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MATERIALS FOR ELECTRONIC DEVICES

20220073447 · 2022-03-10

    Inventors

    Cpc classification

    International classification

    Abstract

    The present application relates to materials for use in electronic devices, to processes for preparing the materials, and to electronic devices containing the materials.

    Claims

    1.-21. (canceled)

    22. A compound of formula (I) ##STR00423## where the variables that occur are as follows: Z, when the —[Ar1].sub.k—N(Ar2)(Ar3) group is bonded thereto, is C, and Z, when the —[Ar1].sub.k—N(Ar2)(Ar3) group is not bonded thereto, is the same or different at each instance and is CR1 or N; Ar1 is the same or different at each instance and is an aromatic ring system which has 6 to 40 aromatic ring atoms and is substituted by R3 radicals, or a heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is substituted by R3 radicals; Ar2 is an aromatic ring system which has 6 to 40 aromatic ring atoms and is substituted by R4 radicals, or a heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is substituted by R4 radicals; Ar3 is an aromatic ring system which has 6 to 40 aromatic ring atoms and is substituted by R4 radicals, or a heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is substituted by R4 radicals; Ar4 is phenyl which may be substituted by R2 radicals or naphthyl which may be substituted by R2 radicals; R1 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R5, CN, Si(R5).sub.3, N(R5).sub.2, P(═O)(R5).sub.2, OR5, S(═O)R5, S(═O).sub.2R5, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R1 radicals may be joined to one another and may form a ring; where the alkyl, alkoxy, alkenyl and alkynyl groups mentioned and the aromatic ring systems and heteroaromatic ring systems mentioned are each substituted by R5 radicals; and where one or more CH.sub.2 groups in the alkyl, alkoxy, alkenyl and alkynyl groups mentioned may be replaced by —R5C═CR5-, —C≡C—, Si(R5).sub.2, C═O, C═NR5, —C(═O)O—, —C(═O)NR5-, NR5, P(═O)(R5), —O—, —S—, SO or SO.sub.2; R2 is the same or different at each instance and is selected from D, F, CN, Si(R5).sub.3, N(R5).sub.2, aromatic ring systems which have 6 to 40 aromatic ring atoms and are substituted by R5 radicals, and heteroaromatic ring systems which have 5 to 40 aromatic ring atoms and are substituted by R5 radicals; R3 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R5, CN, Si(R5).sub.3, N(R5).sub.2, P(═O)(R5).sub.2, OR5, S(═O)R5, S(═O).sub.2R5, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R3 radicals may be joined to one another and may form a ring; where the alkyl, alkoxy, alkenyl and alkynyl groups mentioned and the aromatic ring systems and heteroaromatic ring systems mentioned are each substituted by R5 radicals; and where one or more CH.sub.2 groups in the alkyl, alkoxy, alkenyl and alkynyl groups mentioned may be replaced by —R5C═CR5-, —C≡C—, Si(R5).sub.2, C═O, C═NR5, —C(═O)O—, —C(═O)NR5-, NR5, P(═O)(R5), —O—, —S—, SO or SO.sub.2; R4 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R5, CN, Si(R5).sub.3, N(R5).sub.2, P(═O)(R5).sub.2, OR5, S(═O)R5, S(═O).sub.2R5, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R4 radicals may be joined to one another and may form a ring; where the alkyl, alkoxy, alkenyl and alkynyl groups mentioned and the aromatic ring systems and heteroaromatic ring systems mentioned are each substituted by R5 radicals; and where one or more CH.sub.2 groups in the alkyl, alkoxy, alkenyl and alkynyl groups mentioned may be replaced by —R5C═CR5-, —C≡C—, Si(R5).sub.2, C═O, C═NR5, —C(═O)O—, —C(═O)NR5-, NR5, P(═O)(R5), —O—, —S—, SO or SO.sub.2; R5 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R6, CN, Si(R6).sub.3, N(R6).sub.2, P(═O)(R6).sub.2, OR6, S(═O)R6, S(═O).sub.2R6, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R5 radicals may be joined to one another and may form a ring; where the alkyl, alkoxy, alkenyl and alkynyl groups mentioned and the aromatic ring systems and heteroaromatic ring systems mentioned are each substituted by R6 radicals; and where one or more CH.sub.2 groups in the alkyl, alkoxy, alkenyl and alkynyl groups mentioned may be replaced by —R6C═CR6-, —C≡C—, Si(R6).sub.2, C═O, C═NR6, —C(═O)O—, —C(═O)NR6-, NR6, P(═O)(R6), —O—, —S—, SO or SO.sub.2; R6 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, CN, alkyl or alkoxy groups having 1 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where the alkyl, alkoxy, alkenyl and alkynyl groups, aromatic ring systems and heteroaromatic ring systems mentioned may be substituted by one or more radicals selected from F and CN; k is 0, 1, 2, 3 or 4, where, in the case that k=0, the Ar1 group is absent and the groups that bind to Ar1 in formula (I) are bonded directly to one another; i is 0, 1, 2, 3, 4 or 5; n is 0, 1, 2, 3 or 4; where the two groups ##STR00424## in formula (I), each as a whole including their substituents, are not the same.

