The backbone rigidity and its influence on the morphology and charge mobility of FBT based conjugated polymers

Abstract

A series of three PVTh₄FBT polymers containing different alkyl side chain placement was synthesized. The thermochromic behaviors and DFT calculations indicated that the backbone coplanarity and rigidity of the PVTh₄FBT polymers can be effectively modulated by adjusting the side chain position and density. Higher ordered and better oriented edge-on lamellar packing was formed by P1, which possesses the most rigid backbone among the three polymers and pre-aggregates in the solution. P1 also delivered the highest hole mobility (0.26 cm² V⁻¹ s⁻¹) among the three analogues because its thin-film morphology is in favor of charge transport.