Solution-Processed Thin Film of a Novel Organic Charge-Transfer Complex for Near-Infrared Detection in Field-Effect Transistors

Abstract

Charge-transfer complexes (CTCs) have garnered considerable attention owing to their tunable electronic properties, which arise from the unique interactions between electron donor and acceptor molecules. However, reported fabrication methods remain largely restricted to single crystals produced via drop-casting and coevaporation or thin films prepared by cosublimation, thereby limiting their practical applicability. In this work, we successfully synthesized cocrystals of (Ph-BTBT-C10)(F4TCNQ) with a charge transfer degree (ρ) of 0.19. More importantly, we demonstrated the deposition of these cocrystals as thin films in organic field-effect transistors (OFETs) using a low-cost, rapid, and scalable solution-shearing technique compatible with large-area fabrication. The resulting CTC thin films exhibited n-type semiconducting behavior and showed a pronounced response to infrared light at 1050 nm. The combination of a single-component active layer whose near-infrared (NIR) absorption band can be chemically tuned through donor–acceptor engineering with a scalable solution-based processing method highlights the promise of CTC-based OFETs for advanced IR detection and sensing applications. These results open new perspectives for the technological exploitation of CTCs, a class of materials long studied but rarely integrated into practical devices.