Molecular Design and Alignment for Ambipolar SCLC Mobility in Self‐Assembled Columnar Discogens

Abstract The future of next‐generation electronics relies on low‐cost organic semiconductors that are tailored to simultaneously provide all requisite optoelectronic properties, focusing greatly on ambipolar charge‐transport and solution processability. In this regard, room‐temperature discotic liquid crystals (DLCs) are potential candidates, where quasi‐1D self‐assembly affords a charge‐transport channel along their columnar axis. This work shows a molecular design strategy by utilizing anthraquinone as the primary motif, surrounded by ester functionalized tri‐alkoxy phenyl units to develop room‐temperature DLCs ( 1.1–1.3 ). Here, the polar ester functionality stabilizes the columnar mesophase over a wide range through the involvement of dipole‐dipole interaction along with the π–π stacking. Throughout the entire mesophase transition, reported compounds 1.1–1.3 exhibit a highly ordered 2D columnar oblique (Col ob ) self‐assembly. Space charge limited current (SCLC) experiments reveal balanced ambipolar charge transport, with the maximum hole and electron mobilities of 5.04 and 4.93 cm 2 V −1 s −1 , respectively. From the conoscopic results, their propensity to align in a highly homeotropic fashion is demonstrated. It is further justified by the azimuthal plot corresponding to the (11) peak of grazing incidence small angle X‐ray scattering (GISAXS), denoting the crucial role of the design and alignment for efficient movement of charge carriers in the material.