Stochastic approach to simulation of evaporation-triggered multiple self-assembly of mixed metal nanoparticles and their variable superradiance

We developed a design principle for the evaporation-triggered heterogeneous assembly of different kinds of metal nanoparticles in a two-dimensional environment. A dynamic Monte Carlo simulation shows the formation of island structures of gold nanoparticles (gold islands) surrounded by smaller silver nanoparticles (silver matrix) during the evaporation of organic solvent from the dispersion liquid on the water surface. Our developed principle revealed the spontaneous change in multiple interactions between gold and silver nanoparticles owing to the presence or the absence of solvation repulsion, which plays a crucial role in the formation of gold islands in the silver matrix. Not only the randomly arranged gold islands, but also the surrounding silver matrix phase contributed to the wavelength-tunable light scattering enhanced by a factor of 10² due to the superradiance effect. These results will pave the way for the design of multicolored optical devices based on random plasmonics via controlled interparticle interactions.