    23. The compound according to claim 22, wherein it is a monoamine.

    24. The compound according to claim 22, wherein Z, when the —[Ar1].sub.k—N(Ar2)(Ar3) group is not bonded thereto, is CR1.

    25. The compound according to claim 22, wherein k is 0.

    26. The compound according to claim 22, wherein the —(Ar1).sub.k— group, if k=1, corresponds to one of the following formulae: ##STR00425## ##STR00426## ##STR00427## ##STR00428## ##STR00429## ##STR00430## ##STR00431## ##STR00432## ##STR00433## ##STR00434## ##STR00435## ##STR00436## where the dotted lines represent the bonds to the rest of the formula (I), and where the groups at the positions shown as unsubstituted are each substituted by R3 radicals, where the R3 radicals in these positions are preferably H.

    27. The compound according to claim 22, wherein Ar2 and Ar3 are the same or different at each instance and are selected from phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, fluorenyl, especially 9,9′-dimethylfluorenyl and 9,9′-diphenylfluorenyl, benzofluorenyl, spirobifluorenyl, indenofluorenyl, indenocarbazolyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, benzofuranyl, benzothiophenyl, benzofused dibenzofuranyl, benzofused dibenzothiophenyl, naphthyl-substituted phenyl, fluorenyl-substituted phenyl, spirobifluorenyl-substituted phenyl, dibenzofuranyl-substituted phenyl, dibenzothiophenyl-substituted phenyl, carbazolyl-substituted phenyl, pyridyl-substituted phenyl, pyrimidyl-substituted phenyl, and triazinyl-substituted phenyl, where the groups mentioned are each substituted by one or more R4 radicals.

    28. The compound according to claim 22, wherein exactly one group selected from the Ar2 and Ar3 groups is phenyl substituted by R4 radicals that are preferably selected from H, D, F, CN and alkyl groups having 1 to 10 carbon atoms, and are more preferably H.

    29. The compound according to claim 22, wherein Ar2 and Ar3 are the same or different and are selected from the following formulae: ##STR00437## ##STR00438## ##STR00439## ##STR00440## ##STR00441## ##STR00442## ##STR00443## ##STR00444## ##STR00445## ##STR00446## ##STR00447## ##STR00448## ##STR00449## ##STR00450## ##STR00451## ##STR00452## ##STR00453## ##STR00454## ##STR00455## ##STR00456## ##STR00457## ##STR00458## ##STR00459## ##STR00460## ##STR00461## ##STR00462## ##STR00463## ##STR00464## ##STR00465## ##STR00466## ##STR00467## ##STR00468## ##STR00469## ##STR00470## ##STR00471## ##STR00472## ##STR00473## ##STR00474## ##STR00475## ##STR00476## ##STR00477## ##STR00478## ##STR00479## ##STR00480## ##STR00481## where the groups at the positions shown as unsubstituted are substituted by R4 radicals, where R4 in these positions is preferably H, and where the dotted bond is the bond to the amine nitrogen atom.

