Electron transport of photoconductive n-type liquid crystals based on a redox-active tetraazanaphthacene framework

Abstract

The preparation of two liquid crystals composed of a redox-active tetraazanaphthacene (TANC) framework is reported. The materials form smectic A (SmA) thin-film liquid-crystalline (LC) phases over a wide temperature range. Cyclic voltammetry analysis revealed that LC TANCs behave as organic electron acceptors. The electron mobilities of the thin films were determined by time- of-flight (TOF) measurements, which are the order of 10-4cm 2V-1s-1 in the SmA LC phase. This value is two orders of magnitude larger than those of amorphous organic semiconductors. To the best of our knowledge, very few reports exist on the electron-transporting behaviors of LC N-heteroacene semiconductors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.