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 A compound of the formula (1), ##STR00589## where the following applies to the symbols and indices used: Ar.sup.1, Ar.sup.N are on each occurrence, identically or differently, selected from 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; E.sup.1 is on each occurrence, identically or differently, selected from —BR.sup.0—, —C(R.sup.0).sub.2—, —C(R.sup.0).sub.2—C(R.sup.0).sub.2—, —C(R.sup.0).sub.2—O—, —C(R.sup.0).sub.2—S—, —R.sup.0C═CR.sup.0—, —R.sup.0C═N—, Si(R.sup.0).sub.2, —Si(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)—; or E.sup.1 is a group of formula (E-1), ##STR00590## where the symbol * in formula (E-1) indicates the corresponding group E.sup.1 in formula (1); and E.sup.0 is identically or differently on each occurrence, selected from the group consisting of a single bond, —BR.sup.0—, —C(R.sup.0).sub.2—, —C(R.sup.0).sub.2—C(R.sup.0).sub.2—, —C(R.sup.0).sub.2—O—, —C(R.sup.0).sub.2—S—, —R.sup.0C═CR.sup.0—, —R.sup.0C═N—, Si(R.sup.0).sub.2, —Si(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)—; E.sup.2 is, identically or differently, on each occurrence, selected from the group consisting of —O—, —S—, —S(═O)— and —SO.sub.2—; R.sup.0 to R.sup.5 stand 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).sub.3, B(OR).sub.2, OSO.sub.2R, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by RC═CR, C≡C, Si(R).sub.2, Ge(R).sub.2, Sn(R).sub.2, C═O, C═S, C═Se, P(═O)(R), SO, SO.sub.2, O, S or CONR 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 system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R, where two adjacent substituents R.sup.0, and/or two adjacent substituents R.sup.1, and/or two adjacent substituents R.sup.2, and/or two adjacent substituents R.sup.3, and/or two adjacent substituents R.sup.4, and/or 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; m, n, q stand on each occurrence, identically or differently, for an integer selected from 0, 1, 2, 3 or 4; p stands on each occurrence, identically or differently, for an integer selected from 0, 1, 2 or 3; R 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′).sub.3, B(OR′).sub.2, OSO.sub.2R, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R′, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by R′C═CR′, C≡C, Si(R′).sub.2, Ge(R′).sub.2, Sn(R′).sub.2, C═O, C═S, C═Se, P(═O)(R′), SO, SO.sub.2, O, S or CONR′ 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 system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R′, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R′, where two adjacent substituents R may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R′; 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′; R stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group 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.

2. The compound according to claim 1, wherein Ar.sup.N stands for phenyl, biphenyl, fluorene, spirobifluorene, naphthalene, phenanthrene, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, benzopyridine, benzopyridazine, benzopyrimidine or quinazoline, or for a combination of two to six of these groups, each of which may be substituted by one or more radicals R, where R has the same definition as in claim 1.

3. The compound according to claim 1, wherein Ar.sup.N stands for phenyl, biphenyl, fluorene, naphthalene, phenanthrene, dibenzofuran, dibenzothiophene, carbazole, or for a combination of two to six of these groups, each of which may be substituted by one or more radicals R, where R has the same definition as in claim 1.

4. The compound according to claim 1, wherein the compound is selected from selected from compounds of formula (2), ##STR00591## where the symbols Ar.sup.N, E.sup.1, E.sup.2, Ar.sup.1, R.sup.1 to R.sup.5 and the indices m, n, p and q have the same meaning as in claim 1.

5. The compound according to claim 1, wherein the compound is selected from compounds of formula (3), ##STR00592## where the symbols Ar.sup.N, E.sup.2, Ar.sup.1, R.sup.0, R.sup.1 to R.sup.5 and the indices m, n, p and q have the same meaning as in claim 1.

6. The compound according to one or more of the preceding claims, claim 1, wherein the compound is selected from the compounds of formula (4), ##STR00593## where the symbols Ar.sup.N, E.sup.2, Ar.sup.1, R.sup.0, R.sup.1 to R.sup.5 and the indices m, n, p and q have the same meaning as in claim 1.

