Ion and hole dual-channel transport columnar mesomorphic organic electronic materials with high anisotropic conductivities based on supramolecular discotic ionic liquid crystals

Abstract

Thermotropic ionic liquid crystals (ILCs) are a kind of fascinating functional organic material combining the characteristics and advantages of both liquid crystals (LC) and ionic liquids. Here in this work, a series of supramolecular discotic ILCs of Cn-tri-CTP have been produced through host–guest complexation together with π–π stacking and electrostatic interactions between the readily prepared electrically neutral tris(18-crown-6)triphenylene (tri-CTP) and the facilely available potassium trialkoxybenzenesulfonates with different length alkyl tails of carbon number n = 8, 10, 12, 14, 16. The thus obtained ILC complexes show enantiotropic ordered columnar mesophases, such as center-faced rectangular columnar (Col_r) and oblique columnar (Col_ob) mesophases with broad LC temperature ranges and excellent thermal stability. It is very interesting and fascinating to find that after a simple alignment, such supramolecular discotic ILC complexes in their ordered columnar structures achieve simultaneously anisotropic ionic conductivities as high as 1.99 × 10⁻² S cm⁻¹ and hole mobility reaching 4.6 × 10⁻² cm² V⁻¹ s⁻¹, thus exhibiting fantastic dual-channel transport properties both for ions and holes, which may develop into a kind of versatile organic electronic material for various promising unique applications.