High Electrical Conductivity and Hole Transport in an Insightfully Engineered Columnar Liquid Crystal for Solution‐Processable Nanoelectronics

Abstract

AbstractDiscotic liquid crystals (DLCs) are widely acknowledged as a class of organic semiconductors that can harmonize charge carrier mobility and device processability through supramolecular self‐assembly. In spite of circumventing such a major challenge in fabricating low‐cost charge transport layers, DLC‐based hole transport layers (HTLs) have remained elusive in modern organo‐electronics. In this work, a minimalistic design strategy is envisioned to effectuate a cyanovinylene‐integrated pyrene‐based discotic liquid crystal (PY‐DLC) with a room‐temperature columnar hexagonal mesophase and narrow bandgap for efficient semiconducting behavior. Adequately combined photophysical, electrochemical, and theoretical studies investigate the structure‐property relations, logically correlating them with efficient hole transport. With a low reorganization energy of 0.2 eV, PY‐DLC exhibits superior charge extraction ability from the contact electrodes at low values of applied voltage, achieving an electrical conductivity of 3.22 × 10−4 S m−1, the highest reported value for any pristine DLC film in a vertical charge transport device. The columnar self‐assembly, in conjunction with solution‐processable self‐healed films, results in commendably elevated values of hole mobility (≈10−3 cm2 V‐1s−1). This study provides an unprecedented constructive outlook toward the development of DLC semiconductors as practical HTLs in organic electronics.