EP4320648A1

EP4320648A1 - Materials for organic electroluminescent devices

Info

Publication number: EP4320648A1
Application number: EP22720997.0A
Authority: EP
Inventors: Rouven LINGE; Miriam ENGEL; Sebastian Stolz; Sebastian Meyer
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2021-04-09
Filing date: 2022-04-06
Publication date: 2024-02-14
Also published as: KR20230165916A; TW202305091A; CN117084000A; WO2022214506A1

Abstract

The present invention relates to a composition comprising a compound of formula (H1) and a compound of formula (H2). The present invention furthermore relates to a formulation comprising a composition comprising a compound of formula (H1) and a formula (H2) and a solvent. Finally, the present invention relates to an electronic device comprising a such a composition.

Description

Materials for organic electroluminescent devices

The present invention relates to a composition comprising a compound of formula (H1 ) and a compound of formula (H2). The present invention furthermore relates to a formulation comprising a composition comprising a compound of formula (H1 ) and a formula (H2) and a solvent. Finally, the present invention relates to an electronic device comprising such a composition.

The development of functional compounds for use in electronic devices is currently the subject of intensive research. The aim is, in particular, the development of compounds with which improved properties of electronic devices in one or more relevant points can be achieved, such as, for example, power efficiency and lifetime of the device as well as colour coordinates of the emitted light.

In accordance with the present invention, the term electronic device is taken to mean, inter alia, organic integrated circuits (OICs), organic field-effect transistors (OFETs), organic thin-film transistors (OTFTs), organic light- emitting transistors (OLETs), organic solar cells (OSCs), organic optical detectors, organic photoreceptors, organic field-quench devices (OFQDs), organic light-emitting electrochemical cells (OLECs), organic laser diodes (O-lasers) and organic electroluminescent devices (OLEDs).

Of particular interest is the provision of compounds for use in the last- mentioned electronic devices called OLEDs. The general structure and the functional principle of OLEDs are known to the person skilled in the art and are described, for example, in US 4539507.

Further improvements are still necessary with respect to the performance data of OLEDs, in particular with a view to broad commercial use, for example in display devices or as light sources. Of particular importance in this connection are the lifetime, the efficiency and the operating voltage of the OLEDs and as well as the colour values achieved. In particular, in case of blue-emitting OLEDs, there is potential for improvement with respect to the efficiency, lifetime and operating voltage of the devices.

An important starting point for achieving the said improvements is the choice of the emitter compound and of the host compound. Indeed, the emitter compound is generally employed in the emitting layer in combination with a second compound, which serves as matrix compound or host compound. An emitter compound here is taken to mean a compound which emits light during operation of the electronic device. A host compound in this case is taken to mean a compound which is present in the mixture in a greater proportion than the emitter compound. The term matrix compound and the term host compound can be used synonymously. The host compound preferably does not emit light. Even if a plurality of different host compounds are present in the mixture of the emitting layer, their individual proportions are typically greater than the proportion of the emitter compounds, or the proportions of the individual emitter compounds if a plurality of emitter compounds are present in the mixture of the emitting layer.

Such embodiments have been described for fluorescent emitting layers for example in US 4769292.

If a mixture of a plurality of compounds is present in the emitting layer, the emitter compound is typically the component present in smaller amount, i.e. in a smaller proportion than the other compounds present in the mixture of the emitting layer. In this case, the emitter compound is also referred to as dopant.

Hosts compounds for fluorescent emitters that are known from the prior art are a multiplicity of compounds. The emitting layer may comprise one host compounds or more. Host compounds comprising naphthobisbenzofuran groups have been disclosed in the prior art (for example in WO 2020/089138). Host compounds comprising phenanthrene groups have also been disclosed in the prior art (for example in WO 2009/100925).

However, there is still a need for further host materials or further combinations of host materials for fluorescent emitters, which may be employed in OLEDs and lead to OLEDs having very good properties in terms of lifetime, color emission and efficiency. More particularly, there is a need for host materials or combinations of host materials for fluorescent emitters combining very high efficiencies, very good lifetime and very good thermal stability.

Furthermore, it is known that an OLED may comprise different layers, which may be applied either by vapour deposition in a vacuum chamber or by processing from a solution. The processes based on vapour deposition lead to very good results, but they might be complex and expensive. Therefore, there is also a need for compositions comprising OLED materials that can be easily and reliably processed from a solution. More particularly, there is a need for compositions comprising OLED materials that can be deposited as homogeneous films during the fabrication of OLEDs when processed from a formulation, more particularly from a solution like an ink. In this case, the materials should have good solubility properties in the solution that comprises them and the deposited films comprising OLED materials should be as smooth as possible after the drying step leading to the removing of the solvent. It is important that the deposited layer form a smooth and homogenous film as layer thickness inhomogeneities cause uneven luminance distributions with areas of thinner film thickness showing increased luminance and thicker areas with reduced luminance, which leads to a decrease of the OLED^'s quality. At the same time, the OLEDs comprising the films processed form a solution should exhibit good performances, for example in terms of lifetime, operating voltage and efficiency.

There is furthermore still a need for processes, which lead to stable OLED materials, which are easily purified and easily processed. There is a need for processes, which are economically and qualitatively interesting by providing OLED materials in acceptable purity and with a high yield.

The present invention is thus based on the technical object of providing compositions comprising OLED materials, which are suitable for use in electronic devices, such as OLEDs, more particularly as a matrix component for fluorescent emitters. The present invention is also based on the technical object of providing compositions comprising OLED materials, which are particularly suitable for solution processing. The present invention is also based on the technical object of providing processes.

In investigations on novel compositions for use in electronic devices, it has now been found, that the compositions comprising a compound of formula (H1 ) and a compound of formula (H2) as defined below are eminently suitable for use in electronic devices. In particular, they achieve one or more, preferably all, of the above-mentioned technical objects.

The present application thus relates to a composition comprising a compound of formula (H1 ) and a compound of formula (H2), formula (H1 ) formula (H2) where the following applies to the symbols and indices used:

E¹, E², E³ and E⁴ stand on each occurrence, identically or differently, for a single bond, -BR°- -C(R°)₂- -Si(R°)₂- -C(=0)-, -0-, -S-, -S(=0)-, -S0₂- -N(R°)- or -P(R°)-; with the proviso that, in the ring comprising E¹ and E³, only one group E¹ or E³ might be a single bond and, in the ring comprising E² and E⁴, only one group E² or E⁴ might be a single bond;

X¹ to X¹² stand on each occurrence, identically or differently, for C-R^x, C-Ar^x or N; with the proviso that at least one group selected from X¹ to X¹² stands for a group C-Ar^x and Ar^x stands for a group of formula (Ar^x): formula (Ar^x) where the dashed bond indicates the bonding to the group C in C-Ar^x;

Z¹ to Z¹⁰ stand on each occurrence, identically or differently, for C-R^z, C-Ar^z or N; with the proviso that at least one group selected from Z¹ to Z¹⁰ stands for a group C-Ar^z and Ar^z stands for a group of formula (Ar^z): formula (Ar^z) where the dashed bond indicates the bonding to the group C in C-Ar^z;

Ar¹ is, on each occurrence, identically or differently, an aryl or heteroaryl group having 10 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R^v;

Ar³ is, on each occurrence, identically or differently, an aryl or heteroaryl group having 10 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R^Y;

Ar², Ar⁴, Ar^s are, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R;

R^v, R^x, R^Y, R^z stand on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, C(=0)Ar, P(=0)(Ar)₂, S(=0)Ar, S(=0) Ar, N(R)₂, N(Ar)₂, N0₂, Si(R)3, B(OR)₂, OS0₂R, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH₂ groups may be replaced by RC=CR, CºC, Si(R)₂, Ge(R)₂, Sn(R)₂, C=0, C=S, C=Se, P(=0)(R), SO, S0₂, O, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or N0₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R; where two radicals R^v, two radicals R^x, two radicals R^Y, two radicals R^z may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R;

R° stands on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl group having 1 to 20 C atoms, or a branched or a cyclic alkyl group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH2 groups may be replaced by O or S and where one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring systems having 5 to 40 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two adjacent radicals R°, may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R;

R stands on each occurrence, identically or differently, for FI, D, F, Cl, Br, I, CHO, CN, C(=0)Ar, P(=0)(Ar)₂, S(=0)Ar, S(=0)₂Ar, N(R^')₂, N(Ar)₂, N0₂, Si(R )3, B(OR^')₂, OS0₂R , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R^’, where in each case one or more non-adjacent CH₂ groups may be replaced by R C=CR , CºC, Si(R )₂, Ge(R )₂, Sn(R )₂, C=0, C=S, C=Se, P(=0)(R ), SO, S0₂, O, S or CONR and where one or more FI atoms may be replaced by D, F, Cl, Br, I, CN or N0₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R^’, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R^’; where two radicals R may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R^’; Ar is, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R ;

R^' stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, where in each case one or more non-adjacent CH2 groups may be replaced by SO, SO2, O, S and where one or more H atoms may be replaced by D, F, Cl, Br or I, or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms; and p, s are on each occurrence, identically or differently, 0 or 1 , wherein: when p or s is 0, then the corresponding Ar^s is absent and the group Ar¹ or Ar³ is directly bonded to C in C-Ar^x or C-Ar^z; q, t are on each occurrence, identically or differently, 0, 1 or 2, wherein: when q is 0, then Ar⁴ is absent; when t is 0, then Ar² is absent; when q is 1 or 2, then Ar¹ is substituted by one group or two groups Ar⁴; when t is 1 or 2, then Ar³ is substituted by one group or two groups Ar².

Furthermore, the following definitions of chemical groups apply for the purposes of the present application:

An aryl group in the sense of this invention contains 6 to 60 aromatic ring atoms, preferably 6 to 40 aromatic ring atoms, more preferably 6 to 20 aromatic ring atoms; a heteroaryl group in the sense of this invention contains 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, more preferably 5 to 20 aromatic ring atoms, at least one of which is a heteroatom. The heteroatoms are preferably selected from N, O and S. This represents the basic definition. If other preferences are indicated in the description of the present invention, for example with respect to the number of aromatic ring atoms or the heteroatoms present, these apply.

