NITROGENOUS HETEROCYCLES FOR ORGANIC ELECTROLUMINESCENT DEVICES

[0001] The present invention relates to nitrogenous heterocycles for use in electronic devices, especially in organic electroluminescent devices, and to electronic devices, especially organic electroluminescent devices comprising these materials.

[0002] Electronic devices containing organic compounds are widely known and commercially available. These devices may, for example, in each case comprise one or more hole injection layers, hole transport layers, hole blocker layers, electron transport layers, electron injection layers, exciton blocker layers, electron blocker layers and/or charge generation layers. In general, there is a need for improvement with regard to the properties of these devices, and the compounds used in the above-detailed layers in particular have a major effect on the properties of the devices.

[0003] Furthermore, emitting materials used in organic electroluminescent devices are frequently phosphorescent organometallic complexes. For quantum-mechanical reasons, up to four times the energy efficiency and power efficiency is possible using organometallic compounds as phosphorescent emitters. In electroluminescent devices, especially also in electroluminescent devices that exhibit triplet emission (phosphorescence), there is generally still a need for improvement. The properties of phosphorescent electroluminescent devices are determined not only by the triplet emitters used. More particularly, the other materials used, such as matrix materials, are also of particular significance here. Improvements in these materials can thus also lead to distinct improvements in the properties of the electroluminescent devices.

[0004] Similar statements also apply to organic electroluminescent devices based on phosphorescent emitters, or emitters that exhibit TADF (thermally activated delayed fluorescence).

[0005] EP 3 070 144 A1 and WO 2017/178864 A1 disclose nitrogenous heterocycles that can be used in organic electroluminescent devices. There is no disclosure of compounds according to the present invention.

[0006] In general terms, in the case of these materials, for example for use as matrix materials and hole and/or electron transport materials, there is still a need for improvement, particularly in relation to the efficiency and the operating voltage, but also in relation to the lifetime of the device.

[0007] It is therefore an object of the present invention to provide compounds which are suitable for use in an organic electronic device, especially in an organic electroluminescent device, and which lead to good device properties when used in this device, and to provide the corresponding electronic device.

[0008] More particularly, the object addressed by the present invention is that of providing compounds which lead to a high lifetime, good efficiency and low operating voltage. Particularly the properties of the matrix materials too have a major influence on the lifetime and efficiency of the organic electroluminescent device.

[0009] A further object of the present invention can be considered that of providing compounds suitable for use in phosphorescent or fluorescent electroluminescent devices, especially as a matrix material. It is in particular an object of the present invention to provide matrix materials suitable for blue-, green-, yellow- and red-phosphorescing electroluminescent devices, especially for blue-phosphorescing electroluminescent devices.

[0010] In addition, the compounds, especially when they are used as matrix materials, as hole transport materials or as electron transport materials in organic electroluminescent devices, should lead to devices having excellent lifetime and efficiency.

[0011] A further object can be considered that of providing electronic devices having excellent performance very inexpensively and in constant quality.

[0012] Furthermore, it should be possible to use or adapt the electronic devices for many purposes. More particularly, the performance of the electronic devices should be maintained over a broad temperature range.

[0013] It has been found that, surprisingly, this object is achieved by particular compounds described in detail below that are of good suitability for use in electroluminescent devices and lead to organic electroluminescent devices that show very good properties, especially in relation to lifetime, color purity and efficiency, and operating voltage. The present invention therefore provides these compounds and electronic devices, especially organic electroluminescent devices, comprising such compounds.

[0014] The present invention provides a compound comprising at least one structure of the formula (I), preferably a compound of the formula (I),

where the symbols are as follows:

• • [0015] A is the same or different at each instance and is B(R), B(Ar), P(R)O, P(Ar)O, C(R)₂, C(Ar)₂, Si(R)₂, Si(Ar)₂, Ge(R)₂, Ge(Ar)₂, Ti(R)₂, Ti(Ar)₂, Zr(R)₂, Zr(Ar)₂, Hf(R)₂, Hf(Ar)₂, SO₂ or SO, preferably B(R), B(Ar), P(R)O, P(Ar)O, C(R)₂, C(Ar)₂, Si(R)₂, Si(Ar)₂, Ge(R)₂ or Ge(Ar)₂, more preferably C(R)₂, C(Ar)₂, Si(R)₂, Si(Ar)₂, Ge(R)₂ or Ge(Ar)₂, and most preferably Si(Ar)₂ or Si(R)₂;
  • [0016] Z is the same or different at each instance and is N(R^a), N(Ar^a), O or S, preferably N(R^a) or N(Ar^a) and more preferably N(Ar^a);
  • [0017] X¹ is the same or different at each instance and is N or CR^b, preferably N, with the proviso that not more than two of the X¹, X², X³ groups in one cycle are N, or the X¹ group together with an X² group forms an ortho-bonded aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^b radicals;
  • [0018] X² is the same or different at each instance and is N or CR^b, preferably CR^b, with the proviso that not more than two of the X¹, X², X³ groups in any cycle are N;
  • [0019] X³ is the same or different at each instance and is N or CR^b, with the proviso that not more than two of the X¹, X², X³ groups in one cycle are N, or the X³ group together with an X² group forms an ortho-bonded aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^b radicals, where the X² group forms an aromatic or heteroaromatic ring system with not more than one X¹ or X³ group in any cycle;
  • [0020] R is the same or different at each instance and is H, D, OH, F, Cl, Br, I, CN, NO₂, N(Ar)₂, N(R^c)₂, C(═O)N(Ar)₂, C(═O)N(R^c)₂, C(Ar)₃, C(R^c)₃, Si(Ar)₃, Si(R^c)₃, Ge(R^c)₂, Ge(Ar)₃, B(Ar)₂, B(R^c)₂, C(═O)Ar, C(═O)R^c, P(=O)(Ar)₂, P(=O)(R^c)₂, P(Ar)₂, P(R^c)₂, S(═O)Ar, S(═O)R^c, S(═O)₂Ar, S(═O)₂R^c, OSO₂Ar, OSO₂R^c, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group may in each case be substituted by one or more R^c radicals, where one or more nonadjacent CH₂ groups may be replaced by R^cC=CR^c, C≡C, Si(R^c)₂, Ge(R^c)₂, C=O, C=S, C=Se, C=NR^c, —C(═O)O—, —C(═O)NR^c—, NR^c, P(=O)(R^c), —O—, —S—, SO or SO₂, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R^c radicals, or an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^c radicals, or an arylthio or heteroarylthio group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^c radicals, or a diarylamino, arylheteroarylamino, diheteroarylamino group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^c radicals, or an arylalkyl or heteroarylalkyl group which has 5 to 60 aromatic ring atoms and 1 to 10 carbon atoms in the alkyl radical and may be substituted by one or more R^c radicals; at the same time, one R radical may form a ring system together with a further group, preferably R^b;
  • [0021] Ar is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^c radicals; at the same time, it is possible for two Ar radicals bonded to the same carbon atom, silicon atom, germanium atom, titanium atom, zirconium atom, hafnium atom also to be bridged to one another by a single bond or a bridge selected from B(R^c), C(R^c)₂, Si(R^c)₂, Ge(R^c)₂, C=O, C=NR^c, C=C(R^c)₂, O, S, S═O, SO₂, N(R^c), P(R^c) and P(═O)R^c;
  • [0022] Ar^a is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R^a radicals;
  • [0023] R^a, R^b, R^c is the same or different at each instance and is H, D, OH, F, Cl, Br, I, CN, NO₂, N(Ar′)₂, N(R¹)₂, C(═O)N(Ar′)₂, C(═O)N(R¹)₂, C(Ar′)₃, C(R¹)₃, Si(Ar′)₃, Si(R¹)₃, Ge(Ar′)₃, Ge(R¹)₃, B(Ar′)₂, B(R¹)₂, C(═O)Ar′, C(═O)R¹, P(=O)(Ar′)₂, P(=O)(R¹)₂, P(Ar′)₂, P(R¹)₂, S(═O)Ar′, S(═O)R¹, S(═O)₂Ar′, S(═O)₂R¹, OSO₂Ar′, OSO₂R¹, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group may be substituted in each case by one or more R¹ radicals, where one or more nonadjacent CH₂ groups may be replaced by R¹C=CR¹, C≡C, Si(R¹)₂, Ge(R¹)₂, C═O, C=S, C=Se, C=NR¹, —C(═O)O—, —C(═O)NR¹—, NR¹, P(=O)(R¹), —O—, —S—, SO or SO₂, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R¹ radicals, or an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R¹ radicals; at the same time, two R^a, R^b, R^c radicals may also form a ring system with one another or with a further group, preferably R;
  • [0024] Ar′ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R¹ radicals, where it is possible for two Ar′ radicals bonded to the same carbon atom, silicon atom, germanium atom, nitrogen atom, phosphorus atom or boron atom also to be bridged to one another by a single bond or a bridge selected from B(R¹), C(R¹)₂, Si(R¹)₂, C═O, C=NR¹, C=C(R¹)₂, O, S, S=O, SO₂, N(R¹), P(R¹) and P(═O)R¹;
  • [0025] R¹ is the same or different at each instance and is H, D, F, Cl, Br, I, CN, NO₂, N(Ar″)₂, N(R²)₂, C(═O)Ar″, C(═O)R², P(=O)(Ar″)₂, P(Ar″)₂, B(Ar″)₂, B(R²)₂, C(Ar″)₃, C(R²)₃, Si(Ar″)₃, Si(R²)₃, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 carbon atoms or an alkenyl group having 2 to 40 carbon atoms, each of which may be substituted by one or more R² radicals, where one or more nonadjacent CH₂ groups may be replaced by —R²C=CR²—, —C≡C—, Si(R²)₂, C=O, C=S, C=Se, C=NR², —C(═O)O—, —C(═O)NR²—, NR², P(=O)(R²), —O—, —S—, SO or SO₂ and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R² radicals, or an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R² radicals, or an aralkyl or heteroaralkyl group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R² radicals, or a combination of these systems; at the same time, two or more, preferably adjacent, R¹ radicals may form a ring system with one another; at the same time, one or more R¹ radicals may form a ring system with another part of the compound;
  • [0026] Ar″ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more R² radicals; at the same time, it is possible for two Ar″ radicals bonded to the same carbon atom, silicon atom, nitrogen atom, phosphorus atom or boron atom also to be joined together via a bridge by a single bond or a bridge selected from B(R²), C(R²)₂, Si(R²)₂, C=O, C=NR², C=C(R²)₂, O, S, S=O, SO₂, N(R²), P(R²) and P(═O)R²;
  • [0027] R² is the same or different at each instance and is selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms or an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and in which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I or CN and which may be substituted by one or more alkyl groups each having 1 to 4 carbon atoms, where two or more, preferably adjacent, substituents R² together may form a ring system.

[0028] It may preferably be the case that exactly one X¹, X³ group in one cycle is N, more preferably the X¹ group.

[0029] An aryl group in the context of this invention contains 6 to 40 carbon atoms; a heteroaryl group in the context of this invention contains 3 to 40 carbon atoms and at least one heteroatom, with the proviso that the sum total of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or S. An aryl group or heteroaryl group is understood here to mean either a simple aromatic cycle, i.e. benzene, or a simple heteroaromatic cycle, for example pyridine, pyrimidine, thiophene, etc., or a fused (annelated) aryl or heteroaryl group, for example naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatics joined to one another by a single bond, for example biphenyl, by contrast, are not referred to as an aryl or heteroaryl group but as an aromatic ring system.

