Formation of pyrophosphates across grain boundaries induces the formation of mismatched but oriented interfaces in silver phosphate polypods

Abstract
Interfaces and their misfit defects determine the material properties of a wide range of applications, such as electronic devices, photocatalysts, and structural materials. However, current atomic-level understanding of interfacial structures is limited. Here we reveal that a special interfacial structure, a mismatched but oriented interface formed by two differently structured facets, gives rise to Ag3PO4 polypods at room temperature in aqueous solution. Transmission and scanning electron microscopy results suggest that interfaces of {1 0 0} and {1 1 0}({1 0 0}/(1 1 0}), {1 0 0}/{1 1 1}, {1 1 0}/{1 1 1}, and {1 0 0}/{1 0 0} have certain orientation relationships, corresponding to the structural energy minima and coincident site lattices of interfacial atoms, as demonstrated by molecular dynamics simulations. Density functional theory calculations indicate that the formation of pyrophosphates and/or phosphates rotation across the interface, as well as deformation of Ag-O bonds, compensate for the lattice mismatch at the interfaces. Our work opens a new avenue for a much wider range of interfacial structures, allow for a higher diversity of structures, and shines light on tailoring crystal structures, morphologies, and their resulting properties.

Citation
Ren, P., Lu, Z., Song, M., Liu, L., Wang, B., Wei, N., … Li, D. (2021). Formation of pyrophosphates across grain boundaries induces the formation of mismatched but oriented interfaces in silver phosphate polypods. Applied Surface Science, 149980. doi:10.1016/j.apsusc.2021.149980

Acknowledgements
(Cryo) SEM and a portion of cryo-FIB cutting work were performed using Environmental Molecular Sciences Laboratory (EMSL, grid.436923.9), a DOE Office of Science User Facility sponsored by the Biological and Environmental Research program at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle under Contract No. DE-AC05-76RL01830. Cryo-FIB cutting work and low dose TEM characterization were conducted at King Abdullah University of Science and Technology. This work was supported by the U.S. Department of Energy (DOE), Office of Science (SC), Office of Basic Energy Sciences (BES), Early Career Research program under Award # KC0203020:67037. Supervision of theoretical simulation (P.V.S.) is supported by DOE-SC BES, Division of Materials Sciences and Engineering, under Award No. 10122.

Publisher
Elsevier BV

Journal
Applied Surface Science

DOI
10.1016/j.apsusc.2021.149980

Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S0169433221010564https://www.osti.gov/biblio/1827966

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