Electronic device

Abstract

The present application relates to an electronic device comprising a heteroaromatic compound of a formula (I) as functional material, in particular as electron-transport material and as matrix material for emitter compounds. ##STR00001##

Claims

1. An electronic device comprising an anode, a cathode, and at least one organic layer comprising at least one compound of formula (I): ##STR00347## wherein E is selected on each occurrence, identically or differently, from a single bond, B(R.sup.1), C?O, N(R.sup.1), P(R.sup.1), P(?O)R.sup.1, O, S, S?O, and S(?O).sub.2, wherein both groups E cannot be a single bond; T is on each occurrence, identically or differently, CR.sup.1 or N; W is N; Y is N(R.sup.1), O, or S; Z is on each occurrence, identically or differently, CR.sup.2 or N; R.sup.1 is on each occurrence, identically or differently, H, D, F, C(?O)R.sup.3, CN, Si(R.sup.3).sub.3, N(R.sup.3).sub.2, P(?O)(R.sup.3).sub.2, S(?O)R.sup.3, S(?O).sub.2R.sup.3, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein said groups are optionally substituted by one or more radicals R.sup.3, wherein one or more CH.sub.2 groups in said groups are optionally replaced by C?NR3, C(?O)O R.sup.3C?CR.sup.3, C?C, Si(R.sup.3).sub.2, C?O, C(?O)NR.sup.3, NR.sup.3, P(?O)(R.sup.3), O, S, SO, or SO.sub.2, and wherein one or more H atoms in said groups are optionally replaced by D, F, or CN, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3, or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3; R.sup.2 is on each occurrence, identically or differently, H, D, F, C(?O)R.sup.3, CN, Si(R.sup.3).sub.3, N(R.sup.3).sub.2, P(?O)(R.sup.3).sub.2, S(?O)R.sup.3, S(?O).sub.2R.sup.3, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein said groups are optionally substituted by one or more radicals R.sup.3, wherein one or more CH.sub.2 groups in said 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, C(?O)O, C(?O)NR.sup.3, NR.sup.3, P(?O)(R.sup.3), O, S, SO, or SO.sub.2, and wherein one or more H atoms in said groups are optionally replaced by D, F, or CN, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3, or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3, and wherein two or more radicals R.sup.2 are optionally linked to one another and optionally define an aliphatic or heteroaliphatic ring; R.sup.3 is on each occurrence, identically or differently, H, D, F, C(?O)R.sup.4, CN, Si(R.sup.4).sub.3, N(R.sup.4).sub.2, P(?O)(R.sup.4).sub.2, S(?O)R.sup.4, S(?O).sub.2R.sup.4, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein said groups are optionally substituted by one or more radicals R.sup.4, wherein one or more CH.sub.2 groups in said groups are optionally replaced by R.sup.4C?CR.sup.4, C?C, Si(R.sup.4).sub.2, C?O, C?NR.sup.4, C(?O)O, C(?O)NR.sup.4, NR.sup.4, P(?O)(R.sup.4), O, S, SO, or SO.sub.2, and wherein one or more H atoms in said groups are optionally replaced by D, F, or CN, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.4, or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.4, and wherein two or more radicals R.sup.3 are optionally linked to one another and optionally define a ring; R.sup.4 is on each occurrence, identically or differently, H, D, F, or an aliphatic, aromatic, or heteroaromatic organic radical having 1 to 20 C atoms, wherein one or more H atoms are optionally replaced by D or F; and wherein two or more substituents R.sup.4 are optionally linked to one another and optionally define a ring; n is 0 or 1; wherein at least one group R.sup.1 or R.sup.2 in the compound of formula (I) is selected from an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more radicals R.sup.3.

2. The electronic device of claim 1, wherein at least one group R.sup.1 or R.sup.2 in the compound of formula (I) is selected from a group comprising at least one of the following groups: heteroaryl groups having 5 to 20 aromatic ring atoms which comprise at least one heteroaromatic five-membered ring having two or more heteroatoms selected from the group consisting of N, O, and S; heteroaryl groups having 6 to 20 aromatic ring atoms which comprise at least one heteroaromatic six-membered ring having one or more heteroatoms selected from the group consisting of N, O, and S; and carbazole groups.

