title: Evolutionary shape control during colloidal quantum-dot growth.
abstract: Size-dependent optical properties of semiconductor nanocrystals are of great interest because of the myriad of phenomena stemming from them. The preparation of more complex colloidal shapes will facilitate the systematic study of shape-dependent phenomena. It is shown that a strategy to obtain systematically more complex nanocrystal structures is to exert a sequence of shape-directing steps during the colloidal growth. Using experiments based on multiple reagent injections we show how changes in the type of surfactant introduced during growth of CdSe nanocrystals promotes shape evolution. On this basis, we propose a means to achieve a further generation of shape design in nanometer-sized colloids by using a series of growth steps, each one building from the previous conditions of shape as well as surface-specific reactivity. To understand the shape formation and stability in nanocrystalline colloids, and particularly the importance of surface ligands, we introduce an analogy with the thermodynamics of droplets.
authors.affiliation: Department of Chemistry, 80 St. George Street, Institute for Optical Sciences, and Centre for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: P Sreekumari
authors.initials: PS
authors.lastname: Nair
authors.forename: Karolina P
authors.initials: KP
authors.lastname: Fritz
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Scholes
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D045663:Quantum Dots; D013499:Surface Properties
chemical_list: D003102:Colloids; D046911:Macromolecular Substances