Fast electron low dose tomography for beam sensitive materials

Applications of Transmission Electron Microscopy in Phase Engineering of Nanomaterials

“…For the same reason, employing iDPC-STEM for tomography could be an even better choice. 105 Using electron ptychography data for tomographic reconstruction is another strategy for reducing electron dose consumption (further discussions on electron ptychography can be found in the Outlook section). Ding et al achieved tomographic reconstruction of unstained DNA origami bonded to Au nanoparticles using only 23 ptychographic phase images obtained from different tilt angles.…”

“…To minimize the electron dose consumption, ADF-STEM (β = 1α–2α) − is preferred for atomic electron tomography compared with HAADF-STEM, due to its higher electron utilization efficiency. For the same reason, employing iDPC-STEM for tomography could be an even better choice …”

Low-Dose 4D-STEM Tomography for Beam-Sensitive Nanocomposites

“…One important issue when applying ET is the often significant accumulation of electron dose and therefore beam damage during the serial imaging, resulting in a transformed nanostructure that obstructs a trustworthy 3D reconstruction. ,, The relevance of this problem is even increased for MOFs that are particularly sensitive to electron radiation and which lose their crystallinity already at an accumulated dose of 5–30 electrons/Å 2 . − This amorphization process is often accompanied by a change in the morphology of MOF particles, particularly shrinkage. ,, Whereas amorphization is not an issue for nonatomically resolved tomography, shrinkage is synonymous with a change in the volume, which is not acceptable during tomogram acquisition. Various solutions to reduce the accumulated dose during serial imaging and thus mitigating beam damage have been proposed in the past, but often one has to accept a certain degree of change in the investigated particle. , However, especially when several 3D reconstructions are to be performed on one particle, for example, to investigate transformations as a result of in situ triggers, shrinkage of the sample by the electron beam is not acceptable …”

“…14 One important issue when applying ET is the often significant accumulation of electron dose and therefore beam damage during the serial imaging, resulting in a transformed nanostructure that obstructs a trustworthy 3D reconstruction. 12,15,16 The relevance of this problem is even increased for MOFs that are particularly sensitive to electron radiation and which lose their crystallinity already at an accumulated dose of 5−30 electrons/Å 2 . 17−19 This amorphization process is often accompanied by a change in the morphology of MOF particles, particularly shrinkage.…”

“…Even with a total dose that is up to 2−3 times higher, due to the centering of the particle, the tilt series can be considered an extremely low-dose experiment, compared to typical total doses in the range of 10−10 4 e − /Å 2 for what is generally considered to be a low electron dose in materials sciences. 15,32 The first postprocessing step is identifying suitable angular ranges to generate vSTEM images with sufficient signal for the MOF and the NP, respectively. The camera covers angles between 0 and approximately 134 mrad, allowing us to generate bright-or annular-dark field (ADF) vSTEM images.…”