Molecular Dynamics Study of Temperature Influence on Directional Motion of Gold Nanoparticle on Nanocone Surface

In this work, the directional motion and underlying mechanism of a circular gold nanoparticle (AuNP) on nanocone (NC) surface were studied with the aid of molecular dynamics simulation. Three specific sized AuNP(s) having particular number of atoms and three nanocones having distinct apex angle were utilized in this work. The simulation was run in a temperature range of 300–1300 K to observe the effect of temperature on the directional motion of AuNP located outside of NC surface. The results revealed that the AuNP tends to move toward the larger-diameter direction of the NC at higher temperature range, whereas it stayed intact on the area around the tip of NC at lower temperature range. It was observed that the average velocity of AuNP located outside the NC surface with large apex angle was comparatively lower than that on the NC surface having small apex angle. Furthermore, it was inspected that the interaction energy of the AuNP is reduced heavily as the temperature is increased, and it decayed more in the large diameter AuNP, which resulted in higher velocity of large-diameter AuNP on the NC surface. Moreover, the contact angle of AuNP on a flat silicon surface is observed. It was found that the AuNP stayed intact at low temperature, but it started to deform at higher temperature due to its transition from unmolten (solid) to molten (liquid) state. In addition, the melting temperature of AuNP is also measured by analyzing the potential energy results at different temperatures during the simulation.