

(2) 123.4 g (388 mmol) 2,2′-Dibromo-biphenyl were dissolved in 450 ml dry THF and cooled to −78° C. 135 ml (323 mmol, 2.5 M in Hexane) n-BuLi was added slowly and the mixture was stirred for 45 min. 4,4′-Dicyanobenzophenone (CAS: 32446-66-5) was dissolved in 400 ml dry THF and cooled to −78° C. The mixture of n-Buli and 2,2′-Dibromo-biphenyl was then transferred to the 4,4′-Dicyanobenzophenone solution. The reaction was warmed to room temperature over night and after that quenched with water. THF was evaporated in vacuo and the residue was extracted with ethyl acetate and water. The organic phase was dried, filtered and the solvent was removed in vacuo which resulted in 170 g of crude solid. The crude solid was refluxed over night with 2700 ml acetic acid and 200 ml (37%) hydrochloric acid. After cooling to RT the reaction mixture was poured in water and the resulting solid was filtered off, dissolved in dichloromethane, the solution was washed with water and NaHCO3, the organic phase was dried and the solvent removed in vacuo. The resulting solid was recrystallized in ethyl acetate and finally purified via flash chromatography. The resulting white solid I1 was obtained with a yield of 61% (88 g, 197 mmol).

(3) I8 was made analogous to I1 with a yield of 73% (CAS: 85313-23-1):

(4) ##STR00117##

(5) 25 g (56 mmol) I1 and 19.8 g (62 mmol, 1.1 eq) Bis-biphenyl-4-y-amine were added to 450 ml Toluene. Subsequently 10.2 g (11.2 mmol, 0.2 eq) Pd.sub.2dba.sub.3 and 10.7 g (112 mmol, 2 eq) Sodium-t-butylate were added and the mixture was degassed with argon. After 5 min degassing 25 g (11.2 mmol, 0.2 eq) tri-t-butylphosphine was added and the reaction was stirred at reflux over the weekend. After cooling to RT the mixture was filtered over Celite and subsequently purified via Soxhlet using Toluene as the solvent. The resulting solid was purified via flash chromatography. 14.6 g (21 mmol, 38%) of I2 was obtained.

(6) 22 g (31.3 mmol) I2 was dissolved in 170 ml Toluene and cooled to −78° C. At −78° C. DIBAL-H (250 ml, 1M in Hexane) was added slowly. The mixture was stirred for 30 min at −78° C. and the warmed to RT over night. The reaction was then quenched with MeOH and H.sub.2SO.sub.4. The mixture was extracted with ethyl acetate and washed with water. The resulting solid was purified with flash chromatography. 3.5 g (5 mmol, 16%) of intermediate I3 were obtained.

(7) 3.2 g (4.6 mmol) I3 was dissolved in 125 ml of dry THF. 18.1 g (50.6 mmol) of Methyltriphenylphosphoniumbromied was dissolved in 225 ml dry THF and cooled to −3° C. Then 5.6 g (59 mmol) Sodium-t-butylate was added at −3° C., the suspension was stirred for 60 min at −3° C. Then the solution of I3 in THF was added dropwise, the reaction mixture was stirred for 2 h at 0° C. and the warmed to RT over night. The solution was diluted with Toluene and quenched with water. The organic phase was separated and the aqueous phase was extracted with Toluene. The organic phases were dried and the solvent was evaporated in vacuo. The resulting solid was recrystallized from Toluene/MeOH. 1.9 g (2.7 mmol, 60%) of P1 was obtained as a white solid.

(8) TABLE-US-00003 Starting Amine Material Product Yield P2 I1 11% P3 0 I1 18% P4 I1 27% P9 I8  8%

Synthesis Example 2

(9) ##STR00126## ##STR00127##

(10) 18 g (77 mmol) 2-(4-Bromophenyl)-1,3-dioxolane was dissolved in 150 ml dry THF and cooled to −78° C. 31 ml (77 mmol, 2.5 M solution) of n-Buli was added dropwise and the solution was stirred for one hour at −78° C. 3′-Bromo-biphenyl-2-carboxylic acid (30.8 mmol, 9 g) was dissolved in 25 ml THF and added to the n-BuLi solution at −78° C. The reaction mixture was stirred for 1 h at −78° C. and then warmed to RT over the weekend. Ammoniumchloride solution was added to quench the reaction and the mixture was extracted with ethyl acetate. The combined organic phases were dried and the solvent was evaporated in vacuo. The resulting crude product was dissolved in 60 ml dry Toluene and 60 ml Hydrochloric acid (37%) as well as 115 ml acetic acid was added. The reaction was stirred at 80° C. over night. After cooling down to RT the water was added, the aqueous phase was extracted with toluene and the combined organic phases were washed with water and dried with Na.sub.2SO.sub.4. The solvent was removed in vacuo. The resulting solid was recrystallized in Heptane/Toluene. I4 was obtained as a white product with 76% yield (22.8 mmol, 10.3 g).

