Materials for electronic devices

Abstract

The present invention relates to compounds of the formula (I), to the use of compounds of the formula (I) in electronic devices, and to electronic devices comprising one or more compounds of the formula (I). The invention furthermore relates to the preparation of the compounds of the formula (I) and to formulations comprising one or more compounds of the formula (I).

Claims

1. A compound of formula (I) ##STR00261## wherein: Ar.sup.1 is ##STR00262## which is substituted by at least one radical R.sup.A at a position ortho to the nitrogen, and which Ar.sup.1-1 is optionally further substituted by one or more radicals R.sup.A or R.sup.1, and  X is, identically or differently on each occurrence, CR.sup.A or CR.sup.1, wherein at least one group X per formula must be CR.sup.A, wherein the dashed line on the left denotes the bond from the group Ar.sup.1 to the carbazole group and the dashed line on the right denotes the bond from the group Ar.sup.1 to the nitrogen atom; Ar.sup.2 is an aromatic in system having 6 to 12 aromatic ring atoms, optionally substituted by one or more radicals R.sup.1; R.sup.A is, identically or differently on each occurrence, a straight-chain alkyl group having 1 to 8 C atoms, or a branched alkyl group having 3 to 8 C atoms, each of which is optionally substituted by one or more radicals R.sup.3; R.sup.1 is, identically or differently on each occurrence, H, D, 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 is optionally substituted by one or more radicals R.sup.3, or an aromatic or heteroaromatic ring system having 5 to 20 aromatic ring atoms, optionally substituted by one or more radicals R.sup.3; R.sup.3 is, identically or differently on each occurrence, H, D, F or an aliphatic, aromatic and/or heteroaromatic organic radical haying 1 to 20 C atoms, in which, in addition, one or more H atoms are optionally replaced by D or F; two or more substituents R.sup.3 optionally define an aliphatic or aromatic ring; and where a group R.sup.1 is optionally bonded to any of the free positions of the aromatic rings in formula (I).

2. The compound of claim 1, wherein the radical R.sup.A is bonded to the group Ar.sup.1 in both positions ortho to the nitrogen.

3. The compound of claim 1, wherein the group Ar.sup.1 is one of the following formulae Ar.sup.1-21 or Ar.sup.1-22 ##STR00263##

4. The compound of claim 1, wherein the compound conforms to the following formula (I-1) or formula (I-2) ##STR00264## wherein a group R.sup.1 is optionally bonded to any of the free positions of the aromatic rings in formula (I-1) or formula (I-2), and X.sup.1 to X.sup.4 are selected from CR.sup.A and CH, wherein at least one of the groups X.sup.2 or X.sup.3 in formula (I-1) is CR.sup.A, or at least one of the groups X.sup.1 or X.sup.2 in formula (I-2) is CR.sup.A.

5. A process for the preparation of the compound of claim 1, said process comprising reacting the group Ar.sup.1 with a carbazole derivative and with a fluorene derivative by one or more organometallic coupling reactions.

6. An oligomer, polymer, or dendrimer, comprising one or more compounds of formula (1) ##STR00265## wherein: Ar.sup.1 is an aromatic ring system having 6 to 30 aromatic ring atoms or a heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is substituted by at least one radical R.sup.A and which is optionally further substituted by one or more radicals R.sup.1; Ar.sup.2 is an aromatic ring system having 6 to 30 aromatic ring atoms or a heteroaromatic ring system having 5 to 30 aromatic ring atoms, optionally substituted by one or more radicals R.sup.1; R.sup.A is, identically or differently on each occurrence, F, Cl, CN, Si(R.sup.3).sub.3, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, all of which are optionally substituted by one or more radicals R.sup.3 and where one or more adjacent or non-adjacent CH.sub.2 groups in the above-mentioned groups are optionally replaced by —R.sup.3C═CR.sup.3—, —C≡C—, —Si(R.sup.3).sub.2—, C═O, C═NR.sup.3, —COO—, —CONR.sup.3—, —NR.sup.3—, P(═O)(R.sup.3), —O—, —S—, SO or SO.sub.2 and where one or more H atoms in the above-mentioned groups are optionally replaced by D, F, Cl, Br, I, CN or NO.sub.2; R.sup.1 is, identically or differently on each occurrence, H, F, Cl, Br, I, B(OR.sup.3).sub.2, CHO, C(O)R.sup.3, CR.sup.3═C(R.sup.3).sub.2, CN, COOR.sup.3, CON(R.sup.3).sub.2, Si(R.sup.3).sub.3, N(R.sup.3).sub.2, NO.sub.2, P(═O)(R.sup.3).sub.2, OSO.sub.2R.sup.3, OH, S(═O)R.sup.3, S(═O).sub.2R.sup.3, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, all of which are optionally substituted by one or more radicals R.sup.3 and wherein one or more adjacent or non-adjacent CH.sub.2 groups in the above-mentioned groups are optionally replaced by —R.sup.3C═CR.sup.3—, —C≡C—, —Si(R.sup.3).sub.2, Ge(R.sup.3).sub.2, Sn(R.sup.3).sub.2, C═O, C═S, C═Se, C═NR.sup.3, —COO—, —CONR.sup.3—, NR.sup.3, P(═O)(R.sup.3), —O—, —S—, SO or SO.sub.2 and where one or more H atoms in the above-mentioned groups are optionally 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, optionally substituted by one or more radicals R.sup.3, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, optionally substituted by one or more radicals R.sup.3, or a combination of these systems, wherein two or more radicals R.sup.1 optionally define an aliphatic or aromatic ring; R.sup.3 is, identically or differently on each occurrence, H, D, F or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 C atoms, in which, in addition, one or more H atoms are optionally replaced by D or F; two or more substituents R.sup.3 optionally define an aliphatic or aromatic ring; and where a group R.sup.1 is optionally bonded to any of the free positions of the aromatic rings in formula (I), wherein the bond(s) to said oligomer, polymer, or dendrimer, is optionally localised at any desired positions substituted by R.sup.1 in said formula (I).

