Elastic properties of gold supracrystals: Effects of nanocrystal size, ligand length, and nanocrystallinity

XP Liu and Y Ni and LH He, JOURNAL OF CHEMICAL PHYSICS, 144, 144507 (2016).

DOI: 10.1063/1.4946029

Atomistic molecular dynamics simulations are performed to study the elastic properties of alkylthiol-functionalized gold supracrystals. The predicted Young's and shear moduli are around 1 GPa and 100 MPa, respectively. We show that, with increasing NC size, the Young's modulus decreases while the shear modulus essentially remains invariant; with increasing ligand length, the Young's modulus increases but the shear modulus decreases. Moreover, significant increase in the Young's modulus is seen when the polycrystalline NCs are replaced by single-crystal ones of the same size. All these are in reasonable agreement with available experiments. We attribute the mechanisms to the interaction between capping ligands as well as its variations caused by the change in ligand length and NC geometry. The results may deepen our understanding of elastic properties of the supracrystals and their influential factors. Published by AIP Publishing.

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