An aryl group or heteroaryl group here is taken to mean either a simple aromatic ring, i.e. benzene, or a simple heteroaromatic ring, for example pyridine, pyrimidine or thiophene, or a condensed (annellated) aromatic or heteroaromatic polycycle, for example naphthalene, phenanthrene, quinoline or carbazole. A condensed (annellated) aromatic or heteroaromatic polycycle in the sense of the present application consists of two or more simple aromatic or heteroaromatic rings condensed with one another.

An aryl or heteroaryl group, which may in each case be substituted by the above-mentioned radicals and which may be linked to the aromatic or hetero aromatic ring system via any desired positions, is taken to mean, in particular, groups derived from benzene, naphthalene, anthracene, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene, benzanthracene, benzophenanthrene, tetracene, pentacene, benzopyrene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothio- phene, 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, benzopyridazine, pyrimidine, benzo- pyrimidine, quinoxaline, pyrazine, phenazine, 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. An aryloxy group in accordance with the definition of the present invention is taken to mean an aryl group, as defined above, which is bonded via an oxygen atom. An analogous definition applies to heteroaryloxy groups.

An aromatic ring system in the sense of this invention contains 6 to 60 C atoms in the ring system, preferably 6 to 40 C atoms, more preferably 6 to 20 C atoms. A heteroaromatic ring system in the sense of this invention contains 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, more preferably 5 to 20 aromatic ring atoms, at least one of which is a heteroatom. The heteroatoms are preferably selected from N, O and/or S. An aromatic or heteroaromatic ring system in the sense of this invention is intended to be taken to mean a system which does not necessarily contain only aryl or heteroaryl groups, but instead in which, in addition, a plurality of aryl or hetero aryl groups may be connected by a non-aromatic unit (preferably less than 10% of the atoms other than H), such as, for example, an sp³-hybridised C, Si, N or O atom, an sp²-hybridised C or N atom or an sp-hybridised C atom. Thus, for example, systems such as 9,9’-spirobifluorene, 9,9’-diarylfluorene, triarylamine, diaryl ether, stilbene, etc., are also intended to be taken to be aromatic ring systems in the sense of this invention, as are systems in which two or more aryl groups are connected, for example, by a linear or cyclic alkyl, alkenyl or alkynyl group or by a silyl group. Furthermore, systems in which two or more aryl or heteroaryl groups are linked to one another via single bonds are also taken to be aromatic or heteroaromatic ring systems in the sense of this invention, such as, for example, systems such as biphenyl, terphenyl or diphenyltriazine.

An aromatic or heteroaromatic ring system having 5 - 60 aromatic ring atoms, which may in each case also be substituted by radicals as defined above and which may be linked to the aromatic or heteroaromatic group via any desired positions, is taken to mean, in particular, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, naphtha- cene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenyl- ene, quaterphenyl, fluorene, spirobifluorene, dihydrophenanthrene, dihydro pyrene, tetrahydropyrene, cis- or trans-indenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzo- furan, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyri dine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5, 6-quinoline, benzo-6, 7-quinoline, benzo-7, 8-quinoline, phenothiazine, phenoxazine, pyra- zole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimi- dazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1 ,2-thiazole, 1 ,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1 ,5-diazaanthracene, 2,7-diaza- pyrene, 2,3-diazapyrene, 1 ,6-diazapyrene, 1 ,8-diazapyrene, 4,5-diaza- pyrene, 4,5,9, 10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubin, 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 combinations of these groups.

For the purposes of the present invention, a straight-chain alkyl group having 1 to 40 C atoms or a branched or cyclic alkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, in which, in addition, individual H atoms or CH2 groups may be substituted by the groups mentioned above under the definition of the radicals, is preferably taken to mean the radicals methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoro- methyl, pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl or octynyl. An alkoxy or thioalkyl group having 1 to 40 C atoms is preferably taken to mean methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy,

1-butoxy, s-butoxy, t-butoxy, n-pentoxy, s-pentoxy, 2-methylbutoxy, n-hexoxy, cyclohexyloxy, n-heptoxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy,

2-ethylhexyloxy, pentafluoroethoxy, 2,2,2-trifluoroethoxy, 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, trifluoro- methylthio, pentafluoroethylthio, 2,2,2-trifluoroethylthio, ethenylthio, propenyl- thio, butenylthio, pentenylthio, cyclopentenylthio, hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio, octenylthio, cyclooctenyl- thio, ethynylthio, propynylthio, butynylthio, pentynylthio, hexynylthio, heptynyl- thio or octynylthio.

The formulation that two or more radicals may form a ring with one another is, for the purposes of the present application, intended to be taken to mean, inter alia, that the two radicals are linked to one another by a chemical bond. This is illustrated by the following schemes:

Furthermore, however, the above-mentioned formulation is also intended to be taken to mean that, in the case where one of the two radicals represents hydrogen, the second radical is bonded at the position to which the hydrogen atom was bonded, with formation of a ring. This is illustrated by the following scheme:

When two radicals form a ring with one another, then it is preferred that the two radicals are adjacent radicals. Adjacent radicals in the sense of the present invention are radicals which are bonded to atoms which are linked directly to one another or which are bonded to the same atom.

Preferably, the groups Ar¹, Ar³ stand on each occurrence, identically or differently, for a condensed aryl group having 10 to 18 aromatic ring atoms. More preferably, the groups Ar¹, Ar³ stand on each occurrence, identically or differently, for an anthracene, naphthalene, phenanthrene, tetracene, chrysene, benzanthracene, benzophenanthracene, pyrene, perylene, triphenylene, benzopyrene or fluoranthene, each of which may be substituted by one or more radicals R^v in the case of Ar¹ or R^Y in the case of Ar³ at any free positions. Very preferably, the groups Ar¹, Ar³ stand for an anthracene group, which may be substituted by one or more radicals R^v at any free positions for Ar¹ or by one or more radicals R^Y at any free positions for Ar³.

Examples of suitable groups Ar¹ and Ar³ are the groups of formulae (Ar1-1 ) to (Ar1 -11 ) as represented in the table below: where the groups of formulae (Ar-1 ) to (Ar-11 ) may be bonded to the adjacent groups at any position and may be substituted at each free position by a group R^v in case of Ar¹ and R^Y in case of Ar³.

Among the groups of formulae (Ar1 -1 ) to (Ar1 -11 ), the group of formula (Ar1 - 1 ) is preferred.

Examples of very suitable groups Ar¹ and Ar³ are the groups of formulae (Ar1- -1 ) as represented in the table below: where the dashed bonds indicate the bonding to the adjacent groups; and where the groups of formulae (Ar1 -1 -1 ) to (Ar1 -12-1 ) may be substituted at each free position by a group R^v in the case of Ar¹ or by a group R^Y in the case of Ar³, where R^v and R^Y have the same meaning as above.

Among the groups of formulae (Arl-1-1 ) to (A -12-1 ), the group of formula (Arl-1-1 ) is preferred. It is preferred that, in the compound of formula (H1 ), at least one group selected from X¹ to X⁴ stands for a group C-Ar^x, where Ar^x stands for a group of formula (Ar^x) as defined above and that the groups X⁵ to X¹² stand for C-R^x or N.

Preferably, the compound of formula (H1 ) is selected from the compound of formulae (H1-A) to (H1-D): formula (H1-C) formula (H1-D) where the symbols have the same meaning as above.

Preferably, E¹, E², E³ and E⁴ stand on each occurrence, identically or differently, for a single bond, -C(R°)2-, -Si(R°)2-, -0-, -S- or -N(R°). More preferably, one group selected from E¹ and E³ stands for a single bond and the other group stands for -C(R°)2-, -Si(R°)2-, -0-, -S- or -N(R°) and one group selected from E² and E⁴ stands for a single bond and the other group stands for -C(R°)₂- -Si(R°)₂- -0-, -S- or -N(R°).

More preferably, the compound of formula (H1 ) is selected from the compounds of one of the following formulae:

R R R R formula (H1-A-3) formula (H1-A-4)

formula (H1-C-1) formula (H1-C-2) formula (H1-D-3) formula (H1-D-4) where the symbols R^x, Ar^x have the same meaning as above and the groups E¹, E², E³ and E⁴ stand on each occurrence, identically or differently, for -BR⁰-, -C(R°)2- -Si(R°)2- -C(=0)-, -0-, -S-, -S(=0)-, -SO2-, -N(R⁰)- or - P(R⁰)-.

Among the compounds of formulae (H1-A-1 ) to (H1-D-4), the compounds of formulae (H1-A-1 ), (H1-B-1 ), (H1-C-1 ) and (H1-D-1 ) are preferred.

Preferably, the group Ar^x stands for a group of formula (Ar^x-1 ): where the symbols and indices have the same meaning as above and where the anthracene group may be substituted at each free position by a group R^v.

More preferably, the group Ar^x stands for a group of one of the following formulae:

formula (Ar^x-1A) formula (Ar^x-1B) where the symbols and indices have the same meaning as above and where the anthracene group may be substituted at each free position by a group R^v.

Particularly preferably, the compound of formula (H1) is selected from the compounds of one of the following formulae: formula (H1-A-1-1) formula (H1-B-1-1) where the symbols and indices have the same meaning as above and where the anthracene group may be substituted at each free position by a group R^v.

Preferably, R^v, R^x stand on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40, preferably 3 to 20, more preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH2 groups may be replaced by RC=CR, CºC, O or S and where one or more H atoms may be replaced by D or F, an aromatic or heteroaromatic ring system having 5 to 60, preferably 5 to 40, more preferably 5 to 30, particularly preferably 5 to 18 aromatic ring atoms, which may in each case be sub stituted by one or more radicals R. More preferably, R^x, R^v stand on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 6 C atoms or branched or a cyclic alkyl group having 3 to 20, preferably 3 to 10, more preferably 3 to 6 C atoms, each of which may be substituted by one or more radicals R, an aromatic or heteroaromatic ring system having 5 to 40, preferably 5 to 30, more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R. More preferably, R^x is H or D. More preferably, R^v is H or D.

It is preferred that, in the compound of formula (H2), one group selected from Z¹ to Z⁴ stands for a group C-Ar^z and that one group selected from Z⁵ to Z⁸ stands for a group C-Ar^z, where Ar^z stands for a group of formula (Ar^z) as defined above.

