Controlled Electron Beam Enhanced Crystallization and Dissolution Processes

Crystallization and dissolution are fundamental processes in both natural and industrial systems, yet the detailed mechanisms at the atomic and molecular levels are still only partially understood. Electron beams have conventionally been thought to only damage samples in microscopic observations, but they can be used to control crystallization and dissolution processes, especially when combined with liquid cell transmission electron microscopy (LC-TEM). Recent advances in the controlled use of electron beams in TEM have revolutionized the study of crystallization and dissolution at the nanoscale. LC-TEM enables real-time observation of dynamic processes such as crystal growth, dissolution, and phase transitions in liquid samples. Furthermore, the potential of graphene liquid cells and the usefulness of machine learning are emphasized for improving spatial resolution in LC-TEM research in recent days. These approaches are revealing a series of non-classical phase transition pathways that overturn conventional theories of crystallization and dissolution.
Here, we report on our recent findings, demonstrating how electron beam control highlights various phenomena such as ice formation [1], dolomite crystallization [2], and semiclathrate hydrate (SCH) dissociation [3]. In addition, we show that it is actually difficult to enclose pure water in a graphene cell [4], and that we have successfully reduced noise and enhanced contrast by employing machine learning to improve LC-TEM images acquired at low electron doses during in-situ observation [5]. These techniques have enabled us to refine the time and spatial resolution of LC-TEM, and to study in detail processes that were previously unknown due to the limitations of low-dose imaging. The findings of this study show that controlled electron beam irradiation plays an important role in studying both crystallization and dissolution processes.

[1] T. Yamazaki, Y. Yashima, H. Katsuno, H. Miyazaki, T. Gondo, Y. Kimura, Microscopy and Microanalysis, 29 (2023) 1940.
[2] J. Kim, Y. Kimura, B. Puchala, T. Yamazaki, U. Becker, W. Sun, Science, 382 (2023) 915.
[3] H. Machida, T. Sugahara, H. Hata, T. Ueda, T. Yamazaki, Y. Kimura, JACS, under review.
[4] Y. Yashima, T. Yamazaki, Y. Kimura, ACS Omega, 9 (2024) 39914.
[5] H. Katsuno, Y. Kimura, T. Yamazaki, I. Takigawa, Microscopy and Microanalysis, 30 (2024) 77-84.