Wang Haoyu, Hu Fenglu, Adijiang Adila, Emusani Ramya, Zhang Jieyi, Hu Qihong, Guo Xuefeng, Lee Takhee, Chen Lichuan, Xiang Dong
Institute of Modern Optics and Center of Single-Molecule Sciences, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin 300350, China.
Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
J Am Chem Soc. 2024 Dec 25;146(51):35347-35355. doi: 10.1021/jacs.4c13773. Epub 2024 Dec 12.
In electronic functional chips, one of the most crucial components is the field-effect transistor (FET). To meet the urgent demands for further miniaturization of electronic devices, solid-state single-molecule transistors by molecular orbital gating have been extensively reported. However, under negative bias and positive bias, achieving a distinct gating effect is extremely challenging because molecular orbital gating is independent of the bias polarity. Here, we demonstrated that rectifiers can be realized in single-molecule junctions with a symmetric molecular structure and an electrode material by simply breaking the symmetry of the electrode's chemical potential via ionic adsorption. We further demonstrated that the tunneling current can be gated with opposite change tendencies under negative and positive bias by applying an ionic gating voltage, which eventually results in a reversal of the rectifying direction. Our experiments elucidate that, unlike the classical mechanism for solid molecular FET, the modulation of the electrode's chemical potential, rather than the regulation of molecular orbitals, might dominate the electron transport in the ionic liquid environment upon a gating voltage. Our study gains deeper insights into the mechanism of ionic liquid gating and opens a window for designing high-performance electrochemical-based functional devices.
在电子功能芯片中，最关键的组件之一是场效应晶体管（FET）。为满足电子设备进一步小型化的迫切需求，通过分子轨道门控实现的固态单分子晶体管已被广泛报道。然而，在负偏压和正偏压下，由于分子轨道门控与偏压极性无关，实现明显的门控效应极具挑战性。在此，我们证明，通过离子吸附简单地打破电极化学势的对称性，在具有对称分子结构和电极材料的单分子结中可以实现整流器。我们进一步证明，通过施加离子门控电压，在负偏压和正偏压下隧穿电流可以具有相反的变化趋势，最终导致整流方向反转。我们的实验表明，与固体分子FET的经典机制不同，在门控电压作用下，电极化学势的调制而非分子轨道的调控可能主导离子液体环境中的电子传输。我们的研究对离子液体门控机制有了更深入的了解，并为设计基于电化学的高性能功能器件打开了一扇窗口。