(11) To obtain I5 and P5 the subsequent steps were performed analogous to Intermediates I2 and product P1.

(12) TABLE-US-00004 Name Amine Starting Material Product Yield P6 I4  5% P7 0 16%

Synthesis Example 3

(13) ##STR00133##

(14) 20 g (109 mmol) 2-(4-Bromophenyl)-cyclobutyl was dissolved in 150 ml dry THF and cooled to −78° C. 44 ml (109 mmol, 2.5 M solution) of n-Buli was added dropwise and the solution was stirred for one hour at −78° C. 2′-Bromo-biphenyl-2-carboxylic acid (43.6 mmol, 12.7 g) was dissolved in 25 ml THF and added to the n-BuLi solution at −78° C. The reaction mixture was stirred for 1 h at −78° C. and then warmed to RT over the weekend. Ammoniumchloride solution was added to quench the reaction and the mixture was extracted with ethyl acetate. The combined organic phases were dried and the solvent was evaporated in vacuo. The resulting crude product was dissolved in 60 ml dry Toluene and 60 ml Hydrochloric acid (37%) as well as 115 ml acetic acid was added. The reaction was stirred at 80° C. over night. After cooling down to RT the water was added, the aqueous phase was extracted with toluene and the combined organic phases were washed with water and dried with Na.sub.2SO.sub.4. The solvent was removed in vacuo. The resulting solid was recrystallized in Heptane/Toluene. I6 was obtained as a white product with 85% yield (37.1 mmol, 16.6 g).

(15) I6 (15 g, 33.4 mmol), o-biphenylamine (6.2 g, 36.7 mmol) and Sodium-t-butylate (10.6 g, 110 mmol) were dissolved in 200 ml toluene. The mixture was degassed for 15 minutes and subsequently Pd(dppf)Cl2 (1.8 g, 2.2 mmol) was added. The solution was heated at reflux for 4 hours and then cooled to RT. The mixture was filtered over Alox using toluene as the solvent. The resulting solid was recrystallized from toluene/heptanes. I7 was obtained as a white solid with a yield of 63% (11.3 g, 21 mmol).

(16) 4.7 g (8.5 mmol) 2,7-dibromo-9,9-dioctyl-fluorene and 10 g (18.6 mmol, 2.2 eq) I7 were added to 100 ml Toluene. Subsequently 1.5 g (1.7 mmol, 0.2 eq) Pd.sub.2dba.sub.3 and 1.6 g (17 mmol, 2 eq) Sodium-t-butylate were added and the mixture was degassed with argon. After 5 min degassing 3.8 g (1.7 mmol, 0.2 eq) tri-t-butylphosphine was added and the reaction was stirred at reflux over the weekend. After cooling to RT the mixture was filtered over Celite and subsequently purified via Soxhlet using Toluene as the solvent. The resulting solid was purified via flash chromatography. 9.7 g (6.6 mmol, 78%) of P8 was obtained.

(17) TABLE-US-00005 Amine Starting Material Product Yield P10 32% *The Wittig Reaction was performed analogous to the synthesis of P1.

Comparative Example V1: Synthesis is Described in WO2013007348

(18) ##STR00137##

Device Examples

(19) The cross-linkable small molecules according to the invention can be processed from solution and result in OLEDs which are significantly easier to produce than vacuum-processed OLEDs, but nevertheless have good properties.

(20) Whether the cross-linkable small molecules according to the invention give a completely insoluble layer after cross-linking is tested analogously to WO 2010/097155.

(21) Table C1 shows the remaining layer thickness of the originally 20 nm after the washing operation described in WO 2010/097155. If the layer thickness does not reduce, the formed film is insoluble and the cross-linking is thus adequate.