Preferably, the compound (H2) is selected from the compounds of the following formulae:

(H2-C) (H2-D)

(H2-K) (H2-L) where the symbols have the same meaning as above.

Among the compounds of formulae (H2-A) to (H2-N), the compounds of formulae (H2-A) to (H2-C), (H2-E) to (H2-F) and (H2-H), (H2-K) and (H2-M) are preferred. The compounds of formula (H2-E), (H2-H) und (H2-K) are particularly preferred.

Preferably, the group Ar^z stands for a group of formula (Ar^z-1 ): where the symbols and indices have the same meaning as above and where the anthracene group may be substituted at each free position by a group R^Y. Preferably, the group Ar^z stands for a group of one of the following formulae: formula (Ar^z-1 A) formula (Ai^-I B) where the symbols and indices have the same meaning as above and where the anthracene group may be substituted at each free position by a group R^Y.

More preferably, the compound (H2) is selected from the compounds of the following formulae:

(H2-E-1 ) (H2-F-1 )

(H2-I-1 ) (H2-J-1 )

(H2-M-1 ) (H2-N-1 )

(H2-C-2) (H2-D-2) (H2-G-2) (H2-H-2)

(H2-K-2) (H2-L-2)

(H2-M-2) (H2-N-2) where the symbols and indices have the same meaning as above and where the anthracene group may be substituted at each free position by a group R^Y.

Among the compounds of formulae (H2-A-1 ) to (H2-J-2), the compounds of formulae (H2-A-1 ) to (H2-C-1 ), (H2-E-1 ), (H2-F-1 ), (H2-H-1 ), (H2-E-2), (H2- F-2) and (H2-H-2) are preferred. The compounds of formulae (H2-H-1 ) are very preferred.

Preferably, R^Y, R^z stand on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl, alkoxy orthioalkyl group having 1 to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40, preferably 3 to 20, more preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CFI2 groups may be replaced by RC=CR, CºC, O or S and where one or more FI atoms may be replaced by D or F, an aromatic or heteroaromatic ring system having 5 to 60, preferably 5 to 40, more preferably 5 to 30, particularly preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R. More preferably, R^Y, R^z stand on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 6 C atoms or branched or a cyclic alkyl group having 3 to 20, preferably 3 to 10, more preferably 3 to 6 C atoms, each of which may be substituted by one or more radicals R, an aromatic or heteroaromatic ring system having 5 to 40, preferably 5 to 30, more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R. More preferably, R^z stands for H or D. More preferably, R^Y stands for H or D.

Preferably, the groups Ar², Ar⁴ are on each occurrence, identically or differently, selected from aromatic or heteroaromatic ring systems having 5 to 30, preferably 5 to 25 aromatic ring atoms, which may in each case be sub stituted by one or more radicals R. More preferably, the group Ar², Ar⁴ are selected from the group consisting of phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, phenanthrene, anthracene, triphenylene, fluoranthene, tetracene, chrysene, benzanthracene, benzophenanthracene, pyrene, perylene, indole, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene, carbazole, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinolone, benzopyridine, benzopyridazine, benzopyrimidine, benzimidazole and quinazoline, each of which may be substituted by one or more radicals R; where Ar², Ar⁴ might also be a combination of two or more of the previously cited groups. Particularly preferably, the groups Ar², Ar⁴ are selected from the group consisting of phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, anthracene, phenanthrene, triphenylene, fluoranthene, tetracene, chrysene, benzanthracene, benzophenanthracene, pyrene or perylene, dibenzofuran, carbazole and dibenzothiophene, each of which may be substituted by one or more radicals R at any free positions; and where Ar², Ar⁴ might also be a combination of two or more of the previously cited groups. Very particularly preferably, the groups Ar², Ar⁴ are selected from the group consisting of phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, anthracene, phenanthrene, triphenylene, fluoranthene, dibenzofuran, carbazole and dibenzothiophene, each of which may be substituted by one or more radicals R at any free positions; and where Ar², Ar⁴ might also be a combination of two or more of the previously cited groups.

Examples of suitable groups Ar² and Ar⁴ are the groups of formulae (Ar2-1 ) to (Ar2-27) as depicted in the table below: where the dashed bond indicates the bonding to the adjacent group and where the group R° has the same meaning as above; and where the groups of formulae (Ar2-1 ) to (Ar2-27) may be substituted at each free position by a group R, which has the same meaning as above.

Among the groups of formulae (Ar2-1 ) to (Ar2-27), the groups of formulae (Ar2-1 ), (Ar2-2), (Ar2-3), (Ar2-4), (Ar2-5), (Ar2-8), (Ar2-18), (Ar2-19) are preferred. The groups of formula (Ar2-1 ), (Ar2-2), (Ar2-3), (Ar2-4), (Ar2-5) are very preferred.

Preferably, the group Ar^s stands on each occurrence, identically or differently, for phenyl, biphenyl, fluorene, spirobifluorene, naphthalene, phenanthrene, anthracene, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, benzopyridine, benzopyridazine, benzopyrimidine and quinazoline, each of which may be substituted by one or more radicals R.

Examples of suitable groups Ar^s are the groups of formulae (ArS-1 ) to (ArS- 26) as represented in the table below: where the dashed bonds indicate the bonding to the adjacent groups in formula (H1) or (H2); where the groups of formulae (ArS-1 ) to (ArS-26) may be substituted at each free position by a group R, which has the same meaning as defined above; and where the group E is on each occurrence, identically or differently, selected from -BR⁰-, -C(R°)₂- -Si(R°)₂- -C(=0)-, -0-, -S-, -S(=0)-, -S0₂-, -N(R⁰)-, and -P(R⁰)-, where R° has the same definition as above.

Among the groups of formulae (ArS-1) to (ArS-26), the groups of formulae (ArS-1), (ArS-2), (ArS-3), (ArS-11) and (ArS-12) are preferred. The groups of formula (ArS-1), (ArS-2), (ArS-3) are very preferred.

Preferably, R° stands on each occurrence, identically or differently, for H,

D, F, a straight-chain alkyl group having 1 to 10 C atoms or branched or a cyclic alkyl group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH₂ groups may be replaced by O or S and where one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring systems having 5 to 30, preferably 6 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two adjacent radicals R°, may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R;

Preferably, R stands on each occurrence, identically or differently, for FI, D, F, CN, N(Ar)₂, a straight-chain alkyl, alkoxy orthioalkyl groups having 1 to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl groups having 3 to 40, preferably 3 to 20, more preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R^', where in each case one or more non-adjacent CFH₂ groups may be replaced by R^'C=CR^', CºC, O or S and where one or more FI atoms may be replaced by D or F, or an aromatic or heteroaromatic ring systems having 5 to 60, preferably 5 to 40, more preferably 5 to 30, particularly preferably 6 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R^'. Preferably, Ar is, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40, preferably 5 to 30, more preferably 5 to 25, very more preferably 6 to 18 aromatic ring atoms, which may in each case also be substituted by one or more radicals R ;

Preferably, R^' stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl group having 1 to 10 C atoms or branched or cyclic alkyl group having 3 to 10 C atoms, where in each case one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring system having 5 to 18 C atoms.

The following compounds are examples of compounds of formula (H 1 ):

The following compounds are examples of compounds of formula (H2):

In accordance with a preferred embodiment, the composition comprises a compound of formula (H1), a compound of formula (H2) and at least one fluorescent emitter. The expression “at least one fluorescent emitter” means “one, two, three or more fluorescent emitters”.

In accordance with a very preferred embodiment, the composition comprises the compound of formula (H1 ) as a first host material, the compound of formula (H2) as a second host material and a fluorescent emitter as a dopant material.

Preferably, the composition comprises at least one fluorescent emitter, which comprises at least one of the following group:

- an arylamine containing three substituted or unsubstituted aromatic or heteroaromatic ring systems bonded directly to the nitrogen;

- a bridged triarylamine;

- a condensed aromatic or heteroaromatic ring system having at least 14 aromatic ring atoms;

- an indenofluorene, indenofluorenamine or indenofluorenediamine;

- a benzoindonofluorene, benzoindenofluorenamine or benzoindenofluorenediamine;

- a dibenzoindenofluorene, dibenzoindenofluorenamine or dibenzo- indenofluorenediamine;

- an indenofluorene containing a condensed aryl group having at least 10 aromatic ring atoms;

- a bisindenoindenofluorene;

- an indenodibenzofuran; indenofluorenamine or indenofluorenediamine;

- a fluorene dimer;

- a phenoxazine; or

- a boron derivative.

More preferably, the composition comprises at least one fluorescent emitter of one of the following formulae (E-1 ), (E-2), (E-3) or (E-4) as depicted below: Formula (E-1) where

Ar¹⁰, Ar¹¹, Ar¹²are on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 6 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R; with the proviso that at least one group Ar¹⁰, Ar¹¹, Ar¹² is an aromatic or heteroaromatic ring system having 10 to 40 aromatic ring atoms, containing at least one condensed aryl or heteroaryl group consisting of 2 to 4 aromatic rings condensed with one another, where the aromatic or heteroaromatic ring system may be substituted by one or more radicals

R has the same definition as above; and e is 1 , 2, 3 or 4; more preferably, e is 1 ;

Formula (E-2) where Ar²⁰, Ar²¹, Ar²²are on each occurrence, identically or differently, an aryl or heteroaryl group having 6 to 30 aromatic ring atoms, which may in each case also be substituted by one or more radicals R;

E²⁰ is on each occurrence, identically or differently a group selected from BR, C(R°)2, Si(R°)2, C=0, C=NR°, C=C(R°) , O, S, S=0, SO2, NR°, PR⁰, P(=0)R° or P(=S)R°; wherein Ar²⁰, Ar²¹ and E²⁰ together form a five- membered ring or a six-membered ring, and Ar²¹, Ar²³ and E²⁰ together form a five-membered ring or a six-membered ring;

R° stands on each occurrence, identically or differently, for H, D, F, a straight- chain alkyl group having 1 to 20 , preferably 1 to 10 C atoms or branched or a cyclic alkyl group having 3 to 20, preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH2 groups may be replaced by O or S and where one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring systems having 5 to 40, preferably 5 to 30, more preferably 6 to 18 aromatic ring atoms, which may in each case be sub stituted by one or more radicals R, where two adjacent radicals R°, may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R,

