Colloidal Nanoparticle Metasurfaces: Principles, Fabrication, and Applications

Metasurfaces, a class of two-dimensional metamaterials, exhibit notable optical properties, making them attractive candidates for applications in fields such as the cloaking, biophotonics, and imaging. The realization of these applications is dependent on advancements in fabrication techniques. Conventional "top-down" lithography often faces limitations, such as polycrystallinity and surface roughness. In contrast, "bottom-up" self-assembly methods using colloidal nanoparticles offer a feasible alternative, enabling the fabrication of materials with controlled sizes, shapes, crystallinities, and compositions . This review presents the fundamentals of metasurfaces, providing a physics basis for understanding their optical behaviors. We then focus on recent advances in their fabrication based on colloidal building blocks, especially strategies that overcome the inherent limitations of conventional lithography. Furthermore, we emphasize their reconfigurable optical properties and discuss applications in areas such as holography, perfect absorbers, color displays, luminescence enhancement, and chemical sensing. Finally, we summarize the current state of the field and outline possible directions for future research.