    30. The compound according to claim 22, wherein Ar4 is phenyl which may be substituted by R2 radicals.

    31. The compound according to claim 22, wherein R1 is the same or different at each instance and is selected from H, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms, where the aromatic ring systems and the heteroaromatic ring systems are each substituted by R5 radicals; and R2 is selected from aromatic ring systems which have 6 to 40 aromatic ring atoms and are substituted by R5 radicals; and R3 is the same or different at each instance and is selected from H, N(R5).sub.2, straight-chain alkyl groups having 1 to 20 carbon atoms, branched or cyclic alkyl groups having 3 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms, where the alkyl groups, the aromatic ring systems and the heteroaromatic ring systems are each substituted by R5 radicals; and R4 is the same or different at each instance and is selected from H, N(R5).sub.2, straight-chain alkyl groups having 1 to 20 carbon atoms, branched or cyclic alkyl groups having 3 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms, where the alkyl groups, the aromatic ring systems and the heteroaromatic ring systems are each substituted by R5 radicals; and R5 is the same or different at each instance and is selected from H, straight-chain alkyl groups having 1 to 20 carbon atoms, branched or cyclic alkyl groups having 3 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms, where the alkyl groups, the aromatic ring systems and the heteroaromatic ring systems are each substituted by R6 radicals.

    32. The compound according to claim 22, wherein one or two R1 radicals are selected from aromatic ring systems which have 6 to 40 aromatic ring atoms and are substituted by R5 radicals, and heteroaromatic ring systems which have 5 to 40 aromatic ring atoms and are substituted by R5 radicals, and the other R1 radicals are H.

    33. The compound according to claim 22, wherein i and n are 0.

    34. The compound according to claim 22, wherein the —[Ar1].sub.k—N(Ar2)(Ar3) group is bonded to the fluorenyl group in formula (I) in the 2 position or in the 4 position.

    35. The compound according to claim 22, wherein it corresponds to one of the following formulae: ##STR00482## ##STR00483## ##STR00484## ##STR00485## ##STR00486## ##STR00487## ##STR00488## ##STR00489## where the symbols and indices that occur are as defined in claim 22, and where the bonded R1 radical means that all positions shown as unsubstituted on the benzene ring in question are substituted by R1 radicals.

    36. A process for preparing the compound according to claim 22, wherein a biphenyl derivative bearing two reactive groups, at least one of which is in the ortho position, is metallated and then is added onto a carbonyl derivative containing a phenyl- or naphthyl-substituted phenyl group and a phenyl group bonded to the carbonyl group.

    37. An oligomer, polymer or dendrimer containing one or more compounds according to claim 22, wherein the bond(s) to the polymer, oligomer or dendrimer may be localized at any desired positions substituted by R1, R2, R3 or R4 in formula (I).

    38. A formulation comprising at least one compound according to claim 22 and at least one solvent.

    39. An electronic device comprising at least one compound according to claim 22.

    40. The electronic device according to claim 39, wherein it is an organic electroluminescent device and comprises anode, cathode and at least one emitting layer, and in that the compound is present in a hole-transporting layer or in an emitting layer of the device.

    41. The device according to claim 40, wherein the compound is present in a hole-transporting layer which is a hole transport layer or an electron blocker layer.

    42. A method comprising utilizing the compound according to claim 22 in an electronic device.

    Description

    EXAMPLES

    A) Synthesis Examples

    Example 1-1

    N,9-Bis({[1,1′-biphenyl]-4-yl})-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-fluorene-4-amine

    [0148] ##STR00257##

    9-{[1,1′-Biphenyl]-4-yl}-4-bromo-9-phenylfluorene

    [0149] 14.5 g (46.3 mmol) of 2,2′-dibromobiphenyl is dissolved in a baked-out flask in 150 ml of dried THF. The reaction mixture is cooled to −78° C. At this temperature, 20.5 ml of a 2.3 M solution of n-BuLi in hexane (46.3 mmol) is slowly added dropwise. The mixture is stirred at −70° C. for a further 1 hour. Subsequently, 11.4 g of biphenyl-4-yl(phenyl)methanone (44.13 mmol) is dissolved in 80 ml of THF and added dropwise at −70° C. After the addition has ended, the reaction mixture is left to warm up gradually to room temperature, admixed with NH.sub.4Cl and then concentrated on a rotary evaporator. 200 ml of acetic acid is added cautiously to the concentrated solution and then 50 ml of fuming HCl is added. The mixture is heated to 75° C. and kept there for 6 hours. During this time, a white solid precipitates out. The mixture is then left to cool to room temperature, and the precipitated solids are filtered off with suction and washed with methanol. The residue is dried at 40° C. under reduced pressure. Yield 19.5 g (41 mmol) (90% of theory).

