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

Area of Science:

• Materials Science
• Nanoscience
• Organic Electronics

Background:

• High-performance molecular-scale transistors are crucial for advancing nanoelectronics.
• Developing suitable single-molecule transistor materials presents a significant challenge.

Purpose of the Study:

• To design and synthesize novel diketopyrrolopyrrole (DPP)-based narrow bandgap molecular wires.
• To investigate the effect of tailored molecule-electrode coupling on transistor performance.

Main Methods:

• Synthesis of DPP-based molecular wires.
• Electrochemical gating measurements.
• Conductance measurements and transition voltage spectroscopy (TVS).
• Density Functional Theory (DFT) calculations.

Main Results:

• The molecular wire DPP-C-SMe, with electronic decoupling, showed over 200-fold electrochemical gated modulation.
• Achieved a low subthreshold swing of 105 mV dec⁻¹ within a 1 V potential window.
• Electronic decoupling reduced off-state conductance while maintaining favorable energy alignment for efficient switching.

Conclusions:

• A cooperative design principle integrating a narrow-band gap core with tailored interfacial engineering enhances single-molecule transistor performance.
• Electronic decoupling at the molecule-electrode interface is key to superior transistor characteristics.
• This work advances molecular-scale control of charge transport for functional nanoelectronics.