Institute of Analytical Chemistry, Department of Chemistry , Zhejiang University , Hangzhou 310058 , China.
J Am Chem Soc. 2020 Jan 22;142(3):1222-1226. doi: 10.1021/jacs.9b12833. Epub 2020 Jan 10.
Here we report an electrochemiluminescence (ECL) self-interference spectroscopy technique (designated as ECLIS) with spatial resolution in the normal direction of the electrode surface. Self-interference principally originates from the superposition of ECL emitted directly by luminophores and that reflected from electrode surfaces, resulting in a spectrum consisting of orderly distributed peaks. On the basis of this spectrum and theoretical analysis by the matrix propagation model, the distance between luminophores and the electrode surface can be probed with a vertical resolution on the nanometer scale. We demonstrated first in this work that the height of ECL luminophores assembled on the electrode surface using different molecular linkers, such as double-stranded DNA, could be determined, as well as the possible conformation of linker molecules at the surface. Moreover, the thickness of the ECL emitting layer adjacent to the electrode surface was estimated for the classical coreactant ECL systems involving freely diffusing Ru(bpy) and tri--propylamine in solutions. The thickness was found to vary from ∼350 nm to nearly 1 μm depending on the concentration of Ru(bpy). We believe that ECLIS with a high vertical resolution will provide an easy way to collect molecular conformation information and study ECL reaction mechanisms at electrode interfaces.
在这里，我们报告了一种具有电极表面法向空间分辨率的电化学发光（ECL）自干扰光谱技术（命名为 ECLIS）。自干扰主要源于发光体直接发射的 ECL 与从电极表面反射的 ECL 的叠加，从而产生由有序分布的峰组成的光谱。基于该光谱和矩阵传播模型的理论分析，可以探测到发光体与电极表面之间的距离，其垂直分辨率可达纳米级。在这项工作中，我们首次证明可以确定使用不同分子连接体（如双链 DNA）组装在电极表面上的 ECL 发光体的高度，以及连接体分子在表面上的可能构象。此外，还估计了相邻电极表面的 ECL 发射层的厚度，对于涉及在溶液中自由扩散的 Ru(bpy)和三丙胺的经典共反应物 ECL 体系而言。厚度取决于 Ru(bpy)的浓度，范围从约 350nm 到近 1μm。我们相信，具有高垂直分辨率的 ECLIS 将为收集分子构象信息和研究电极界面处的 ECL 反应机制提供一种简便的方法。