[0030] An electron-deficient heteroaryl group in the context of the present invention is a heteroaryl group having at least one heteroaromatic six-membered ring having at least one nitrogen atom. Further aromatic or heteroaromatic five-membered or six-membered rings may be fused onto this six-membered ring. Examples of electron-deficient heteroaryl groups are pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, quinazoline or quinoxaline.

[0031] An aromatic ring system in the context of this invention contains 6 to 60 carbon atoms in the ring system. A heteroaromatic ring system in the context of this invention contains 3 to 60 carbon atoms and at least one heteroatom in the ring system, with the proviso that the sum total of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or S. An aromatic or heteroaromatic ring system in the context of this invention shall be understood to mean a system which does not necessarily contain only aryl or heteroaryl groups, but in which it is also possible for two or more aryl or heteroaryl groups to be joined by a nonaromatic unit, for example a carbon, nitrogen or oxygen atom. For example, systems such as fluorene, 9,9′-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ethers, stilbene, etc. shall also be regarded as aromatic ring systems in the context of this invention, and likewise systems in which two or more aryl groups are joined, for example, by a short alkyl group. Preferably, the aromatic ring system is selected from fluorene, 9,9′-spirobifluorene, 9,9-diarylamine or groups in which two or more aryl and/or heteroaryl groups are joined to one another by single bonds.

[0032] In the context of the present invention, an aliphatic hydrocarbyl radical or an alkyl group or an alkenyl or alkynyl group which may contain 1 to 20 carbon atoms and in which individual hydrogen atoms or CH₂ groups may also be substituted by the abovementioned groups is preferably understood to mean the methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, neopentyl, cyclopentyl, n-hexyl, neohexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl radicals. An alkoxy group having 1 to 40 carbon atoms is preferably understood to mean methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, n-pentoxy, s-pentoxy, 2-methylbutoxy, n-hexoxy, cyclohexyloxy, n-heptoxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy and 2,2,2-trifluoroethoxy. A thioalkyl group having 1 to 40 carbon atoms is understood to mean especially methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio, i-butylthio, s-butylthio, t-butylthio, n-pentylthio, s-pentylthio, n-hexylthio, cyclohexylthio, n-heptylthio, cycloheptylthio, n-octylthio, cyclooctylthio, 2-ethylhexylthio, trifluoromethylthio, pentafluoroethylthio, 2,2,2-trifluoroethylthio, ethenylthio, propenylthio, butenylthio, pentenylthio, cyclopentenylthio, hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio, octenylthio, cyclooctenylthio, ethynylthio, propynylthio, butynylthio, pentynylthio, hexynylthio, heptynylthio or octynylthio. In general, alkyl, alkoxy or thioalkyl groups according to the present invention may be straight-chain, branched or cyclic, where one or more nonadjacent CH₂ groups may be replaced by the abovementioned groups; in addition, it is also possible for one or more hydrogen atoms to be replaced by D, F, Cl, Br, I, CN or NO₂, preferably F, Cl or CN, further preferably F or CN, especially preferably CN.

[0033] An aromatic or heteroaromatic ring system which has 5-60 or 5-40 aromatic ring atoms and may also be substituted in each case by the abovementioned radicals and which may be joined to the aromatic or heteroaromatic system via any desired positions is understood to mean especially groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, triphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, hexaazatriphenylene, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole, or groups derived from combinations of these systems.

[0034] The wording that two or more radicals together may form a ring, in the context of the present description, should be understood to mean, inter alia, that the two radicals are joined to one another by a chemical bond with formal elimination of two hydrogen atoms. This is illustrated by the following scheme:

[0035] In addition, however, the abovementioned wording shall also be understood to mean that, if one of the two radicals is hydrogen, the second radical is bonded to the position to which the hydrogen atom was bonded, forming a ring. This will be illustrated by the following scheme:

[0036] In a preferred configuration, the compounds of the invention may preferably comprise at least one structure of the formulae (I-1) to (I-11), and are more preferably selected from the compounds of the formulae (I-1) to (I-11):

where the symbols Z, A and R^b have the definitions given above, especially for formula (I), and X is N or C(R^b), preferably C(R^b). Preferably, not more than 3 and more preferably not more than two of the X groups are N.

[0037] Preference is given here to structures/compounds of the formulae (I-1) to (I-4), particular preference to structures/compounds of the formulae (I-1) and/or (I-2), and very particular preference to structures/compounds of the formula (I-1).

[0038] The Z group is preferably N(Ar^a), where preferred configurations of the Ar^a group are also set out hereinafter in connection with the Ar group that may be part of the Z radical.

[0039] The A group is preferably B(Ar), P(Ar)O, C(Ar)₂, Si(Ar)₂ or Ge(Ar)₂, where preferred configurations of the Ar group are also set out hereinafter in connection with the Ar^a group that may be part of the A radical.

[0040] It may preferably be the case that the Ar, Ar^a and/or R radical is an aromatic or heteroaromatic ring system which has 5 to 18 aromatic ring atoms, preferably 6 to 13 aromatic ring atoms, and may be substituted by one or more R^a or R^c radicals.

[0041] In addition, it may be the case that the Ar and/or Ar^a group is the same or different at each instance and is selected from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, anthracene, phenanthrene or triphenylene, each of which may be substituted by one or more R^c or R^a radicals, preferably phenyl, biphenyl, fluorene, dibenzofuran, triphenylene, carbazole, indolocarbazole.

[0042] The Ar^a group and/or the Ar group may preferably be a phenyl group substituted by at least one R^a or R^c radical, where the substituent is in ortho, meta or para position based on the nitrogen atom in the N(Ar^a) group or the boron, phosphorus, carbon, silicon or germanium atom of the A group. For example, if the R^a or R^c radical is a phenyl group, an ortho-, meta- or para-biphenyl group may be formed.

[0043] If the Ar^a group and/or the Ar group is a triazine group, it may preferably be the case that the triazine group has two R^a or R^c radicals that are not H or D, where the two R^a or R^c radicals are preferably an aromatic or heteroaromatic ring system which has 5 to 60, preferably 6 to 30, aromatic ring atoms and may be substituted in each case by one or more R¹ radicals.

[0044] Moreover, the Ar^a group and/or the Ar group may preferably be a phenyl group substituted by at least one R^a or R^c radical, where the substituent together with the phenyl group represented by the Ar^a group and/or the Ar group is formed a fluorene radical which may be bonded via the 1, 2, 3 or 4 position, a spirobifluorene radical which may be bonded via the 1, 2, 3 or 4 position, an indole radical, a benzofuran radical, a benzothiophene radical, a carbazole radical which may be bonded via the 1, 2, 3 or 4 position, a dibenzofuran radical which may be bonded via the 1, 2, 3 or 4 position, a dibenzothiophene radical which may be bonded via the 1, 2, 3 or 4 position, an indenocarbazole radical or an indolocarbazole radical.

[0045] In a further preferred embodiment, it may be the case that the A group is C(R)₂, Si(R)₂ or Ge(R)₂, where preferred R radicals are selected from straight-chain alkyl groups having 1 to 40 carbon atoms or alkenyl or alkynyl groups having 2 to 40 carbon atoms or branched or cyclic alkyl groups having 3 to 20 carbon atoms, where this group may in each case be substituted by one or more R^c radicals.

[0046] In a further configuration, it may be the case that the structure/compound according to the present invention comprises at least one electron transport group and/or an electron-withdrawing radical. Electron transport groups are widely known in the technical field and promote the ability of compounds to transport and/or to conduct electrons. Examples of electron transport groups are pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinazoline, quinoxaline, quinoline, isoquinoline, imidazole and/or benzimidazole groups, with particular preference for triazine groups. The electron-withdrawing radicals especially include SO₂, B(R), B(Ar), P(R)O, P(Ar)O, which may be present, for example, as the A group. In addition, these electron-withdrawing radicals may also be present as substituent R^a, R^b, R^c in the structure/compound of formula (I) and/or formulae (I-1) to (I-11), for example as substituents B(Ar′)₂, B(R¹)₂, P(=O)(Ar′)₂, P(=O)(R¹)₂, S(═O)₂Ar′, S(═O)₂R¹. In addition, electron-withdrawing radicals also include, for example, C═O groups or CN radicals that may be present as substituent in the structures, for example as substituent C(═O)Ar, C(═O)Ar′, C(═O)R^c, C(═O)R^a or C(═O)R¹.

[0047] In a further configuration, it may be the case that the structure/compound according to the present invention at least one hole transport group. Hole transport groups are likewise known in the technical field, and they preferably include triarylamine or carbazole groups.

[0048] The present compounds are especially suitable as host material for emitters, preferably as host material for singlet, triplet and TADF emitters, electron transport material, electron injection material, hole conductor material, hole injection material, electron blocker material, hole blocker material, in an electronic device. The specific properties of the compounds depend here on the type and number of the respective functional groups. Compounds comprising one, two or more electron transport groups and/or electron-withdrawing radicals, but not a hole transport group, are especially suitable as host material, electron transport material, electron injection material and/or hole blocker material. Compounds comprising one, two or more hole transport groups, but not an electron transport group and/or electron-withdrawing radicals, are especially suitable as host material, hole conductor material, hole injection material and/or electron blocker material. Compounds comprising one, two or more hole transport groups and one, two or more electron transport groups and/or electron-withdrawing radicals are especially suitable as host material.

[0049] It may also be the case that at least one of, preferably all of, the R, R^a radicals is/are not H, preferably not H, D, OH, NO₂, F, Cl, Br, I.

[0050] In a further preferred embodiment, it may be the case that the compounds of the invention include a structure of the formulae (II-1) to (II-8), where the compounds of the invention may more preferably be selected from the compounds of the formulae (II-1) to (II-8)

where the symbols A and R^b have the definition given above, especially for formula (I), and the further symbols are as follows:

• • [0051] X^a is the same or different at each instance and is N, CR^a or C if a group is bonded to the structure, preferably CR^a or C, with the proviso that not more than three of the X^a groups in any cycle are N, where R^a has the definition given above, especially for formula (I);
  • [0052] Y is the same or different at each instance and is B(R^a), C(R^a)₂, Si(R^a)₂, Ge(R^a)₂, C═O, C=NR^a, C=C(R^a)₂, O, S, S═O, SO₂, N(R^a), P(R^a) or P(═O)R^a, preferably N(R^a), O, S, B(R^a), C(R^a)₂, Si(R^a)₂ or Ge(R^a)₂, more preferably N(R^a), O or S, where R^a has the definition given in claim 1, or if a group is bonded to the structure is C(R^a)—, Si(R^a)—, Ge(R^a)—;
  • [0053] n is 0, 1, 2 or 3, preferably 0, 1 or 2; and
  • [0054] m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2.

[0055] Preference is given here to structures/compounds of the formulae (II-1), (II-2) and (II-3), particular preference to structures/compounds of the formulae (II-1) and (II-2), and very particular preference to structures/compounds of the formula (II-1).

[0056] In formulae (II-1) to (II-8), it may be the case that X^a is C if a group is bonded to the particular structure. This group is especially the ring structure provided with an Y radical and shown in formula (II-2) or (II-4). This ring structure may be bonded here via a X^a radical or via Y, in which latter case Y is C(R^a)—, Si(R^a)—, Ge(R^a)—.

