Colloidal nanoparticles (NPs) including nanowires and nanosheets made by chemical methods involve many organic ligands. When the structure of NPs is investigated via transmission electron microscopy (TEM), the organic ligands act as a source for e-beam induced deposition and this causes substantial build-up of carbon layers in the investigated areas, which is typically referred to as "contamination" in the field of electron microscopy. This contamination is often more severe for scanning TEM, a technique that is based on a focused electron beam and hence higher electron dose rate. In this paper, we report a simple and effective method to clean drop-cast TEM grids that contain NPs with ligands. Using a combination of activated carbon and ethanol, this method effectively reduces the amount of ligands on TEM grids, and therefore greatly improves the quality of electron microscopy images and subsequent analytical measurements. This efficient and facile method can be helpful during electron microscopy investigation of different kinds of nanomaterials that suffer from ligand-induced contamination.

中文翻译：

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清洁 TEM 网格上配体污染的简单方法

胶体纳米粒子 (NPs) 包括通过化学方法制成的纳米线和纳米片，涉及许多有机配体。当通过透射电子显微镜 (TEM) 研究 NPs 的结构时，有机配体充当电子束诱导沉积的来源，这会导致研究区域中碳层的大量堆积，这通常被称为“污染”在电子显微镜领域。对于扫描 TEM 而言，这种污染通常更为严重，这是一种基于聚焦电子束的技术，因此电子剂量率更高。在本文中，我们报告了一种简单有效的方法来清洁含有带配体的 NP 的滴铸 TEM 网格。该方法使用活性炭和乙醇的组合，有效地减少了 TEM 网格上的配体数量，因此大大提高了电子显微镜图像和后续分析测量的质量。这种高效而简便的方法在电子显微镜研究中对受配体诱导污染的不同类型的纳米材料很有帮助。