Coalescence of colloidal cadmium chalcogenide nanocrystals by controlled stripping of the surface ligands

Abstract

Exploiting colloidal semiconductor nanocrystals (NCs) as building blocks for higher-order nanostructures can expand the field of nanoscience. For this reason, understanding the controlled coalescence of colloidal semiconductor NCs passivated with surface ligands is a big challenge for nanoscience research. Herein, we report a facile approach for activating the surface of CdSe NCs by stripping the carboxylate ligands with an alkylammonium–selenide complex for coalescence. The surface of as-prepared CdSe NC turned sparsely passivated and stoichiometric by the addition of alkylammonium–selenide complex; subsequently, coalescence readily occurred. Controlled coalescence or heterostructures can be realized through sophisticated control of the surface state of NCs. We anticipate that the surface-activated colloidal semiconductor NCs will act as promising nanoscale building blocks for fabricating functional nanostructures. Using a method described in this work, it is possible to not only understand the formation mechanism of coalescence, but to also construct higher-order supernanostructures.