7. A formulation comprising at least one compound of claim 1 and at least one solvent.

8. A formulation comprising at least one oligomer, polymer, or dendrimer, of claim 6 and at least one solvent.

9. The compound of claim 1, wherein the compound is present in an electronic device.

10. The compound of claim 1, wherein the compound is present in an organic electroluminescent device (OLED).

11. The oligomer, polymer, or dendritner, of claim 6, wherein said oligomer, polymer, or dendrimer, is present in an electronic device.

12. The oligomer, polymer, or dendrimer, of claim 6, wherein said oligomer, polymer, or dendrimer, is present in an organic electroluminescent device (OLED).

13. An electronic device comprising at least one compound of claim 1, wherein the electronic device is selected from an organic integrated circuit (O-IC), organic field-effect transistor (O-FET), organic thin-film transistor (O-TFT), organic light-emitting transistor (O-LET), organic solar cell (O-SC), organic optical detector, organic photoreceptor, organic field-quench device (O-FQD), light-emitting electrochemical cell (LEC), organic laser diode (O-laser) and organic electroluminescent device (OLED).

14. An electronic device comprising at least one oligomer, polymer, or dendrimer, of claim 6, wherein the electronic device is selected from an organic integrated circuit (O-IC), organic field-effect transistor (O-FET), organic thin-film transistor (O-TFT), organic light-emitting transistor (O-LET), organic solar cell (O-SC), organic optical detector, organic photoreceptor, organic field-quench device (O-FQD), light-emitting electrochemical cell (LEC), organic laser diode (O-laser) and organic electroluminescent device (OLED).

15. The electronic device of claim 13, wherein the electronic device is an organic electroluminescent device, and wherein said at least one compound is employed as hole-transport material in a hole-transport layer or hole-injection layer and/or is employed as matrix material in an emitting layer.

16. The electronic device of claim 14, wherein the electronic device is an organic electroluminescent device, and wherein said at least one oligomer, polymer, or dendrimer, is employed as hole-transport material in a hole-transport layer or hole-injection layer and/or is employed as matrix material in an emitting layer.

17. A compound of formula (I) ##STR00266## wherein: Ar.sup.1 is one of formula Ar.sup.1-21 or formula Ar.sup.1-22 ##STR00267## which is substituted by at least one radical R.sup.A at a position ortho to the nitrogen, and which Ar.sup.1-21 or Ar.sup.1-22 is optionally further substituted by one or more radicals R.sup.A or R.sup.1, and  X is, identically or differently on each occurrence, CR.sup.A or CR.sup.1, wherein at least one group X per formula must be CR.sup.A, wherein the dashed line on the left denotes the bond from the group Ar.sup.1 to the carbazole group and the dashed line on the right denotes the bond from the group Ar.sup.1 to the nitrogen atom, Ar.sup.2 is an aromatic ring system having 6 to 12 aromatic ring atoms, optionally substituted by one or more radicals R.sup.1; R.sup.A is, identically or differently on each occurrence, a straight-chain alkyl group having 1 to 8 C atoms, which is optionally substituted by one or more radicals R.sup.3, or a branched alkyl having 3 to 8 C atoms, which is optionally substituted by one or more radicals R.sup.3; R.sup.1 is, identically or differently on each occurrence, H, D, 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 is optionally substituted by one or more radicals R.sup.3, or an aromatic or heteroaromatic ring system having 5 to 20 aromatic ring atoms, optionally substituted by one or more radicals R.sup.3; R.sup.3 is, identically or differently on each occurrence, H, D, F or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 C atoms, in which, in addition, one or more H atoms are optionally replaced by D or F; two or more substituents R.sup.3 optionally define an aliphatic or aromatic ring; and where a group R.sup.1 is optionally bonded to any of the free positions of the aromatic rings in formula (I).

