Bisbenzofuran-fused indeno[1,2-B]fluorene derivatives and related compounds as materials for organic electroluminescent devices (OLED)

Abstract

The present invention relates to Bisbenzofuran-fused indeno[1,2-b]fluorene derivatives and related compounds as materials for organic electroluminescent devices (OLEDs).

Claims

1. A compound of formula (1-1a)-(1-6a): ##STR00306## ##STR00307## wherein Z is on each occurrence, identically or differently, CR or N; E is on each occurrence, identically or differently, selected from the group consisting of —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—, Ge(R.sup.0).sub.2, —C(═O)—, —C(═NR.sup.0)—, —C(═C(R.sup.0).sub.2)—, —O—, —S—, —Se—, —S(═O)—, —SO.sub.2—, —N(R.sup.0)—, —P(R.sup.0)— and —P((═O)R.sup.0)—, X is on each occurrence, identically or differently, selected from the group consisting of —O—, —S—, —S(═O)—, —SO.sub.2—, —N(R.sup.0)—, —BR.sup.0—, Si(R.sup.0).sub.2, —P(R.sup.0)—, and —P((═O)R.sup.0)—; W is on each occurrence, identically or differently, CR or N; R and R.sup.0 are on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, CN, N(Ar).sub.2, C(═O)Ar, P(═O)(Ar).sub.2, S(═O)Ar, S(═O).sub.2Ar, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, OSO.sub.2R.sup.2, 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, each of which is optionally substituted by one or more radicals R.sup.2, wherein one or more non-adjacent CH.sub.2 groups are optionally replaced by R.sup.2C═CR.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, O, S, or CONR.sup.2 and wherein one or more H atoms are optionally 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 is optionally substituted by one or more radicals R.sup.2, or an aryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2, and wherein two adjacent substituents R and/or two adjacent substituents R.sup.0 optionally define a mono- or polycyclic, aliphatic ring system or aromatic ring system, which is optionally substituted by one or more radicals R.sup.2; R.sup.1 is on each occurrence, identically or differently, D, F CN, C(═O)Ar, P(═O)(Ar).sub.2, S(═O)Ar, S(═O).sub.2Ar, —Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, OSO.sub.2R.sup.2, 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, each of which is optionally substituted by one or more radicals R.sup.2, wherein one or more non-adjacent CH.sub.2 groups are optionally replaced by R.sup.2C═CR.sup.2, 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, O, S, or CONR.sup.2 and wherein one or more H atoms are optionally 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 is optionally substituted by one or more radicals R.sup.2, or an aryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2, and wherein two adjacent substituents R.sup.1 optionally define a mono- or polycyclic, aliphatic ring system or aromatic ring system, which is optionally substituted by one or more radicals R.sup.2; R.sup.2 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, CN, N(Ar).sub.2, C(═O)Ar, P(═O)(Ar).sub.2, S(═O)Ar, S(═O).sub.2Ar, NO.sub.2, Si(R.sup.3).sub.3, B(OR.sup.3).sub.2, OSO.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, each of which is optionally substituted by one or more radicals R.sup.3, wherein one or more non-adjacent CH.sub.2 groups are optionally replaced by R.sup.3C═CR.sup.3, Si(R.sup.3).sub.2, Ge(R.sup.3).sub.2, Sn(R.sup.3).sub.2, C═O, C═S, C═Se, P(═O)(R.sup.3), SO, SO.sub.2, O, S, or CONR.sup.3 and wherein one or more H atoms are optionally 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 is optionally substituted by one or more radicals R.sup.3, or an aryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.3, and wherein two adjacent substituents R.sup.2 optionally define a mono- or polycyclic, aliphatic ring system or aromatic ring system, which is optionally substituted by one or more radicals R.sup.3; R.sup.3 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy, or thioalkyl group having 1 to 20 C atoms or a branched or cyclic alkyl, alkoxy, or thioalkyl group having 3 to 20 C atoms, wherein one or more non-adjacent CH.sub.2 groups are optionally replaced by SO, SO.sub.2, O, S and wherein one or more H atoms are optionally replaced by D, F, Cl, Br, or I, or an aromatic or heteroaromatic ring system having 5 to 24 C atoms; and Ar is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.3.

