Local Tracking of Single Ions Dynamics at Solid-Liquid Interfaces

离子在自然界中无处不在。它们在无数过程中发挥着至关重要的作用，从蛋白质的功能使地球上的生命成为可能，到矿物质的形成和海洋酸度的调节。在技术上，离子作为复合材料的结构元素以及能量转换和存储中的电荷载体更加重要。无论是在生物体中还是在尖端电池中，离子在传输、转换和储存能量方面都发挥着核心作用。由于大多数离子的尺寸很小，固液界面的交换和传输过程往往受固体的结构和化学特征（如缺陷）的影响，就像一个柱子或一个水坑干扰了忙碌地下通道中拥挤人群的自然运动。因此，为了充分了解离子的动力学，能够在浸没固体的界面处跟踪单个离子是至关重要的;任何平均测量都会消除固体主要表面特征的影响。迄今为止，这还不可能，由于缺乏实验技术：大多数现有的方法依赖于某种形式的平均超过许多离子，以获得精确的信息，该奖学金的目标是开发一种新型的显微镜，能够探测局部和原位的单离子在浸没固体表面的动态，同时时空分辨率超过1纳米和50纳秒。这种新的显微镜随后将被用于揭示使某些离子有效地通过复合材料而阻止其他离子迁移的分子机制，它还将被用于研究模型生物界面处的单离子动力学，并回答生物系统中其他无法解决的问题。重要的是，这个实验平台将开辟直接比较实验结果与在相同空间和时间尺度上进行的计算机模拟的可能性。

Ions are ubiquitous in nature. They play a crucial role in countless processes, from the function of proteins rendering life possible on earth to the formation of minerals and the regulation of the ocean's acidity. In technology, ions are even more important both as structural elements for composite materials and as charge carriers in energy conversion and storage. Whether in living organisms or in cutting edge batteries, ions occupy a central role in transporting, converting and storing energy. This process usually hinges of charge exchanges that occur at the interface between a solid surface and a liquid in which the ions are dissolved.Because of the small size of most ions, exchange and transport processes at solid-liquid interfaces tend to be dominated by structural and chemical features of the solid such as defects; much like a pillar or a puddle disturbing the natural movement of a crowed in a busy underground passage. It is therefore crucial to be able to follow single ions at the interface with immersed solids in order to fully understand ions' dynamics; any averaged measurement smears out the impact of the dominating surface features of the solid. To date this has not been possible due a lack of experimental technique: most existing approach rely of some form of averaging over many ions in order to derive precise information.The goal of this fellowship is to develop a novel type of microscope able to probe locally and in-situ the dynamics of single ions at the surface of immersed solids with a simultaneous spatiotemporal resolution exceeding 1 nanometre and 50 nanoseconds. This new microscope will subsequently be used uncover the molecular mechanisms enabling certain ions to migrate efficiently through composite materials while preventing others.It will also be used to investigate the dynamics of single ions at model biointerfaces and answer otherwise inaccessible questions for biological systems. It will also be Significantly, this experimental platform will open up the possibility to directly compare experimental results with computer simulations conducted on the same spatial and temporal scales.