Multi-layer kagome lattices assembled with isotropic spherical colloids via heteroepitaxial growth

The control of structure is crucial for diverse applications of colloidal crystals. Open-structure colloidal crystals are promising in their novel optical or mechanical properties, yet fabrication remains a significant challenge. Here, we demonstrate fabrication of multi-layer colloidal kagome lattices via heteroepitaxial growth. Unlike previous methods that rely on anisotropic particles, such as Janus particles, our approach utilizes common isotropic spherical polystyrene particles. We fabricated multi-layered kagome lattices, in contrast to techniques that were limited to forming single layers. The first layer in the kagome lattice formation on a substrate was a multi-step process, as revealed by in situ-observations. Then repeated stacking of kagome lattice layers occurred stably. This heteroepitaxial growth technique offers a feasible approach to self-assemble open-structure colloidal crystals.