3. The electronic device of claim 1, wherein at least one group R.sup.1 or R.sup.2 in the compound of formula (I) is selected from groups of formulae (Het-a) to (Het-e): ##STR00348## wherein Ar.sup.1is an aromatic or heteroaromatic ring system having 5 to 20 aromatic ring atoms optionally substituted by one or more radicals R.sup.3; V is on each occurrence, identically or differently, N or CR.sup.3; k is 0 or 1; the dashed line denotes the bond to the remainder of the compound; and wherein at least one group V in the ring in formula (Het-a), (Het-d), and (Het-e) is N.

4. The electronic device of claim 1, wherein n is 1.

5. The electronic device of claim 1, wherein all Z are CR.sup.2.

6. The electronic device of claim 1, wherein E is on each occurrence, identically or differently, a single bond, C?O, N(R.sup.1), O, S, S?O, or S(?O).sub.2, wherein both groups E cannot be a single bond.

7. The electronic device of claim 1, wherein said electronic device is selected from the group consisting of organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, organic light-emitting electrochemical cells, organic laser diodes, and organic electroluminescent devices.

8. The electronic device of claim 1, wherein said electronic device comprises the compound of formula (I) in an electron-transport layer or comprises the compound of formula (I) in an emitting layer as matrix material in combination with one or more dopants.

9. A compound of formula (I-1): ##STR00349## wherein E.sup.2 is on each occurrence, identically or differently, a single bond, C?O, N(R.sup.1), O, or S, wherein both groups E.sup.2 cannot be a single bond; T is on each occurrence, identically or differently, CR.sup.1 or N; Y is N(R.sup.1), O, or S; Z is on each occurrence, identically or differently, CR.sup.2 or N; R.sup.1 is on each occurrence, identically or differently, H, D, F, C(?O)R.sup.3, CN, Si(R.sup.3).sub.3, N(R.sup.3).sub.2, P(?O)(R.sup.3).sub.2, S(?O)R.sup.3, S(?O).sub.2R.sup.3, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein said groups are optionally substituted by one or more radicals R.sup.3, wherein one or more CH.sub.2 groups in said 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, C(?O)O, C(?O)NR.sup.3, NR.sup.3, P(?O)(R.sup.3), O, S, SO, or SO.sub.2, and wherein one or more H atoms in said groups are optionally replaced by D, F, or CN, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3, or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3; R.sup.2 is on each occurrence, identically or differently, H, D, F, C(?O)R.sup.3, CN, Si(R.sup.3).sub.3, N(R.sup.3).sub.2, P(?O)(R.sup.3).sub.2, S(?O)R.sup.3, S(?O).sub.2R.sup.3, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein said groups are optionally substituted by one or more radicals R.sup.3, wherein one or more CH.sub.2 groups in said 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, C(?O)O, C(?O)NR.sup.3, NR.sup.3, P(?O)(R.sup.3), O, S, SO, or SO.sub.2, and wherein one or more H atoms in said groups are optionally replaced by D, F, or CN, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3, or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.3, and wherein two or more radicals R.sup.2 are optionally linked to one another and optionally define an aliphatic or heteroaliphatic ring; R.sup.3 is on each occurrence, identically or differently, H, D, F, C(?O)R.sup.4, CN, Si(R.sup.4).sub.3, N(R.sup.4).sub.2, P(?O)(R.sup.4).sub.2, S(?O)R.sup.4, S(?O).sub.2R.sup.4, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein said groups are optionally substituted by one or more radicals R.sup.4, wherein one or more CH.sub.2 groups in said groups are optionally replaced by R.sup.4C?CR.sup.4, C?C, Si(R.sup.4).sub.2, C?O, C?NR.sup.4, C(?O)O, C(?O)NR.sup.4, NR.sup.4, P(?O)(R.sup.4), O, S, SO, or SO.sub.2, and wherein one or more H atoms in said groups are optionally replaced by D, F, or CN, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.4, or an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R.sup.4, and wherein two or more radicals R.sup.3 are optionally linked to one another and optionally define a ring; R.sup.4 is on each occurrence, identically or differently, H, D, F, or an aliphatic, aromatic, or heteroaromatic organic radical having 1 to 20 C atoms, wherein one or more H atoms are optionally replaced by D or F; and wherein two or more substituents R.sup.4 are optionally linked to one another and optionally define a ring; n is 0 or 1; wherein at least one group R.sup.1 or R.sup.2 in the compound of formula (I) is selected from an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more radicals R.sup.3; and wherein at least one group R.sup.1 is selected from groups of formulae (Het-a) to (Het-e): ##STR00350## wherein Ar.sup.1 is an aromatic or heteroaromatic ring system having 5 to 20 aromatic ring atoms optionally substituted by one or more radicals R.sup.3; V is on each occurrence, identically or differently, N or CR.sup.3; k is 0 or 1; the dashed line denotes the bond to the remainder of the compound; and wherein at least one group V in the ring in formula (Het-a), (Het-d), and (Het-e) is N.

