There has been considerable interest in the colloidal self-assembly of photonic crystals with a diamond structure, owing to their exceptional optical properties, such as a wide photonic bandgap and relative insensitivity to disorder. These materials are valuable for applications in optical circuits, low-threshold lasers, sensors, and solar cells. Given the three-dimensional nature of photonic crystals, colloidal self-assembly is a favored fabrication method.

In this context, we outline several different approaches for the self-assembly of colloidal diamond and zincblende. Some methods utilize specific DNA interactions, while others rely on depletion interactions. One notable advantage of the depletion interaction is its capacity to guide particles that come into contact at any point on their surfaces toward the desired interlocking configuration. This funneling mechanism significantly accelerates crystallization kinetics, allowing for crystallization at lower particle concentrations. The most effective routes may involve a combination of both types of interactions.