In chemistry, colloid is a homogeneous mixture, which is heterogeneous, and contains two different states of matter, one dispersed phase and the other continuous phase. The dispersed phase can be particles with interfaces composed of many atoms or molecules (10^3-10^6), with a size (diameter) between 1nm and 1000nm. Colloids are not necessarily all gels, nor are they necessarily liquids. Colloidal diamond, English: Colloidal Diamond, is a stable, self-assembled diamond structure of tiny materials. Since the 1990s, colloidal diamond has been the dream of researchers. It can make light waves as useful as electrons in calculations and is expected to be used in many other applications. The idea of colloidal diamonds was put forward decades ago, but no one could reliably produce this structure in the past.

Stefano Sacanna and David J. Pine (co-corresponding author) of New York University and others have realized the self-assembly behavior of colloidal cubic diamond by using partially compressed tetrahedral clusters and stretchable sticky patch particles. This self-assembly process is mainly based on the combination of patch-patch adsorption behavior and a three-dimensional interlocking mechanism, where the three-dimensional interlocking mechanism can realize the function of selective interlacing bond orientation. The calculated structure of the photonic band structure reveals that the lattice of the self-assembled material has a wide and complete photonic band gap. The colloidal particles in the self-assembled cubic diamond structure are highly constrained, have mechanical stability, and can maintain the diamond structure under dry conditions. Based on the above results, the study believes that this type of diamond structure can be used as an ideal template for the preparation of new photonic crystal materials with cubic diamond symmetry. Related results are published online in Nature as an article entitled “Colloidal diamond”.