Jiawei Wan1,2,Qiubo Zhang1,Jiayun Liang2,Karen Bustillo1,Zakaria Al Balushi2,Mark Asta1,2,Haimei Zheng1,2
Lawrence Berkeley National Laboratory1,University of California, Berkeley2
Jiawei Wan1,2,Qiubo Zhang1,Jiayun Liang2,Karen Bustillo1,Zakaria Al Balushi2,Mark Asta1,2,Haimei Zheng1,2
Lawrence Berkeley National Laboratory1,University of California, Berkeley2
Liquid cell transmission electron microscopy (TEM) has become a powerful tool for the study of nanoparticle movement and self-assembly. By tracking the individual nanoparticle motion, mechanisms of the movement can be achieved. Extensive studies have demonstrated that various interaction forces contribute to the nanoparticle motion, which lead to the self-assembly of nanoparticles into one-dimensional chains, two-dimensional patterns, and three-dimensional architectures. Nanoparticle motion can be introduced predominantly by electron beam illumination, in which nanoparticles resemble the light-activated nanomotors. Herein, using cadmium chloride tetrahydrate (CdCl<sub>2<sup>.</sup></sub>4H<sub>2</sub>O) nanomotor as an example, we studied the relationship between the configurational asymmetry and consequent motion of a nanomotor. Using in situ liquid cell TEM, we observed the directional motion of a CdCl<sub>2</sub><sup>.</sup>4H<sub>2</sub>O nanomotor under electron beam irradiation. The movement dynamics were regulated by the configurational asymmetry of the nanoparticles, which was caused by the difference in the reaction activity of various crystal facets. High resolution TEM images and numerical simulations showed a working mechanism that was related to the electric field generated around the nanomotor. This work points out the influence of asymmetry on the dynamics of nanomotors. Also, this study contributes to the understanding of mechanisms on nanoparticle movements and self-assembly, and suggests a new strategy for designing nanodevices for applications.