title: Restructuring and remodeling of NaREF4 nanocrystals by electron irradiation.
abstract: NaREF4 nanocrystals are found to be highly manipulable by electron beam irradiation. With 200 kV electron beam irradiation, both 14.6 nm spherical NaGdF4 :Yb,Er nanoparticles and 44.7 nm × 34.1 nm ellipsoidal NaYF4 :Yb,Er nanorods form hollow structures and eventually convert to the corresponding REF3 upon prolonged irradiation. Furthermore, the NaYF4 nanorods fractured with irradiation with a 100 kV electron source are found to be subsequently self-healed when irradiated with a 200 kV source. The detailed experimental results, in combination with theoretical analysis, suggest that knock-on effects, specific lattice energy, and the inherently low surface energy of NaREF4 collectively contribute to the formation of the hollow structures. These mechanisms allow controlled engineering and manipulation of RE nanomaterials on the nanometer scale.
authors.affiliation: Institute of Chemistry, the Chinese Academy of Sciences, Bei Yi Jie 2, Zhong Guan Cun, Beijing, 100190, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Sun
authors.forename: Bingru
authors.initials: B
authors.lastname: Wang
authors.forename: Ivan
authors.initials: I
authors.lastname: Kempson
authors.forename: Chunyan
authors.initials: C
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Hou
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Gao
keywords: electron beam irradiation; electron microscopy; nanoparticles; radiation damage; structural evolution