R has the same definition as above; p, qare on each occurrence, identically or differently, 0 or 1 , with the proviso that p + q = 1 ; r is 1 , 2 Oder 3;

Formula (E-3) where

Ar³⁰, Ar³¹, Ar³² stand on each occurrence, identically or differently, for a substituted or unsubstituted aryl or heteroaryl group having 5 to 22, preferably 5 to 18, more preferably 6 to 14 aromatic ring atoms;

E³⁰ stands for B or N;

E³¹, E³², E³³ stand on each occurrence, identically or differently, for 0, S, C(R°)2, C=0, C=S, C=NR°, C=C(R°)2, Si(R°)₂, BR°, NR°, PR°, SO2, Se0₂ or a chemical bond, with the proviso that if E³⁰ is B, then at least one of the groups E³¹, E³², E³³ stands for NR° and if E³⁰ is N, then at least one of the groups E³¹, E³², E³³ stands for BR°;

R° has the same definition as above; s, t, u are on each occurrence, identically or differently, 0 or 1 , with the proviso that s + t + u > 1 ;

Formula (E-4) where

Ar⁴⁰ Ar⁴¹, Ar⁴² stand on each occurrence, identically or differently, for a substituted or unsubstituted aryl or heteroaryl group having 5 to 22, preferably 5 to 18, more preferably 6 to 14 aromatic ring atoms;

E⁴¹, E⁴², E⁴³ stand on each occurrence, identically or differently, for O, S, C(R°)2, C=0, C=S, C=NR°, C=C(R°)2, Si(R°)₂, BR°, NR°, PR°, SO2, Se0₂ or a chemical bond, with the proviso that at least one of the groups E⁴¹, E⁴², E⁴³ is present and stands for a chemical bond;

R° has the same definition as above; i, g, h are on each occurrence, identically or differently, 0 or 1 , with the proviso that i + g + h > 1 .

Preferably, the fluorescent emitter of formula (E-1 ) comprises at least one group Ar¹⁰, Ar¹¹ or Ar¹², preferably Ar¹⁰, which is selected from the groups of formulae (Ar¹⁰-1 ) to (Ar¹⁰-24): where the groups Ar¹⁰-1 to Ar¹⁰-24 may be substituted at all free positions by one or more radicals R; and where

E¹⁰ is on each occurrence, identically or differently a group selected from BR°, C(R°)_2I Si(R°)₂ C=0, C=NR°, C=C(R°)2, O, S, S=0, SO2, NR°, PR⁰, P(=0)R° or P(=S)R°, preferably E¹⁰ is C(R°)₂; where R° has the same definition as above;

E¹¹ is on each occurrence, identically or differently a group selected from C=0, O, S, S=0 or SO2, preferably O or S, more preferably O; and Ar¹³is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R.

In accordance with a preferred embodiment, the emitters of formula (E-1 ) comprise a group Ar¹⁰ selected from the groups of formulae (Ar¹⁰-15) to (Ar¹⁰- 22), wherein d is preferably equal to 1 and wherein preferably at least one group Ar¹¹, Ar¹² is selected from the groups of formulae (Ar¹⁰-15) to (Ar¹⁰-22). In accordance with a very preferred embodiment, the emitter of formula (E-1) is selected from the emitters of formulae (E-1-1) to (E-1 -6), where the symbols have the same meaning as above and where: f is 0, 1 or 2; and the benzene rings represented above in the compounds of formulae (E-1-1) to (E-1 -6) may be substituted at all free positions by one or more radicals R. Particularly preferably, the compounds of formula (E-1) are selected from the compounds of formulae (E-1-1-A) to (E-1-6-A), where the symbols and indices have the same meaning as above and where the benzene rings represented above in the compounds of formulae (E-1-1- A) to (E-1 -6-A) may be substituted at all free positions by one or more radicals R.

Preferably, the fluorescent emitter of formula (E-2) is selected from fluorescent emitters of formula (E-2-1 ) to (E-2-43), where the groups of formulae (E-2-1 ) to (E-2-43) may be substituted at all free positions by one or more radicals R; and where E²⁰ has the same definition as above. Preferably, E²⁰ is C(R°)2.

The compounds of formula (E-2) are preferably selected from the compounds of formulae (E-2-32) to (E-2-43). More preferably, the compounds of formula (E-2) are selected from the compounds (E-2-32-A) to (E-2-43-A): where the symbols have the same meaning as above and where the benzene and naphthalene rings represented above in the compounds of formulae (E- 2-32-A) to (E-2-43-A) may be substituted at all free positions by one or more radicals R.

Preferably, the fluorescent emitter of formula (E-3) is selected from fluorescent emitters of formula (E-3-1 ),

Formula (E-3-1 ) where the symbols and indices have the same meaning as above.

More preferably, the fluorescent emitter of formula (E-3) is selected from fluorescent emitters of formula (E-3-2), Formula (E-3-2) where the symbols E³⁰ to E³³ have the same meaning as above; where t is 0 or 1 , wherein when t is 0, the group E³² is absent and radicals R¹⁰ are present, which replace the bonds to E³²; and where

R¹⁰ stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, Si(R )3, B(OR^')₂, 0S0₂R , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R^', where in each case one or more non-adjacent CH₂ groups may be replaced by R C=CR , CºC, Si(R^')₂, Ge(R )₂, Sn(R )₂, C=0, C=S, C=Se, P(=0)(R ), SO, S0₂, O, S or CONR^' and where one or more FI atoms may be replaced by D, F, Cl, Br, I, CN or N0₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be sub stituted by one or more radicals R^', or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R^'; where two adjacent substituents R¹⁰ may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R^'; where R^' has the same definition as above. Even more preferably, the fluorescent emitter of formula (E-3) is selected from fluorescent emitters of formula (E-3-3) and (E-3-4),

Formula (E-3-3) Formula (E-3-4) where the symbols and indices have the same meaning as above.

Preferably, the fluorescent emitter of formula (E-4) is selected from fluorescent emitters of formula (E-4-1 ) or (E-4-2),

Formula (E-4-1) Formula (E-4-2) where E⁴¹ and E⁴² stand on each occurrence, identically or differently, for 0, S, C(R°)2, C=0, C=S, C=NR°, C=C(R°)2, Si(R°)₂, BR°, NR°, PR⁰, SO2, Se0₂ or a chemical bond, where E⁴¹ is preferably bond;

R²⁰ stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, C(=0)Ar, P(=0)(Ar)₂, S(=0)Ar, S(=0) Ar, N(R , N(Ar)₂, NO2, Si(R )3, B(OR^')2, OSO2R , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R^', where in each case one or more non-adjacent CH2 groups may be replaced by R C=CR , CºC, Si(R )2, Ge(R^')2, Sn(R^')2, C=0, C=S, C=Se, P(=0)(R ), SO, SO2, O, S or CONR^' and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R^', or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R^'; where two adjacent substituents R²⁰ may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R^'; where R^' has the same definition as above; g is O or

More preferably, the fluorescent emitter of formula (E-4) is selected from fluorescent emitters of formula (E-4-1-A) or (E-4-2-A),

Formula (E-4-1-A) Formula (E-4-2-A) where the symbols have the same meaning as above.

In accordance with a preferred embodiment, the fluorescent emitter of formula (E-1 ), (E-2), (E-3) or (E-4) comprises a group RS, wherein the group RS is selected:

- from branched or cyclic alkyl groups represented by the general following formula a group of formula (RS-a),

(RS-a) wherein

R²², R²³, R²⁴ are at each occurrence, identically or differently, selected from H, 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 above-mentioned groups may each be substituted by one or more radicals R²⁵, and where two of radicals R²², R²³, R²⁴ or all radicals R²², R²³, R²⁴ may be joined to form a (poly)cyclic alkyl group, which may be substituted by one or more radicals R²⁵;

R²⁵ is at each occurrence, identically or differently, selected from a straight-chain alkyl group having 1 to 10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms; with the proviso that at each occurrence at least one of radicals R²², R²³ and R²⁴ is other than H, with the proviso that at each occurrence all of radicals R²², R²³ and R²⁴ together have at least 4 carbon atoms and with the proviso that at each occurrence, if two of radicals R²², R²³, R²⁴ are H, the remaining radical is not a straight-chain; or from branched or cyclic alkoxy groups represented by the general following formula (RS-b)

(RS-b) wherein

R²⁶, R²⁷, R²⁸ are at each occurrence, identically or differently, selected from H, 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 above-mentioned groups may each be substituted by one or more radicals R²⁵ as defined above, and where two of radicals R²⁶, R²⁷, R²⁸ or all radicals R²⁶, R²⁷, R²⁸ may be joined to form a (poly)cyclic alkyl group, which may be substituted by one or more radicals R²⁵ as defined above; with the proviso that at each occurrence only one of radicals R²⁶, R²⁷ and R²⁸ may be H;

- from aralkyl groups represented by the general following formula (RS-c)

(RS-c) wherein

R²⁹, R³⁰, R³¹ are at each occurrence, identically or differently, selected from H, 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 above-mentioned groups may each be substituted by one or more radicals R³², or an aromatic ring system having 6 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R³², and where two or all of radicals R²⁹, R³⁰, R³¹ may be joined to form a (poly)cyclic alkyl group or an aromatic ring system, each of which may be substituted by one or more radicals R³²;

R³² is at each occurrence, identically or differently, selected from a straight-chain alkyl group having 1 to 10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms, or an aromatic ring system having 6 to 24 aromatic ring atoms; with the proviso that at each occurrence at least one of radicals R²⁹, R³⁰ and R³¹ is other than H and that at each occurrence at least one of radicals R²⁹, R³⁰ and R³¹ is or contains an aromatic ring system having at least 6 aromatic ring atoms;

- from aromatic ring systems represented by the general following formula

(RS-d)

(RS-d) wherein

R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently, selected from H, 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 above-mentioned groups may each be substituted by one or more radicals R³², or an aromatic ring system having 6 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R³², and where two or more of radicals R⁴⁰ to R⁴⁴ may be joined to form a (poly)cyclic alkyl group or an aromatic ring system, each of which may be substituted by one or more radicals R³² as defined above; or from groups of formula (RS-e), formula (RS-e) where the dashed bond in formula (RS-e) indicates the bonding to the fluorescent emitter, where Ar⁵⁰, Ar⁵¹ stand on each occurrence, identically or differently, for an aromatic or heteroaromatic ring systems having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R; and where m is an integer selected from 1 to 10.

