Fabrication of newly structured colloidal photonic crystals

Realization of complete photonic band gap (CPBG) in colloidal photonic crystals has been a grand challenge for material scientists. This paper introduced two approaches towards this goal. One is to adopt the ellipsoids as the building blocks to form 3D ordered crystalline arrays under the guide of the magnetic field. The orientation of the main axis of the particles can be adjusted by changing the relative orientation of the magnetic field. The other approach is to fabricate colloidal crystals with crystalline lattice other than fcc, such as triclinic, simple cubic and body-centered-cubic lattices by selective etching the polymer shells of the prefabricated SiO₂@PMMA opal. Both approaches presented promising routs towards the realization of CPBG in the visible region.