Patent ID: 8518559

Claim:
A compound of formula (I): wherein: Ar 1 is phenylene; Ar2 and Ar3 are both 9,9-dialkylfluorenylene; Ar 4 and Ar 5 are both phenylene and are connected to each other by a single bond; Ar 6 and Ar 7 are the same and both are phenyl, 4-trifluoromethylphenyl, 2-naphthyl, 3-benzothiophenyl, phenanthrenyl, 9,9-dihexylfluorenyl, pyrenyl, 9-phenylcarbazolyl, 4-cyanophenyl, 7-(4′-cyanophenyl)-9,9-dihexylfluorenyl or any one of the following groups: wherein each of R, R′, R″ and R′″ is independently halo, cyano, nitro, carbonyl, thionyl, sulphonyl, alkyl, perfluoroalkyl, alkoxy, aryl, arylene vinylene, or arylene ethynylene, and q is an integer from 0 to 6, wherein alkyl is a branched or unbranched monovalent hydrocarbon group, having 1 to 18 carbon atoms; and each of m, n, p, r, s, x and y is 1.