On morphologies of gold nanoparticles grown from molecular dynamics simulation

Area of Science:

• Computational materials science
• Nanoparticle synthesis and characterization
• Physical chemistry

Background:

• Experimental studies have observed varying morphologies in synthesized gold nanoparticles.
• The underlying mechanisms governing nanoparticle shape and population statistics remain incompletely understood.
• Previous research by Koga and Sugawara highlighted specific nanoparticle ratios in experimental observations.

Purpose of the Study:

• To simulate the initial nucleation, coalescence, and kinetic growth of vapor-synthesized gold nanoparticles.
• To investigate the influence of coalescence and temperature on nanoparticle morphology.
• To provide a computational explanation for experimentally observed trends in nanoparticle morphology ratios.

Main Methods:

• Utilized a newly fitted gold embedded atom method potential for atomic-level simulations.
• Simulated the processes of nucleation, coalescence (sintering), and kinetic growth.
• Analyzed population statistics and compared simulation results with experimental HREM data.

Main Results:

• Simulation results closely mirrored experimental observations in nanoparticle types and ratios.
• Early-stage coalescence and lower temperatures were identified as key factors for Dh and fcc morphologies.
• Atom-by-atom growth conditions exclusively produced the Ih morphology.

Conclusions:

• Coalescence and temperature play critical roles in determining gold nanoparticle morphology during synthesis.
• The findings offer a potential explanation for the size-dependent increase in Dh to Ih ratios.
• The study validates the embedded atom method potential for simulating nanoparticle formation dynamics.