Preferably, the index m in the group of formula (RS-e) is an integer selected from 1 to 6, very preferably from 1 to 4.

Preferably, Ar⁵⁰, Ar⁵¹ stand on each occurrence, identically or differently, for an aromatic or heteroaromatic ring systems having 5 to 40, preferably 5 to 30, more preferably 6 to 18 aromatic ring atoms, which may in each case be sub stituted by one or more radicals R. More preferably, Ar⁵⁰, Ar⁵¹ are selected from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, anthracene, phenanthrene, triphenylene, fluoranthene, dibenzofuran, carbazole and dibenzothiophene, which may in each case be substituted by one or more radicals R. Very preferably, at least one group Ar⁵⁰ or Ar⁵¹ is a fluorene, which may be substituted by one or more radicals R.

More particularly, it is preferred that at least one group Ar⁵⁰ stands for a group of formula (Ar50-2) and/or at least one group Ar⁵¹ stands for a group of formula (Ar51-2), the dashed bonds in formula (Ar50-2) indicate the bonding to the fluorescent emitter and to a group Ar⁵⁰ or Ar⁵¹; and the dashed bond in formula (Ar51-2) indicates the bonding to Ar⁵⁰;

E⁴ is selected from -C(R^0a)2-, -Si(R^0a)2-, -0-, -S- or -N(R^0a)-, preferably - C(R^0a)₂;

R^0a stands on each occurrence, identically or differently, for H, D, F, CN, a straight-chain alkyl group having 1 to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or branched or cyclic alkyl group having 3 to 40, preferably 3 to 20, more preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R, an aromatic or heteroaromatic ring system having 5 to 60, preferably 5 to 40, more preferably 5 to 30, very preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R; where two adjacent substituents R^0a may form a mono- or polycyclic, aliphatic ring system or aromatic ring system, which may be substituted by one or more radicals R, which has the same meaning as above; and the groups of formulae (Ar50-2) and (Ar51-2) may be substituted at each free position by a group R, which has the same meaning as above.

The group RS is preferably located at a position, where it replaces R, R° or

R; Examples of fluorescent emitters which may be employed in the composition comprising the compounds of formulae (H1 ) and (H2) are aromatic anthra- cenamines, aromatic anthracenediamines, aromatic pyrenamines, aromatic pyrenediamines, aromatic chrysenamines or aromatic chrysenediamines. An aromatic anthracenamine is taken to mean a compound in which one diarylamino group is bonded directly to an anthracene group, preferably in the 9-position. An aromatic anthracenediamine is taken to mean a compound in which two diarylamino groups are bonded directly to an anthracene group, preferably in the 9,10-position. Aromatic pyrenamines, pyrenediamines, chrysenamines and chrysenediamines are defined analogously thereto, where the diarylamino groups are preferably bonded to the pyrene in the 1 -position or in the 1 ,6-position. Further preferred emitters are bridged triarylamines, for example in accordance with WO 2019/111971 , WO201 9/240251 and WO 2020/067290. Further preferred emitters are indenofluorenamines or indenofluorenediamines, for example in accordance with WO 2006/108497 or WO 2006/122630, benzoindenofluorenamines or benzoindenofluorenediamines, for example in accordance with WO 2008/ 006449, and dibenzoindenofluorenamines or dibenzoindenofluorene- diamines, for example in accordance with WO 2007/140847, and the indenofluorene derivatives containing condensed aryl groups which are disclosed in WO 2010/012328. Still further preferred emitters are benzanthracene derivatives as disclosed in WO 2015/158409, anthracene derivatives as disclosed in WO 2017/036573, fluorene dimers connected via heteroaryl groups like in WO 2016/150544 or phenoxazine derivatives as disclosed in WO 2017/028940 and WO 2017/028941. Preference is likewise given to the pyrenarylamines disclosed in WO 2012/048780 and WO 2013/185871. Preference is likewise given to the benzoindenofluorenamines disclosed in WO 2014/037077, the benzofluorenamines disclosed in WO 2014/106522 and the indenofluorenes disclosed in WO 2014/111269 or WO 2017/036574, WO 2018/007421. Also preferred are the emitters comprising dibenzofuran or indenodibenzofuran moieties as disclosed in WO 2018/095888, WO 2018/095940, WO 2019/076789, WO 2019/170572 as well as in the unpublished applications PCT/EP2019/072697, PCT/EP2019/072670 and PCT/EP2019/072662. Preference is likewise given to boron derivatives as disclosed, for example, in WO 2015/102118, CN108409769, CN107266484, WO2017195669, US2018069182 as well as in the unpublished applications EP 19168728.4, EP 19199326.0 and EP 19208643.7.

In the case of the present invention, very suitable fluorescent emitters are the indenofluorene derivatives disclosed in WO 2018/007421 and the dibenzofuran derivatives disclosed in WO 2019/076789.

Examples of preferred fluorescent emitting compounds, which may be employed in the composition comprising the compounds of formulae (H1 ) and (H2) are depicted in the following table:

In accordance with the invention, the compound of formula (H1 ) and the compound of formula (H2) are present together in the composition, preferably in a homogeneous mixture. Preferably, the compound of formula (H1 ) is present in the composition in a proportion of 1 - 99 %, preferably 10 - 90 %, more preferably 20 - 80 %, particularly preferably 30 - 75%, very particularly preferably 35 - 70%.

Preferably, the compound of formula (H2) is present in the composition according to the invention in a proportion of 1 - 99 %, preferably 10 - 90 %, more preferably 20 - 80 %, particularly preferably 25 - 70%, very particularly preferably 30 - 60%.

According to a preferred embodiment, the composition according to the invention further comprises at least one fluorescent emitter. In this case, it is preferred that the fluorescent emitter is present in the composition in a proportion of 0.1 and 50.0%, preferably between 0.5 and 20.0%, particularly preferably between 1.0 and 10.0%.

The specifications of the proportions in % are, for the purposes of the present application, taken to mean % by vol. if the compounds are applied from the gas phase and % by weight if the compounds are applied from solution.

For the processing of the compounds according to the invention from the liquid phase, for example by coating processes like spin coating or by printing processes, formulations of the compositions according to the invention are necessary. These formulations can be, for example, solutions, dispersions or emulsions. It may be preferred to use mixtures of two or more solvents for this purpose. The solvents are preferably selected from organic and inorganic solvents, more preferably organic solvents. The solvents are very preferably selected from hydrocarbons, alcohols, esters, ethers, ketones and amines. Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF, methyl-TFIF, THP, chlorobenzene, dioxane, phenoxytoluene, in particular 3- phenoxytoluene, (-)-fenchone, 1 ,2,3,5-tetramethylbenzene, 1 ,2,4,5-tetra- methylbenzene, 1-methylnaphthalene, 1-ethylnaphthalene, decylbenzene, phenyl naphthalene, menthyl isovalerate, para tolyl isobutyrate, cyclohexal hexanoate, ethyl para toluate, ethyl ortho toluate, ethyl meta toluate, decahydronaphthalene, ethyl 2-methoxybenzoate, dibutylaniline, dicyclohexylketone, isosorbide dimethyl ether, decahydronaphthalene, 2- methylbiphenyl, ethyl octanoate, octyl octanoate, diethyl sebacate, 3,3- dimethylbiphenyl, 1 ,4-dimethylnaphthalene, 2,2^'-dimethylbiphenyl, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, a-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclo hexanone, 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 or mixtures of these solvents.

The present invention therefore furthermore relates to a formulation com prising a compound formula (H1 ) and a compound of formula (H2) according to the invention and at least one solvent. The solvent may be one of the above-mentioned solvents or a mixture of these solvents.

The proportion of the organic solvent in the formulation according to the invention is preferably at least 60% by weight, preferably at least 70% by weight and more preferably at least 80% by weight, based on the total weight of the formulation.

A formulation in accordance with the present invention can be employed for the production of a layer or multilayered structure in which the organofunc- tional materials are present in layers, as are required for the production of preferred electronic or opto-electronic components, such as OLEDs. The formulation of the present invention can preferably be employed for the formation of a functional layer comprising a composition according to the present invention on a substrate or on one of the layers applied to the substrate.

Still further object of the invention is a process for the production of an electronic device, wherein at least one layer is obtained from the application of a formulation of the present invention. Preferably, a formulation according to the invention is applied to a substrate or to another layer and then dried.

The functional layer obtained from the formulation according to the invention can be produced, for example, by flood coating, dip coating, spray coating, spin coating, screen printing, relief printing, gravure printing, rotary printing, roller coating, flexographic printing, offset printing or nozzle printing, preferably ink-jet printing on a substrate or one of the layers applied to the substrate.

After the application of a formulation according to the invention to a substrate or a functional layer already applied, a drying step can be carried out in order to remove the solvent. Preferably, the drying step comprises a vacuum drying, which is preferably followed by an annealing of the layer. The vacuum drying here can preferably be carried out at a pressure in the range from 10⁷ mbar to 1 bar, particularly preferably in the range from 10⁶ mbar to 1 bar. The vacuum drying is preferably carried out at a temperature in the range from 10 to 40°C, more preferably 15 to 30°C. The vacuum drying step is preferably followed by a thermal annealing of the layer. The thermal annealing of the layer preferably takes places at a temperature of from 120°C to 180°C, preferably from 130°C to 170°C, more preferably 140°C to 160°C.

Therefore, the present invention relates to a process for the production of an electronic device comprising at least one layer comprising a composition according to the present invention, wherein the process comprises the following steps: a) Preparation of a formulation according to the invention; b) Application of the formulation prepared in step a) on a substrate or on another layer in order to form a layer comprising a composition according to the present invention; c) Drying of the layer in order to remove the solvent.

Preferably, in step b), the formulation is applied by processing from a liquid phase, more preferably via a coating method or a printing method, very more preferably by a printing method, particularly preferably by an inkjet printing method.

Another object of the invention is an electronic device, which comprises anode, cathode and at least one functional layer in between, where this functional layer comprises a composition according to the invention. Preferably, the at least one functional layer comprising a composition according to the invention is an emitting layer.