(22) TABLE-US-00006 TABLE C1 Check of the residual layer thickness from originally 20 nm after washing test Residual layer thickness after washing test [in nm] Polymer Crosslinking at 220° C. V1 19.2 P1 18.9 P10 20

(23) As can be seen in Table C1, all three molecules V1, P1 and P10 show acceptable cross-linking at 220° C. Due to its 4 cross-linking groups, the layer out of cross-linked P10 is completely insoluble.

(24) The production of solution-based OLEDs of this type has already been described many times in the literature, for example in WO 2004/037887 and WO 2010/097155. The process is adapted to the circumstances described below (layer-thickness variation, materials).

(25) The molecules according to the invention are used in the following layer sequence: substrate, ITO (50 nm), PEDOT (80 nm), hole-transport layer (HTL) (20 nm), emission layer (EML) (60 nm), hole-blocking layer (HBL) (10 nm) electron-transport layer (ETL) (40 nm), cathode.

(26) Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm serve as substrate. These are coated with PEDOT:PSS for better processing. The spin coating is carried out from water in air. The layer is dried by heating at 180° C. for 10 minutes. PEDOT:PSS is purchased from Heraeus Precious Metals GmbH & Co. KG, Germany. The hole-transport and emission layers are applied to these coated glass plates.

(27) The compounds according to the invention and comparative compounds, in each case dissolved in toluene, are used as hole-transport layer. The typical solids content of such solutions is about 7 g/l if the layer thickness of 20 nm 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 60 minutes.

(28) The emission layer is always composed of at least one matrix material (host material) and an emitting dopant (emitter). Furthermore, mixtures of a plurality of matrix materials and co-dopants may occur. An expression such as H1 (92%):dopant (8%) here means that material H1 is present in the emission layer in a proportion by weight of 92% and the dopant is present in the emission layer in a proportion by weight of 8%. The mixture for the emission layer is dissolved in toluene. The typical solids content of such solutions is about 18 g/l if, as here, the layer thickness of 60 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 160° C. for 10 minutes.

(29) The materials used in the present case are shown in Table C2.

(30) TABLE-US-00007 TABLE C2 Structural formulae of the materials used in the emission layer H1 H2 0 TEG

(31) The materials for the hole-blocking layer and electron-transport layer are applied by thermal vapour deposition in a vacuum chamber and are shown in Table C3. 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 coevaporation.

(32) TABLE-US-00008 TABLE C3 HBL and ETL materials used ETM1 ETM2

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

(34) The precise structure of the OLEDs is shown in Table C4. Column HTL shows the molecule used and the temperature at which the layer is dried by heating and crosslinked.

(35) TABLE-US-00009 TABLE C4 Structure of the OLEDs HTL EML Example Molecule T [° C.] Composition C01 V1 220° C. H1 30%; H2 55%; TEG 15% C02 P1 220° C. H1 30%; H2 55%; TEG 15% C03 P10 220° C. H1 30%; H2 55%; TEG 15%

(36) The OLEDs are characterised by standard methods. For this purpose, the electroluminescence spectra, current/voltage/luminous density characteristic lines (IUL characteristic lines) assuming Lambert emission characteristics and the (operating) lifetime are determined. The IUL characteristic lines are used to determine characteristic numbers such as the operating voltage (in V) and the external quantum efficiency (in %) at a certain luminance. LT80 @ 10000 cd/m.sup.2 is the lifetime by which the OLED has dropped from an initial luminance of 10000 cd/m.sup.2 to 80% of the initial intensity, i.e. to 8000 cd/m.sup.2.

(37) The properties of the various OLEDs are summarised in Table C5. Example C01 is a comparative examples, both other examples show properties of OLEDs according to the invention.

(38) TABLE-US-00010 TABLE C5 Properties of the OLEDs Efficiency at Voltage at LT80 at 1000 cd/m.sup.2 1000 cd/m.sup.2 10000 cd/m.sup.2 Example % EQE [V] [h] C01 17.0 4.8 110 C02 16.6 5.1 140 C03 17.0 4.9 190

(39) As Table C5 shows, the polymers according to the invention give rise to improvements over the prior art, in particular with respect to lifetime, on use as hole-transport layer in OLEDs. Green emitting OLEDs comprising the materials according to the invention are produced.

(40) Example C03 shows better lifetime than example C01: although the molecule P10 has four cross-linking groups, the lifetime is better than in example C01, where molecule V1 has only two cross-linking groups. Molecule P10 is according to the invention and improves lifetime significantly.