    [0150] The following compounds are prepared in an analogous manner: The yields here are between 40% and 90%

    TABLE-US-00001 Reactant 1 Reactant 2 Product I-2 [00258]embedded image   CAS No.: 2128-93-0 [00259]embedded image [00260]embedded image I-3 [00261]embedded image   CAS No.: 3378-09-4 [00262]embedded image [00263]embedded image I-4 [00264]embedded image   CAS No.: 14704-34-8 [00265]embedded image [00266]embedded image I-5 [00267]embedded image [00268]embedded image [00269]embedded image [00270]embedded image Isomeric compounds are separated by means of recrystallization I-6 [00271]embedded image [00272]embedded image [00273]embedded image I-7 [00274]embedded image [00275]embedded image [00276]embedded image I-8 [00277]embedded image [00278]embedded image [00279]embedded image

    N,9-Bis({[1,1′-biphenyl]-4-yl})-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-fluorene-4-amine

    [0151] 10.0 g of N-{1,1′-biphenyl]-4-yl}-9,9-dimethylfluoren-2-amine (27.7 mmol) and 13.1 g of 9-{[1,1′-biphenyl]-4-yl}-4-bromo-9-phenylfluorene (27.7 mol) are dissolved in 300 ml of toluene. The solution is degassed and saturated with N.sub.2. Thereafter, 340 mg (0.83 mmol) of S-Phos and 250 mg (0.28 mmol) of Pd.sub.2(dba).sub.3 are added thereto, and then 4.6 g of sodium tert-butoxide (41.5 mmol) is added. The reaction mixture is heated to boiling under a protective atmosphere for 3 h. The mixture is subsequently partitioned between toluene and water, and the organic phase is washed three times with water and dried over Na.sub.2SO.sub.4 and concentrated by rotary evaporation. After the crude product has been filtered through silica gel with toluene, the remaining residue is recrystallized from heptane/toluene. The yield is 16.7 g (80% of theory). The substance is finally sublimed under high vacuum; the purity is 99.9%.

    [0152] The compounds below are prepared in an analogous manner. The yields here are between 65% and 90%.

    TABLE-US-00002 Reactant 1 Reactant 2 Product 1-2 [00280]embedded image [00281]embedded image [00282]embedded image 1-3 [00283]embedded image [00284]embedded image [00285]embedded image 1-4 [00286]embedded image [00287]embedded image [00288]embedded image 1-5 [00289]embedded image [00290]embedded image [00291]embedded image 1-6 [00292]embedded image [00293]embedded image [00294]embedded image 1-7 [00295]embedded image [00296]embedded image [00297]embedded image 1-8 [00298]embedded image [00299]embedded image [00300]embedded image 1-9 [00301]embedded image [00302]embedded image [00303]embedded image 1-10 [00304]embedded image [00305]embedded image [00306]embedded image 1-11 [00307]embedded image [00308]embedded image [00309]embedded image 1-12 [00310]embedded image [00311]embedded image [00312]embedded image 1-13 [00313]embedded image [00314]embedded image [00315]embedded image 1-14 [00316]embedded image [00317]embedded image [00318]embedded image 1-15 [00319]embedded image [00320]embedded image [00321]embedded image 1-16 [00322]embedded image [00323]embedded image [00324]embedded image 1-17 [00325]embedded image [00326]embedded image [00327]embedded image 1-18 [00328]embedded image [00329]embedded image [00330]embedded image

    Example 2-1

    N-{[1,1′-Biphenyl]-4-yl}-N-[4-(9-{[1,1′-biphenyl]-4-yl}-9-phenyl-9H-fluoren-4-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine

    [0153] ##STR00331##

    Intermediate III-1: 9-{[1,1′-Biphenyl]-4-yl}-4-(4-chlorophenyl)-9-phenylfluorene

    [0154] 5.90 g (37.7 mmol) of 4-chlorophenylboronic acid and 15 g (37.7 mmol) of Intermediate I-1 are suspended in 200 ml of THF and 38 ml of a 2M potassium carbonate solution (75.5 mmol). 0.87 g (0.76 mmol) of tetrakis(triphenylphosphine)palladium is added to this suspension, and the reaction mixture is heated under reflux for 12 h. After cooling, the organic phase is removed, filtered through silica gel, washed three times with 100 ml of water and then concentrated to dryness. After the crude product has been filtered through silica gel with toluene, 15.46 g (95%) of Intermediate III-1 is obtained.