[0057] In one embodiment, it may be the case that, in structures/compounds of the formulae (II-1) to (II-8), not more than three, preferably two, X^a groups per ring are N, and preferably all X^a are CR^a; preferably at least one, more preferably at least two of the X^a groups per ring are selected from C—H and C-D.

[0058] It may further be the case that at least one, preferably at least two and more preferably three X^a groups per ring are N, where these groups are preferably nonadjacent. These structures/compounds preferably comprise electron transport groups and are therefore particularly suitable as electron transport materials and/or matrix materials.

[0059] In a further preferred embodiment, it may be the case that the compounds of the invention include a structure of the formulae (III-1) to (III-12), where the compounds of the invention may more preferably be selected from the compounds of the formulae (III-1) to (III-12)

where the symbols A, R^a and R^b have the definitions given above, especially for formula (I), and the further symbols are as follows:

• • [0060] Y is the same or different at each instance and is B(R^a), C(R^a)₂, Si(R^a)₂, Ge(R^a)₂, C═O, C=NR^a, C=C(R^a)₂, O, S, S═O, SO₂, N(R^a), P(R^a) or P(═O)R^a, preferably N(R^a), O, S, B(R^a), C(R^a)₂, Si(R^a)₂ or Ge(R^a)₂, more preferably N(R^a), 0 or S;
  • [0061] j is 0, 1 or 2;
  • [0062] n is 0, 1, 2 or 3, preferably 0, 1 or 2;
  • [0063] m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2;
  • [0064] l is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2.

[0065] Preference is given here to structures/compounds of the formulae (III-1) to (III-8), particular preference to structures/compounds of the formulae (Ill-1), (III-2), (III-5) and (III-6), and very particular preference to structures/compounds of the formulae (III-1) and (III-2).

[0066] The sum total of the indices j, m, n and l in structures/compounds of the formulae (III-1) to (III-12) is preferably not more than 6, especially preferably not more than 4 and more preferably not more than 2.

[0067] In a further preferred embodiment, it may be the case that the compounds of the invention include a structure of the formulae (IV-1) to (IV-48), where the compounds of the invention may more preferably be selected from the compounds of the formulae (IV-1) to (IV-48)

where the symbols R^a, R^b and R^c have the definitions given above, especially for formula (I), and the further symbols are as follows:

• • [0068] M is the same or different at each instance and is C, Si, Ge, Ti, Zr or Hf, preferably C, Si or Ge, more preferably Si;
  • [0069] Y is the same or different at each instance and is B(R^a), C(R^a)₂, Si(R^a)₂, Ge(R^a)₂, C═O, C=NR^a, C=C(R^a)₂, O, S, S═O, SO₂, N(R^a), P(R^a) or P(═O)R^a, preferably N(R^a), O, S, B(R^a), C(R^a)₂, Si(R^a)₂ or Ge(R^a)₂, more preferably N(R^a), 0 or S;
  • [0070] j is 0, 1 or 2;
  • [0071] n is 0, 1, 2 or 3, preferably 0, 1 or 2;
  • [0072] m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2;
  • [0073] l is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2.

[0074] Preference is given here to structures/compounds of the formulae (IV-1) to (IV-8), (IV-13) to (IV-20), (IV-25), (IV-26), (IV-29), (IV-30) and (IV-38), particular preference to structures/compounds of the formulae (IV-1), (IV-2), (IV-5), (IV-6), (IV-13), (IV-14), (IV-25) and (IV-26), and very particular preference to structures/compounds of the formulae (IV-1), (IV-2), (IV-13) and (IV-14).

[0075] The sum total of the indices j, m, n and l in structures/compounds of the formulae (IV-1) to (IV-48) is preferably not more than 6, especially preferably not more than 4 and more preferably not more than 2.

[0076] When two radicals that may especially be selected from R, R^a, R^b, R^c, R¹ and/or R² form a ring system with one another, this ring system may be mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic. In this case, the radicals which together form a ring system may be adjacent, meaning that these radicals are bonded to the same carbon atom or to carbon atoms directly bonded to one another, or they may be further removed from one another. In addition, the ring systems provided with the substituents R, R^a, R^b, R^c, R¹ and/or R² may also be joined to one another via a bond, such that this can bring about a ring closure.

[0077] In a preferred development of the present invention, it may be the case that at least two, preferably adjacent, R, R^a, R^b, R^c radicals together with the further groups to which the two R, R^a, R^b, R^c radicals are bonded form a fused ring. In a preferred configuration, it may be the case that ring structures described in document WO 2022/079068 A1, filed on Oct. 13, 2021 at the European Patent Office under the application number PCT/EP2021/078240, are formed; for the purposes of disclosure, the description of the fused ring structures shown in these documents and described by the ring elements of the formulae (RA-1) to (RA-12), (RA-1a) to (RA-4f) and/or (RB) on pages 37 to 40 of document WO 2022/079068 A1 are incorporated into the present application by reference thereto. The above-detailed ring structures shown in detail in document WO 2022/079068 A1 and preferably comprising the ring elements of the formulae (RA-1) to (RA-12) and (RA-1a) to (RA-4f) lead in particular to structures/compounds of the invention that have a surprisingly low refractive index.

[0078] It may additionally be the case that the substituents R^a, R^b, R^c, R¹ and R² according to the above formulae do not form a fused aromatic or heteroaromatic ring system, more preferably do not form a ring system, with the ring atoms of the ring system to which the substituents R^a, R^b, R^c, R¹ and R² are bonded. This includes the formation of a fused aromatic or heteroaromatic ring system with possible substituents R² that may be bonded to the substituents R^a, R^b, R^c and R¹.

[0079] It may also be the case that at least one R^a, R^b, R^c radical is the same or different at each instance and is selected from the group consisting of H, D, a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms or an aromatic or heteroaromatic ring system selected from the groups of the following formulae Ar-1 to Ar-76, or the R^a, R^b, R^c radical is the same or different at each instance and is selected from the group consisting of H, D or an aromatic or heteroaromatic ring system selected from the groups of the following formulae Ar-1 to Ar-76, and/or the Ar′ group is the same or different at each instance and is selected from the groups of the following formulae Ar-1 to Ar-76:

where R¹ has the definitions given above, the dotted bond represents the bond to the corresponding group and in addition:

• • [0080] Ar¹ is the same or different at each instance and is a divalent aromatic or heteroaromatic ring system which has 6 to 18 aromatic ring atoms and may be substituted in each case by one or more R¹ radicals;
  • [0081] A is the same or different at each instance and is C(R¹)₂, NR¹, O or S;
  • [0082] p is 0 or 1, where p=0 means that the Ar¹ group is absent and that the corresponding aromatic or heteroaromatic group is bonded directly to the corresponding radical;
  • [0083] q is 0 or 1, where q=0 means that no A group is bonded at this position and R¹ radicals are bonded to the corresponding carbon atoms instead.

[0084] Preference is given here to structures of the formulae (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16), (Ar-40), (Ar-41), (Ar-42), (Ar-43), (Ar-44), (Ar-45), (Ar-46), (Ar-69), (Ar-70), (Ar-76), and particular preference to structures of the formulae (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16).

[0085] When the abovementioned groups for structures of the formulae (Ar-1) to (Ar-76) have two or more A groups, possible options for these include all combinations from the definition of A. Preferred embodiments in that case are those in which one A group is NR¹ and the other A group is C(R¹)₂ or in which both A groups are NR¹ or in which both A groups are O.

[0086] When A is NR¹, the substituent R¹ bonded to the nitrogen atom is preferably an aromatic or heteroaromatic ring system which has 5 to 24 aromatic ring atoms and may also be substituted by one or more R² radicals. In a particularly preferred embodiment, this R¹ substituent is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms, especially 6 to 18 aromatic ring atoms, which does not have any fused aryl groups and which does not have any fused heteroaryl groups in which two or more aromatic or heteroaromatic 6-membered ring groups are fused directly to one another, and which may also be substituted in each case by one or more R² radicals. Preference is given to phenyl, biphenyl, terphenyl and quaterphenyl. Preference is further given to triazine, pyrimidine and quinazoline as listed above for Ar-47 to Ar-50, Ar-57 and Ar-58, where these structures, rather than by R¹, may be substituted by one or more R² radicals.

[0087] When A is C(R¹)₂, the substituents R¹ bonded to this carbon atom are preferably the same or different at each instance and are a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which may also be substituted by one or more R² radicals. Most preferably, R¹ is a methyl group or a phenyl group. In this case, the R¹ radicals together may also form a ring system, which leads to a spiro system.

[0088] There follows a description of preferred R^a, R^b and R^c radicals.

[0089] In a preferred embodiment of the invention, R^a, R^b and R^c are the same or different at each instance and are selected from the group consisting of H, D, F, CN, NO₂, Si(R¹)₃, B(OR¹)₂, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl group may be substituted in each case by one or more R¹ radicals, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R¹ radicals.

[0090] In a further-preferred embodiment of the invention, radical R^a, R^b and R^c is the same or different at each instance and is selected from the group consisting of H, D, F, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl group may be substituted in each case by one or more R¹ radicals, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R¹ radicals.

[0091] It may also be the case that at least one R^a, R^b and R^c radical, preferably one substituent R^a, R^b and R^c, is the same or different at each instance and is selected from the group consisting of H, D, an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and may be substituted by one or more R¹ radicals, or an N(Ar′)₂ group; more preferably, at least one substituent R^a, R^b and R^c is the same or different at each instance and is selected from the group consisting of an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and may be substituted by one or more R¹ radicals. In a further-preferred embodiment of the invention, the substituents R^a, R^b and R^c either form a fused ring or the R^a, R^b and R^c radical is the same or different at each instance and is selected from the group consisting of H, D, an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and may be substituted by one or more R¹ radicals, or an N(Ar′)₂ group. More preferably, the R^a, R^b and R^c radical, preferably the substituent R^a, R^b and R^c, is the same or different at each instance and is selected from the group consisting of H or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 18 aromatic ring atoms, more preferably having 6 to 13 aromatic ring atoms, each of which may be substituted by one or more R¹ radicals.

[0092] It may also be the case that at least one R^a, R^b and R^c radical is an aromatic or heteroaromatic ring system which has 5 to 13 aromatic ring atoms and may be substituted by one or more R¹ radicals.

[0093] It may preferably be the case that at least one radical, preferably one substituent R^a, R^b and R^c is selected from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which may be substituted by one or more R¹ radicals. What is meant more particularly here by the expression “substituent” is that R^a, R^b and R^c are not H, preferably not H and not D. In addition, the substituents R^a, R^b and R^c may be the same or different if two or more substituents selected from the aromatic or heteroaromatic groups mentioned are present.

