The desire to image specimens in liquids has led to the development of open-cell and closed-cell techniques in transmission electron microscopy (TEM). The closed-cell approach is currently more common in TEM and has yielded new insights into a number of biological and materials processes in liquid environments. The open-cell approach, which requires an environmental TEM (ETEM), is technically challenging but may be advantageous in certain circumstances due to fewer restrictions on specimen and detector geometry. Here, we demonstrate a novel approach to open-cell liquid TEM, in which we use salt particles to facilitate the in situ formation of droplets of aqueous solution that envelope specimen particles coloaded with the salt. This is achieved by controlling sample temperature between 1 and 10°C and introducing water vapor to the ETEM chamber above the critical pressure for the formation of liquid water on the salt particles. Our use of in situ hydration enables specimens to be loaded into a microscope in a dry state using standard 3 mm TEM grids, allowing specimens to be prepared using trivial sample preparation techniques. Our future aim will be to combine this technique with an in situ light source to study photocorrosion in aqueous environments.

中文翻译：

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用于水溶液中样品原位表征的开孔环境透射电子显微镜技术

在液体中对样品进行成像的愿望导致了透射电子显微镜 (TEM) 中开孔和闭孔技术的发展。闭孔方法目前在 TEM 中更为常见，并对液体环境中的许多生物和材料过程产生了新的见解。需要环境 TEM (ETEM) 的开孔方法在技术上具有挑战性，但由于对样品和探测器几何形状的限制较少，因此在某些情况下可能具有优势。在这里，我们展示了一种开孔液体 TEM 的新方法，其中我们使用盐颗粒来促进原位形成包裹着与盐共载的样品颗粒的水溶液液滴。这是通过将样品温度控制在 1 到 10°C 之间并将水蒸气引入 ETEM 室来实现的，该压力高于在盐颗粒上形成液态水的临界压力。我们的使用原位水合使样品能够使用标准的 3 mm TEM 网格在干燥状态下装入显微镜，从而可以使用简单的样品制备技术制备样品。我们未来的目标是将这项技术与原位用于研究水环境中的光腐蚀的光源。