Polyterrylenes: synthesis and regioregularity effect on p-type charge transport and deep-red light photodetection in OFETs

Abstract

Polymers of higher rylene dyes remain largely unexplored despite their promising photophysical properties, due to the synthetic challenges and poor solubility, in contrast to their well-studied lower homologs, perylene and naphthalene derivatives. In this study, we report the first synthesis of terrylene-based regioregular and regioirregular homopolymers, namely rr-Polyterrylene and ri-Polyterrylene, respectively. Selective bromination of our previously synthesized 7,8-bis(hexadecyloxy)terrylene (TER-C16) furnished the corresponding dibromoterrylene. Then, Ni(0)-mediated Yamamoto homocoupling reaction produced the first soluble terrylene-based homopolymers. Both polymers achieved high solubility, high thermal stability, alongside very high molecular weight. Owing to these properties, the polymers were successfully deployed in organic field-effect transistors (OFETs), achieving p-type mobility 27 times higher than the monomeric unit TER-C16. Moreover, the photoresponsive OFETs from rr-Polyterrylene demonstrated 116-times improved photodetection ability compared to TER-C16 with specific detectivity (D*) of 4.3 × 10¹⁰ Jones in the deep red region, which is the highest among terrylenes and their derivatives. This work introduced the synthesis of dibromoterrylene, a versatile synthetic intermediate with significant potential for constructing diverse polymers. The strategic functionalization of terrylene molecules revealed a novel synthetic approach, enabling innovative polymer construction and facilitating significant advances in organic electronics, specifically OFETs and organic phototransistors (OPTs).