    [0155] The compounds below are prepared in an analogous manner. The yields here are between 40% and 90%.

    TABLE-US-00003 Reactant 1 Reactant 2 Product III- 2 [00332]embedded image [00333]embedded image [00334]embedded image III- 3 [00335]embedded image [00336]embedded image [00337]embedded image III- 4 [00338]embedded image [00339]embedded image [00340]embedded image III- 5 [00341]embedded image [00342]embedded image [00343]embedded image III- 6 [00344]embedded image [00345]embedded image [00346]embedded image 2- 2 [00347]embedded image [00348]embedded image [00349]embedded image III- 7 [00350]embedded image [00351]embedded image [00352]embedded image III- 8 [00353]embedded image [00354]embedded image [00355]embedded image III- 9 [00356]embedded image [00357]embedded image [00358]embedded image 2- 3 [00359]embedded image [00360]embedded image [00361]embedded image 2- 12 [00362]embedded image [00363]embedded image [00364]embedded image 2- 13 [00365]embedded image [00366]embedded image [00367]embedded image III- 10 [00368]embedded image [00369]embedded image [00370]embedded image III- 11 [00371]embedded image [00372]embedded image [00373]embedded image

    N-{[1,1′-Biphenyl]-4-yl}-N-[4-(9-{[1,1′-biphenyl]-4-yl}-9-phenyl-9H-fluoren-4-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine

    [0156] Analogously to Example 1-1, N-{[1,1′-biphenyl]-4-yl}-N-[4-(9-{[1,1′-biphenyl]-4-yl}-9-phenyl-9H-fluoren-4-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (compound 2-1) and the compounds below are prepared. The yields here are between 40% and 85%.

    TABLE-US-00004 Reactant 1 Reactant 2 Product 2- 4 [00374]embedded image [00375]embedded image [00376]embedded image 2- 5 [00377]embedded image [00378]embedded image [00379]embedded image 2- 6 [00380]embedded image [00381]embedded image [00382]embedded image 2- 7 [00383]embedded image [00384]embedded image [00385]embedded image 2- 8 [00386]embedded image [00387]embedded image [00388]embedded image 2- 9 [00389]embedded image [00390]embedded image [00391]embedded image 2- 10 [00392]embedded image [00393]embedded image [00394]embedded image 2- 11 [00395]embedded image [00396]embedded image [00397]embedded image III- 12 [00398]embedded image [00399]embedded image [00400]embedded image 2- 14 [00401]embedded image [00402]embedded image [00403]embedded image

    B) Device Examples

    1) General Production Process for the OLEDs and Characterization of the OLEDs

    [0157] Glass plaques which have been coated with structured ITO (indium tin oxide) in a thickness of 50 nm are the substrates to which the OLEDs are applied.

    [0158] The OLEDs basically have the following layer structure: substrate/hole injection layer (HIL)/hole transport layer (HTL)/electron blocker layer (EBL)/emission layer (EML)/electron transport layer (ETL)/electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer of thickness 100 nm. The exact structure of the OLEDs can be found in the tables which follow. The materials required for production of the OLEDs are shown in a table below.

    [0159] All materials are applied by thermal vapour deposition in a vacuum chamber. In this case, the emission layer consists of at least one matrix material (host material) and an emitting dopant (emitter) which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as H:SEB (95%:5%) mean here that the material H is present in the layer in a proportion by volume of 95% and SEB in a proportion of 5%.

    [0160] In an analogous manner, the electron transport layer and the hole injection layer also consist of a mixture of two materials. The structures of the materials that are used in the OLEDs are shown in Table 3.

