2-Phenylbenzotiophene-based liquid crystalline semiconductors

Abstract

We report a novel liquid crystalline semiconductor constructed from a biologically and pharmacologically active building block molecule, namely 6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene, presenting efficient luminescence and medium charge mobility rate. A series of mesogenic 2-phenylbenzothiophene derivatives (nPBT) was simply and rapidly obtained in good yields by successive demethylation/alkylation reactions of the available methoxy precursor. The semiconducting behavior of three PBT compounds in the various mesophases was investigated by transient photocurrent TOF technique. Hole mobility rates of ca. 4 × 10-3 cm2 V-1 s-1 were measured in the lower temperature ordered mesophase for all of them, with the best performances however obtained for the shortest homolog (n = 6).