Electrochemiluminescence (ECL) is a powerful analytical approach that enables the optical readout of electrochemical processes. Over the last few years, ECL has gained considerable attention due to its large number of applications, including chemical sensing, bioanalysis and microscopy. In these fields, the promotion of ECL at bipolar electrodes has offered unprecedented opportunities thanks to wireless electrochemical addressing. Herein, we take advantage of the synergy between ECL and bipolar electrochemistry (BE) for imaging light-emitting layers shaped by hydrodynamics, polarization effects and the nature of the electrochemical reactions taking place wirelessly on a rotating bipolar electrode. The proof-of-principle is established with the model ECL system [Ru(bpy)₃]²⁺/tri-n-propylamine. Interestingly, the ECL-emitting region moves and expands progressively from the anodic bipolar pole to the cathodic one where ECL reactants should neither be generated nor ECL be observed. Therefore, it shows a completely unusual behavior in the ECL field since the region where ECL reagents are oxidized does not coincide with the zone where ECL light is emitted. In addition, the ECL patterns change progressively to an “ECL croissant” and then to a complete ring shape due to the hydrodynamic convection. Such an approach allows the visualization of complex light-emitting patterns, whose shape is directly controlled by the rotation speed, chemical reactivity and BE-induced polarization. Indeed, the bipolar electrochemical addressing of the electrode breaks the circular symmetry of the reported rotating system. This unexplored and a priori simple configuration yields unique ECL behavior and raises new curious questions from the theoretical and experimental points of view in analytical chemistry. Finally, this novel wireless approach will be useful for the development of original ECL systems for analytical chemistry, studies of electrochemical reactivity, coupling microfluidics with ECL and imaging.

中文翻译：

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旋转双极电极上的流体动力学形成的复杂电化学发光图案


电化学发光 (ECL) 是一种强大的分析方法，可以光学读出电化学过程。在过去的几年中，ECL 由于其大量的应用（包括化学传感、生物分析和显微镜）而受到广泛关注。在这些领域，由于无线电化学寻址，ECL在双极电极上的推广提供了前所未有的机遇。在这里，我们利用 ECL 和双极电化学 (BE) 之间的协同作用，对由流体动力学、偏振效应和旋转双极电极上无线发生的电化学反应的性质形成的发光层进行成像。利用ECL模型系统[Ru(bpy) ₃ ] ²⁺ /三正丙胺建立了原理验证。有趣的是，ECL 发射区域逐渐从阳极双极移动并扩展到阴极双极，在阴极双极既不会产生 ECL 反应物，也不会观察到 ECL。因此，它在 ECL 场中表现出完全不寻常的行为，因为 ECL 试剂被氧化的区域与 ECL 光发射的区域并不重合。此外，由于流体动力对流，ECL 图案逐渐变为“ECL 羊角面包”，然后变为完整的环形。这种方法可以实现复杂发光图案的可视化，其形状直接由旋转速度、化学反应性和BE诱导偏振控制。事实上，电极的双极电化学寻址打破了所报道的旋转系统的圆形对称性。 这种未经探索的简单配置产生了独特的 ECL 行为，并从分析化学的理论和实验角度提出了新的好奇问题。最后，这种新颖的无线方法将有助于开发用于分析化学、电化学反应研究、微流体与 ECL 和成像耦合的原始 ECL 系统。