Anti-phase boundary accelerated exsolution of nanoparticles in non-stoichiometric perovskite thin films

Hyeon Han*, Yaolong Xing, Bumsu Park, Dmitry I. Bazhanov, Yeongrok Jin, John T. S. Irvine, Jaekwang Lee, Sang Ho Oh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)
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Exsolution of excess transition metal cations from a non-stoichiometric perovskite oxide has sparked interest as a facile route for the formation of stable nanoparticles on the oxide surface. However, the atomic-scale mechanism of this nanoparticle formation remains largely unknown. The present in situ scanning transmission electron microscopy combined with density functional theory calculation revealed that the anti-phase boundaries (APBs) characterized by the a/2 < 011> type lattice displacement accommodate the excess B-site cation (Ni) through the edge-sharing of BO6 octahedra in a non-stoichiometric ABO3 perovskite oxide (La0.2Sr0.7Ni0.1Ti0.9O3-δ) and provide the fast diffusion pathways for nanoparticle formation by exsolution. Moreover, the APBs further promote the outward diffusion of the excess Ni toward the surface as the segregation energy of Ni is lower at the APB/surface intersection. The formation of nanoparticles occurs through the two-step crystallization mechanism, i.e., the nucleation of an amorphous phase followed by crystallization, and via reactive wetting on the oxide support, which facilitates the formation of a stable triple junction and coherent interface, leading to the distinct socketing of nanoparticles to the oxide support. The atomic-scale mechanism unveiled in this study can provide insights into the design of highly stable nanostructures.
Original languageEnglish
Article number6682
Number of pages10
JournalNature Communications
Publication statusPublished - 5 Nov 2022


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