The electronic device is preferably selected from organic electroluminescent device (OLEDs), organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic solar cells, dye-sensitised organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells, organic laser diodes and organic plasmon emitting devices. More preferably, the electronic device is an organic electroluminescent device (OLED).

The organic electroluminescent device comprises a cathode, an anode and at least one emitting layer, which comprises a composition according to the invention. 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-blocking layers, electron-transport layers, electron-injection layers, exciton-blocking layers, electron-blocking layers and/or charge-generation layers. It is likewise possible for interlayers, which have, for example, an exciton-blocking function, to be introduced between two emitting layers. However, it should be pointed out that each of these layers does not necessarily have to be present. The organic electroluminescent device here may comprise one emitting layer or a plurality of emitting layers. If a plurality of emission layers are present, these preferably have in total a plurality of emission maxima between 380 nm and 750 nm, resulting overall in white emission, i.e. various emitting compounds which are able to fluoresce or phosphoresce are used in the emitting layers. Particular preference is given to systems having three emitting layers, where the three layers exhibit blue, green and orange or red emission (for the basic structure see, for example, WO 2005/011013). These can be fluorescent or phosphorescent emission layers or hybrid systems, in which fluorescent and phosphorescent emission layers are combined with one another.

The electronic device concerned may comprise a single emitting layer comprising the composition according to the invention or it may comprise two or more emitting layers.

The composition according to the present invention may comprise one or more further matrix materials.

Preferred further matrix materials are selected from the classes of the oligoarylenes (for example 2,2‘,7,7‘-tetraphenylspirobifluorene in accordance with EP 676461 or dinaphthylanthracene), in particular the oligoarylenes containing condensed aromatic groups, the oligoarylenevinylenes (for example DPVBi or spiro-DPVBi in accordance with EP 676461 ), the polypodal metal complexes (for example in accordance with WO 2004/081017), the hole-conducting compounds (for example in accordance with WO 2004/058911 ), the electron-conducting compounds, in particular ketones, phosphine oxides, sulfoxides, etc. (for example in accordance with WO 2005/084081 and WO 2005/084082), the atropisomers (for example in accordance with WO 2006/048268), the boronic acid derivatives (for example in accordance with WO 2006/117052) or the benzanthracenes (for example in accordance with WO 2008/145239). Particularly preferred matrix materials are selected from the classes of the oligoarylenes, comprising naphthalene, anthracene, benzanthracene and/or pyrene or atropisomers of these com pounds, the oligoarylenevinylenes, the ketones, the phosphine oxides and the sulfoxides. Very particularly preferred matrix materials are selected from the classes of the oligoarylenes, comprising anthracene, benzanthracene, benzophenanthrene and/or pyrene or atropisomers of these compounds. An oligoarylene in the sense of this invention is intended to be taken to mean a compound in which at least three aryl or arylene groups are bonded to one another.

Generally preferred classes of material for use as corresponding functional materials in the organic electroluminescent devices according to the invention are indicated below.

Suitable charge-transport materials, as can be used in the hole-injection or hole-transport layer or electron-blocking layer or in the electron-transport layer of the electronic device according to the invention, are, for example, the com pounds disclosed in Y. Shirota et al. , Chem. Rev. 2007, 107(4), 953-1010, or other materials as are employed in these layers in accordance with the prior art.

Materials which can be used for the electron-transport layer are all materials as are used in accordance with the prior art as electron-transport materials in the electron-transport layer. Particularly suitable are aluminium complexes, for example Alq3, zirconium complexes, for example Zrq4, lithium complexes, for example LiQ, benzimidazole derivatives, triazine derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline derivatives, quinoline derivatives, oxadiazole derivatives, aromatic ketones, lactams, boranes, diazaphosphole derivatives and phosphine oxide derivatives. Furthermore, suitable materials are derivatives of the above-mentioned compounds, as disclosed in JP 2000/053957, WO 2003/060956, WO 2004/028217, WO 2004/080975 and WO 2010/072300.

Preferred hole-transport materials which can be used in a hole-transport, hole-injection or electron-blocking layer in the electroluminescent device according to the invention are indenofluorenamine derivatives (for example in accordance with WO 06/122630 or WO 06/100896), the amine derivatives disclosed in EP 1661888, hexaazatriphenylene derivatives (for example in accordance with WO 01/049806), amine derivatives containing condensed aromatic rings (for example in accordance with US 5,061 ,569), the amine derivatives disclosed in WO 95/09147, monobenzoindenofluorenamines (for example in accordance with WO 08/006449), dibenzoindenofluorenamines (for example in accordance with WO 07/140847), spirobifluorenamines (for example in accordance with WO 2012/034627 or WO 2013/120577), fluorenamines (for example in accordance with the as applications EP 2875092, EP 2875699 and EP 2875004), spirodibenzopyranamines (for example in accordance with WO 2013/083216) and dihydroacridine derivatives (for example in accordance with WO 2012/150001 ). The compounds according to the invention can also be used as hole-transport materials.

The cathode of the organic electroluminescent device preferably comprises metals having a low work function, metal alloys or multilayered structures comprising various metals, such as, for example, alkaline-earth metals, alkali metals, main-group metals or lanthanoids (for example Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Also suitable are alloys comprising an alkali metal or alkaline- earth metal and silver, for example an alloy comprising magnesium and silver. In the case of multilayered structures, further metals which have a relatively high work function, such as, for example, Ag or Al, can also be used in addition to the said metals, in which case combinations of the metals, such as, for example, Ca/Ag, Mg/Ag or Ag/Ag, are generally used. It may also be preferred to introduce a thin interlayer of a material having a high dielectric constant between a metallic cathode and the organic semiconductor. Suitable for this purpose are, for example, alkali metal fluorides or alkaline-earth metal fluorides, but also the corresponding oxides or carbonates (for example LiF, U2O, BaF2, MgO, NaF, CsF, CS2CO3, etc.). Furthermore, lithium quinolinate (LiQ) can be used for this purpose. The layer thickness of this layer is preferably between 0.5 and 5 nm.

The anode preferably comprises materials having a high work function. The anode preferably has a work function of greater than 4.5 eV vs. vacuum. Suitable for this purpose are on the one hand metals having a high redox potential, such as, for example, Ag, Pt or Au. On the other hand, metal/metal oxide electrodes (for example AI/Ni/NiOx, Al/PtOx) may also be preferred. For some applications, at least one of the electrodes must be transparent or partially transparent in order to facilitate either irradiation of the organic material (organic solar cells) or the coupling-out of light (OLEDs, O-lasers). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is furthermore given to conductive, doped organic materials, in particular conductive doped polymers.

The device is appropriately (depending on the application) structured, pro vided with contacts and finally sealed, since the lifetime of the devices according to the invention is shortened in the presence of water and/or air.

In a preferred embodiment, the organic electroluminescent device according to the invention is characterised in that one or more layers are coated by means of a sublimation process, in which the materials are applied by vapour deposition in vacuum sublimation units at an initial pressure of less than 10⁵ mbar, preferably less than 10^-6 mbar. However, it is also possible here for the initial pressure to be even lower, for example less than 10⁷ mbar.

Preference is likewise given to an organic electroluminescent device, char acterised in that one or more layers are coated by means of the OVPD (organic vapour phase deposition) process or with the aid of carrier-gas sublimation, in which the materials are applied at a pressure of between 10⁵ mbar and 1 bar. A special case of this process is the OVJP (organic vapour jet printing) process, in which the materials are applied directly through a nozzle and are thus structured (for example M. S. Arnold et at., Appl. Phys. Lett. 2008, 92, 053301).

Preference is furthermore given to an organic electroluminescent device, characterised in that one or more layers are produced from solution, such as, for example, by spin coating, or by means of any desired printing process, such as, for example, screen printing, flexographic printing, nozzle printing or offset printing, but particularly preferably LITI (light induced thermal imaging, thermal transfer printing) or ink-jet printing. Soluble compounds of the formula (I) are necessary for this purpose. High solubility can be achieved through suitable substitution of the compounds.

Also possible are hybrid processes, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapour deposition. Thus, it is possible, for example, to apply the emitting layer from solution and to apply the electron-transport layer by vapour deposition.

These processes are generally known to the person skilled in the art and can be applied by him without inventive step to organic electroluminescent devices comprising the compounds according to the invention.

In accordance with the invention, the electronic devices comprising one or more compounds according to the invention can be employed in displays, as light sources in lighting applications and as light sources in medical and/or cosmetic applications (for example light therapy).

The invention will now be explained in greater detail by the following examples, without wishing to restrict it thereby.

Syntheses examples a) Host H1

The syntheses of the hosts of formula (H1 ) are known to the person skilled in the art and are described, for example, in WO 2010/151006 and WO 2020/089138. Further syntheses examples are described below:

Synthesis of H1-1

Under an argon atmosphere, an oven dried flask is equipped with a magnetic stir bar, 1 (2417686-30-5) (13.0 g, 36.9 mmol, I .O equiv.), 2 (2377545-66-7) (18.4 g, 54 mmol), tris(dibenzylideneacetone) dipalladium (1.3 g, 1.4 mmol), SPhos (1.16 g, 2.8 mmol) and potassium fluoride (5.3 g, 92.3 mmol). Toluene (150 ml_), 1 ,4-dioxane (150 ml_) and water (150 ml_) is added and the mixture is refluxed overnight. The raw product is purified by column chromatography and sublimation. The desired product is isolated as colorless solid (5.2 g, 9.1 mmol, 25 %).

Following compounds can be synthesized in an analogous manner:

Synthesis of A6 5 g (8.9 mmol) 2417297-74-4 are dissolved in 100 ml toluene-d8. At room temperature 4.7 ml (0.05 mol) trifluoro-methanesulfonic acid are added dropwise. The solution turns black and it is stirred for 2.5 h at room temperature. By keeping the temperature constant 20 ml of deuterium oxide are added. The solution turns orange. After 16 hours 50 ml of an aqueous potassium phosphate solution and 50 ml toluene are added. The organic phase is washed with water and dried over magnesium sulfate. The crude material is filtered over silica (toluene). The product is purified by column chromatography (silica, toluene/heptane) and crystallization out of toluene/heptane. The remaining solvents are removed by sublimation. The grade of deuteration is obtained by NMR spectroscopy and LC-MS. The group “-H/D” means that the grade of deuteration at the corresponding position is around 50%.