7. The compound according to claim 1, wherein the compound is selected from the compounds of formula (4-1) to (4-4), ##STR00594## where the symbols Ar.sup.N, E.sup.2, Ar.sup.1, R.sup.0, R.sup.1 to R.sup.5 have the same meaning as in claim 1.

8. The compound according to claim 1, wherein the compound is selected from formulae (4-1a) to (4-4a), ##STR00595## where the symbols Ar.sup.N, E.sup.2, Ar.sup.1, R.sup.0 and R.sup.1 have the same meaning as in claim 1.

9. The compound according to claim 1, wherein the compound comprises at least one group R.sup.1 selected from an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms.

10. The compound according to according to claim 1, wherein the compound is selected from formulae (4-1b) to (4-4b), ##STR00596## where the symbols Ar.sup.N, E.sup.2, Ar.sup.1 and R.sup.0 have the same meaning as in claim 1.

11. The compound according to claim 1, wherein E.sup.2 stands for O.

12. The compound according to claim 1, wherein Ar.sup.1 stands on each occurrence, identically or differently, for phenyl, biphenyl, fluorene, spirobifluorene, naphthalene, phenanthrene, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, benzopyridine, benzopyridazine, benzopyrimidine, quinazoline, each of which may be substituted by one or more radicals R, or for a combination of two to six of these groups, each of which may be substituted by one or more radicals R, where R has the same meaning as in claim 1.

13. The compound according to claim 1, wherein Ar.sup.1 stands on each occurrence, identically or differently, for an aromatic or heteroaromatic ring system selected from phenyl, biphenyl, fluorene or naphthalene, each of which may be substituted by one or more radicals R, or for a combination of two to six groups selected from phenyl, biphenyl, fluorene or naphthalene, each of which may be substituted by one or more radicals R, where R has the same meaning as in claim 1.

14. The compound according to claim 1, wherein Ar.sup.1 is selected from the groups of formulae (Ar1-1) to (Ar1-22), ##STR00597## ##STR00598## ##STR00599## ##STR00600## where in formulae (Ar1-1) to (Ar1-22): the dashed bond indicates the bonding to the structure of formula (1); the group R.sup.N in formula (Ar1-14) stands on each occurrence, identically or differently, for H, D, a straight-chain alkyl group having 1 to 40 C atoms or branched or cyclic alkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH.sub.2 groups may be replaced by RC═CR, C≡C, C═O, C═S, SO, SO.sub.2, O or S, and where one or more H atoms may be replaced by D, F or CN, 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, where two adjacent substituents R.sup.N may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R, where R has the same meaning as in claim 1; the group R.sup.0a in formulae (Ar1-12) and (Ar1-19) to (Ar1-22) has the same definition as the group R.sup.0 as defined in claim 1; the groups of formulae (Ar1-1) to (Ar1-22) may be substituted at each free position by a group R, which has the same meaning as in claim 1.

15. A polymer, oligomer or dendrimer containing one or more compounds according to claim 1, where the bond(s) to the polymer, oligomer or dendrimer may be localised at any positions in formula (1) which is substituted by R.sup.0, R.sup.1, R.sup.2, R.sup.3, R.sup.4 or R.sup.5.

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

17. An electronic device comprising at least one compound according to to claim 1, wherein the device is 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.

18. An organic electroluminescent device which comprises the compound according to claim 1 is employed as a fluorescent emitter or as a matrix material for fluorescent emitters.

19. A formulation comprising at least one polymer, oligomer or dendrimer according to claim 15 and at least one solvent.

20. An electronic device comprising at least one polymer, oligomer or dendrimer according to claim 15, wherein the device is 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.

Description

A) SYNTHESES EXAMPLES

[0125] A-1) Part 1

[0126] Synthesis Building Block BB-I:

##STR00498##

[0127] 117.9 g (401 mmol) starting material a, 100 g (401 mmol) starting material b and 203.1 g (882 mmol) potassium phosphate monohydrate are mixed in 1.6 L toluene/water/dioxane (2:1:1) and degassed. To the mixture, palladium acetate (0.9 g, 4 mmol) and tri-ortho-tolylphosphine (2.44 g, 8 mmol) are added and the mixture is stirred at reflux for 16 h. After cooling the mixture to room temperature, the phases are separated. The aqueous phase is further extracted with ethyl acetate (2×300 mL). The combined organic phases are washed multiple times with water, dried over sodium sulfate and finally removed in vacuum. The crude is filtered over a plug of SiO.sub.2/Al.sub.2O.sub.3 using ethyl acetate as solvent. After removing the solvent in vacuum, an oil is obtained in quantitative yield.