10. The compound of claim 9, wherein Y is NR.sup.1.

11. The compound of claim 9, wherein E.sup.2 is on each occurrence, identically or differently, a single bond, NR.sup.1, O, or S, wherein both groups E.sup.2 cannot be a single bond.

12. An oligomer, polymer, or dendrimer comprising one or more compounds of claim 9, wherein the bond(s) to the polymer, oligomer, or dendrimer are optionally localised at any positions in formula (I-1) substituted by R.sup.1 or R.sup.2.

13. A formulation comprising at least one polymer, oligomer, or dendrimer of claim 12 and at least one solvent.

14. A formulation comprising at least one compound of claim 9 and at least one solvent.

Description

WORKING EXAMPLES

(1) The following working examples serve to illustrate the invention. They should not be interpreted as restrictive.

(2) A) Synthesis Examples

(3) The following syntheses are carried out, unless indicated otherwise, under a protective-gas atmosphere in dried solvents.

(4) Synthesis of Precursors:

Example Int-1a

2-Phenyl-3,9-dihydro-1,3,9-triazacyclopenta[b]-fluorene

(5) ##STR00285##

(6) 5 g (50 mmol) of benzaldehyde is added dropwise to 9.8 g (50 mmol) of 9H-carbazole-2,3-diamine in 300 ml of DMF and 10 ml of conc. sulfuric acid, and the mixture is stirred at room temperature for 2 h. The mixture is added to 500 g of ice and extracted with dichloromethane. The organic phase is washed with 4?50 ml of H.sub.2O, dried over MgSO.sub.4, and the solvents are removed in vacuo. The pure product is obtained by recrystallisation. The content of product according to HPLC is 98% with an overall yield of 7.3 g (25 mmol, 52%).

(7) The following compounds can be obtained analogously:

(8) TABLE-US-00003 Ex. Starting material Starting material Product Int-1b 86439-50-1 110677-45-7 Int-1c 24258-73-9 0 Int-1d 86439-50-1 Int-1e 106020-19-3

(9) TABLE-US-00004 Ex. Yield Int-1b 54% Int-1c 49% Int-1d 66% Int-1e 53%
Synthesis of Compounds According to the Invention:

Example 2a

2-(4-Carbazol-9-ylphenyl)-3-(4,6-diphenylpyrimidin-2-yl)-3H-9-thia-1,3-diazacyclopenta[b]fluorene

(10) ##STR00298##

(11) 13.1 g (28.2 mmol) of 2-(4-carbazol-9-ylphenyl)-3H-9-thia-1,3-diazacyclopenta[b]fluorene are dissolved in 225 ml of dimethylformamide under protective-gas atmosphere, and 1.5 g of NaH, 60% in mineral oil, (37.5 mmol) are added. After 1 h at room temperature, a solution of 2-chloro-4,6-diphenyl-1,3,5-triazine (8.5 g, 31.75 mmol) in 75 ml of dimethylformamide is added dropwise. The reaction mixture is then stirred at room temperature for 12 h. After this time, the reaction mixture is poured onto ice and extracted three times with dichloromethane. The combined organic phases are dried over Na.sub.2SO.sub.4 and evaporated. The residue is extracted with hot toluene and recrystallised from toluene, finally sublimed in a high vacuum. The purity is 99.9%. The yield is 14.8 g (21 mmol, 80%).

