Electron tomography is essential for investigating the three-dimensional (3D) structure of nanomaterials. However, many of these materials, such as metal-organic frameworks (MOFs), are extremely sensitive to electron radiation, making it difficult to acquire a series of projection images for electron tomography without inducing electron-beam damage. Another significant challenge is the high contrast in high-angle annular dark field scanning transmission electron microscopy that can be expected for nanocomposites composed of a metal nanoparticle and an MOF. This strong contrast leads to so-called metal artifacts in the 3D reconstruction. To overcome these limitations, we here present low-dose electron tomography based on four-dimensional scanning transmission electron microscopy (4D-STEM) data sets, collected using an ultrafast and highly sensitive direct electron detector. As a proof of concept, we demonstrate the applicability of the method for an Au nanostar embedded in a ZIF-8 MOF, which is of great interest for applications in various fields, including drug delivery.

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ACS Materials Letters
Centrum Wiskunde & Informatica, Amsterdam (CWI), The Netherlands

Hugenschmidt, M., Jannis, D., Kadu, A., Grünewald, L., De Marchi, S., Pérez-Juste, J., … Bals, S. (2023). Low-Dose 4D-STEM tomography for beam-sensitive nanocomposites. ACS Materials Letters, 6(1), 165–173. doi:10.1021/acsmaterialslett.3c01042