AB INITIO STUDY OF SILVER NANOPARTICLES, GRAIN BOUNDARIES AND THEIR QUADRUPLE JUNCTIONS

1,2 POLSTEROVÁ Svatava
Co-authors:
1,2 VŠIANSKÁ Monika 1 FRIÁK Martin 1 PIZÚROVÁ Naděžda 3 SOKOVNIN Sergey 1,2 ŠOB Mojmír
Institutions:
1 Institute of Physics of Materials, v.v.i., Czech Academy of Sciences, Brno, Czech Republic, EU, polsterova@mail.muni.cz, 230038@mail.muni.cz, friak@ipm.cz, pizurova@ipm.cz
2 Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic, EU, mojmir@ipm.cz
3 Institute of Electrophysics Ural Branch RAS, Yekaterinburg, Russia
4 Ural Federal University, Yekaterinburg, Russia, sokovnin@iep.uran.ru
Conference:
13th International Conference on Nanomaterials - Research & Application, Orea Congress Hotel Brno, Czech Republic, EU, October 20 - 22, 2021
Proceedings:
Proceedings 13th International Conference on Nanomaterials - Research & Application
Pages:
344-350
ISBN:
978-80-88365-00-6
ISSN:
2694-930X
Published:
22nd November 2021
Proceedings of the conference have already been published in Scopus and we are waiting for evaluation and potential indexing in Web of Science.
Metrics:
138 views / 68 downloads
Abstract

Motivated by our experimental research related to silver nanoparticles with various morphologies, we have employed quantum-mechanical calculations to provide our experiments with theoretical insight. We have computed properties of a 181-atom decahedral silver nanoparticle and two types of internal extended defects, 𝛴5(210) grain boundaries (GBs) and quadruple junctions (QJs) of these GBs. We have employed a supercell approach with periodic boundary conditions. Regarding the thermodynamic stability of the decahedral nanoparticle, its energy is higher than that of a defect-free face-centered cubic (fcc) Ag by 0.34 eV/atom. As far as the 𝛴5(210) GB is concerned, its energy amounts to 0.7 J/m2 and we predict that the studied GBs would locally expand the volume of the lattice. Importantly, the system with GBs is found rather close to the limit of mechanical stability. In particular, the computed value of the shear-related elastic constant C66 is as low as 9.4 GPa with the zero/negative value representing a mechanically unstable system. We thus predict that the 𝛴5(210) GBs may be prone to failure due to specific shearing deformation modes. The studied GBs have also the value of Poisson’s ratio for some loading directions close to zero. Next, we compare our results related solely to 𝛴5(210) GBs with those of a system where multiple intersecting 𝛴5(210) GBs form a network of quadruple junctions. The value of the critical elastic constant C66 is higher in this case, 13 GPa, and the mechanical stability is, therefore, better in the system with QJs.

Keywords: Nanoparticles, silver, grain boundaries, junctions, quantum-mechanical calculations, elasticity

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