[0094] Preferred aromatic or heteroaromatic ring systems represented by substituent R, R^a, R^b and R^c or Ar, Ar^a or Ar′ are selected from phenyl, biphenyl, especially ortho-, meta- or para-biphenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorene which may be joined via the 1, 2, 3 or 4 position, spirobifluorene which may be joined via the 1, 2, 3 or 4 position, naphthalene, especially 1- or 2-bonded naphthalene, indole, benzofuran, benzothiophene, carbazole which may be joined via the 1, 2, 3 or 4 position, dibenzofuran which may be joined via the 1, 2, 3 or 4 position, dibenzothiophene which may be joined via the 1, 2, 3 or 4 position, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which may be substituted by one or more R^a, R^c, R¹ or R² radicals. Particularly preferred aromatic or heteroaromatic ring systems represented by substituent R, R^a, R^b and R^c or Ar, Ar^a or Ar′ are the above-detailed structures (Ar-1) to (Ar-76), preference being given to structures of the formulae (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16), (Ar-69), (Ar-70), (Ar-76), and particular preference to structures of the formulae (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16). With regard to the structures (Ar-1) to (Ar-76), it should be stated that these are shown with a possible substituent R¹. In the case of the ring systems Ar^a, these possible substituents R¹ should be replaced by R^a, and in the case of Ar, these possible substituents R¹ should be replaced by R^c.

[0095] Further suitable R^a, R^b, R^c groups are groups of the formula —Ar⁴—N(Ar²)(Ar³) where Ar², Ar³ and Ar⁴ are the same or different at each instance and are an aromatic or heteroaromatic ring system which has 5 to 24 aromatic ring atoms and may be substituted in each case by one or more R¹ radicals. The total number of aromatic ring atoms in Ar², Ar³ and Ar⁴ here is not more than 60 and preferably not more than 40.

[0096] Ar⁴ and Ar² here may be bonded to one another and/or Ar² and Ar³ to one another also by a single bond or a group selected from C(R¹)₂, NR¹, O or S. Preferably, Ar⁴ and Ar² are joined to one another and Ar² and Ar³ to one another in the respective ortho position to the bond to the nitrogen atom.

[0097] In a further embodiment of the invention, none of the Ar², Ar³ and Ar⁴ groups are bonded to one another.

[0098] Preferably, Ar⁴ is an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms, preferably 6 to 12 aromatic ring atoms, and may be substituted in each case by one or more R¹ radicals. More preferably, Ar⁴ is selected from the group consisting of ortho-, meta- or para-phenylene or ortho-, meta- or para-biphenyl, each of which may be substituted by one or more R¹ radicals, but are preferably unsubstituted.

[0099] Most preferably, Ar⁴ is an unsubstituted phenylene group.

[0100] Preferably, Ar² and Ar³ are the same or different at each instance and are an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms and may be substituted in each case by one or more R¹ radicals. Particularly preferred Ar² and Ar³ groups are the same or different at each instance and are selected from the group consisting of benzene, ortho-, meta- or para-biphenyl, ortho-, meta- or para-terphenyl or branched terphenyl, ortho-, meta- or para-quaterphenyl or branched quaterphenyl, 1-, 2-, 3- or 4-fluorenyl, 1-, 2-, 3- or 4-spirobifluorenyl, 1- or 2-naphthyl, indole, benzofuran, benzothiophene, 1-, 2-, 3- or 4-carbazole, 1-, 2-, 3- or 4-dibenzofuran, 1-, 2-, 3- or 4-dibenzothiophene, indenocarbazole, indolocarbazole, 2-, 3- or 4-pyridine, 2-, 4- or 5-pyrimidine, pyrazine, pyridazine, triazine, phenanthrene or triphenylene, each of which may be substituted by one or more R¹ radicals. Most preferably, Ar² and Ar³ are the same or different at each instance and are selected from the group consisting of benzene, biphenyl, especially ortho-, meta- or para-biphenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorene, especially 1-, 2-, 3- or 4-fluorene, or spirobifluorene, especially 1-, 2-, 3- or 4-spirobifluorene.

[0101] In a further preferred embodiment of the invention, R¹ is the same or different at each instance and is selected from the group consisting of H, D, F, CN, a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, where the alkyl group may be substituted in each case by one or more R² radicals, or an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms and may be substituted in each case by one or more R² radicals. In a particularly preferred embodiment of the invention, R¹ is the same or different at each instance and is selected from the group consisting of H, a straight-chain alkyl group having 1 to 6 carbon atoms, especially having 1, 2, 3 or 4 carbon atoms, or a branched or cyclic alkyl group having 3 to 6 carbon atoms, where the alkyl group may be substituted by one or more R² radicals, but is preferably unsubstituted, or an aromatic or heteroaromatic ring system which has 6 to 13 aromatic ring atoms and may be substituted in each case by one or more R² radicals, but is preferably unsubstituted.

[0102] In a further preferred embodiment of the invention, R² is the same or different at each instance and is H, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, which may be substituted by an alkyl group having 1 to 4 carbon atoms, but is preferably unsubstituted.

[0103] At the same time, in compounds of the invention that are processed by vacuum evaporation, the alkyl groups preferably have not more than five carbon atoms, more preferably not more than 4 carbon atoms, most preferably not more than 1 carbon atom. For compounds that are processed from solution, suitable compounds are also those substituted by alkyl groups, especially branched alkyl groups, having up to 10 carbon atoms or those substituted by oligoarylene groups, for example ortho-, meta- or para-terphenyl or branched terphenyl or quaterphenyl groups.

[0104] In a preferred configuration, the structures/compounds of the invention have been deuterated. The structures/compounds of the invention preferably have a high degree of deuteration. It may preferably be the case that the degree of deuteration is at least 50%, preferably at least 80%, especially preferably at least 90% and most preferably at least 95%. The degree of deuteration is determined from the numerical ratio of deuterium to the sum total of deuterium and ¹H hydrogen (D/(D+H)*100). The compounds have especially preferably been fully deuterated.

[0105] The compounds of the invention are suitable in particular for use in blue-emitting electroluminescent devices. Depending on the layer, these require materials having a high triplet level. However, many substituents having fused aromatic or heteroaromatic groups can lead to lowering of the triplet level.

[0106] Accordingly, naphthyl structures are preferred over anthracene structures. In addition, fluorenyl, spirobifluorenyl, dibenzofuranyl and/or dibenzothienyl structures are preferred over naphthyl structures.

[0107] Particular preference is given to structures having no fusion, for example phenyl, biphenyl, terphenyl and/or quaterphenyl structures.

[0108] It may also more preferably be the case that the Ar, R radical does not comprise any anthracene group; preferably, none of the Ar, Ar^a, R, R^a, R^b and R^c radicals, more preferably none of the Ar, Ar^a, R, R^a, R^b, R^c, R¹ and R² radicals, comprises an anthracene group.

[0109] Very especially preferably, it may further be the case that the Ar, R radicals does not comprise any aromatic or heteroaromatic ring system having three aromatic 6-membered rings fused in a linear manner, where preferably none of the Ar, Ar^a, R, R^a, R^b and R^c radicals, more preferably none of the Ar, Ar^a, R, R^a, R^b, R^c, R¹ and R² radicals, comprises an aromatic or heteroaromatic ring system having three aromatic 6-membered rings fused in a linear manner.

[0110] When the compound of the invention is substituted by aromatic or heteroaromatic R^a, R^b, R^c, R¹ or R² groups, it is preferable when these do not have any aryl or heteroaryl groups having more than two aromatic six-membered rings fused directly to one another. More preferably, the substituents do not have any aryl or heteroaryl groups having six-membered rings fused directly to one another at all. The reason for this preference is the low triplet energy of such structures. Fused aryl groups which have more than two aromatic six-membered rings fused directly to one another but are nevertheless also of good suitability in accordance with the invention are phenanthrene and triphenylene, since these also have a high triplet level.

[0111] It may additionally be the case that none of the Ar, Ar^a, R, R^a, R^b and R^c radicals, preferably none of the Ar, Ar^a, R, R^a, R^b, R^c, R¹ and R² radicals, comprises or forms a fluorenone group. This includes substituents bonded to the Ar, Ar^a, R, R^a, R^b, R^c radicals, etc. A fluorenone comprises a 5-membered ring with a CO group to which two aromatic 6-membered rings are fused.

[0112] When the compounds of the formula (I) or the preferred embodiments are used as matrix material for a phosphorescent emitter or in a layer directly adjoining a phosphorescent layer, it is further preferable when the compound does not contain any fused aryl or heteroaryl groups in which more than two six-membered rings are fused directly to one another. An exception to this is formed by phenanthrene and triphenylene, which, because of their high triplet energy, may be preferable in spite of the presence of fused aromatic six-membered rings.

[0113] It may also be the case that the compound includes exactly two or exactly three structures of formula (I), (I-1) to (I-11), (II-1) to (II-8), (III-1) to (III-12) and/or (IV-1) to (IV-48).

[0114] In a preferred configuration, the compounds are selected from compounds of the formula (D-1):

where the L¹ group is a connecting group, preferably a bond or an aromatic or heteroaromatic ring system which has 5 to 40, preferably 5 to 30, aromatic ring atoms and may be substituted by one or more R^a radicals, and the further symbols used have the definitions given above, especially for formula (I), where the L¹ group forms a bond to the base structure in place of a hydrogen atom or a substituent; preferably, the L¹ group is bonded to the Z, A radicals.

[0115] In a further preferred embodiment of the invention, L¹ is a bond or an aromatic or heteroaromatic ring system which has 5 to 14 aromatic or heteroaromatic ring atoms, preferably an aromatic ring system which has 6 to 12 carbon atoms and which may be substituted by one or more R^a radicals, but is preferably unsubstituted, where R^a may have the definition given above, especially for formula (I). More preferably, L¹ is an aromatic ring system having 6 to 10 aromatic ring atoms or a heteroaromatic ring system having 6 to 13 heteroaromatic ring atoms, each of which may be substituted by one or more R¹ radicals, but is preferably unsubstituted, where R¹ may have the definition given above, especially for formula (I).

[0116] Further preferably, the symbol L¹ shown in formula (D1) inter alia is the same or different at each instance and is a bond or an aryl or heteroaryl radical having 5 to 24 ring atoms, preferably 6 to 13 ring atoms, more preferably 6 to 10 ring atoms, such that an aromatic or heteroaromatic group of an aromatic or heteroaromatic ring system is bonded to the respective atom of the further group directly, i.e. via an atom of the aromatic or heteroaromatic group.

[0117] It may additionally be the case that the L¹ group shown in formula (D1) comprises an aromatic ring system having not more than four, preferably not more than three, more preferably not more than two, fused aromatic and/or heteroaromatic 6-membered rings, and preferably does not comprise any fused aromatic or heteroaromatic ring system.

[0118] Examples of suitable aromatic or heteroaromatic ring systems L¹ are selected from the group consisting of ortho-, meta- or para-phenylene, ortho-, meta- or para-biphenylene, terphenylene, especially branched terphenylene, quaterphenylene, especially branched quaterphenylene, fluorenylene, spirobifluorenylene, dibenzofuranylene, dibenzothienylene and carbazolylene, each of which may be substituted by one or more R¹ radicals, but are preferably unsubstituted.

[0119] In a preferred configuration, a compound of the invention can be represented by at least one of the structures of formulae (I), (I-1) to (I-11), (II-1) to (II-8), (III-1) to (III-12) and/or (IV-1) to (IV-48). Preferably, compounds of the invention, preferably comprising structures of formulae (I), (I-1) to (I-11), (II-1) to (II-8), (III-1) to (III-12) and/or (IV-1) to (IV-48), have a molecular weight of not more than 5000 g/mol, preferably not more than 4000 g/mol, particularly preferably not more than 3000 g/mol, especially preferably not more than 2000 g/mol, more especially preferably not more than 1200 g/mol and most preferably not more than 900 g/mol.