    [0161] The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, the external quantum efficiency (EQE, measured in %) as a function of the luminance, calculated from current-voltage-luminance characteristics assuming Lambertian radiation characteristics, and the lifetime are determined. The parameter EQE @ 10 mA/cm.sup.2 refers to the external quantum efficiency which is attained at 10 mA/cm.sup.2. The parameter U @ 10 mA/cm.sup.2 refers to the operating voltage at 10 mA/cm.sup.2. The lifetime LT is defined as the time after which the luminance drops from the starting luminance to a certain proportion in the course of operation with constant current density. An LT80 figure means here that the lifetime reported corresponds to the time after which the luminance has dropped to 80% of its starting value. The figure @60 or 40 mA/cm.sup.2 means here that the lifetime in question is measured at 60 or 40 mA/cm.sup.2.

    [0162] 2) Use of the Compounds of the Invention in the HIL/HTL and EBL of Blue-Fluorescing and Green-Phosphorescing Devices

    [0163] OLEDs are produced with the following structure:

    TABLE-US-00005 TABLE 1 OLED structure HIL HTL EBL EML ETL EIL Ex. Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm I1 HTM-4:p-doped HTM-4 EBM H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I14 HTM-7:p-doped HTM-7 EBM H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I2 HTM:p-doped HTM HTM-1 H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I3 HTM:p-doped HTM HTM-2 H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I4 HTM:p-doped HTM HTM-3 H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I5 HTM:p-doped HTM HTM-4 H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I6 HTM:p-doped HTM HTM-5 H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) 20 nm (50%) 30 nm 1 nm I7 HTM:p-doped HTM HTM-6 H:SEB ETM:LiQ LiQ (5%) 20 nm 180 nm 10 nm (5%) (50%) 30 nm 1 nm 20 nm I8 HTM:p-doped HTM HTM-1 TMM-1:TMM-2 ETM:LiQ LiQ (5%) 20 nm 220 nm 10 nm (28%):TEG (50%) 30 nm 1 nm (12%) 30 nm I9 HTM:p-doped HTM HTM-2 TMM-1:TMM-2 ETM:LiQ LiQ (5%) 20 nm 220 nm 10 nm (28%):TEG (50%) 30 nm 1 nm (12%) 30 nm I10 HTM:p-doped HTM HTM-3 TMM-1:TMM-2 ETM:LiQ LiQ (5%) 20 nm 220 nm 10 nm (28%):TEG (50%) 30 nm 1 nm (12%) 30 nm I11 HTM:p-doped HTM HTM-4 TMM-1:TMM-2 ETM:LiQ LiQ (5%) 20 nm 220 nm 10 nm (28%):TEG (50%) 30 nm 1 nm (12%) 30 nm I12 HTM:p-doped HTM HTM-5 TMM-1:TMM-2 ETM:LiQ LiQ (5%) 20 nm 220 nm 10 nm (28%):TEG (50%) 30 nm 1 nm (12%) 30 nm I13 HTM:p-doped HTM HTM-6 TMM-1:TMM-2 ETM:LiQ LiQ (5%) 20 nm 220 nm 10 nm (28%):TEG (50%) 30 nm 1 nm (12%) 30 nm

    [0164] OLEDs I1 and I14 show the use of compounds HTM-4 and HTM-7 according to the application in the HIL (p-doped) and HTL of a blue-fluorescing OLED.

    [0165] OLEDs I2 to I7 show the use of compounds HTM-1 to HTM-6 according to the application in the EBL of blue-fluorescing OLEDs.

    [0166] OLEDs I8 to I13 show the use of compounds HTM-1 to HTM-6 according to the application in the EBL of green-phosphorescing OLEDs.

    [0167] The OLEDs show the following values for operating voltage, EQE and lifetime:

    TABLE-US-00006 TABLE 2 OLED data U @ 10 EQE @ 10 LT80 @ 60/40* mA/cm.sup.2 (V) mA/cm.sup.2 (%) mA/cm.sup.2 (h) I1 4.1 8.8 220 I14 4.3 8.4 310 I2 3.9 8.5 280 I3 4.0 8.9 250 I4 3.8 8.8 260 I5 3.8 8.9 250 I6 4.0 8.6 200 I7 3.9 8.7 300 I8 3.9 17.2  310* I9 4.0 17.8  270* I10 3.9 16.8  270* I11 3.8 16.6  340* I12 3.9 16.8  220* I13 4.1 17.2  300*

    [0168] The OLEDs show a good lifetime, high efficiency and low operating voltage. This result is obtained in all three OLED structures used and for all compounds according to the application used above.

