New synthesis of two-dimensional CdSe/CdS core@shell dot-in-hexagonal platelet nanoheterostructures with interesting optical properties

Abstract

A new strategy for the synthesis of fluorescent monodispersed 2-dimensional (2D) CdSe/CdS core/shell hexagonal platelet nanocrystals has been demonstrated. Because of the stronger affinity of the –NH₂ group of oleylamine to the (0001Se) facet comprising three dangling bonds in CdSe seeds, oleylamine acts as the sole surfactant responsible for hindering the growth of the CdS shell in the 0001 and 000 facets and for helping the shell growth anisotropically in the 〈100〉 direction. The as-synthesized products were thoroughly characterized using XRD, TEM/HRTEM, HAADF and STEM for determining the crystal structure, growth mechanism and the position of the seed inside a core/shell nanocrystal. Optical absorption, PL, PLE and TRPL studies revealed efficient photoexcitation and the possibility of polarized emission from 2D core/shell nanocrystals.