Yield: 2.8 g (4.8 mmol; 54%). b) Host H2

The syntheses of the hosts of formula (H2) are known to the person skilled in the art and are described, for example, in WO 2009/100925. Further syntheses examples are described below:

Synthesis of compound A1 : 7.9 g (32 mmol) 3,6-Dichloro-phenanthrene (20851-90-5), 30.4 g (80 mmol) 4,4,5,5-tetramethyl-2-(10-phenyl-9-anthracenyl)-1 ,3,2-dioxaborolane (460347-59-5), 29.5 g (128 mmol) potassium phosphate monohydrate are dissolved in 750 ml THF/water (2:1). 813 mg (0.96 mmol) XPhos Palladacycle Gen. 3 are added and the mixture is stirred at 65°C. After 16 hours the reaction mixture is allowed to come to room temperature. The reaction mixture is filtered and washed with cold THF. The precipitate is purified by hot extraction over aluminum oxide (toluene) and further purified by crystallization out of toluene/ethanol and toluene/heptane up to a purity of >99.9 by FIPLC. The remaining solvents are removed by tempering at 300 °C at 10^-5 bar for 2 hours.

Yield: 4.9 g (7.2 mmol, 23%) of a pale yellow solid

Following compounds can be synthesized in analogous manner:

Synthesis of compound 11 :

9.3 g (32 mmol) 3-Bromo-6-chloro-phenanthrene (892550-44-6), 13.3 g (35 mmol) 4,4,5,5-tetramethyl-2-(10-phenyl-9-anthracenyl)-1 ,3,2-dioxaborolane (460347-59-5), 11.5 g (50mmol) potassium phosphate monohydrate are dissolved in 750 ml THF/water (2:1 ). 813 mg ( 0 96 mmol) ) XPhos Palladacycle Gen. 3 are added and the mixture is stirred at 65°C. After 16 hours the reaction mixture is allowed to come to room temperature. The mixture is diluted with 300 ml toluene. The aqueous phase is extracted with toluene (2x200 ml) and the combined organic phases are washed with water (2x 200 ml) dried over magnesium sulfate, filtered and reduced under reduced pressure. The remaining solid is filtered over silica (toluene) and crystalized out of toluene/ethanol up to a purity of 98% by HPLC.

Yield 10.7 g (23 mmol, 72%)

Following compounds can be synthesized in analogous manner:

Synthesis of compound B1 : 9.3 g (20 mmol) 11, 16.0 g (30 mmol) 4,4,5,5-tetramethyl-2-(10-{5-phenyl-

[1 , 1 '-biphenyl]-3-yl}anthracen-9-yl)-1 ,3,2-dioxaborolane (1016653-38-5), 11.5 g (SOmmol) potassium phosphate monohydrate are dissolved in 750 ml THF/water (2: 1). 813 mg ( 0.96 mmol) ) XPhos Palladacycle Gen. 3 are added and the mixture is stirred at 65°C. After 16 hours the reaction mixture is allowed to come to room temperature. The mixture is diluted with 300 ml toluene. The aqueous phase is extracted with toluene (2x200 ml) and the combined organic phases are washed with water (2x 200 ml) dried over magnesium sulfate, filtered and reduced under reduced pressure. The remaining solid purified by hot extraction over aluminum oxide (toluene) and crystalized out of toluene/ethanol and toluene/heptane up to a purity of >99.9% by HPLC. The remaining solvents are removed by tempering at 300°C and 10⁵ bar for 2 hours.

Yield: 7.5 g (9 mmol, 45%)

Following compounds can be synthesized in analogous manner:

B) Fabrication of OLEDs

The production of solution-based OLEDs has already been described many times in the literature, for example in WO 2004/037887 and WO 2010/097155. The process is adapted to the circumstances described below (layer-thickness variation, materials).

The inventive material combinations are used in the following layer sequence:

- substrate,

- ITO (50 nm),

- Hole injection layer (20 nm),

- hole transport layer (20 nm),

- emission layer (EML) (35 nm),

- electron-blocking layer (HBL) (10 nm),

- electron-transport layer (ETL) (40 nm),

- cathode (Al) (100 nm).

Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm serve as substrate. These are coated with the buffer (PEDOT:PSS) Clevios P VP Al 4083 (Heraeus Clevios GmbH, Leverkusen). The spin coating of the buffer is carried out from water in air. The layer is subse quently dried by heating at 180°C for 20 minutes. The hole transport layers and the emission layers are applied to the glass plates coated in this way. The hole-transport layer is either the polymer of the structure shown in table 1 (HTM1), which is synthesized in accordance with W02013156130 or the polymer HTM2 (table 1), which is synthesized in accordance with WO201 8/114882. The polymer is dissolved in toluene, so that the solution typically has a solid content of approx. 6 g/l if, as here, the layer thickness of 20 nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, in the present case argon, and dried by heating at 225°C for 30 min.

The emission layer is composed of the host material HM or a mixture of two host materials (HM1+HM2) and the emitting material (E). The weight ratios are indicated in Table 3. The mixture for the emission layer is dissolved in toluene. The solids content of such solutions is about 10 mg/ml if, as here, the layer thickness of 35 nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert- gas atmosphere, and dried by heating at 150°C for 10 minutes. The materials of the present case are shown in table 2a and table 2b.

Table 2a: Structural formulae of the example host materials

The materials for the electron-blocking layer and the electron-transporting layer are likewise applied by thermal vapour deposition in a vacuum chamber and are shown in table 3. The electron-blocking layer consists of the material ETM1 and the electron-transporting layer consists of the two materials ETM1 and ETM2, which are mixed with one another in a proportion by volume of 55% of ETM1 and 45% of ETM2 by co-evaporation. The cathode is formed by thermal evaporation of an aluminium layer with a thickness of 100 nm.

Table 3: Structural formulae of the electron transport materials

The OLEDs are characterised by standard methods. For this purpose, the electroluminescence spectra are recorded, the current efficiency (measured in cd/A) and the external quantum efficiency (EQE, measured in percent) as a function of the luminous density assuming Lambert emission characteristics are calculated from current/voltage/luminous density char acteristic lines (IUL characteristic lines). The electroluminescence spectra are recorded at a luminous density of 1000 cd/m², and the CIE 1931 x and y colour coordinates are calculated from this data. The lifetime LT90 @

1000 cd/m² is defined as the time after which the initial luminous density of 1000 cd/m² has dropped by 10%.

Use of inventive compounds as emitting material in fluorescent OLEDs

The inventive compounds are especially suitable as host when blended with a fluorescent blue dopant to form the emissive layer of a fluorescent blue OLED device. The properties of the various OLEDs are summarised in table 3. References 1 to 12 represent the single host references, whereas examples 1 to 7 show properties of OLEDs containing material mixtures of the present invention.

Table 3: Device data of solution processed OLEDs

Table 3 shows that Reference 1, which uses host material HM1-1 with 1% emitter E1, leads to a good EQE and limited lifetime. Reference 2, which uses host material HM2-1 with the same amount of emitter, leads to a significantly reduced efficiency but much longer lifetime. Mixing both host materials leads for both mixtures of 69:30:1 and a 49:50:1 to a significantly improved lifetime compared to Reference 1 (with only a very small trade-off in efficiency) and an increase in efficiency and lifetime compared to Reference 2. All examples in Table 3 show according to the present invention an improvement in lifetime, when mixing a good and a bad performing host material. This is independent of the emitter type and its concentration.

Claims

Patent Claims

1. Composition comprising a compound of formula (H1) and a compound of formula (H2), formula (H2) where the following applies to the symbols and indices used:

E¹, E², E³ and E⁴ stand on each occurrence, identically or differently, for a single bond, -BR°- -C(R°)₂- -Si(R°)₂- -C(=0)-, -0-, -S-, -S(=0)-, -SO2-, -N(R°)- or -P(R°)-; with the proviso that, in the ring comprising E¹ and E³, only one group E¹ or E³ might be a single bond and, in the ring comprising E² and E⁴, only one group E² or E⁴ might be a single bond; X¹ to X¹² stand on each occurrence, identically or differently, for C-R^x, C-Ar^x or N; with the proviso that at least one group selected from X¹ to X¹² stands for a group C-Ar^x and Ar^x stands for a group of formula (Ar^x): formula (Ar^x) where the dashed bond indicates the bonding to the group C in C-Ar^x;

Ar², Ar⁴, Ar^s are, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R; R^v, R^x, R^Y, R^z stand on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, C(=0)Ar, P(=0)(Ar)₂, S(=0)Ar, S(=0)₂Ar, N(R)₂, N(Ar)₂, N0₂, Si(R)3, B(OR)₂, 0S0₂R, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH₂ groups may be replaced by RC=CR, CºC, Si(R)₂, Ge(R)₂, Sn(R)₂, C=0, C=S, C=Se, P(=0)(R), SO, S0₂, 0, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or N0₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R; where two radicals R^v, two radicals R^x, two radicals R^Y, two radicals R^z may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R;

R° stands on each occurrence, identically or differently, for FI, D, F, a straight-chain alkyl group having 1 to 20 C atoms, or a branched or a cyclic alkyl group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CFH₂ groups may be replaced by O or S and where one or more FI atoms may be replaced by D or F, or an aromatic or heteroaromatic ring systems having 5 to 40 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two adjacent radicals R°, may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R;

R stands on each occurrence, identically or differently, for FI, D, F, Cl, Br, I, CHO, CN, C(=0)Ar, P(=0)(Ar)₂, S(=0)Ar, S(=0)₂Ar, N(R , N(Ar)₂, N0₂, Si(R )3, B(OR^')₂, OS0₂R , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R , where in each case one or more non-adjacent Chte groups may be replaced by R C=CR , CºC, Si(R )2, Ge(R^’)2, Sn(R^’)2, C=0, C=S, C=Se, P(=0)(R ), SO, SO2, O, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R^’, or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R^'; where two radicals R may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R^’;

Aris, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R^';

R^’ stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, where in each case one or more non-adjacent CFI2 groups may be replaced by SO, SO2, O, S and where one or more FI atoms may be replaced by D, F, Cl, Br or I, or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms; and p, s are on each occurrence, identically or differently, 0 or 1 , wherein: when p or s is 0, then the corresponding Ar^s is absent and the group Ar¹ or Ar³ is directly bonded to C in C-Ar^x or C-Ar^z; q, t are on each occurrence, identically or differently, 0, 1 or 2, wherein: when q is 0, then Ar⁴ is absent; when t is 0, then Ar² is absent; when q is 1 or 2, then Ar¹ is substituted by one group or two groups Ar⁴; when t is 1 or 2, then Ar³ is substituted by one group or two groups Ar².

