Technology of Producing Photonic Crystal Colloidal Films by Centrifugation

Photonic crystals are optical materials that are often fabricated by assembly of particles into periodically arranged structures. Colloidal assemblies are attractive due to their size tunability and three-dimensional structure. Despite the large number of methods for obtaining such films, their production with an adjustable structure still remains a challenge. This paper shows the centrifugation assembly method carried out in a test tube. Due to the "dehydration" of silica particles during centrifugation, the spontaneous formation of capillary water bridges between the particles ensures the binding and pre-shrinkage of the assembled array at the interface of the liquids. Thus, the resulting structure has fewer cracks.