18. An electronic device comprising at least one compound of claim 17, wherein the electronic device is selected from an organic integrated circuit (O-IC), organic field-effect transistor (O-FET), organic thin-film transistor (O-TFT), organic light-emitting transistor (O-LET), organic solar cell (O-SC), organic optical detector, organic photoreceptor, organic field-quench device (O-FQD), light-emitting electrochemical cell (LEC), organic laser diode (O-laser) and organic electroluminescent device (OLED).

19. The compound of claim 17, wherein R.sup.1 is selected from the group consisting of benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, fluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiopliene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxa-zole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1,5diazaanthracene, 2,7-diazapyrene, pyrene, 2,5-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperyiene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubin, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,5-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5tetrazine, purine, pteridine, indolizine and benzothiadiazoie, wherein R.sup.1 is optionally substituted by one or more radicals R3, and Ar.sup.2 is selected from the group consisting of benzene, naphthalene, biphenyl, biphenylene terphenyl, and terphenylene.

20. A compound of formula ##STR00268##

21. A compound of formula ##STR00269##

22. A compound of formula ##STR00270##

23. A compound of formula ##STR00271##

24. A compound of formula ##STR00272##

Description

USE EXAMPLES

(1) The following syntheses were carried out under a protective-gas atmosphere, unless indicated otherwise. The starting materials were purchased from ALDRICH or ABCR.

A) Synthesis Example 1

Synthesis of biphenyl-4-yl-(9,9-dimethyl-9H-fluoren-2-yl)-[2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine

(2) ##STR00251##

a) 2-Methyl-4-(9-phenyl-9H-carbazol-3-yl)phenylamine

(3) Firstly degassed 9-phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole (77.0 g, 209 mmol), then degassed 4-bromo-2-methyl-phenylamine (42.7 g, 229 mmol) and subsequently tetrakistriphenyl-phosphinepalladium (12.0 g, 10 mmol) are added to a mixture of toluene (1.5 l), dioxane (600 ml) and 2 M potassium carbonate solution (1.04 l). The reaction mixture is stirred at 90° C. for 20 h, cooled to room temperature for work-up and diluted with toluene and water. The organic phase is separated off, washed with water, dried and evaporated. After filtration of the residue through silica gel (heptane/toluene/dichloromethane), 2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenylamine is isolated in the form of a yellow oil (28.0 g, 39% of theory).

b) (9,9-Dimethyl-9H-fluoren-2-yl)-[2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine

(4) 1,1′-Bis(diphenylphosphino)ferrocene (408 mg, 0.7 mmol), palladium acetate (165 mg, 0.7 mmol) and sodium tert-butoxide (6.1 g, 64 mmol) are added to a solution of 2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenylamine (24.6 g, 49 mmol) and 2-bromo-9,9-dimethyl-9H-fluorene (13.4 g, 49 mmol) in degassed toluene (100 ml), and the mixture is heated under reflux for 2 h. The reaction mixture is cooled to room temperature, diluted with toluene and filtered firstly through Celite and subsequently through silica gel. A further filtration column (ethyl acetate/heptane) gives a pale-yellow solid, which is extracted with heptane in a Soxhlet extractor and recrystallised a number of times from heptane, giving (9,9-dimethyl-9H-fluoren-2-yl)-[2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine in the form of a pale-yellow solid (12.4 g, 47% of theory).

c) Biphenyl-4-yl-(9,9-dimethyl-9H-fluoren-2-yl)-[2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine

(5) 1,1′-Bis(diphenylphosphino)ferrocene (191 mg, 0.3 mmol), palladium acetate (77 mg, 0.3 mmol) and sodium tert-butoxide (2.9 g, 30 mmol) are added to a solution of (9,9-dimethyl-9H-fluoren-2-yl)-[2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine (12.4 g, 23 mmol) and 4-bromobiphenyl (5.4 g, 23 mmol) in degassed toluene (50 ml), and the mixture is heated under reflux for 20 h. The reaction mixture is cooled to room temperature, diluted with toluene and filtered firstly through Celite and subsequently through aluminium oxide. The crude product is subsequently recrystallised a number of times from heptane and purified by sublimation twice in vacuo (p=3×10.sup.−4 mbar, T=301° C.). The product biphenyl-4-yl-(9,9-dmethyl-9H-fluoren-2-yl)-[2-methyl-4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine is isolated in the form of a pale-yellow solid (3.3 g, 21% of theory, purity >99.9% according to HPLC).

