Long Xia, Xu Wangping, Duan Tingting, Lin Liyan, Guo Yandong, Yan Xiaohong, Cao Juexian, Hu Yong
Hunan Institute of Advanced Sensing and Information Technology, Xiangtan University, Xiangtan, China.
College of Electronic and Optical Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China.
iScience. 2024 Feb 20;27(3):109292. doi: 10.1016/j.isci.2024.109292. eCollection 2024 Mar 15.
Understanding and tuning charge transport in molecular junctions is pivotal for crafting molecular devices with tailored functionalities. Here, we report a novel approach to manipulate the absorption configuration within a 4,4'-bipyridine (4,4'-BPY) molecular junction, utilizing the scanning tunneling microscope break junction technique in a concentration-dependent manner. Single-molecule conductance measurements demonstrate that the molecular junctions exhibit a significant concentration dependence, with a transition from high conductance (HC) to low conductance (LC) states as the concentration decreases. Moreover, we identified an additional conductance state in the molecular junctions besides already known HC and LC states. Flicker noise analysis and theoretical calculations provided valuable insights into the underlying charge transport mechanisms and single-molecule absorption configurations concerning varying concentrations. These findings contribute to a fundamental comprehension of charge transport in concentration-dependent molecular junctions. Furthermore, they offer promising prospects for controlling single-molecule adsorption configurations, thereby paving the way for future molecular devices.
理解和调节分子结中的电荷传输对于制造具有定制功能的分子器件至关重要。在此，我们报告了一种利用扫描隧道显微镜断结技术以浓度依赖方式操纵4,4'-联吡啶（4,4'-BPY）分子结内吸收构型的新方法。单分子电导测量表明，分子结表现出显著的浓度依赖性，随着浓度降低，会从高电导（HC）状态转变为低电导（LC）状态。此外，我们在分子结中除了已有的HC和LC状态外，还识别出了另一种电导状态。闪烁噪声分析和理论计算为不同浓度下潜在的电荷传输机制和单分子吸收构型提供了有价值的见解。这些发现有助于从根本上理解浓度依赖型分子结中的电荷传输。此外，它们为控制单分子吸附构型提供了有前景的方向，从而为未来的分子器件铺平了道路。
