Gnanasekaran Karthik, Rosenmann Nathan D, Dos Reis Roberto, Gianneschi Nathan C
Materials and Structural Analysis, Thermo Fisher Scientific Inc., 5350 NE Dawson Creek Drive Hillsboro, Oregon 97124, United States.
Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, Illinois 60208, United States.
Nano Lett. 2024 Aug 21;24(33):10161-10168. doi: 10.1021/acs.nanolett.4c02242. Epub 2024 Aug 6.
We report a systematic analysis of electron beam damage of the zeolitic imidazolate framework (ZIF-8) during liquid cell transmission electron microscopy (LCTEM). Our analysis reveals ZIF-8 morphology is strongly affected by solvent used (water vs dimethylformamide), electron flux applied, and imaging mode (i.e., TEM vs STEM), while ZIF-8 crystallinity is primarily affected by accumulated electron fluence. Our observations indicate that the stability of ZIF-8 morphology is higher in dimethylformamide (DMF) than in water. However, electron diffraction indicates that ZIF-8 nanocrystals lose crystallinity at critical fluence of ∼80 eÅ independent of the presence of solvent. Furthermore, 4D-STEM analysis as a method reveals the extent of electron beam damage beyond the imaging area and indicates that radiolytic reactions are more pronounced in TEM mode than in STEM mode. These results illustrate the significance of radiolysis occurring while imaging ZIF-8 and present a workflow for assessing damage in LCTEM experiments.
我们报告了在液池透射电子显微镜(LCTEM)中对沸石咪唑酯骨架(ZIF-8)电子束损伤的系统分析。我们的分析表明,ZIF-8的形态受到所用溶剂(水与二甲基甲酰胺)、施加的电子通量以及成像模式(即TEM与STEM)的强烈影响,而ZIF-8的结晶度主要受累积电子注量的影响。我们的观察结果表明,ZIF-8在二甲基甲酰胺(DMF)中的形态稳定性高于在水中的稳定性。然而,电子衍射表明,ZIF-8纳米晶体在临界注量约为80 eÅ时失去结晶度,与溶剂的存在无关。此外,作为一种方法的4D-STEM分析揭示了成像区域之外的电子束损伤程度,并表明辐射分解反应在TEM模式下比在STEM模式下更明显。这些结果说明了在对ZIF-8成像时发生的辐射分解的重要性,并提出了一种在LCTEM实验中评估损伤的工作流程。