(12) The following compounds can be obtained analogously:

(13) TABLE-US-00005 Ex. Starting material Starting material Product 2b 00 01 2c 02 857550-84-6 03 04

(14) TABLE-US-00006 Ex. Yield 2b 58% 2c 67%

(15) The following compounds can be obtained analogously with 2 eq. of NaH and 2 eq. of 2-chloro-4,6-diphenyl-1,3,5-triazine:

(16) TABLE-US-00007 Ex. Starting material Starting material Product 2d 05 06 07 2e 08 09 0 2f 2 eq.

(17) TABLE-US-00008 Ex. Yield 2d 69% 2e 77% 2f 73%

Example 3a

2-Phenyl-1-(9-phenyl-9H-carbazol-3-yl)-1H-benzo[4,5]-furo[2,3:4,5]benzo[1,2-d]imidazole

(18) ##STR00314##

(19) 13.5 g (42.12 mmol) of 3-bromo-9-phenyl-9H-carbazole, 13.2 g (47 mmol) of 2-phenyl-1H-benzo[4,5]furo[2,3:4,5]benzo[1,2-d]imidazole and 29.2 g of Rb.sub.2CO.sub.3 are suspended in 250 ml of p-xylene. 0.95 g (4.2 mmol) of Pd(OAc).sub.2 and 12.6 ml of a 1M tri-tert-butylphosphine solution are added to this suspension. The reaction mixture is heated under reflux for 16 h. After cooling, the organic phase is separated off, washed three times with 200 ml of water and subsequently evaporated to dryness. The residue is extracted with hot toluene, recrystallised from toluene and finally sublimed in a high vacuum. The purity is 99.9%. Yield: 18 g (34 mmol), 76% of theory.

(20) The following compounds can be obtained analogously:

(21) TABLE-US-00009 Ex. Starting material Starting material Product 3b 94994-62-4 3c 0 3d 21426-61-9 3e 242-93-3 78500-89-7 3f 823802-18-2 3g 0 59225-35-3

(22) TABLE-US-00010 Ex. Yield 3b 76% 3c 85% 3d 56% 3e 76% 3f 41% 3g 53%

(23) The following compounds can be obtained analogously with 2 eq. of 3-bromo-9-phenyl-9H-carbazole:

(24) TABLE-US-00011 Ex. Starting material Starting material Product 3h 3j

(25) TABLE-US-00012 Ex. Yield 3h 64% 3j 55%

Example 4a

2-Carbazol-9-yl-9-oxa-3-thia-1-azacyclopenta[b]fluorene

(26) ##STR00339##

(27) 500 ml of toluene, 2.3 g (2.5 mmol) of tris(dibenzylideneacetone)dipalladium(0), 10 ml of 1M t-Bu.sub.3P in toluene and sodium tert-butoxide 11.5 g (120 mmol) are added to 15.6 g (50 mmol) of 2,2 dibromo-1,1-biphenyl. 9.6 g (40 mmol) of 9-oxa-3-thia-1-azacyclopenta[b]fluoren-2-ylamine are subsequently added. The batch is heated at 110? C. for 20 h, then cooled to room temperature, and 400 ml of water are added. The mixture is extracted with ethyl acetate, the combined organic phases are then dried over sodium sulfate, and evaporated under reduced pressure. The residue is recrystallised from toluene and from dichloromethane/isopropanol. The yield is 8.5 g (22 mmol), corresponding to 55% of theory.

