Equilibrium Morphology of Plasmonic Au/Polystyrene Dimeric Nanoparticle

초록

Growth of a metal on nanoparticles has been considered to be a useful synthetic tool in a wide variety of applications ranging from catalysis to nanomedicine. This technique can combine more than two functionalities into a single nanoparticle. Most of the methods for such growth rely on a trial-and-error approach to produce grown nanoparticles with the desired sizes and shapes, which is rather time consuming and difficult to reproduce. Here we systematically studied the equilibrium morphology of metal/dielectric dimeric nanoparticle. A computational model was developed by considering the diffusion and surface energy of a metal and the interface energy between the metal and a dielectric. As a proof-of-concept, the growth of Au on a dimeric nanoparticle consisting of Au and polystyrene (PS) was considered. The effects of the surface and interface energy, the concentration of Au ion over the course of the growth, and the size of PS on the shape (i.e., morphology) of the grown nanoparticle were examined. Interestingly, the effects of the surface and interface energy of Au on its coverage of PS are found to be relatively negligible compared to the other two factors. A diagram for the equilibrium morphology with respect to the concentration of Au ion and the size of PS is proposed, which is qualitatively consistent with the experiment.

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