Mechanisms for the Shape-Control and Shape-Evolution of Colloidal Semiconductor Nanocrystals


  • The author is grateful to the financial support from the Center for Sensing Technology and Research (C-Star) at the University of Arkansas, the joint MRSEC center at the University of Arkansas and Oklahoma University, the Career Award from the NSF DMR, and the NSF grant from the NSF CHE.


The shape of CdSe and other semiconductor nanocrystals is controlled, producing dots, rods, rice-shaped particles, tetrapods, or other elongated shapes. Monomer concentration in the growth solution is the determining factor in shape-control and shape-evolution. The elongated shapes could be transformed into more spherical shapes if the monomer concentration in the solution was lowered to a certain level, and spherically shaped nanocrystals could grow to elongated shapes by simply increasing the monomer concentration. The precursors are stable, inexpensive, and relatively non-toxic, and therefore good choices for the growth of nearly monodisperse and shape-controlled nanocrystals.