Making Coaxial Wires Out of Janus Dendrimers for Efficient Charge Transport.

Abstract

Highly conductive coaxial supramolecular wires are prepared by using a new family of Janus dendrimers that combines two rigid aromatic parts and two flexible aliphatic parts. The two external regions consist of a promesogenic block based on a third generation Percec-type dendron with four terminal dodecyloxy alkyl chains, whereas the two internal regions are formed by one, two, or three carbazole units bearing flexible spacers. These functional Janus dendrimers self-organize in columnar liquid crystal phases with a strong coaxial segregation within each column. Interestingly, the charge mobility studies revealed that these Janus dendrimers display semiconductor properties with hole mobility values up to 0.5 cm2 V-1 s-1, depending on the packing within the columns which can be tuned by the number of carbazole functional units. The high hole mobility values measured in these materials are among the highest values reported for columnar liquid crystals.