Enhancing the Self-Assembly of Binary Colloidal Crystals with Confinement

Photonic crystals with a bandgap in the visible-light range have been theorized to self-assemble from a binary colloidal dispersion but difficulties remain in robustly assembling high-quality crystals in quantities sufficient for large-scale applications. Computational methods give insight into the conditions under which photonic crystals can self-assemble. In this study, we performed hard-particle Monte Carlo simulations of tetrahedral and octahedral nanoparticles in spherical and flat-wall geometries to determine the influence of confinement on the process and products of crystallization compared to the bulk. Confinement was found to improve crystallization at non-ideal stoichiometries but did not lower the minimal packing fraction at which crystallization occurred throughout the system. Crystals formed under confinement exhibited higher crystallinity and lower quantities of secondary phase defects. These findings demonstrate the potential for enhanced control over the synthesis of novel materials with tailored structures and properties for photonic applications.