Depletion-Induced\nTunable Assembly of Complementary\nPlatonic Solids

Multicomponent self-assembly has been explored to create\nnovel\nmetamaterials from nanoparticles of different sizes and compositions,\nbut the assembly of nanoparticles with complementary shapes remains\nrare. Recent binary assemblies were mediated by DNA base pairing or\ninduced by solvent evaporation. Here, we introduce depletion-induced\nself-assembly (DISA) as a novel approach to constructing tunable binary\nlattices. <i>In situ</i> structural analysis in the real\nand reciprocal spaces demonstrates DISA of a binary mixture of octahedra\nand tetrahedra into extended supercrystals with <i>Fm</i>3̅<i>m</i> symmetry. The interparticle distance,\nadjustable by depletant concentration, offers a versatile method for\nassembling nanoparticles into ordered structures while they remain\ndispersed in a liquid phase. We show that DISA can control the packing\nfraction of such binary supercrystals between φ = 0.37 and φ\n= 0.66, much lower than dense packing in the dry state. These findings\nhighlight DISA’s potential for creating complex and highly\nordered metamaterials with tailored properties.