2. The compound of claim 1, wherein X is O or S.

3. The compound of claim 1, wherein E is —C(R.sup.0).sub.2— or —Si(R.sup.0).sub.2—.

4. The compound of claim 1, wherein the compound is selected from the group consisting of compounds of formulae (1-1b) through (1-6c): ##STR00308## ##STR00309## ##STR00310##

5. The compound of claim 1, wherein when R.sup.1 is an aromatic or heteroaromatic ring system, then R.sup.1 is selected on each occurrence, identically or differently, from the group consisting of formula (R.sup.1-1): ##STR00311## wherein the dashes denotes the bond to the structure of formula (1); Ar.sup.3 and Ar.sup.4 are selected on each occurrence, identically or differently, from the group consisting of benzene, naphthalene, anthracene, phenanthrene, biphenyl, terphenyl, fluorene, benzofluorene, spirobifluorene, cis-indenofluorene, trans-indenofluorene, cis-benzindenofluorene, trans-benzindenofluorene, furan, benzofuran, dibenzofuran, thiophene, benzothiophene, dibenzothiophene, pyrrole, indole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, pyrazole, indazole, imidazole, benzimidazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, pyrazine, quinoxaline, 1,3,5-triazine, 1,2,4-triazine, and 1,2,3-triazine, which are optionally substituted by one or more radicals R.sup.2; and n is an integer from 0 to 20.

6. The compound of claim 5, wherein Ar.sup.3 and Ar.sup.4 are on each occurrence, identically or differently, selected from the group consisting of benzene, naphthalene, anthracene, phenanthrene, biphenyl, terphenyl, fluorene, benzofluorene, spirobifluorene, cis-indenofluorene, trans-indenofluorene, cis-benzindenofluorene, trans-benzindenofluorene, furan, benzofuran, dibenzofuran, thiophene, benzothiophene, dibenzothiophene, pyrrole, indole, carbazole, indolocarbazole, and indenocarbazole, which in each case is optionally substituted by one or more radicals R.sup.2.

7. The compound of claim 1, wherein R.sup.0 is on each occurrence, identically or differently, H, D, F, CN, a straight-chain alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms, each of which is optionally substituted by one or more radicals R.sup.2, wherein one or more H atoms are optionally replaced by F, or an aryl or heteroaryl group having 5 to 25 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2, and wherein two adjacent substituents R.sup.0 optionally define a mono- or polycyclic, aliphatic ring system or aromatic ring system, which is optionally substituted by one or more radicals R.sup.2.

8. The compound of claim 1, wherein R.sup.0 is on each occurrence, identically or differently, for H, D, F, CN, a straight-chain alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms, each of which was optionally substituted by one or more radicals R.sup.2, and wherein one or more H atoms is optionally replaced by F.

9. An oligomer, polymer, or dendrimer comprising one or more compounds of claim 1, wherein the bond(s) to the polymer, oligomer, or dendrimer are located at any desired position in formula (1) substituted by R or R.sup.1.

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

11. A formulation comprising at least one oligomer, polymer, or dendrimer of claim 9 and at least one solvent.

12. An electronic device comprising at least one compound of claim 1, wherein the electronic 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.

13. An electronic device comprising at least one oligomer, polymer, or dendrimer of claim 9, wherein the electronic 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.

14. The electronic device of claim 12, wherein the electronic device is an organic electroluminescent device and the at least one compound is employed as a fluorescent emitter or as a matrix material for fluorescent emitters.

15. The electronic device of claim 13, wherein the electronic device is an organic electroluminescent device and the at least one oligomer, polymer, or dendrimer is employed as a fluorescent emitter or as a matrix material for fluorescent emitters.

16. The compound of claim 1, wherein the compound is of the formula (1-1a).

17. The compound of claim 1, wherein the compound is of the formula (1-2a).

18. The compound of claim 1, wherein the compound is of the formula (1-3a).

19. The compound of claim 1, wherein the compound is of the formula (1-4a).

20. The compound of claim 1, wherein the compound is of the formula (1-5a).

Description

WORKING EXAMPLES

A) Synthesis Examples

(1) Synthesis Scheme:

(2) ##STR00246##
Compound Ia

(3) ##STR00247##

(4) 2,5-Dibromo-terephthalic acid diethyl ester (20 g, 53 mmol), dibenzofuran-1-boronic acid (29 g, 137 mmol) and tripotassiumphosphate monohydrate (48.5 g, 160 mmol) were added to water/toluene/dioxane (1:1:1, 0.5 L). The solution was saturated with argon. Palladium(II)-acetate (118 mg, 0.5 mmol) and tri-o-tolyl-phosphine (480 mg, 1.6 mmol) were added and the reaction mixture was refluxed for 16 hours. After cooling down to room temperature, toluene (500 mL) was added and the organic phase was washed with water (3×500 mL) and then concentrated under reduced pressure. The residue was purified by recrystallization from toluene/ethanol. Yield: 22.2 g (40 mol; 76%).

