C─H Arylation-Derived Organic Conjugated Molecules for Optoelectronic Synaptic Transistors

Photonic organic field-effect transistors (OFETs) mimicking biological neurons hold great promise for neuromorphic computing. However, current organic optoelectronic materials still suffer from limited functionality and the low atom economy of conventional synthesis methods (such as Suzuki and Stille couplings). Herein, two isomeric organic conjugated molecules, p-Ph2FTT and o-Ph2FTT, employing noncovalent conformational locks with excellent planarity are first developed via an eco-friendly, tin-free direct C─H activation strategy. Due to the different fluorine substitution positions on the benzene ring, the p-Ph2FTT molecule exhibits superior planarity compared with o-Ph2FTT, resulting in superior charge transport performance in OFETs. Employing p-Ph2FTT as a photosensitizer, the fabricated p-Ph2FTT/PDVT-10 synaptic transistor exhibits distinct synaptic responses under blue light stimulation, demonstrating excellent synaptic plasticity and a remarkable photosensitivity of 6.7 × 10⁴. Furthermore, an artificial neural network constructed by this transistor achieves an overall recognition accuracy of 92.84% for handwritten digits. This investigation establishes a paradigm for the green synthesis of multifunctional molecular materials, facilitating the integration of eco-friendly chemistry and high-performance electronics for neuromorphic computing.