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On the Thermodynamics and Experimental Control of Twinning in Metal Nanocrystals
Author(s) -
Gilroy Kyle D.,
Puibasset Joël,
Vara Madeline,
Xia Younan
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201705443
Subject(s) - nanocrystal , icosahedral symmetry , crystal twinning , materials science , amorphous solid , molecular dynamics , work (physics) , chemical physics , nanoparticle , density functional theory , thermodynamics , nanotechnology , chemistry , crystallography , computational chemistry , physics , metallurgy , microstructure
This work demonstrates a new strategy for controlling the evolution of twin defects in metal nanocrystals by simply following thermodynamic principles. With Ag nanocrystals supported on amorphous SiO 2 as a typical example, we establish that twin defects can be rationally generated by equilibrating nanoparticles of different sizes through heating and then cooling. We validate that Ag nanocrystals with icosahedral, decahedral, and single‐crystal structures are favored at sizes below 7 nm, between 7 and 11 nm, and greater than 11 nm, respectively. This trend is then rationalized by computational studies based on density functional theory and molecular dynamics, which show that the excess free energy for the three equilibrium structures correlate strongly with particle size. This work not only highlights the importance of thermodynamic control but also adds another synthetic method to the ever‐expanding toolbox used for generating metal nanocrystals with desired properties.