[0128] The following compounds can be synthesized in an analogous manner:

TABLE-US-00004 Compound Starting material Starting material Product BB-I.a [00499]   CAS 912824-85-2 [00500] [00501]

[0129] Synthesis BB-II:

##STR00502##

[0130] MeMgCl (461 mL, 3 M in THF, 1.38 mol) is added dropwise to a pre-cooled THF suspension (0° C., 1.5 L) of compound BB-I (135 g, 0.4 mol) and CeCl.sub.3 (199 g, 0.8 mol). After completion of the reaction, a saturated aqueous solution of NH.sub.4Cl is added to quench the excess of MeMgCl, and the organic phase is extracted three times with ethyl acetate. The organic fractions are combined and washed with water and brine, successively. The volatiles were removed in vacuum to yield the desired product. 129 g (96%).

[0131] The following compounds can be synthesized in an analogous manner:

TABLE-US-00005 Compound Starting material Product BB-II.a [00503] [00504]

[0132] Synthesis of BB-III:

##STR00505##

[0133] To a solution of compound BB-II (129 g, 383 mmol) in toluene (1 L), 50 g of Amberlyst-15 are added. The mixture is stirred at reflux overnight. The mixture is cooled down to room temperature and the Amberlyst-15 filtered off. The solvent is removed in vacuum and the crude product is purified by column chromatography (SiO.sub.2, heptane). Yield: 106.2 g (87%). The following compounds can be synthesized in an analogous manner:

TABLE-US-00006 Compound Starting material Product BB-III.a [00506] [00507]

[0134] Synthesis BB-IV:

##STR00508##

[0135] To a solution of compound BB-III (100 g, 314 mmol) in CH.sub.2Cl.sub.2 (1.2 L), N-bromosuccinimide (55.83 g, 314 mmol) and HBr (32% solution in acetic acid, 0.5 mL) are added. The reaction is heated at 30° C. for 4 days. After completion of the reaction, Na.sub.2S.sub.2O.sub.3 (300 mL, saturated aqueous solution) is added and the mixture is stirred vigorously for 30 minutes. The phases are separated and the organic phase is washed several times with water. The solvent is removed in vacuum and the crude product vigorously stirred with ethanol to yield a white solid. Yield: 119.8 g (96%).

[0136] The following compounds can be synthesized in an analogous manner:

TABLE-US-00007 Compound Starting material Product BB-IV.a [00509] [00510]

[0137] Synthesis Intermediate BB-V:

##STR00511##

[0138] 30.0 g (75.4 mmol) BB-IV, 9.2 g (75.4 mmol) phenylboronic acid and 16.0 g (151 mmol) sodium carbonate are mixed in 600 mL toluene/dioxane/water (2:1:2) and degassed. To the mixture, Tetrakis(triphenylphosphine) palladium (2.2 g, 1.9 mmol) is added and the mixture is stirred at reflux for 4 h. After cooling the mixture to room temperature, 400 mL of ethyl acetate is added and the phases are separated. The organic phase is washed multiple times with water and the solvent is removed in vacuum. Afterwards, the organic phase is filtrated over a plug of silica using ethyl acetate as solvent. The solvent is removed in vacuum and the crude product vigorously stirred with ethanol to yield a white solid. Yield: 28.3 g (95%).