[0120] In addition, it is a feature of preferred compounds of the invention that they are sublimable. These compounds generally have a molar mass of less than about 1200 g/mol.

[0121] It may also be the case that the compound comprising structures of formula (I), preferably the compound of formula (I) or a preferred embodiment of that structure/compound, is not in direct contact with a metal atom, and is preferably not a ligand for a metal complex.

[0122] The abovementioned preferred embodiments may be combined with one another as desired within the restrictions defined in claim 1. In a particularly preferred embodiment of the invention, the abovementioned preferences occur simultaneously.

[0123] Examples of preferred compounds according to the embodiments detailed above are the compounds detailed in the following table:

	1
	2
	3
	4
	5
	6
	7
	8
	9
	10
	11
	12
	13
	14
	15
	16
	17
	18
	19
	20
	21
	22
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[0124] The base structure of the compounds of the invention can be prepared by the routes outlined in the schemes which follow. The individual synthesis steps here, for example coupling reactions that lead to C—C bond formation and/or C—N bond formation, are known in principle to the person skilled in the art. These include BUCHWALD, SUZUKI, YAMAMOTO, STILLE, HECK, NEGISHI, SONOGASHIRA and HIYAMA reactions. Further information relating to the synthesis of the compounds of the invention can be found in the synthesis examples.

[0125] The schemes that follow describe the preparation of inventive compounds of the formula (I-1) by way of example, such that further compounds of the invention, especially compounds of the formulae (I-2) to (I-11) can be obtained by similar synthesis routes that proceed from different parent structures. For this purpose, reference is made in particular to the examples in which compounds of the formulae (I-2) and (I-3) are described. The person skilled in the art will use corresponding amine compounds for preparation of compounds of the formulae (I-4) to (I-11).

[0126] For example, it is possible to prepare compounds of the invention in three steps from starting materials known from the literature in the form of N-benzylated 2-chloroimidazoles (1) and anilines (2) (scheme 1).

[0127] These are first converted in stage 1 to the N,N-bisbenzylated bis(2-imidazolyl)amines (3) in the presence of lithium tert-butoxide in m-xylene at 120° C. according to W. Sang et al., Adv. Synth. Catal., 2021, 363, 1408. Subsequently, according to A. A. Haddach et al, Tetrahedron Letters, 2002, 43, 399, the benzyl protecting groups are detached by the action of potassium tert-butoxide and oxygen in DMSO/THF (stage 2) to give the free bis(2-imidazolyl)amines (4). Alternatively, the detachment can be detached by hydrogenolysis reactions known to the person skilled in the art, for example in the tetrahydrofuran/methanol/Pd-charcoal/H₂ system.

[0128] Finally, in stage 3, deprotonation of the bis(2-imidazolyl)amines (4) with n-BuLi is followed by coupling with the electrophiles E. Electrophiles used may be dihalides, for example RBCl₂, R₂CCl₂, R₂SiCl₂, R₂GeCl₂, SiCl₄, GeCl₄, RP(O)Cl₂, SO₂Cl₂, SeO₂Cl₂ (R=alkyl, aryl, heteroaryl).

[0129] N-Benzylated 2-chloroimidazoles and 3-chloropyrazoles, and also 3-chlorobenzpyrazoles, can be converted analogously.

[0130] Proceeding from the 2,2′-oxo- or -thioimidazoles or -benzimidazoles (6) known from the literature, the inventive compounds (7) can be obtained (scheme 2).

[0131] The definition of the symbols used in the schemes set out above corresponds essentially to that which was defined for formula (I), dispensing with numbering and complete representation of all symbols for reasons of clarity.

[0132] The present invention therefore further provides a process for preparing a compound of the invention, wherein a base skeleton having an aromatic amino group is synthesized and at least one aromatic or heteroaromatic radical is introduced, preferably by a nucleophilic aromatic substitution reaction or a coupling reaction.

[0133] In a preferred configuration of the process, it may be the case that the at least one aromatic or heteroaromatic radical is an imidazole or benzimidazole compound, where the imidazole or benzimidazole compound is symmetric in relation to the two nitrogen atoms.

[0134] This configuration can especially prevent the formation of isomers, since the above-detailed intermediates can display tautomerism.

[0135] It is possible by these methods, if necessary followed by purification, for example recrystallization or sublimation, to obtain the compounds of the invention in high purity, preferably more than 99% (determined by means of ¹H NMR and/or HPLC).

[0136] The compounds of the invention may also be mixed with a polymer. It is likewise possible to incorporate these compounds covalently into a polymer. This is especially possible with compounds substituted by reactive leaving groups such as bromine, iodine, chlorine, boronic acid or boronic ester, or by reactive polymerizable groups such as olefins or oxetanes. These may find use as monomers for production of corresponding oligomers, dendrimers or polymers. The oligomerization or polymerization is preferably effected via the halogen functionality or the boronic acid functionality or via the polymerizable group. It is additionally possible to crosslink the polymers via groups of this kind. The compounds and polymers of the invention may be used in the form of a crosslinked or uncrosslinked layer.

[0137] The invention therefore further provides oligomers, polymers or dendrimers containing one or more of the above-detailed structures of the formula (I) and preferred embodiments of this formula or compounds of the invention, wherein one or more bonds of the compounds of the invention or of the structures of the formula (I) and preferred embodiments of that formula to the polymer, oligomer or dendrimer are present. According to the linkage of the structures of the formula (I) and preferred embodiments of this formula or of the compounds, these therefore form a side chain of the oligomer or polymer or are bonded within the main chain. The polymers, oligomers or dendrimers may be conjugated, partly conjugated or nonconjugated. The oligomers or polymers may be linear, branched or dendritic. For the repeat units of the compounds of the invention in oligomers, dendrimers and polymers, the same preferences apply as described above.

[0138] For preparation of the oligomers or polymers, the monomers of the invention are homopolymerized or copolymerized with further monomers. Preference is given to copolymers wherein the units of formula (I) or the preferred embodiments recited above and hereinafter are present to an extent of 0.01 to 99.9 mol %, preferably 5 to 90 mol %, more preferably 20 to 80 mol %. Suitable and preferred comonomers which form the polymer base skeleton are chosen from fluorenes (for example according to EP 842208 or WO 2000/022026), spirobifluorenes (for example according to EP 707020, EP 894107 or WO 2006/061181), paraphenylenes (for example according to WO 92/18552), carbazoles (for example according to WO 2004/070772 or WO 2004/113468), thiophenes (for example according to EP 1028136), dihydrophenanthrenes (for example according to WO 2005/014689), cis- and trans-indenofluorenes (for example according to WO 2004/041901 or WO 2004/113412), ketones (for example according to WO 2005/040302), phenanthrenes (for example according to WO 2005/104264 or WO 2007/017066) or else a plurality of these units. The polymers, oligomers and dendrimers may contain still further units, for example hole transport units, especially those based on triarylamines, and/or electron transport units.

[0139] Additionally of particular interest are compounds of the invention which feature a high glass transition temperature. In this connection, preference is given especially to compounds of the invention comprising structures of the formula (I) or the preferred embodiments recited above and hereinafter which have a glass transition temperature of at least 70° C., more preferably of at least 110° C., even more preferably of at least 125° C. and especially preferably of at least 150° C., determined in accordance with DIN 51005 (2005-08 version).

[0140] For the processing of the compounds of the invention from a liquid phase, for example by spin-coating or by printing methods, formulations of the compounds of the invention are required. These formulations may, for example, be solutions, dispersions or emulsions. For this purpose, it may be preferable to use mixtures of two or more solvents. Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF, methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, especially 3-phenoxytoluene, (−)-fenchone, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1-methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, α-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane, NMP, p-cymene, phenetole, 1,4-diisopropylbenzene, dibenzyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 2-isopropylnaphthalene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, 1,1-bis(3,4-dimethylphenyl)ethane, 2-methylbiphenyl, 3-methylbiphenyl, 1-methylnaphthalene, 1-ethylnaphthalene, ethyl octanoate, diethyl sebacate, octyl octanoate, heptylbenzene, menthyl isovalerate, cyclohexyl hexanoate or mixtures of these solvents.

[0141] The present invention therefore further provides a formulation or a composition comprising at least one compound of the invention and at least one further compound. The further compound may, for example, be a solvent, especially one of the abovementioned solvents or a mixture of these solvents. If the further compound comprises a solvent, this mixture is referred to herein as formulation. The further compound may alternatively be at least one further organic or inorganic compound which is likewise used in the electronic device, for example an emitting compound and/or a further matrix material. It may preferably be the case that at least one further compound is selected from the group consisting of fluorescent emitters, phosphorescent emitters, emitters that exhibit TADF, host materials, electron transport materials, electron injection materials, hole conductor materials, hole injection materials, electron blocker materials and hole blocker materials, preferably host materials.

[0142] The present invention further provides for the use of a compound of the invention in an electronic device, especially in an organic electroluminescent device. It may preferably be the case that the compound of the invention is used in an electronic device as host material, electron transport material, electron injection material, hole conductor material, hole injection material, electron blocker material, hole blocker material.

[0143] It may further be the case that a compound of the invention is used as host material, electron transport material, electron injection material or hole blocker material, and this compound of the invention comprises at least one electron transport group and/or one electron-withdrawing radical, with preferred electron transport groups and/or electron-withdrawing radicals having been defined above.

[0144] It may further be the case that a compound of the invention is used as host material, hole conductor material, hole injection material or electron blocker material, and this compound of the invention at least one hole transport group, with preferred electron transport groups and/or electron-withdrawing radicals having been defined above.

[0145] It may further be the case that a compound of the invention is used as host material and this compound of the invention comprises both at least one hole transport group and at least one electron transport group and/or an electron-withdrawing radical.

[0146] The present invention still further provides an electronic device comprising at least one compound of the invention. An electronic device in the context of the present invention is a device comprising at least one layer comprising at least one organic compound. This component may also comprise inorganic materials or else layers formed entirely from inorganic materials.

[0147] The electronic device is more preferably selected from the group consisting of organic electroluminescent devices (OLEDs, sOLED, PLEDs, LECs, etc.), preferably organic light-emitting diodes (OLEDs), organic light-emitting diodes based on small molecules (sOLEDs), organic light-emitting diodes based on polymers (PLEDs), light-emitting electrochemical cells (LECs), organic laser diodes (O-laser), organic plasmon-emitting devices (D. M. Koller et aL., Nature Photonics 2008, 1-4), organic integrated circuits (O-ICs), organic field-effect transistors (0-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O—SCs), organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs) and organic electrical sensors, preferably organic electroluminescent devices (OLEDs, sOLED, PLEDs, LECs, etc.), more preferably organic light-emitting diodes (OLEDs), organic light-emitting diodes based on small molecules (sOLEDs), organic light-emitting diodes based on polymers (PLEDs), especially phosphorescent OLEDs.

[0148] The organic electroluminescent device comprises cathode, anode and at least one emitting layer. Apart from these layers, it may also comprise further layers, for example in each case one or more hole injection layers, hole transport layers, hole blocker layers, electron transport layers, electron injection layers, exciton blocker layers, electron blocker layers and/or charge generation layers. It is likewise possible for interlayers having an exciton-blocking function, for example, to be introduced between two emitting layers. However, it should be pointed out that not necessarily every one of these layers need be present. In this case, it is possible for the organic electroluminescent device to contain an emitting layer, or for it to contain a plurality of emitting layers. If a plurality of emission layers are present, these preferably have several emission maxima between 380 nm and 750 nm overall, such that the overall result is white emission; in other words, various emitting compounds which may fluoresce or phosphoresce are used in the emitting layers. Especially preferred are systems having three emitting layers, where the three layers show blue, green and orange or red emission. The organic electroluminescent device of the invention may also be a tandem electroluminescent device, especially for white-emitting OLEDs.

