Compound comprising at least one structure of the formula where the symbols used are as follows: R 1, R 2, R 3, R 4 is the same or different at each instance and is H, D, F, Si(R 5) 3, a straight-chain alkyl or alkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3 to 40 carbon atoms, each of which may be substituted by one or more R 5 radicals, where one or more nonadjacent CH 2 groups may be replaced by -O- and where one or more hydrogen atoms may be replaced by D or F, or an aromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R 5 radicals, or a combination of these systems; at the same time, it is also possible for two or more adjacent R 1 substituents together to form a mono- or polycyclic, aliphatic or aromatic ring system; at the same time, it is also possible for two or more adjacent R 2 substituents together to form a mono- or polycyclic, aliphatic ring system; at the same time, it is also possible for two or more adjacent R 3 substituents together to form a mono- or polycyclic, aliphatic ring system; at the same time, it is also possible for two or more adjacent R 4 substituents together to form a mono- or polycyclic, aliphatic ring system; R 5 is the same or different at each instance and is H, D, F, Si(R 6) 3, a straight-chain alkyl or alkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3 to 40 carbon atoms, each of which may be substituted by one or more R 6 radicals, where one or more nonadjacent CH 2 groups may be replaced by -O- and where one or more hydrogen atoms may be replaced by D or F, or an aromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R 6 radicals, or a combination of these systems; at the same time, it is also possible for two or more adjacent R 5 substituents together to form a mono- or polycyclic, aliphatic or aromatic ring system; R 6 is the same or different at each instance and is H, D, F or an aliphatic and/or aromatic hydrocarbyl radical having 1 to 20 carbon atoms, in which hydrogen atoms may also be replaced by F; at the same time, it is also possible for two or more adjacent R 6 substituents together to form a mono- or polycyclic, aliphatic or aromatic ring system; m is independently 0 or 1, where the sum total of the indices m is not more than 1; n is independently 0, 1, 2, 3 or 4; o is independently 0, 1, 2, 3, 4 or 5; with the proviso that the R 2 radicals and the R 4 radicals comprise a total of at least 12 aromatic carbon ring atoms. R 1, R 2, R 3, R 4 is the same or different at each instance and is H, D, F, Si(R 5) 3, a straight-chain alkyl or alkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3 to 40 carbon atoms, each of which may be substituted by one or more R 5 radicals, where one or more nonadjacent CH 2 groups may be replaced by -O- and where one or more hydrogen atoms may be replaced by D or F, or an aromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R 5 radicals, or a combination of these systems; at the same time, it is also possible for two or more adjacent R 1 substituents together to form a mono- or polycyclic, aliphatic or aromatic ring system; at the same time, it is also possible for two or more adjacent R 2 substituents together to form a mono- or polycyclic, aliphatic ring system; at the same time, it is also possible for two or more adjacent R 3 substituents together to form a mono- or polycyclic, aliphatic ring system; at the same time, it is also possible for two or more adjacent R 4 substituents together to form a mono- or polycyclic, aliphatic ring system; R 5 is the same or different at each instance and is H, D, F, Si(R 6) 3, a straight-chain alkyl or alkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3 to 40 carbon atoms, each of which may be substituted by one or more R 6 radicals, where one or more nonadjacent CH 2 groups may be replaced by -O- and where one or more hydrogen atoms may be replaced by D or F, or an aromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R 6 radicals, or a combination of these systems; at the same time, it is also possible for two or more adjacent R 5 substituents together to form a mono- or polycyclic, aliphatic or aromatic ring system; R 6 is the same or different at each instance and is H, D, F or an aliphatic and/or aromatic hydrocarbyl radical having 1 to 20 carbon atoms, in which hydrogen atoms may also be replaced by F; at the same time, it is also possible for two or more adjacent R 6 substituents together to form a mono- or polycyclic, aliphatic or aromatic ring system; m is independently 0 or 1, where the sum total of the indices m is not more than 1; n is independently 0, 1, 2, 3 or 4; o is independently 0, 1, 2, 3, 4 or 5;