Asymmetric quantum dot growth via temperature cycling

The morphology of semiconductive quantum dots (qdots) and quantum rods (qrods) has been shown to be tailored by choice of ligand, size, and crystal structure. In this paper, we show that temperature cycling during nucleation and growth can also tailor morphology. By quenching nucleation and growth after precursor injection, followed by slow temperature ramping, we are able to first synthesis CdSe qdots with teardrop morphology and Wurtzite crystallinity. Using these teardrops as core seeds, CdS shells can be epitaxially deposited also using temperature cycling to fabricate CdSe/CdS core/shell structures with novel asymmetric head–tail morphology. These qdots and qrods were characterized for optical absorption, photoluminescent emission, morphology, and crystal structure.