Flip-flop dynamics in smectic liquid-crystal organic semiconductors revealed by molecular dynamics simulations

Asymmetric liquid-crystal (LC) organic semiconductors, such as 2-decyl-7-(p-tolyl)-[1]benzothieno[3,2-b][1]benzothiophene (pTol-BTBT-C₁₀), exhibit high mobilities exceeding 10 cm² V^-1 s^-1. The LC phases play important roles in thermal stability and self-assembly ordering during film deposition and annealing. In this study, we show molecular dynamics simulations of pTol-BTBT-C₁₀ and reveal a unique mechanism of the molecular flip-flop motion at the smectic E/smectic B phase transition.