(5) In an analogous manner, the following compounds can be obtained:

(6) TABLE-US-00003 Starting Material Starting Material Product Yield Ib   CAS 18013-97-3   CAS 100124-06-9 0 75% Ic Ic-A (see below)   CAS 100124-06-9 69%

(7) ##STR00253##

(8) 2-Bromo-5-chloro-terephthalic acid diethyl ester (60.5 g, 0.24 mol, CAS:340148-60-9), dibenzofuran-1-pinacolatoboronic ester (78.5 g, 0.27 mol) and tripotassiumphosphate monohydrate (223.4 g, 0.97 mol) were added to water/toluene/dioxane (1:1:1, 1 L). The solution was saturated with argon. Palladium(II)-acetate (547 mg, 2.4 mmol) and tri-o-tolyl-phosphine (2.2 g, 7.3 mmol) were added and the reaction mixture was refluxed for 16 hours. After cooling down to room temperature, toluene (500 mL) was added and the organic phase was washed with water (3×500 mL) and then concentrated under reduced pressure. The residue was purified by recrystallization from toluene/ethanol. Yield: 65.5 g (0.19 mol; 72%).

(9) ##STR00254##

(10) 21 g (38 mmol) of the Ia diluted in 0.5 L THF were added to 37.5 g (40 mmol) cerium(III) chloride and 200 ml THF and the mixture was stirred for 30 minutes and cooled to 0° C. 101 ml (304 mol) methylmagnesiumchloride (3 M in THF) was added dropwise to the reaction mixture at 0° C. The reaction mixture was allowed to warm to room temperature. After 16 hours, 800 ml of an aqueous saturated solution of ammonium chloride were added at 0° C. Ethyl acetate (2×300 mL) was added, the combined organic phases were washed with water (2×300 mL) and concentrated under reduced pressure. The residue was purified by stirring in ethanol. Yield: 18.6 g (35.3 mmol, 93%).

(11) In an analogous manner, the following compounds can be obtained:

(12) TABLE-US-00004 Starting Material Product Yield IIb 98% IIc 97%

(13) ##STR00259##

(14) 18.4 g (34 mmol) of IIa were solved in 750 mL toluene and 5 g amberlyst 15 were added. The reaction mixture was refluxed for 16 hours using a DeanStark apparatus. After cooling down to room temperature, amberlyst was removed by filtration and the organic phase was concentrated under reduced pressure. The residue was purified by several recrystallizations from ethanol and heptane/toluene.

(15) Yield: 12.2 g (25 mmol; 73%).

(16) In an analogous manner, the following compounds can be obtained:

(17) TABLE-US-00005 Starting Material Product Yield IIIb 0 77% IIIc 78%

(18) ##STR00264##

(19) IIIa (12.5 g, 25 mmol) was suspended in 0.5 L chloroform. Bromine (9 g, 56 mmol) in 350 ml chloroform was added dropwise. The reaction mixture was stirred at room temperature. After 16 hours, 20 ml of an aqueous saturated solution of ammonium chloride were added and the mixture was stirred for 15 minutes. Water (1 L) was added, the organic phase was washed with water (3×500 mL) and the combined organic phases were concentrated under reduced pressure. The residue was purified by several recrystallizations from chloroform and toluene. Yield: 12.0 g (19 mmol; 73%).

(20) In analogous manner, the following compounds can be obtained:

(21) TABLE-US-00006 Starting Material Product Yield IVb 69% IVc 78%

(22) ##STR00269##

(23) IVa (12.1 g, 19 mmol), 9,9-dimethyl-9H-fluorene-2-boronic acid (13.7 g, 58 mmol) and tripotassiumphosphate monohydrate (25.7 g, 0.11 mol) were mixed in 300 mL toluene/dioxane/water (2:1:1). Palladium(II)-acetate (0.31 g, 0.45 mmol) and tri-tert-butylphosphonium tetrafluoroborate (0.26 g, 1.4 mmol) were added and the reaction mixture was refluxed for 16 hours. After cooling down to room temperature, 200 mL water was added and the organic phase was washed with water (3×200 mL). The combined organic phases were concentrated under reduced pressure. The residue was purified by several recrystallizations from toluene and finally by sublimation.

(24) Yield: 8.7 g (0.010 mol; 53%)

(25) In an analogous manner, the following compounds can be obtained:

(26) TABLE-US-00007 Starting Material A Starting Material B Product Yield IVb 0   CAS 333432-28-3 58% IVc   CAS 333432-28-3 61% IVd   CAS 98437-24-2 57% IVe 0 68% IVf 63% ↓ IVg   CAS 98437-24-2 54%

B) Device Examples

(27) B-1) Device Examples Processed from Vapor: Production of OLEDs

(28) The manufacturing of the OLED devices is performed accordingly to WO 04/05891 with adapted film thicknesses and layer sequences. The following examples V1, V2, E3 and E4 (see Table 1) show data of various OLED devices.

