Unraveling the impact of template geometry and confinement on template-assisted self-assembly of nanoparticles

Abstract

Directed self-assembly (DSA) of nanoparticles onto templated substrates facilitates the design of plasmonic, photovoltaic, and semiconducting devices. It is commonly thought that the wedge-mechanism of DSA of micrometer sized particles onto templated surfaces would apply to DSA of sub-10 nm particles. Using many-body dissipative particle dynamics simulations, we present a model to understand the mechanisms of DSA of sub-10 nm particles onto an array of nanocavities as a template. The simulation results suggest that the random hopping mechanism ahead of the receding meniscus plays the major role in DSA of sub-10 nm particles. The simulation results provide a phase diagram of DSA yield as a function of liquid film thickness (confinement) and nanoparticle density. Furthermore, we find that the DSA yield of sub-10 nm particles varies with the nanoparticle diameter to cavity size ratio. The impact of template geometry, cavity size and spacing, and nanoparticle ordering in the bulk on the DSA yield will also be discussed. Overall, the present study provides new insights into the potential mechanisms of DSA of nanoparticles onto templated substrates and the relevant driving factors, which help future experimental design of DSA onto templated surfaces at sub-10 nm scales.