[0149] The compound of the invention may be used in different layers, according to the exact structure. Preference is given to an organic electroluminescent device comprising a compound of formula (I) or the above-recited preferred embodiments in an emitting layer as host material for fluorescent emitters, phosphorescent emitters or for emitters that exhibit TADF (thermally activated delayed fluorescence), especially for phosphorescent emitters. In addition, the compound of the invention can also be used in an electron transport layer, electron injection layer and/or in a hole transport layer, hole injection layer and/or in an exciton blocker layer and/or in a hole blocker layer. More preferably, the compound of the invention is used as matrix material for phosphorescent emitters, especially for red-, orange-, green-, yellow- or blue-phosphorescing emitters, in an emitting layer, as electron transport or hole blocker material in an electron transport or hole blocker layer, or as a hole transport or electron blocker material in a hole transport or electron blocker layer. The suitability of the various compounds of formula (I) has been shown above in connection with preferred uses.

[0150] When the compound of the invention is used as matrix material for a phosphorescent compound in an emitting layer, it is preferably used in combination with one or more phosphorescent materials (triplet emitters).

[0151] Phosphorescence in the context of this invention is understood to mean luminescence from an excited state having higher spin multiplicity, i.e. a spin state >1, especially from an excited triplet state. In the context of this application, all luminescent complexes with transition metals or lanthanides, especially all iridium, platinum and copper complexes, shall be regarded as phosphorescent compounds.

[0152] The mixture of the compound of the invention and the emitting compound contains between 99% and 1% by volume, preferably between 98% and 10% by volume, more preferably between 97% and 60% by volume and especially between 95% and 80% by volume of the compound of the invention, based on the overall mixture of emitter and matrix material. Correspondingly, the mixture contains between 1% and 99% by volume, preferably between 2% and 90% by volume, more preferably between 3% and 40% by volume and especially between 5% and 20% by volume of the emitter, based on the overall mixture of emitter and matrix material.

[0153] In one embodiment of the invention, the compound of the invention is used here as the sole matrix material (“single host”) for the phosphorescent emitter.

[0154] A further embodiment of the present invention is the use of the compound of the invention as matrix material for a phosphorescent emitter in combination with a further matrix material. Suitable matrix materials which can be used in combination with the inventive compounds are aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones, for example according to WO 2004/013080, WO 2004/093207, WO 2006/005627 or WO 2010/006680, triarylamines, carbazole derivatives, e.g. CBP (N,N-biscarbazolylbiphenyl) or the carbazole derivatives disclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527, WO 2008/086851 or WO 2013/041176, indolocarbazole derivatives, for example according to WO 2007/063754 or WO 2008/056746, indenocarbazole derivatives, for example according to WO 2010/136109, WO 2011/000455, WO 2013/041176 or WO 2013/056776, azacarbazole derivatives, for example according to EP 1617710, EP 1617711, EP 1731584, JP 2005/347160, bipolar matrix materials, for example according to WO 2007/137725, silanes, for example according to WO 2005/111172, azaboroles or boronic esters, for example according to WO 2006/117052, triazine derivatives, for example according to WO 2007/063754, WO 2008/056746, WO 2010/015306, WO 2011/057706, WO 2011/060859 or WO 2011/060877, zinc complexes, for example according to EP 652273 or WO 2009/062578, diazasilole or tetraazasilole derivatives, for example according to WO 2010/054729, diazaphosphole derivatives, for example according to WO 2010/054730, bridged carbazole derivatives, for example according to WO 2011/042107, WO 2011/060867, WO 2011/088877 and WO 2012/143080, triphenylene derivatives, for example according to WO 2012/048781, dibenzofuran derivatives, for example according to WO 2015/169412, WO 2016/015810, WO 2016/023608, WO 2017/148564 or WO 2017/148565, or biscarbazoles, for example according to JP 3139321 B2.

[0155] In a preferred configuration, a compound containing a structure/compound of formula (I) or the above-recited preferred embodiments which is used as host material is preferably in combination:

• • [0156] with one or more phosphorescent materials (triplet emitters); and/or
  • [0157] with one or more fluorescent materials; and/or
  • [0158] with a compound having TADF properties, where TADF stands for “Thermally Activated Delayed Fluorescence”.

[0159] Preference is given here to forming a hyperfluorescence system as described in WO 2012/133188 and/or a hyperphosphorescence system as in US 2017271611. This combination is a preferred embodiment according to the present invention.

[0160] WO 2015/091716 A1 and WO 2016/193243 A1 disclose OLEDs containing both a phosphorescent compound and a fluorescent emitter in the emission layer, where the energy is transferred from the phosphorescent compound to the fluorescent emitter (hyperphosphorescence). As the person skilled in the art knows, host materials have higher singlet and triplet energies as compared to the emitters in order that the energy from the host material will also be transferred to the emitter with maximum efficiency. The systems disclosed in the prior art have exactly such an energy relation.

[0161] The present invention also relates to electronic devices containing an organic layer, preferably a light-emitting layer, wherein the organic layer comprises:

• • [0162] a compound containing a structure/compound of formula (I) or the above-recited preferred embodiments as host material;
  • [0163] optionally a second compound as co-host material;
  • [0164] a sensitizer; and
  • [0165] a fluorescent emitter,
    where the sensitizer is a phosphorescent compound (triplet emitter) or a TADF compound.

[0166] Preferred emitters that can be used in combination with a compound of the invention are described inter alia by Sungho Nam et al., Adv. Sci. 2021, 2100586 and Eungdo Kin et al., Sci. Adv. 2022, 8, eabq 1641. There are also descriptions of preferred triplet emitters or triplet emitter classes, also called sensitizers in connection with a hyperphosphorescence system, in EP 3 435 438 A2, where the emitters 2 and 3 on page 21 are preferred; in CN 109111487, where the compounds shown on pages 76 and 77 are preferred; in US 2020/0140471, where the compounds shown on pages 166 to 175 are preferred; in KR2020108705, where the compounds shown on pages 8 to 14 are preferred; in US 2019/0119312, where the compounds shown on pages 114 to 121 are preferred; and in US 2020/0411775, where the compounds shown on pages 123 to 128 are preferred. In addition, preferred fluorescent emitters or classes of fluorescent emitters are described in WO 2021/090932, where the on pages 129 to 133, 157 to 166, 171 to 187, 200 to 211, 222 to 227, 236 to 252, 255 are preferred; in WO 2020/054676, where the compounds shown on pages 44 to 104 are preferred; in WO 2020/017931, where the compounds shown on pages 17 to 39 are preferred; in WO 2020/218079, where the compounds shown on pages 64 to 258 are preferred; in WO 2018/212169, where the compounds shown on pages 33 to 42 are preferred; in WO 2019/235452, where the compounds shown on pages 46 to 168 are preferred; in U.S. Pat. No. 10,249,832, where the compounds shown on pages 19 to 106 are preferred; and in WO 2021/014001, where the compounds shown on pages 107 to 129 are preferred.

[0167] It is likewise possible for a further phosphorescent emitter which emits at a shorter wavelength than the actual emitter to be present as co-host material in the mixture. Particularly good results are achieved when the emitter used is a red-phosphorescing emitter and the co-host material used in combination with the compound of the invention is a yellow-phosphorescing emitter.

[0168] In addition, the co-host material used may be a compound that does not take part in charge transport to a significant degree, if at all, as described, for example, in WO 2010/108579. Especially suitable in combination with the compound of the invention as co-matrix material are compounds which have a large bandgap and themselves take part at least not to a significant degree, if any at all, in the charge transport of the emitting layer. Such materials are preferably pure hydrocarbons. Examples of such materials can be found, for example, in WO 2009/124627 or in WO 2010/006680. In this context, it should be emphasized that compounds of the invention have advantageous properties without specific functional groups, for example hole transport groups and/or electron transport groups.

[0169] Suitable phosphorescent compounds (=triplet emitters) are especially compounds which, when suitably excited, emit light, preferably in the visible region, and also contain at least one atom of atomic number greater than 20, preferably greater than 38 and less than 84, more preferably greater than 56 and less than 80, especially a metal having this atomic number. Preferred phosphorescence emitters used are compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially compounds containing iridium or platinum.

[0170] Examples of the above-described emitters can be found in applications WO 00/70655, WO 2001/41512, WO 2002/02714, WO 2002/15645, EP 1191613, EP 1191612, EP 1191614, WO 05/033244, WO 05/019373, US 2005/0258742, WO 2009/146770, WO 2010/015307, WO 2010/031485, WO 2010/054731, WO 2010/054728, WO 2010/086089, WO 2010/099852, WO 2010/102709, WO 2011/032626, WO 2011/066898, WO 2011/157339, WO 2012/007086, WO 2014/008982, WO 2014/023377, WO 2014/094961, WO 2014/094960, WO 2015/036074, WO 2015/104045, WO 2015/117718, WO 2016/015815, WO 2016/124304, WO 2017/032439 and WO 2018/011186. In general, all phosphorescent complexes as used for phosphorescent electroluminescent devices according to the prior art and as known to those skilled in the art in the field of organic electroluminescence are suitable, and the person skilled in the art will be able to use further phosphorescent complexes without exercising inventive skill.

[0171] Examples of phosphorescent dopants are listed in the following table:

[0172] The compounds of the invention are especially also suitable as matrix materials for phosphorescent emitters in organic electroluminescent devices, as described, for example, in WO 98/24271, US 2011/0248247 and US 2012/0223633. In these multicolor display components, an additional blue emission layer is applied by vapor deposition over the full area to all pixels, including those having a color other than blue.

[0173] In a further embodiment of the invention, the organic electroluminescent device of the invention does not contain any separate hole injection layer and/or hole transport layer and/or hole blocker layer and/or electron transport layer, meaning that the emitting layer directly adjoins the hole injection layer or the anode, and/or the emitting layer directly adjoins the electron transport layer or the electron injection layer or the cathode, as described, for example, in WO 2005/053051. It is additionally possible to use a metal complex identical or similar to the metal complex in the emitting layer as hole transport or hole injection material directly adjoining the emitting layer, as described, for example, in WO 2009/030981.

[0174] In the further layers of the organic electroluminescent device of the invention, it is possible to use any materials as typically used according to the prior art. The person skilled in the art will therefore be able, without exercising inventive skill, to use any materials known for organic electroluminescent devices in combination with the inventive compounds of formula (I) or the above-recited preferred embodiments.

[0175] Additionally preferred is an organic electroluminescent device, characterized in that one or more layers are coated by a sublimation process. In this case, the materials are applied by vapor deposition in vacuum sublimation systems at an initial pressure of less than 10⁻⁵ mbar, preferably less than 10⁻⁶ mbar. However, it is also possible that the initial pressure is even lower, for example less than 10⁻⁷ mbar.

[0176] Preference is likewise given to an organic electroluminescent device, characterized in that one or more layers are coated by the OVPD (organic vapor phase deposition) method or with the aid of a carrier gas sublimation. In this case, the materials are applied at a pressure between 10⁻⁵ mbar and 1 bar. A special case of this method is the OVJP (organic vapor jet printing) method, in which the materials are applied directly by a nozzle and thus structured.