B) Device Examples

Use of the Material According to the Invention HTM1 as a Hole Transporting Material in an OLED

(6) OLEDs are produced by a general process in accordance with WO 2004/058911, which is adapted to the circumstances described here (layer-thickness variation, materials used).

(7) The following examples V1, V2 and E1 (Tables 1 and 2) give both comparative OLED data and data obtained with the material according to the invention HTM1.

(8) Glass plates coated with structured ITO (indium tin oxide) in a thickness of 150 nm are coated with 20 nm of PEDOT (spin-coated from water; purchased from H. C. Starck, Goslar, Germany; poly(3,4-ethylenedioxy-2,5-thiophene)) for improved processing. These coated glass plates are the substrates to which the OLEDs are applied. The layer sequence of the OLEDs is substrate/hole-injection layer (HIL)/hole-transport layer (HTL)/optional interlayer (IL)/electron blocking layer (EBL)/emission layer (EML)/electron-transport layer (ETM)/optional electron injection layer (EIL)/cathode. The cathode is formed by a 100 nm thick aluminium layer.

(9) The detailed structure of the OLEDs is shown in Table 1. The compounds used for the OLED are shown in Table 3.

(10) All materials are applied by thermal vapor deposition in a vacuum chamber. The emitting layer comprises at least one host material (matrix) and at least one dopant material (emitter material) which is added by co-evaporation. An entry H1:SEB1 (95%/5%) in this case means that a mixture of materials H1 in 95 volume percent and SEB1 in 5 volume percent is present in the layer. Besides the emitting layer, also other layers, e.g. the electron transport layer, may comprise a mixture of two or more materials.

(11) The OLEDs are characterised by standard methods. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd/A), the power efficiency (measured in lm/W) and the external quantum efficiency (EQE, measured in percent) as a function of the luminance, calculated from current/voltage/luminance characteristic lines (IUL characteristic lines), and the lifetime are determined. The spectra are measured at a luminance density of 1000 cd/m.sup.2. From this, the color coordinates (CIE 1931 x,y) are calculated. U @ 1000 cd/m.sup.2 in Table 2 means the voltage necessary for a luminance density of 1000 cd/m.sup.2. Eff @ 1000 cd/m.sup.2 means the external current efficiency at a luminance density of 1000 cd/m.sup.2. LT65 @ 6000 cd/m.sup.2 is the lifetime at 6000 cd/m.sup.2 until the luminance density has dropped to 65% of its initial value, e.g. to 3900 cd/m.sup.2. The data obtained for the different OLEDs is shown in Table 2.

(12) The materials according to the invention are particularly suitable for use in a HTL or an EBL, either als a single compound or in mixture with one or more other compounds.

(13) E1 shows data obtained with the material according to the invention HTM1 used as a hole transport material. In the comparative examples V1 and V2, the compounds known in the state of the art NPB (V1) and HTMV1 (V2) are used.

(14) The comparison shows that the inventive compound leads to a higher efficiency and lifetime of the OLED than the NPB.

(15) Compared with HTMV1, the lifetime improves whereas the efficiency remains nearly constant.

(16) TABLE-US-00006 TABLE 1 OLED structures IL HTL IL EBL EML ETL EIL Thickness/ Thickness/ Thickness/ Thickness/ Thickness/ Thickness/ Thickness/ Bsp. nm nm nm nm nm nm nm V1 HIL1 HIL2 HIL1 NPB H1(95%):SEB1(5%) ETM1(50%):LiQ(50%) LiQ 5 nm 140 nm 5 nm 20 nm 20 nm 30 nm 1 nm V2 HIL1 HIL2 HIL1 HTMV1 H1(95%):SEB1(5%) ETM1(50%):LiQ(50%) LiQ 5 nm 140 nm 5 nm 20 nm 20 nm 30 nm 1 nm E1 HIL1 HIL2 HIL1 HTM1 H1(95%):SEB1(5%) ETM1(50%):LiQ(50%) LiQ 5 nm 140 nm 5 nm 20 nm 20 nm 30 nm 1 nm

(17) TABLE-US-00007 TABLE 2 OLED data U @ Eff @ LT65 @ 1000 cd/m2 1000 cd/m2 6000 cd/m.sup.2 CIE Bsp. V cd/A h x y V1 4.2 9.6 110 0.14 0.16 V2 4.1 10.7 165 0.14 0.16 E1 3.8 10.5 195 0.14 0.16

(18) TABLE-US-00008 TABLE 3 Structures of the compounds used 0