2. Composition according to claim 1, characterized in that, in the compound of formula (H 1 ), at least one group selected from X¹ to X⁴ stands for a group C-Ar^x where Ar^x stands for a group of formula (Ar^x) as defined in claim 1 and the groups X⁵ to X¹² stand for C-R^x or N, where R^x is as defined in claim 1.

3. Composition according to claim 1 or 2, characterized in that the compound of formula (H1) is selected from the compound of formulae (H1-A) to (H1- D): formula (H1-C) formula (H1-D) where the symbols have the same meaning as in claim 1.

4. Composition according to one or more of the preceding claims, characterized in that the compound of formula (H1) is selected from the compounds of one of the following formulae:

R R R R formula (H1-A-3) formula (H1-A-4)

formula (H1-C-1) formula (H1-C-2) where the symbols R^x, Ar^x have the same meaning as in claim 1 and the groups E¹, E², E³ and E⁴ stand on each occurrence, identically or differently, for-BR⁰-, -C(R°)₂-, -Si(R°)₂-, -C(=0)-, -0-, -S-, -S(=0)-, -S0₂-, - N(R⁰)- or -P(R⁰)-.

5. Composition according to one or more of the preceding claims, characterized in that, in the compound of formula (H2), one group selected from Z¹ to Z⁴ stands for a group C-Ar^z and one group selected from Z⁵ to Z⁸ stands for a group C-Ar^z, where Ar^z stands for a group of formula (Ar^z) as defined in claim 1.

6. Composition according to one or more of the preceding claims, characterized in that the compound (H2) is selected from the compounds of the following formulae,

(H2-C) (H2-D)

(H2-K) (H2-L)

where the symbols have the same meaning as in claim 1.

7. Composition according to one or more of the preceding claims, characterized in that the groups Ar¹ and Ar³, are on each occurrence, identically or differently, selected from the group consisting of anthracene, naphthalene, phenanthrene, tetracene, chrysene, benzanthracene, benzo- phenanthracene, pyrene, perylene, triphenylene, benzopyrene, fluoranthene, each of which may be substituted at each free position by a group R^v in case of Ar¹ and R^Y in case of Ar³, where R^v and R^Y have the same meaning as in claim 1.

8. Composition according to one or more of the preceding claims, characterized in that the groups Ar¹ and Ar³ are selected from the groups of formulae (Ar-1 ) to (Ar-11 ), where the groups of formulae (Ar-1 ) to (Ar-11 ) may be bonded to the adjacent groups at any position and may be substituted at each free position by a group R^v in case of Ar¹ and R^Y in case of Ar³, where R^v and R^Y have the same meaning as in claim 1.

9. Composition according to one or more of the preceding claims, characterized in that the group Ar^x stands for a group of formula (Ar^x-1 ): where the symbols and indices have the same meaning as in claim 1 and where the anthracene group may be substituted at each free position by a group R^v, where R^v has the same meaning as in claim 1.

10. Composition according to one or more of the preceding claims, characterized in that the group Ar^x stands for a group of one of the following formulae: where the symbols and indices have the same meaning as in claim 1 and where the anthracene group may be substituted at each free position by a group R^v, where R^v has the same meaning as in claim 1.

11. Composition according to one or more of the preceding claims, characterized in that the group Ar^z stands for a group of formula (Ar^z-1 ):

where the symbols and indices have the same meaning as in claim 1 and where the anthracene group may be substituted at each free position by a group R^Y, where R^Y has the same meaning as in claim 1.

12. Composition according to one or more of the preceding claims, characterized in that the group Ar^z stands for a group of one of the following formulae: formula (Ar^z-1 A) formula (Ar^z-1B) where the symbols and indices have the same meaning as in claim 1 and where the anthracene group may be substituted at each free position by a group R^Y, where R^Y has the same meaning as in claim 1.

13. Composition according to one or more of the preceding claims, characterized in that the groups Ar² and Ar⁴ are on each occurrence, identically or differently, selected from the group consisting of phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, anthracene, phenanthrene, triphenylene, fluoranthene, tetracene, chrysene, benzanthracene, benzophenanthracene, pyrene or perylene, dibenzofuran, carbazole and dibenzothiophene, each of which may be substituted by one or more radicals R at any free positions; and where Ar², Ar⁴ might also be a combination of two or more of the previously cited groups.

14. Composition according to one or more of the preceding claims, characterized in that it further comprises a fluorescent emitter.

15. Composition according to one or more of the preceding claims, characterized in that it comprises the compound of formula (H1 ) as a first host material, the compound of formula (H2) as a second host material and a fluorescent emitter as a dopant material.

16. Composition according to one or more of the preceding claims, characterized in that it comprises a fluorescent emitter selected from the group consisting of:

- a bridged triarylamine;

- an indenofluorene, indenofluorenamine or indenofluorenediamine;

- a benzoindonofluorene, benzoindenofluorenamine or benzoindenofluorenediamine;

- a dibenzoindenofluorene, dibenzoindenofluorenamine or dibenzo- indenofluorenediamine; - an indenofluorene containing a condensed aryl group having at least 10 aromatic ring atoms;

- a bisindenoindenofluorene;

- an indenodibenzofuran; indenofluorenamine or indenofluorenediamine;

- a fluorene dimer;

- a phenoxazine; and

- a boron derivative.

17. Composition according to one or more of the preceding claims, characterized in that it comprises a fluorescent emitter of formula (E-1 ), (E- 2), (E-3) or (E-4),

Formula (E-1) where

Ar¹⁰, Ar¹¹, Ar¹² are on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 6 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R; with the proviso that at least one group Ar¹⁰, Ar¹¹, Ar¹² is an aromatic or heteroaromatic ring system having 10 to 40 aromatic ring atoms, containing at least one condensed aryl or heteroaryl group consisting of 2 to 4 aromatic rings condensed with one another, where the aromatic or heteroaromatic ring system may be substituted by one or more radicals R;

R has the same definition as in claim 1 ; and e is 1 , 2, 3 or 4; more preferably, e is 1 ;

Formula (E-2) where

Ar²⁰, Ar²¹, Ar²² are on each occurrence, identically or differently, an aryl or heteroaryl group having 6 to 30 aromatic ring atoms, which may in each case also be substituted by one or more radicals R;

E²⁰ is on each occurrence, identically or differently a group selected from BR, C(R°)₂, Si(R°)₂, C=0, C=NR°, C=C(R°)₂, 0, S, S=0, S0₂, NR°, PR⁰, P(=0)R° or P(=S)R°; wherein Ar²⁰, Ar²¹ and E²⁰ together form a five-membered ring or a six-membered ring, and Ar²¹, Ar²³ and E²⁰ together form a five-membered ring or a six-membered ring;

R° stands on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl group having 1 to 20 , preferably 1 to 10 C atoms or branched or a cyclic alkyl group having 3 to 20, preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non- adjacent CH₂ groups may be replaced by O or S and where one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring systems having 5 to 40, preferably 5 to 30, more preferably 6 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two adjacent radicals R°, may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R,

R has the same definition as in claim 1 ; p, q are on each occurrence, identically or differently, 0 or 1 , with the proviso that p + q = 1 ; r is 1 , 2 Oder 3;

Formula (E-3) where

E³⁰ stands for B or N;

E³¹, E³², E³³ stand on each occurrence, identically or differently, for 0, S, C(R°)2, C=0, C=S, C=NR°, C=C(R°)2, Si(R°)₂, BR°, NR°, PR°, SO2, Se02 or a chemical bond, with the proviso that if E³⁰ is B, then at least one of the groups E³¹, E³², E³³ stands for NR° and if E³⁰ is N, then at least one of the groups E³¹, E³², E³³ stands for BR°;

R° has the same definition as above; s, t, u are on each occurrence, identically or differently, 0 or 1 , with the proviso that s + t + u > 1.

Formula (E-4) where

Ar⁴⁰, Ar⁴¹, Ar⁴² stand on each occurrence, identically or differently, for a substituted or unsubstituted aryl or heteroaryl group having 5 to 22, preferably 5 to 18, more preferably 6 to 14 aromatic ring atoms;

E⁴¹, E⁴², E⁴³ stand on each occurrence, identically or differently, for O, S, C(R°)2, C=0, C=S, C=NR°, C=C(R°)2, Si(R°)₂, BR°, NR°, PR°, SO2, Se02 or a chemical bond, with the proviso that at least one of the groups E⁴¹, E⁴², E⁴³ is present and stands for a chemical bond;

18. Formulation comprising at least one composition according to one or more of the claims 1 to 17 and at least one solvent.

19. Process for the production of an electronic device comprising at least one layer comprising a composition according to one or more of the claims 1 to 17: a) Preparation of a formulation comprising at least one composition according to one or more of the claims 1 to 17 and at least one solvent; b) Application of the formulation prepared in step a) on a substrate or on another layer in order to form a layer; c) Drying of the layer in order to remove the solvent.

20. Process according to claim 19, characterised in that the formulation is applied by a coating method or a printing method.

21. Process according to claim 19 or 20, characterized in that the formulation is applied by flood coating, dip coating, spray coating, spin coating, screen printing, relief printing, gravure printing, roller coating, inkjet printing, rotary printing, flexographic printing, offset printing, slot die coating or nozzle printing.

22. Electronic device comprising anode, cathode, and at least one emitting layer, where the emitting layer comprises a composition according to one or more of claims 1 to 17.

23. Electronic device according to claim 22, selected from the group consisting of organic electroluminescent devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic solar cells, dye-sensitised organic solar cells, organic optical detectors, organic photoreceptors, organic field- quench devices, light-emitting electrochemical cells, organic laser diodes and organic plasmon emitting devices.