[0177] Preference is additionally given to an organic electroluminescent device, characterized in that one or more layers are produced from solution, for example by spin-coating, or by any printing method, for example screen printing, flexographic printing, offset printing, LITI (light-induced thermal imaging, thermal transfer printing), inkjet printing or nozzle printing. For this purpose, soluble compounds are needed, which are obtained, for example, through suitable substitution.

[0178] Formulations for applying a compound of formula (I) or the preferred embodiments thereof detailed above are novel. The present invention therefore further provides formulations containing at least one solvent and a compound according to formula (I) or the preferred embodiments thereof detailed above.

[0179] In addition, hybrid methods are possible, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapor deposition.

[0180] Those skilled in the art are generally aware of these methods and are able to apply them without exercising inventive skill to organic electroluminescent devices comprising the compounds of the invention.

[0181] The compounds of the invention and the organic electroluminescent devices of the invention have in particular the feature of an improved efficiency and/or operating voltage with respect to the prior art. Furthermore, these compounds and the organic electroluminescent devices obtainable therefrom show an improved lifetime. In a particular variant, the compounds of the invention and the organic electroluminescent devices of the invention especially feature a low refractive index (RI) compared to the prior art. In addition, preferred compounds of the invention show a high triplet T1 level, and so these compounds are especially suitable as host material for blue-emitting triplet emitters.

[0182] The electronic devices of the invention, especially organic electroluminescent devices, are notable for one or more of the following surprising advantages over the prior art:

• • [0183] 1. Electronic devices, especially organic electroluminescent devices, comprising compounds of formula (I) or the preferred embodiments recited above and hereinafter, have excellent efficiency, especially as matrix material, as electron-conducting materials or as hole-conducting materials. In this context, inventive compounds of formula (I) or the preferred embodiments recited above and hereinafter bring about a low operating voltage when used in electronic devices.
  • [0184] 2. Electronic devices, especially organic electroluminescent devices, comprising compounds of formula (I) or the preferred embodiments recited above and hereinafter, have a very good lifetime, especially as matrix material, as electron-conducting materials or as hole-conducting materials. In this context, these compounds especially bring about low roll-off, i.e. a small drop in power efficiency of the device at high luminances.
  • [0185] 3. The inventive compounds of formula (I) or the preferred embodiments recited above and hereinafter exhibit very high stability and lifetime.
  • [0186] 4. Electronic devices, especially organic electroluminescent devices, comprising compounds of formula (I) or the preferred embodiments recited above and hereinafter, have a high T1 level, especially as matrix material, as electron-conducting materials or as hole-conducting materials.
  • [0187] 5. With compounds of formula (I) or the preferred embodiments recited above and hereinafter, it is possible to avoid the formation of optical loss channels in electronic devices, especially organic electroluminescent devices. As a result, these devices feature a high PL efficiency and hence high EL efficiency of emitters, and excellent energy transmission of the matrices to dopants.
  • [0188] 6. Compounds of formula (I) or the preferred embodiments recited above and hereinafter have excellent glass film formation.
  • [0189] 7. Compounds of formula (I) or the preferred embodiments recited above and hereinafter form very good films from solutions.

[0190] These abovementioned advantages are not accompanied by an inordinately high deterioration in the further electronic properties.

[0191] It should be pointed out that variations of the embodiments described in the present invention are covered by the scope of this invention. Any feature disclosed in the present invention may, unless this is explicitly ruled out, be exchanged for alternative features which serve the same purpose or an equivalent or similar purpose. Thus, any feature disclosed in the present invention, unless stated otherwise, should be considered as an example of a generic series or as an equivalent or similar feature.

[0192] All features of the present invention may be combined with one another in any manner, unless particular features and/or steps are mutually exclusive. This is especially true of preferred features of the present invention. Equally, features of non-essential combinations may be used separately (and not in combination).

[0193] It should also be pointed out that many of the features, and especially those of the preferred embodiments of the present invention, should themselves be regarded as inventive and not merely as some of the embodiments of the present invention. For these features, independent protection may be sought in addition to or as an alternative to any currently claimed invention.

[0194] The technical teaching disclosed with the present invention may be abstracted and combined with other examples.

[0195] The invention is illustrated in detail by the examples which follow, without any intention of restricting it thereby. The person skilled in the art will be able to use the information given to execute the invention over the entire scope disclosed and to prepare further compounds of the invention without exercising inventive skill and to use them in electronic devices or to employ the process of the invention.

[0196] The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The metal complexes are additionally handled with exclusion of light or under yellow light. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. The respective figures in square brackets or the numbers quoted for individual compounds relate to the CAS numbers of the compounds known from the literature. In the case of compounds that can have multiple enantiomeric, diastereomeric or tautomeric forms, one form is shown in a representative manner.

[0197] Procedure analogous to W. Sang et al., Adv. Synth. Catal., 2021, 363, 1408, see page 1415, “The LiOtBu promoted reactions”. Starting materials: 5.34 g (22 mmol) of 2-chloro-1-(phenylmethyl)-1H-benzimidazole [43181-78-8], 931 mg (10 mmol) of aniline [62-53-3], 3.20 g (40 mmol) of lithium tert-butoxide [1907-33-1], 20 ml of m-xylene, 30 h, 120° C. Removal of the volatile components under reduced pressure, chromatographic purification (Torrent automated column system from A. Semrau). Yield: 3.85 g (7.6 mmol) 76%; purity: about 97% by ¹H-NMR.

[0198] Procedure analogous to W. Sang et al., Chem. Asian J., 2020, 15, 129.

[0199] Starting materials: 5.34 g (22 mmol) of 2-bromo-1-(phenylmethyl)-1H-benzimidazole [161885-73-0], 931 mg (10 mmol) of aniline [62-53-3], 13.0 g (40 mmol) of cesium carbonate, 112 mg (0.5 mmol) of palladium(II) acetate, 50 ml of toluene, 16 h, 110° C. Removal of the volatile components under reduced pressure, chromatographic purification (Torrent automated column system from A. Semrau). Yield: 4.05 g (8 rm mol) 80%; purity: about 97% by ¹H-NMR.

[0200] Starting materials: Stir 5.06 g (10 mmol) of stage 1, 2.0 g of Pd/C, dry, 10% w/w, 5 ml of HCl, 4M in dioxane, 120 ml of MeOH, under a hydrogen atmosphere at standard pressure at 25° C. for 4 h. Filter off catalyst using a Celite bed, wash through with MeOH, concentrate the filtrate. Take up the hydrochloride in dichloromethane (DCM), adjust to pH 7 with 1 N NaOH, filter off the precipitated solids with suction, separate the phases of the mother liquor, concentrate DCM phase. Combine solids and concentrated DCM phase, take up in 100 ml of MeOH, draw off EtOH under reduced pressure (azeotropic drying), dry solids under reduced pressure. Yield: 3.03 g (9.3 mmol) 93%; purity: about 97% by ¹H-NMR.

[0201] The following compounds can be prepared analogously:

Ex.	Reactants	Product
S2	43181-78-8     769-92-6
S3	43181-78-8     8762-7
S4	43181-78-8     344298-96-0
S5	43181-78-8     25176-17-4
S6	43181-78-8     2243-47-2
S7	184832-31-3     90-41-5
S8	184832-31-3     108714-73-4
S9	43181-78-8     2249831-75-0
S10	43181-78-8     2249831-77-2
S11	43181-78-8     1579281-06-3
S12	43181-78-8     2273942-41-7
S13	43181-78-8     2609786-46-9
S14	43181-78-8     4106-66-5
S15	43181-78-8     50548-40-8
S16	43181-78-8     50548-43-1
S17	43181-78-8     2609787-33-7
S18	43181-78-8     2609787-36-0
S19	43181-78-8     2458169-86-1
S20	43181-78-8     2609787-30-4
S21	43181-78-8     1638263-75-8
S22	43181-78-8     2609786-36-7
S23	43181-78-8     2609786-43-6
S24	43181-78-8     1448337-95-8
S25	43181-78-8     1191512-09-0
S26	43181-78-8     2458169-88-3
S27	43181-78-8     3366-65-2
S28	43181-78-8     17169-81-2
S29	43181-78-8     17075-02-4
S30	98842-69-4     78832-53-8
S31	43181-78-8     91-59-8
S32	55675-78-0 344298-96-0
S33	426832-88-4 2243-47-2
S34	426832-88-4 90-41-5
S35	426832-88-4 50548-40-8
S36	426832-88-4 2609787-30-4
S37	426832-88-4 17169-81-2
S38	50877-43-5 2243-47-2
S39	43181-78-8 184832-31-3 90-41-5
S40	43181-78-8 426832-88-4 2243-47-2

[0202] To a solution of 3.25 g (10 mmol) of S1 in 100 ml of THE is added dropwise, at −78° C., 12.5 ml (20 mmol) of n-BuLi, 1.6 M in n-hexane, and the mixture is stirred for a further 30 min. Subsequently, a solution of 1.59 g (10 mmol) of dichlorophenylborane [873-51-8] in 30 ml of THE is added dropwise, and the mixture is stirred for a further 1 h and then allowed to gradually warm up to trust temperature. After 12 h, the THF is removed under reduced pressure, the residue is taken up in 50 ml of dichloromethane, the lithium chloride is filtered off, and the filtrate is absorbed onto Isolute and chromatographed (Torrent automated column system from A. Semrau). The product thus obtained is purified by repeated hot extraction crystallization (customary organic solvents or combinations thereof, preferably acetonitrile-DCM, 1:3 to 3:1 vv) and fractional sublimation or heat treatment under high vacuum. Yield: 2.91 g (7.1 mmol), 71%; purity: about 99.9% by HPLC.

[0203] It is possible to prepare the following compounds analogously, with adjustment of the respective stoichiometry to the reactants used, in yields of typically 40-90%:

Ex.	Reactants	Product
B2	S5
B3	S6     39767-04-9
B4	S9     105789-80-8
B5	S16     2762939-41-1
B6	S14     2254340-29-7
B7	S7     2809362-95-4
B8	S2     2051-90-3
B9	S3     33267-42-4
B10	S10     20735-05-1
B11	S17     6326-59-6
B12	S25     408530-36-9
B13	S11     75-78-5
B14	S12     18147-18-7
B15	S8     2406-33-9
B16	S15     17887-41-1
B17	S17     18414-45-4
B18	S4     18557-48-7
B19	S12     18557-47-6
B20	S19    490023-82-0
B21	S21     1884425-36-8
B22	S22     2766686-03-5
B23	S13     2819689-91-1
B24	S17     2413727-38-3
B25	S18     1393343-28-6
B26	S20     2413727-11-2
B27	S22     637356-26-4
B28	S23     80-10-4
B29	S24     33584-32-6
B30	S30     2362515-08-8
B31	S24     49789-80-2
B32	S24     18030-58-5
B33	S26     2757200-73-8
B34	S27     18676-65-8
B35	S28     80-10-4
B36	S29     1884425-36-8
B37	S31     2413727-11-2
B38	S1 SiCl4 10026-04-7
B39	S16 10026-04-7
B40	S1     32962-41-7
B41	S9     1613-66-7
B42	S21     64526-48-3
B43	S15     52026-54-7
B44	S1 GeCl4 10038-98-9
B45	S15     824-72-6
B46	S21     657-81-8
B47	S28     91270-74-5
B48	S7     2215082-82-7
B49	S1     2226919-96-4
B50	S14     2226919-97-5
B51	S11 SO2 7446-09-5
B52	S32 2809362-95-4
B53	S32 10026-04-7
B54	S33 2762939-41-1
B55	S33 18557-48-7
B56	S34 18030-58-5
B57	S35 33584-32-6
B58	S36     1613-66-7
B59	S37 2215082-82-7
B60	S38 10038-98-9
B61	S39 2809362-95-4
B62	S40 2762939-41-1
B100	929088-61-9 2762939-41-1
B101	929088-61-9 2254340-29-7
B102	929088-61-9 6326-59-6
B103	929088-61-9 2413727-11-2
B104	929088-61-9 32962-41-7
B105	929088-61-9 10038-98-9
B106	929088-61-9 2226919-97-5
B200	2469-66-1 2762939-41-1
B201	2469-66-1 10026-04-7
B202	344326-94-9     490023-82-0
B203	127574-32-7 33584-32-6
B300	S1 TiCl4 7550-45-0
B400	S1 ZrCl4 10026-11-6
B500	S1 HfCl4 13499-05-3

[0204] OLEDs of the invention and OLEDs according to the prior art are produced by a general method according to WO 2004/058911, which is adapted to the circumstances described here (variation in layer thickness, materials used).

