Computer analysis of the structure of Ag nanoparticles obtained by vacuum-thermal synthesis

Abstract

One of the ways to create plasmonic nanoparticles is through a physical method of synthesizing by thermal evaporation in a vacuum, which was chosen for analysis through computer simulation. Experimental data on the initial and annealed silver nanoparticles obtained in this manner were studied. It was found that small Ag nanoparticles (D < 3.5 nm) exhibited nearly ideal FCC structure, while larger nanoparticles unexpectedly showed predominantly icosahedral or decahedral modifications. To assess the mechanisms behind these experimental results, a study on the stability of Ag nanocluster structures with diameters D = 2.0–10.0 nm was conducted using molecular dynamics. Based on computer analysis of synthesis processes, subsequent cooling of Ag nanoparticles, and their thermal annealing, it was demonstrated that the theoretical discrepancy in the structure of experimentally obtained nanoparticles could only be explained by significant deformation of small Ag nanoparticles occurring during their deposition on a substrate in a liquid state. Possible ways to control the structure of Ag nanoparticles were identified. The regularities identified through computer simulation can be utilized in the preparation of Ag nanoparticles using physical synthesis methods.