(29) Substrate Pre-Treatment of Examples V1-E4:

(30) Glass plates with structured ITO (50 nm, indium tin oxide) are coated with 20 nm PEDOT:PSS (Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate, CLEVIOS™ P VP Al 4083 from Heraeus Precious Metals GmbH Germany, spin-coated from a water-based solution) to form the substrates on which the OLED devices are fabricated.

(31) The OLED devices have in principle the following layer structure: Substrate, ITO (50 nm), Buffer (20 nm), Hole injection layer (HTL1 95%, HIL 5%) (20 nm), Hole transporting layer (HTL) (see table 1), Emissive layer (EML) (see table 1), Electron transporting layer (ETL) (20 nm), Electron injection layer (EIL) (3 nm), Cathode.

(32) The cathode is formed by an aluminium layer with a thickness of 100 nm. The detailed stack sequence is shown in Table 1. The materials used for the OLED fabrication are presented in Table 3.

(33) All materials are applied by thermal vapour deposition in a vacuum chamber. The emission layer here always consists of at least one matrix material (host material=H) and an emitting dopant (emitter=D), which is mixed with the matrix material or matrix materials in a certain proportion by volume by co-evaporation. An expression such as H1:D1 (97%:3%) here means that material H1 is present in the layer in a proportion by volume of 97%, whereas D1 is present in the layer in a proportion of 3%. Analogously, the electron-transport layer may also consist of a mixture of two or more materials.

(34) The OLED devices are characterised by standard methods. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd/A) and the external quantum efficiency (EQE, measured in % at 1000 cd/m.sup.2) are determined from current/voltage/luminance characteristic lines (IUL characteristic lines) assuming a Lambertian emission profile. The electroluminescence (EL) spectra are recorded at a luminous density of 1000 cd/m.sup.2 and the CIE 1931 x an y coordinates are then calculated from the EL spectrum. EQE @ 1000 cd/m.sup.2 is defined as the external quantum efficiency at luminous density of 1000 cd/m2. For all experiments, the lifetime LT80 is determined. The lifetime LT80 @ 60 mA/cm.sup.2 is defined as the time after which the initial luminous density (cd/m2) at a constant current density of 60 mA/cm.sup.2 has dropped by 20%. The device data of various OLED devices is summarized in Table 2.

(35) The examples V1 and V2 represent the comparative example according to the state-of-the-art. The example E3 and E4 shows data of inventive OLED devices.

(36) In the following section, several examples are described in more detail to show the advantages of the inventive OLED devices.

(37) Use of Inventive Compounds as Emitting Material in Fluorescent OLEDs

(38) The inventive compounds are especially suitable as an emitter (dopant) when blended into a fluorescent blue matrix to form the emissive layer of a fluorescent blue OLED device. The representative example is D1 and D2. Comparative compound for the state-of-the-art are represented by VD-1 and VD-2 (structures see table 3).

(39) The use of the inventive compound as an emitter (dopant) in a fluorescent blue OLED device results in significantly improved device data (E3 and E4) compared to state-of-the-art examples (V1 and V2), especially in terms of external quantum efficiency and deeper blue color. This demonstrates the applicability of the inventive compound as emitting material in fluorescent blue OLED devices. The material can be also used also as hole transporting material.

(40) TABLE-US-00008 TABLE 1 Stack sequence of OLEDs HTL Example (195 nm) EML (20 nm) V1 HTL2 H(97%): VD-1 (3%) V2 HTL2 H(97%): VD-2 (3%) E3 HTL2 H(97%): D1 (3%) E4 HTL2 H(97%): D2 (3%)

(41) TABLE-US-00009 TABLE 2 Device data of OLEDs EQE [%] LT 80 [h] @ 1000 @ 60 Example CIE x CIE y cd/m.sup.2 mA/m.sup.2 V1 0.14 0.13 6.9 95 V2 0.14 0.14 7.2 140 E3 0.15 0.10 8.2 145 E4 0.15 0.09 7.9 135

(42) TABLE-US-00010 TABLE 3 Chemical structure of OLED materials HIL HTL1 HTL2 0 EIL H VD-1 VD-2 D1 D2 ETL
B-2) Device Examples Processed from Solution: Production of OLEDs

(43) The production of solution-based OLEDs is described in principle in the literature, for example in WO 2004/037887 and WO 2010/097155. In the following examples, the two production methods (application from gas phase and solution processing) were combined, so that processing up to and including the emission layer was carried out from solution and the subsequent layers (hole-blocking layer/electron-transport layer) were applied by vacuum vapour deposition. The general processes described above are for this purpose adapted to the circumstances described here (layer-thickness variation, materials) and combined as follows.