[0139] The following compounds can be synthesized in an analogous manner:

TABLE-US-00008 Starting Comp. material Starting material Product BB-V.b BB-IV.a [00512] [00513] BB-V.c BB-IV [00514] [00515] BB-V.d BB-IV.a [00516] [00517] BB-V.e BB-IV [00518] [00519] BB-V.f BB-IV [00520] [00521] BB-V.g BB-IV [00522] [00523] BB-V.h BB-IV [00524] [00525] BB-V.i BB-IV CAS 1010100-76-1 [00526] BB-V.j BB-IV.a CAS 1010100-76-1 [00527]

[0140] A-2) Part 2

[0141] Scheme Synthesis Example of Intermediate VII-a

##STR00528##

[0142] Synthesis Intermediate V-a:

[0143] 27.5 g (69.1 mmol) BB-IV, 13.1 g (72.6 mmol) (2-methoxycarbonylphenyl)boronic acid and 35.0 g (152.1 mmol) potassium phosphate monohydrate are mixed in 300 mL toluene and degassed. To the mixture, 2-dicyclohexylphosphino-2′,4′,6′-triisopropyl-1,1′-biphenyl)[2-(2′-amino-1,1′-biphenyl)]palladium(II) methanesulfonate (1.18 g, 2.07 mmol) is added and the mixture is stirred at reflux for 3 h. After cooling the mixture to room temperature, 300 mL water are added and the phases are separated. The organic phase is washed multiple times with water and the solvent is removed in vacuum. Afterwards, the crude product is purified by column chromatography (SiO.sub.2, toluene). Yield: 28.2 g (90%).

[0144] In a similar manner, the following compounds can also be prepared:

TABLE-US-00009 Examples Intermediate IV Intermediate V V-b [00529] [00530]

[0145] Synthesis Intermediate VI-a:

[0146] Intermediate VI-a can be prepared in a similar manner as intermediate II-a starting from V-a (28.0 g, 61.8 mmol), MeMgCl (71 mL, 3 M in THF, 213 mmol) and CeCl.sub.3 (30.5 g, 124 mmol) in 350 mL of THF. Yield: 25.5 g (91%).

[0147] In a similar manner, the following compounds can also be prepared:

TABLE-US-00010 Examples Intermediate V Intermediate VI VI-b [00531] [00532] VI-c [00533] [00534]

[0148] Synthesis Intermediate VII-a:

[0149] Intermediate VII-a can be synthesized following the same procedure as intermediate III-a starting from 25 g (55 mmol) of VI-a and 12 g of Amberlyst-in 300 mL of toluene. Yield: 20.4 g (85%).

[0150] In a similar manner, the following compounds can also be prepared:

TABLE-US-00011 Examples Intermediate VI Intermediate VII VII-b [00535] [00536] VII-c [00537] [00538]

[0151] Synthesis of Intermediate VIII-a and VIII-b

##STR00539##

[0152] Intermediate VIII-a and VIII-b can be synthesized in analogous manner like BB-IV.

[0153] Synthesis of Intermediate IX-a and IX-b

##STR00540##

[0154] Intermediate IX-a and IX-b can be synthesized in analogous manner like BB-V by using CAS 1010100-76-1 as boronate ester starting material.

[0155] A-3) Part 3

[0156] Synthesis of the Amine Int1.1:

##STR00541##

[0157] 4.41 g (26.0 mmol) biphenyl-2-ylamine, 11.31 g (26.0 mmol) VII-a and 6.82 g (70.9 mmol) sodium tertbutylate are mixed in 300 mL toluene and degassed. Afterwards, 563 mg (1.4 mmol)S-Phos and 151 mg (0.7 mmol) palladium acetate are added and the mixture is stirred at reflux for 16 h. After cooling the mixture at room temperature, 200 mL of water is added and the phases are separated. The crude product is filtrate over a plug of aluminium oxide using toluene as solvent. The product is further purified by recrystallizations from toluene/heptane. Yield: 10.48 g (71%).

[0158] The following compounds can be synthesized in an analogous manner:

TABLE-US-00012 Comp. SM SM Product Int1.2 VII-a [00542] [00543] Int1.3 VII-a [00544] [00545] Int1.4 VII-b [00546] [00547] Int1.6 VII-a [00548] [00549] Int1.7 VII-a [00550] [00551] Int1.8 IX-a [00552] [00553] Int1.9 IX-b [00554] [00555] Int1.10 VII-a [00556] [00557] Int1.11 VII-c [00558] [00559]

[0159] A-4) Part 4

[0160] Synthesis of Compound 1:

##STR00560##

[0161] 17.5 g (30.8 mmol) Int1.1, 12.2 g (30.8 mmol) VII-a and 17.8 g (185 mmol) sodium tertbutylate are mixed in 700 mL toluene and degassed. Afterwards, 1.45 g (3.5 mmol)S-Phos and 389 mg (1.7 mmol) palladium acetate are added and the mixture is stirred at reflux for 16 h. After cooling the mixture at room temperature, 200 mL of water is added and the phases are separated. The crude product is filtrate over a plug of aluminium oxide using toluene as solvent. The product is further purified by recrystallizations from toluene/heptane up to a purity of >99.9% by HPLC. Yield: 13.1 g (46%).

