A New Possibility for Making Diamond Colloidal Crystals

Systems constructed by periodic patterns of materials with different dielectric constants are regarded as photonic crystals, capable of controlling and manipulating light flow in a certain frequency range, commensurate with the length scale of the crystal. The holy grail in photonic materials, diamond, still remains a challenge to synthesize at the colloidal length scale. Anisotropic nanoparticles prove a promising route for colloidal diamond, with entropy motivating face-to-face alignment, leading to self-assembly of complex crystals. These principles led to the discovery that truncated tetrahedral nanoparticles would self-assemble diamond, although this route can lead to crystalline disorder, which will reduce or extinguish the photonic band gap. Here we explore new ways to assemble diamond, self-assembly with modified gyrobifastigial (mGBF) nanoparticles, whose shape is constructed from two anti-aligned triangular prisms. We demonstrate the parameter space which leads to the self-assembly of diamond and summarize the benefits of diamond self-assembled via the mGBF to previous methods. We also introduce a potential route for creating mGBF particles through dimerization of triangular prisms using attractive patches and report the impact of this substructure on the photonic properties.