(44) The device structure used is thus as follows: substrate, ITO (50 nm), PEDOT (20 nm), hole-transport layer (HTL) (20 nm), emission layer (92% of host, 8% of dopant) (60 nm), electron-transport layer (ETL2) (20 nm), electron-injection layer (EIL) (3 nm) cathode (Al) (100 nm).

(45) The substrates used are glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm. For better processing, these are coated with the buffer PEDOT:PSS (Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate, CLEVIOS™ P VP Al 4083 from Heraeus Precious Metals GmbH Germany). 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 hole-transport and emission layers are applied to the glass plates coated in this way.

(46) The hole-transport layer is the polymer of the structure shown in Table 5, which was synthesised in accordance with WO 2010/097155. The polymer is dissolved in toluene, so that the solution typically has a solid content of approx. 5 g/l if, as here, the layer thickness of 20 nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, in the present case argon, and dried by heating at 180° C. for 60 min.

(47) The emission layer (EML) is always composed of at least one matrix material (host=H) and an emitting dopant (emitter=D). An expression such as H1 (92%): D1 (8%) here means that material H1 is present in the emission layer in a proportion by weight of 92% and dopant D1 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 solid content of such solutions is approx. 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 140° C. for 10 minutes. The materials used are shown in Table 5.

(48) The materials for the electron-transport layer, the electron-injection layer and for the cathode are applied by thermal vapour deposition in a vacuum chamber. The electron-transport layer, for example, may consist of more than one material, which are admixed with one another in a certain proportion by volume by co-evaporation. An expression such as ETM:EIL (50%:50%) would mean that materials ETM and EIL are present in the layer in a proportion by volume of 50% each. The materials used in the present case are shown in Table 5.

(49) 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), and finally the lifetime of the components is determined. The electroluminescence spectra are recorded at a luminous density of 1000 cd/m.sup.2, and the CIE 1931 x and y colour coordinates are calculated from this data. The term EQE @ 1000 cd/m.sup.2 denotes the external quantum efficiency at an operating luminous density of 1000 cd/m2. The lifetime LD80 @ 10 mA/cm.sup.2 is the time which passes until the initial luminance at a driving current density of 10 mA/cm.sup.2 has dropped by 20%. The data obtained for the various OLEDs are summarised in Table 4.

(50) Use of Compounds According to the Invention as Fluorescent Emitter Materials in Organic Light Emitting Diodes

(51) The compounds according to the invention are particularly suitable as emitter materials in blue-fluorescent OLEDs. Emitters D3 and D4 are shown as compounds according to the invention. The state-of-the-art compound for comparison is represented by V-D3 and V-D4. All emitters are used in combination with either host H1 or H2.

(52) Examples E9 to E12 show in a comparative examination with Comparative Examples V5 to V8 that compounds D3 and D4 according to the invention achieve an improved external quantum efficiency (EQE) and an increased lifetime (LD80) with deep-blue emission as compared to comparative material V-D1 and V-D2.

(53) TABLE-US-00011 TABLE 4 Device data of the OLEDs EQE @ LD80 @ 1000 10mA/ Host Emitter cd/m.sup.2 cm.sup.2 CIE Example 92% 8% % [h] x y V5 H1 V-D1 2.9 140 0.14 0.13 V6 H2 V-D2 3.3 160 0.15 0.13 E7 H1 D3 3.7 190 0.14 0.16 E8 H2 D3 3.9 200 0.14 0.17 E9 H1 D4 4.8 240 0.14 0.18 E10 H2 D4 4.9 250 0.14 0.18

(54) TABLE-US-00012 TABLE 5 Structures of the materials used HTL H1 H2 00 V-D1 01 V-D2 02 D3 03 D4 04 EIL 05 ETL2

(55) Compounds according to the invention possess decent solubility and thus are well suitable for solution processing. By this technique, electronic devices based on blue fluorescent emitters with excellent performance data can be generated.

(56) Alternatively, or in addition, the compounds according to the invention may serve as host materials inside the emission layer (EML), as hole injection material (HIL), as hole transporting material (HTL), as electron transporting material (ETL) or as electron-injection material (EIL) in an organic light emitting diode.