Wang Zixiao, Liu Ruihong, Chen Hong-Yuan, Wang Hui
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450001, China.
JACS Au. 2021 Aug 6;1(10):1700-1707. doi: 10.1021/jacsau.1c00292. eCollection 2021 Oct 25.
Probing and tuning the electron tunneling in metal electrode-insulator-metal nanoparticle systems provide a unique vision for understanding the fundamental mechanism of electrochemistry and broadening the horizon in practical applications of molecular electronics in many electrochemical systems. Here we report a plasmonic imaging technique to monitor the local double-layer charging of individual Au nanoparticles deposited on gold electrode separated by monolayer of -alkanethiol molecules. The thickness of molecular monolayer tunes the tunneling kinetics and conductivity, which predicts the heterogeneous behavior on the modified electrode surface for different electrochemical systems. We studied the distance dependence of the electron tunneling and double layer charging processes by a plasmonic-based electrical impedance microscopy. By performing fast Fourier transform analysis of the recorded plasmonic image sequences, we can quantify the interfacial impedance of single nanoparticles and the tunneling decay constant of molecular layer. We further observed the electron neutralization dynamics during single-nanoparticle collisions on different surfaces. This optical readout of electron tunneling demonstrates an imaging approach to determine the electrical properties of metal electrode-insulator-metal nanoparticle systems, which include the electron tunneling mechanism and local impedance.
探索和调节金属电极-绝缘体-金属纳米粒子系统中的电子隧穿，为理解电化学的基本机制以及拓宽分子电子学在许多电化学系统中的实际应用视野提供了独特视角。在此，我们报告一种等离子体成像技术，用于监测沉积在由单层链烷硫醇分子隔开的金电极上的单个金纳米粒子的局部双层充电情况。分子单层的厚度调节隧穿动力学和电导率，这预示了不同电化学系统在修饰电极表面的异质行为。我们通过基于等离子体的电阻抗显微镜研究了电子隧穿和双层充电过程的距离依赖性。通过对记录的等离子体图像序列进行快速傅里叶变换分析，我们可以量化单个纳米粒子的界面阻抗和分子层的隧穿衰减常数。我们还进一步观察了不同表面上单纳米粒子碰撞过程中的电子中和动力学。这种电子隧穿的光学读出展示了一种确定金属电极-绝缘体-金属纳米粒子系统电学性质的成像方法，这些性质包括电子隧穿机制和局部阻抗。
