High-Performance Electrochemically Gated Single-Molecule Transistor Enabled by Interfacial Engineering

Molecular-scale transistors, particularly those with high performance, are critical for advancing nanoelectronics toward practical applications. However, developing high-performance single-molecule transistor materials remains a significant challenge. Here, we design and synthesize a series of diketopyrrolopyrrole (DPP)-based narrow bandgap molecular wires with tailored molecule-electrode coupling. The molecular wire DPP-C-SMe, featuring electronic decoupling at the molecule-electrode interface, exhibits remarkable electrochemical gated modulation (>200-fold) and a low subthreshold swing (105 mV dec^-1) within a 1 V potential window─significantly surpassing its coupled counterpart and ranking among the highest-performing single-molecule electrochemical transistors reported to date. Through combined conductance measurements, transition voltage spectroscopy (TVS), and DFT calculations, we elucidate that the electronic decoupling in DPP-C-SMe reduces the off-state conductance by lowering the low-bias transmission coefficient, while the preserved favorable energy alignment enables efficient nonresonant/near-resonant switching under electrochemical gating. This cooperative design principle is the key to its superior transistor performance. These findings provide a new strategic design principle that synergistically integrates a narrow-band gap molecular core with tailored interfacial engineering for high-performance single-molecule electrochemical transistors and advances the molecular-scale control of charge transport in functional nanoelectronics.