Chen Yiming, Wang Xinwei, Wang Xijuan, Zhang Xinhuan, Chen Chuanxiang, Yuan Saisai, Duan Ping, Li Jin
School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, 212100 Zhenjiang, China.
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 264003 Yantai, China.
J Colloid Interface Sci. 2025 Feb 15;680(Pt B):96-104. doi: 10.1016/j.jcis.2024.11.085. Epub 2024 Nov 14.
Strong molecule-electrode coupling originating from orbit hybridization between gold and the delocalized molecular wires in single-molecule junctions facilitates facile transport towards smart molecular devices. In this paper, we report ultra-highly conductive single-molecule circuits based on highly delocalized nickel bis(dithiolene) (NiS) molecular junctions using scanning tunneling microscope break junction technique. Single-molecule charge transport measurement of both NiS reveals they exhibits high conductance of 10G and 10G, respectively. Moreover, under intervention of high bias voltage the molecular conductance could be further improved to approximately 10G, the highest value reported to date with similar molecular lengths. Theoretical calculations suggest that the strong hybridization of the π-channels and the gold electrodes in both junctions exists and it further extends from molecule-electrode interfaces to metal electrodes as visualized by the isosurface plots of the transmitting eigenstate, which lead to not only a distinct energy shift of the dominated LUMO peaks toward Fermi level, but also broad peaks in the LUMO resonance in the transmission functions. In addition, the both molecular junctions show remarkable photoconductance of approximately 10G under resonant light excitation, due to possible exciton binding in these junctions. Interestingly, the conductance switching of both molecular junctions under optoelectronic modulation is highly reversible, forming a multi-stimulus responsive molecular switch. This work not only provides a building block for fabricating highly conducting molecular wires with strong molecule-electrode coupling, but also lays a foundation for designing optoelectronic modulated functional molecule-scale devices.
源自单分子结中黄金与离域分子线之间轨道杂化的强分子-电极耦合，有助于向智能分子器件的便捷传输。在本文中，我们报告了基于高度离域的双（二硫烯）镍（NiS）分子结，采用扫描隧道显微镜断结技术的超高导电单分子电路。对两种NiS进行的单分子电荷传输测量表明，它们分别展现出10G和10G的高电导。此外，在高偏置电压的干预下，分子电导可进一步提高至约10G，这是迄今报道的类似分子长度中的最高值。理论计算表明，两个结中π通道与金电极之间存在强杂化，并且如传输本征态的等值面图所示，它从分子-电极界面进一步延伸至金属电极，这不仅导致主导的最低未占分子轨道（LUMO）峰向费米能级发生明显的能量偏移，而且在传输函数中的LUMO共振中出现宽峰。此外，由于这些结中可能存在激子束缚，两个分子结在共振光激发下均表现出约10G的显著光电导。有趣的是，两个分子结在光电调制下的电导切换具有高度可逆性，形成了一种多刺激响应分子开关。这项工作不仅为制造具有强分子-电极耦合的高导电分子线提供了一个构建模块，也为设计光电调制功能分子尺度器件奠定了基础。
