Low-Cost Synthesis of Soluble Bay-Substituted Terrylenes for p-Type Charge Transport and Efficient Photodetection on Field-Effect Transistors

Abstract

Since its first synthesis by Clar in 1948, terrylene has garnered significant research interest due to its extended π-conjugated system and exceptional optoelectronic properties. Its peri-substituted diimide derivatives, i.e. terrylenediimides (TDIs), have demonstrated extensive applications in organic field-effect transistors (OFETs), bulk heterojunction (BHJ) organic solar cells, and bioimaging. Despite this potential, the widespread adoption of terrylene-based materials remains limited due to their innate synthetic challenges and poor solubility. To address these challenges, herein, we report a novel, cost-effective route to synthesize bay-substituted terrylenes via a Grignard-Kumada cross-coupling reaction sequence followed by a dehydrohalogenation step. The incorporation of three different alkyloxy chains (-OC8H17, -OC12H25, and -OC16H33) at the bay positions significantly enhances their solubility in common organic solvents. The enhanced solubility enabled the fabrication of solution-processed terrylene-based OFET and organic phototransistor (OPT) devices for the first time, allowing systematic investigation of the effect of alkyloxy chain lengths on the hole mobility and photodetection performance. The fabricated OFETs exhibited p-type semiconducting behavior, with the shortest alkyl chain (-OC8H17) containing TER-C8 achieving the highest hole mobility compared to the other two analogs (83 times higher mobility than the -OC16H33 containing TER-C16). These terrylene-based devices exhibited exceptional photoresponse characteristics, achieving high-performance metrics including external quantum efficiency (EQE) and specific detectivity (D*), reaching over 1010 Jones. Therefore, our works introduced a novel and low-cost synthesis route for highly soluble terrylenes and their first successful implementation in organic field-effect transistors and organic phototransistor devices.