(28) The following compounds can be obtained analogously:

(29) TABLE-US-00013 Ex. Starting material Starting material Product Yield 4b 0 97339-25-8 61% 4c 58%

(30) Other reference materials are:

(31) ##STR00346##
B) Quantum-chemical Simulations of Compounds According to the Invention and Reference Materials

(32) The HOMO and LUMO positions and the triplet/singlet level of the organic compounds are determined via quantum-chemical calculations. To this end, the Gaussian03W program package (Gaussian Inc.) is used. In order to calculate organic substances without metals, firstly a geometry optimisation is carried out using a semi-empirical Ground State/Semi-empirical/Default Spin/AM1 method (Charge 0/Spin Singlet). An energy calculation is subsequently carried out on the basis of the optimised geometry. In this, the TD-SCF/DFT/Default Spin/B3PW91 method with the 6-31 G(d) base set (Charge 0/Spin Singlet) is used. The most important results are HOMO/LUMO levels and energies for the triplet and singlet excited states. The first excited singlet state and the first excited triplet state are the most important and are called T1 and S1. The energy calculation gives the HOMO HEh or LUMO LEh in hartree units. The HOMO and LUMO values in electron volts are determined therefrom as follows, where these relationships arise from the calibration with reference to cyclic voltammetry measurements:
HOMO(eV)=((HEh*27.212)?0.9899)/1.1206
LUMO(eV)=((LEh*27.212)?2.0041)/1.385

(33) These values are to be regarded for the purposes of this application as the energetic position of the HOMO level or LUMO level of the materials. As an example, an HOMO of ?0.20047 hartrees and an LUMO of ?0.07772 hartrees are obtained from the calculation for compound 2a (see also Table 1), which corresponds to a calibrated HOMO of ?5.75 eV and a calibrated LUMO of ?2.97 eV.

(34) The following examples show how compounds which are ideally suitable in each case can be identified by quantum-chemical calculations from compounds having the common basic structure according to the invention for the various uses in an OLED (as ETM, as HTM, as TMM).

(35) TABLE-US-00014 TABLE 1 Summary of the energy levels of the compounds according to the invention and TMM1 as reference HOMO LUMO T1 [eV] [eV] [eV] preferred uses TMM1 ?5.68 ?2.39 2.84 Matrix & ETM 2a ?5.75 ?2.97 2.52 ETM 2b ?5.99 ?2.95 2.59 Matrix & ETM 2c ?6.02 ?2.98 2.66 Matrix & ETM 2d ?5.80 ?2.94 2.48 ETM 2e ?5.95 ?2.90 2.54 ETM 2f ?5.65 ?2.79 2.55 ETM 3a ?5.82 ?2.42 2.70 Matrix 3b ?5.87 ?2.49 2.70 Matrix 3c ?5.42 ?2.54 2.52 HTM 3d ?5.15 ?2.34 2.56 Matrix & HTM 3e ?5.97 ?2.48 2.86 Matrix 3f ?4.90 ?2.20 2.56 Matrix & HTM 3g ?5.20 ?2.55 2.26 HTM 3h ?5.30 ?2.30 2.67 Matrix 3j ?5.33 ?2.40 2.59 Matrix &HTM 4a ?5.96 ?2.60 2.70 Matrix 4b ?6.33 ?3.56 2.34 ETM 4c ?5.76 ?2.60 2.63 Matrix

(36) The T1 level of TEG1 is 2.52 eV, which was derived from the onset of the photoluminescence spectrum of TEG1 in toluene. An optimum matrix material for TEG1 should therefore have a T1 level of >2.52 eV, preferably ?2.57 eV. The compounds according to the invention from Table 1 in the case of which matrix is indicated under preferred use are therefore particularly suitable for this use.

(37) For use as ETM, the compound should ideally have an LUMO <?2.6 eV, therefore the compounds according to the invention from Table 1 in the case of which ETM is indicated under preferred use are particularly suitable. And as HTM, the compound should preferably have an HOMO ??5.45 eV, therefore the compounds according to the invention from Table 1 in which HTM is indicated under preferred use are particularly suitable.

(38) C) Device Examples

(39) Preparation of Solutions and Compositions Comprising Matrix Materials and TEG1 for Use in OLEDs

(40) Solutions having the compositions in Table 2 are prepared as follows: firstly, 200 mg of the matrix material and 50 mg of TEG1 are dissolved in 10 ml of chlorobenzene and stirred until the solution is clear. The solution is filtered using a Millipore Millex LS, hydrophobic PTFE 5.0 ?m filter.