[0205] In the examples which follow, the results for various OLEDs are presented. Cleaned glass plates (cleaning in Miele laboratory glass washer, Merck Extran detergent) coated with structured ITO (indium tin oxide) of thickness 50 nm are pretreated with UV ozone for 25 minutes (UVP PR-100 UV ozone generator). These coated glass plates form the substrates to which the OLEDs are applied.

[0206] The compounds of the invention can be used in the hole injection layer (HIL), hole transport layer (HTL) and in the electron blocker layer (EBL). All materials are applied by thermal vapor deposition in a vacuum chamber. The emission layer (EML) here always consists of at least one matrix material (host material) SMB (see table 1) and an emitting dopant (dopant, emitter) D, which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as SMB:D (97:3%) mean here that the material SMB is present in the layer in a proportion by volume of 97% and the dopant D in a proportion of 3%. Analogously, the electron transport layer may also consist of a mixture of two materials; see table 1. The materials used to produce the OLEDs are shown in table 5 or relate to the synthesis examples detailed above.

[0207] The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, current efficiency (measured in cd/A), power efficiency (measured in lm/W) and external quantum efficiency (EQE, measured in percent) as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming Lambertian emission characteristics, and also lifetime are determined. EQE in (%) and voltage in (V) are reported at a luminance of 1000 cd/m². Lifetime is determined at a starting luminance of 10000 cd/m². The measured period of time within which the brightness of the reference has dropped to 80% of initial brightness is set at 100%. The lifetime of the OLED components containing the compounds of the invention is reported in percent relative to the reference.

The OLEDs have the Following Layer Structure:

• • [0208] Hole injection layer (HIL) composed of HTM doped with 5% NDP-9 (commercially available from Novaled), 20 nm
  • [0209] Hole transport layer (HTL), see table 1
  • [0210] Electron blocker layer (EBL), see table 1
  • [0211] Emission layer (EML), see table 1
  • [0212] Electron transport layer (ETL), see table 1
  • [0213] Electron injection layer (EIL) composed of ETM2, 1 nm
  • [0214] Cathode composed of aluminum, 100 nm

TABLE 1
Structure of blue fluorescence OLED components
	HTL	EBL	EML	ETL
Ex.	thickness	thickness	thickness	thickness
BF1	HTM1	EBM1	SMB1:D1	B37:ETM2
	180 nm	10 nm	(95%:5%) 20 nm	(50%:50%) 30 nm
BF2	HTM1	EBM1	SMB1:D1	B52:ETM2
	180 nm	10 nm	(95%:5%) 20 nm	(50%:50%) 30 nm
BF3	HTM1	EBM1	SMB2:D1	B47:ETM2
	180 nm	10 nm	(95%:5%) 20 nm	(50%:50%) 30 nm
BF4	HTM1	EBM1	SMB3:D1	B49:ETM2
	180 nm	10 nm	(95%:5%) 20 nm	(50%:50%) 30 nm

TABLE 2
Results for blue fluorescence OLED components
	Ex.	EQE (%) 1000 cd/m2	Voltage (V) 1000 cd/m2
	BF1	8.3	4.0
	BF2	8.1	3.9
	BF3	8.5	3.7
	BF4	8.1	3.8

[0215] The inventive compounds A can be used in the hole injection layer (HIL), the hole transport layer (HTL), the electron blocker layer (EBL) and the emission layer (EML) as matrix material (host material) M (see table 5) or A (see materials of the invention). For this purpose, all the materials are applied by thermal vapor deposition in a vacuum chamber. The emission layer here always consists of at least one or more than one matrix material M and a phosphorescent dopant Ir which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as M1:M2:Ir (55%:35%:10%) mean here that the material M1 is present in the layer in a proportion by volume of 55%, M2 in a proportion by volume of 35% and Ir in a proportion by volume of 10%. Analogously, the electron transport layer may also consist of a mixture of two materials. The exact structure of the OLEDs can be found in table 3. The materials used to produce the OLEDs are shown in table 5 or relate to the synthesis examples detailed above.

[0216] The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, current efficiency (measured in cd/A), power efficiency (measured in lm/W) and external quantum efficiency (EQE, measured in percent) as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming Lambertian emission characteristics, and also lifetime are determined. EQE in (%) and voltage in (V) are reported at a luminance of 1000 cd/m². Lifetime is determined at a starting luminance of 1000 cd/m² for blue and red, and 10 000 cd/m² for green and yellow. The measured period of time within which the brightness of the reference has dropped to 80% of initial brightness is set at 100%. The lifetime of the OLED components containing the compounds of the invention is reported in percent relative to the respective reference.

The OLEDs have the Following Layer Structure:

• • [0217] Hole injection layer (HIL) composed of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm
  • [0218] Hole transport layer (HTL), see table 3
  • [0219] Electron blocker layer (EBL), see table 3
  • [0220] Emission layer (EML), see table 3
  • [0221] Hole blocker layer (HBL), see table 3
  • [0222] Electron transport layer (ETL), composed of ETM1:ETM2 (50%:50%), 30 nm
  • [0223] Electron injection layer (EIL) composed of ETM2, 1 nm
  • [0224] Cathode composed of aluminum, 100 nm

TABLE 3
Structure of phosphorescence OLED components
	HTL	EBL	EML	HBL
Ex.	thickness	thickness	thickness	thickness
Blue
Ref-BP1	HTM1	EBM2	M3:Ref1:IrB1	HBM2
	180 nm	20 nm	(40%:50%:10%) 25 nm	5 nm
BP1	HTM1	B8	M3:M4:IrB1	HBM2
	180 nm	20 nm	(40%:50%:10%) 25 nm	5 nm
BP2	HTM1	EBM2	M3:B60:IrB1	HBM2
	180 nm	20 nm	(40%:50%:10%) 25 nm	5 nm
BP3	HTM1	B53	M3:M4:IrB1	HBM2
	180 nm	20 nm	(30%:60%:10%) 25 nm	5 nm
BP4	HTM1	EBM2	M3:B43:IrB1	HBM2
	180 nm	20 nm	(30%:60%:10%) 25 nm	5 nm
BP5	HTM1	EBM2	M3:B21:IrB1	HBM2
	180 nm	20 nm	(30%:60%:10%) 25 nm	5 nm
BP6	HTM1	EBM2	M3:B29:IrB1	HBM2
	180 nm	20 nm	(40%:50%:10%) 25 nm	5 nm
BP7	HTM1	EBM2	M3:B17:IrB1	HBM2
	180 nm	20 nm	(30%:60%:10%) 25 nm	5 nm
BP8	HTM1	EBM2	M3:B41:IrB1	HBM2
	180 nm	20 nm	(40%:560%:10%) 25 nm	5 nm
BP9	HTM1	B53	M3:B24:IrB1	B49
	180 nm	20 nm	(30%:60%:10%) 25 nm	5 nm
Green
GP1	HTM1	B30	M1:M2:IrG1	HBM1
	50 nm	20 nm	(30%:60%:10%) 40 nm	5 nm
GP2	HTM1	EBM1	B40:IrG1	HBM1
	50 nm	20 nm	(80%:20%) 40 nm	5 nm
GP3	HTM1	EBM1	B7:M2:IrG1	HBM1
	50 nm	20 nm	(30%:60%:10%) 40 nm	5 nm
GP4	HTM1	EBM1	B32:M2:IrG1	HBM1
	50 nm	20 nm	(50%:40%:10%) 40 nm	5 nm
GP5	HTM1	EBM1	M1:M2:IrG1	B35
	50 nm	20 nm	(30%:60%:10%) 40 nm	5 nm
Yellow
GP50	HTM1	EBM1	B42:IrG2	HBM1
	50 nm	20 nm	(80%:20%) 40 nm	5 nm
GP51	HTM1	EBM1	B52:IrG2	HBM1
	50 nm	20 nm	(80%:20%) 40 nm	5 nm
GP52	HTM1	EBM1	M1:M2:IrG2	B37
	50 nm	20 nm	(30%:60%:10%) 40 nm	5 nm
Red
RP1	HTM1	EBM1	B31:IrR1	HBM1
	50 nm	20 nm	(90%:10%) 35 nm	10 nm
RP2	HTM1	B30	M5:IrR1	HBM1
	50 nm	20 nm	(92%:8%) 35 nm	10 nm

TABLE 4
Results for phosphorescent OLED components
	Ex.	EQE (%) 1000 cd/m2	Voltage (V) 1000 cd/m2
Blue
	Ref-BP1	20.2	4.6
	Ref-BP2	19.3	4.9
	BP1	22.3	4.2
	BP2	22.5	4.1
	BP3	22.3	4.0
	BP4	23.0	3.9
	BP5	22.5	4.0
	BP6	22.7	3.9
	BP7	22.5	4.1
	BP8	22.2	4.0
	BP9	21.7	4.3
Green
	GP1	21.5	3.0
	GP2	22.3	3.1
	GP3	22.4	2.9
	GP4	22.7	3.0
	GP5	23.0	3.3
Yellow
	GP50	30.4	2.9
	GP51	30.1	2.8
	GP52	31.2	3.1
Red
	RP1	16.9	3.2
	RP2	16.7	3.4

TABLE 5
Structural formulae of the materials used
HTM1
136463-07-5
EBM1
1450933-44-4
EBM2
1206465-62-4
Ref1
2009314-82-1
WO2017178864
M1
1822310-86-0
M2
1643479-47-3
M3 = HBM2
1201800-83-0
M4
342638-54-4
M5
1398395-92-0
HBM1
1955543-57-3
ETM1
1819335-36-8
ETM2
25387-93-3
SMB1
1087346-88-0
SMB2
667940-34-3
SMB3
1627916-48-6
Fluorescent blue
D1
1182175-27-4
Phosphorescent blue
IrB1
1541114-98-0
Phosphorescent green
IrG1
2245866-06-0
Phosphorescent yellow
IrG2
2245945-28-0
Phosphorescent deep red
IrR1
1562420-79-4