    TABLE-US-00007 TABLE 3 Materials used [00404]embedded image p-Dopant [00405]embedded image HTM [00406]embedded image EBM [00407]embedded image H [00408]embedded image SEB [00409]embedded image TMM-1 [00410]embedded image TMM-2 [00411]embedded image TEG [00412]embedded image ETM [00413]embedded image LiQ [00414]embedded image HTM-1 [00415]embedded image HTM-2 [00416]embedded image HTM-3 [00417]embedded image HTM-4 [00418]embedded image HTM-5 [00419]embedded image HTM-6 [00420]embedded image HTM-7 [00421]embedded image Ref-1 [00422]embedded image Ref-2

    [0169] 3) Comparative Experiment with Compounds HTM-4 and Ref-1

    [0170] Compound HTM-4 according to the application is compared with reference compound Ref-1. The compounds differ merely in the substituents at the bridgehead carbon of the fluorene and are otherwise identical: in the case of HTM-4, there is asymmetric substitution there, with a phenyl group and a meta-biphenyl group as substituents. In Ref-1 there is symmetric substitution in the position mentioned, with two phenyl groups.

    [0171] An OLED stack is used, as also used in Part 2), in which the compounds are present in the EBL in a blue-fluorescing stack. Ref-1 here shows a voltage at 10 mA/cm.sup.2 of 3.7 V and EQE at 10 mA/cm.sup.2 of 8.5%. HTM-4, in the equivalent structure 15, shows a better EQE of 8.9% at similar voltage (3.8 V).

    [0172] This shows the advantage that results from the use of an asymmetric substitution at the bridgehead carbon atom, especially a substitution by biphenyl and phenyl on that atom, compared to a symmetric substitution by two phenyl groups.

    TABLE-US-00008 TABLE 4 Device setup comparative example Ref-1 vs. HTM-4 HIL HTL EBL EML ETL EIL Ex. Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm C1 HTM:p-doped HTM Ref-1 H:SEB(5%) ETM:LiQ(50%) LiQ (5%) 20 nm 180 nm 10 nm 20 nm 30 nm 1 nm I5 HTM:p-doped HTM HTM-4 H:SEB(5%) ETM:LiQ(50%) LiQ (5%) 20 nm 180 nm 10 nm 20 nm 30 nm 1 nm

    [0173] 4) Comparative Experiment with Compounds HTM-7 and Ref-2

    [0174] Compound HTM-7 according to the application is compared with reference compound Ref-2. The compounds differ merely in the substituents at the bridgehead carbon atom of the fluorene: Ref-2 has alkyl substitution on the phenyl group at the bridgehead carbon atom mentioned, whereas HTM-7 does not have alkyl substitution.

    [0175] An OLED structure is used, as also used in Part 2), in which the compounds are present in the HIL and HTL in a blue-fluorescing stack.

    [0176] Reference compound Ref-2 here shows a voltage at 10 mA/cm.sup.2 of 4.2 V. The lifetime LT80, measured at 60 mA/cm.sup.2, is 150 h. HTM-7, by contrast, in the equivalent structure, shows a significantly better LT80 of 310 h at comparable voltage (4.3 V).

    [0177] This shows the improvement that results from the omission of alkyl groups on the substituents at the bridgehead carbon atom. This improvement is not limited to the structures shown, but occurs in general.

    TABLE-US-00009 TABLE 5 Device setup comparative example Ref-2 vs. HTM-7 HIL HTL EBL EML ETL EIL Ex. Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm C2 Ref-2:p-doped Ref-2 EBM H:SEB(5%) ETM:LiQ(50%) LiQ (5%) 20 nm 180 nm 10 nm 20 nm 30 nm 1 nm I14 HTM-5:p-doped HTM-7 EBM H:SEB(5%) ETM:LiQ(50%) LiQ (5%) 20 nm 180 nm 10 nm 20 nm 30 nm 1 nm