(41) TABLE-US-00015 TABLE 2 Composition of the solutions Ratio (based Composition on weight) Concentration Solution Ref TMM1 + TEG1.sup. 75%:25% 25 mg/ml Solution 1 2b + TEG1 75%:25% 25 mg/ml Solution 2 2c + TEG1 75%:25% 25 mg/ml Solution 3 3a + TEG1 75%:25% 25 mg/ml Solution 4 3b + TEG1 75%:25% 25 mg/ml Solution 5 3d + TEG1 75%:25% 25 mg/ml Solution 6 3e + TEG1 75%:25% 25 mg/ml Solution 7 .sup.3f + TEG1 75%:25% 25 mg/ml Solution 8 3h + TEG1 75%:25% 25 mg/ml Solution 9 .sup.3j + TEG1 75%:25% 25 mg/ml Solution 11 4a + TEG1 75%:25% 25 mg/ml Solution 12 4c + TEG1 75%:25% 25 mg/ml

(42) The solutions are used in order to produce the emitting layer of OLEDs. The corresponding solid composition can be obtained by evaporating the solvent from the solutions. This can be used for the preparation of further formulations.

(43) Production of the OLEDs

(44) OLED-Ref to OLED12 having the structure ITO/PEDOT/interlayer/EML/cathode are produced in accordance with the following procedure using the corresponding solutions with the compositions in Table 2: 1) Coating of 80 nm of PEDOT (Clevios? PVP AI 4083) to an ITO-coated glass substrate by spin coating, and drying by heating at 120? C. for 10 minutes. 2) Coating of a 20 nm interlayer by spin coating of a toluene solution of HIL-012 (Merck KGaA) (concentration 0.5% by weight) in a glove box. 3) Drying of the interlayer by heating at 180? C. for 1 h in a glove box. 4) Coating of an 80 nm emitting layer by spin coating of a corresponding solution in accordance with Table 2. 5) Drying of the device by heating at 180? C. for 10 min. 6) Application of a Ba/Al cathode by vapour deposition (3 nm+150 nm). 7) Encapsulation of the device.
Measurements and Comparison of the Results

(45) The OLEDs obtained in this way are characterised by standard methods. The following properties are measured here: UIL characteristics, electroluminescence spectrum, colour coordinates, efficiency and operating voltage. The results are summarised in Table 3, where OLED-Ref serves as comparison in accordance with the prior art. In Table 3, U.sub.on stands for the use voltage, and U(100) stands for the voltage at 100 cd/m.sup.2.

(46) TABLE-US-00016 TABLE 3 Measurement results of the OLEDs according to the invention and the comparative examples Max. eff. U.sub.on U(100) CIEx @ CIEy @ [cd/A] [V] [V] 100 cd/m.sup.2 100 cd/m.sup.2 OLED-Ref 8.2 3.8 6.5 0.33 0.62 OLED1 26.1 3.1 4.9 0.34 0.62 OLED2 24.5 2.5 3.6 0.33 0.62 OLED3 16.4 3.0 4.9 0.34 0.63 OLED4 14.6 3.1 5.2 0.34 0.62 OLED5 13.4 3.1 4.9 0.33 0.62 OLED6 14.3 3.3 5.4 0.34 0.62 OLED7 10.4 2.8 4.4 0.30 0.58 OLED8 12.9 2.5 3.6 0.33 0.62 OLED9 14.7 3.3 5.4 0.34 0.62 OLED11 23.0 2.8 4.3 0.34 0.62 OLED12 27.0 2.7 3.8 0.33 0.62

(47) As can be seen from Table 3, significantly improved phosphorescent OLEDs with respect to operating voltage and efficiency are in all cases obtained on use of the compounds according to the invention as matrix materials. All OLEDs exhibit comparable colour coordinates.

(48) The technical effects observed are not restricted to the system shown. They can also be achieved, for example, using other phosphorescent emitters and on use of additional co-matrices.