Peanut-Shaped and Rodlike Quantum-Dot Homodimers Epitaxially Attached along the Wurtzite ⟨1010⟩ Axis.

Monodisperse CdSe@CdS dot@platelet quantum dots (QDs), free of stacking faults, are synthesized for formation of the peanut-shaped homodimers connected by an epitaxial neck (p-dimers). Instead of attachment along the wurtzite ⟨1120⟩ axis of QDs with stacking faults, the stacking-fault-free QDs attach to each other along the wurtzite ⟨1010⟩ axis. Furthermore, the reaction system enables in situ epitaxial neck-filling to form rodlike homodimers (r-dimers). The resulting p-dimers and r-dimers are monodisperse in size, inter-QD connecting dimension (i.e., neck or filled neck), and QD-QD alignment, allowing resolution of energy gap between bonding and antibonding levels at an ensemble level. Formation of r-dimers not only enhances quantum coupling between two epitaxially attached QDs but also augments optical properties of artificial diatomic molecules. These advancements pave the way for the solution-phase synthesis of high-quality artificial molecules for fundamental research and technical applications.