Template-free synthesis of colloidal quantum dot assemblies with molecule-like architectures.

Designing colloidal assemblies with molecule-like architectures comprising more than two electronically coupled quantum dots has often required technologically complex, expensive, and top-down nanofabrication. Here we demonstrate a one-pot chemical synthesis of dimeric, trimeric, and tetrameric assemblies of coupled molecule-like quantum dots (CMQDs), using ZnSe@ZnS quantum dots as model. We show that the "valence" of these "artificial atoms" can be readily tuned by the amount of a suitable ligand in the reaction mixture, and that high-temperature fusion yields highly ordered oriented attachment and strong electron coupling between bound QDs. The shapes of the fused assemblies echo the canonical sp-, sp²-, and sp³-hybridization motifs and can be interpreted as appropriately shaped confining potential wells for electrons and holes. This work establishes an experimentally accessible entry point to related "artificial molecules" with controllable chemical composition, geometry, and electronic structure. The enhanced or emergent properties of such nanomaterials are anticipated to advance applications in optoelectronics, sensing, and quantum photonic technologies.