Gold nanoparticles aggregation on graphene using Reactive force field: A molecular dynamic study

We examine the aggregation behavior of AuNPs of different sizes on graphene as function of temperature using molecular dynamic simulations with Reax Force Field. In addition, the consequences of such aggregation on the morphology of AuNPs and the charge transfer behavior of AuNP-Graphene hybrid structure are analyzed. The aggregation of AuNPs on graphene is confirmed from the center of mass distance calculation. The simulation results indicate that the size of AuNPs and temperature significantly affect the aggregation behavior of AuNPs on graphene. The strain calculation showed that shape of AuNPs changes due to the aggregation and the smaller size AuNPs on graphene exhibit more shape changes than larger AuNPs at all the temperatures studies in this work. The charge transfer calculation reveals that, the magnitude of charge transfer is higher for larger AuNPs-graphene composite when compared with smaller AuNPs-graphene composite. The charge transfer trend and the trends seen in the number of Au atoms directly in touch with graphene are identical. Hence, our results conclude that, quantity of Au atoms directly in contact with graphene during aggregation is primarily facilitates charge transfer between AuNPs and graphene. Our results on the size dependent strain and charge transfer characteristics of AuNPs will aid in the development of AuNPs-graphene composites for sensor applications.

Automated summary

We investigated the aggregation behavior of AuNPs on graphene at different temperatures using molecular dynamic simulations. The results showed that the size of AuNPs and temperature have significant effects on the aggregation behavior. Smaller AuNPs exhibited more shape changes due to aggregation, while larger AuNPs showed higher charge transfer. The quantity of Au atoms in direct contact with graphene during aggregation primarily facilitated the charge transfer between AuNPs and graphene. Our findings will contribute to the development of AuNPs-graphene composites for sensor applications.