The steric hindrance effect of bulky groups on the formation of columnar superlattices and optoelectronic properties of triphenylene-based discotic liquid crystals

Abstract

2- and 3,6-position bulky group substituted triphenylene discotic carboxylic esters by adjusting the steric hindrance using different alkyl and aromatic rings including cycloalkylane, adamantane, and furan were synthesized and fully investigated. Their self-assembly properties were exhaustively examined by POM, DSC, 1D WAXD, and 2D WAXD methods together with the electrostatic potential calculations. The results showed that most of them can form long-range ordered 2D columnar superlattices under the combined effects of dipole–dipole interactions and steric hindrances. The long-range ordered columnar superlattices and the perfectly aligned monodomains can be achieved by adjusting the steric hindrance effect of bulky groups. Ultimately, charge carrier mobilities were measured by the time-of-flight method and most of them can reach an order of magnitude of 10⁻² cm² V⁻¹ s⁻¹, which make them a category of promising candidates for organic optoelectronic devices.