[0162] The following compounds can be synthesized in an analogous manner:

TABLE-US-00013 Am- SM ine Product 2 BB- V Int 1.2 [00561] 3 BB- V Int 1.3 [00562] 4 BB- V Int 1.4 [00563] 5 BB- V Int 1.5 [00564] 6 BB- V Int 1.6 [00565] 7 BB- V Int 1.7 [00566] 8 BB- V.b Int 1.1 [00567] 9 BB- V.c Int 1.1 [00568] 10 BB- V.d Int 1.1 [00569] 11 BB- V.e Int 1.1 [00570] 12 BB- V.f Int 1.1. [00571] 13 BB- V.g Int 1.1 [00572] 14 BB- V.h Int 1.1 [00573] 15 BB- V.i Int 1.8 [00574] 16 BB- V.i Int 1.9 [00575] 17 BB- V.j Int 1.8 [00576] 18 BB- V.j Int 1.9 [00577] 19 BB- V Int 1.10 [00578] 20 BB- V Int. 11 [00579]

B) FABRICATION OF OLEDS

[0163] The production of solution-based OLEDs 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).

[0164] The inventive material combinations are used in the following layer sequence: [0165] substrate, [0166] ITO (50 nm), [0167] Buffer (40 nm), [0168] emission layer (EML) (40 nm), [0169] hole-blocking layer (HBL) (10 nm) [0170] electron-transport layer (ETL) (30 nm), [0171] cathode (Al) (100 nm).

[0172] Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm serve as substrate. These are coated with the buffer (PEDOT) Clevios P VP Al 4083 (Heraeus Clevios GmbH, Leverkusen). The spin coating of the buffer is carried out from water in air. The layer is subsequently dried by heating at 180° C. for 10 minutes. The emission layers are applied to the glass plates coated in this way.

[0173] The emission layer (EML) is composed of the matrix material (host material) H and the emitting dopant (emitter) D. Both materials are present in the emission layer in a proportion of 97% by weight H and 3% by weight D. 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 40 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 120° C. for 10 minutes. The materials used in the present case are shown in Table A.

TABLE-US-00014 TABLE A Structural formulae of the solution processed materials in the EML [00580] H [00581] SdT1 [00582] SdT2 [00583] D1 [00584] D2 [00585] D3 [00586] D4

[0174] 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 B. The hole-blocking layer (HBL) consists of ETM. The electron-transport layer (ETL) consists of the two materials ETM and LiQ, which are mixed with one another in a proportion by volume of 50% each by co-evaporation. The cathode is formed by the thermal evaporation of an aluminium layer with a thickness of 100 nm.

TABLE-US-00015 TABLE B Structural formulae of vapor processed OLED materials [00587] ETM [00588] LiQ

[0175] 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 EQE1000 denotes the external quantum efficiency at an operating luminous density of 1000 cd/m.sup.2.

[0176] The properties of the various OLEDs are summarised in table C. Examples V1 and V2 are the comparative examples, whereas E3 to E6 show properties of OLEDs containing materials of the present invention.

TABLE-US-00016 TABLE C Device data of solution processed OLEDs EML EML EQE 1000 Example host dopant [%] CIE x/y V1 H SdT1 1.9 0.15/0.05 V2 H SdT2 2.6 0.16/0.08 E3 H D1 3.9 0.14/0.13 E4 H D2 4.2 0.14/0.14 E5 H D3 3.7 0.14/0.12 E6 H D4 4.9 0.14/0.15

[0177] Table C shows that use of materials (D1 to D4) according to the present invention give rise to improvements over the prior art (SdT1 and SdT2) when used as fluorescent blue emitters, in particular with respect to efficiency.