Modulating the Short-Range Correlation through the Assembly of Anisotropic Colloidal Clusters

Disordered structures with short-range correlation exhibit unique photonic or thermal properties, often arising from the self-assembly of monodisperse microspheres. Colloidal clusters, aggregates of a defined number of microspheres, have anisotropic shapes and offer a unique approach to tailor the short-range correlation compared to traditional isotropic microspheres. However, this potential remains largely unexplored. To this end, we have prepared triangular and tetrahedral colloidal clusters and coassemble them with polystyrene microspheres into both monolayers and thick films (∼10 μm) over 5 mm × 5 mm areas. Through combining scanning electron microscopy images and laser scattering measurements, we show that increasing cluster concentration from 0% to 40% increases disorder in both thin and thick films. Beyond 40%, the short-range order in thin films plateaus, while it increases with triangular clusters but decreases with tetrahedral clusters in thick films. The distinct roles of triangular and tetrahedral clusters offer new insights into design of correlated disordered materials for novel applications.