CdSe@CdS Dot@Platelet Nanocrystals: Controlled Epitaxy, Monoexponential Decay of Two-Dimensional Exciton, and Nonblinking Photoluminescence of Single Nanocrystal

摘要

Wurtzite CdSe@CdS dot@platelet nanocrystals, dot-shaped CdSe nanocrystals encased within epitaxially grown CdS nanoplatelets, are controllably synthesized with nearly monodisperse size and shape distribution and outstanding photoluminescence (PL) properties. The excellent size and shape control with their lateral to thickness dimension ratio up to 3:1 is achieved by systematically studying the synthetic parameters, which results in a simple, tunable, yet reproducible epitaxy scheme. These special types of core/shell nanocrystals possess two-dimensional emission dipoles with the ab plane of the wurtzite structure. While their near-unity PL quantum yield and monoexponential PL decay dynamics are at the same level of the state-of-art CdSe/CdS core/shell nanocrystals in dot shape, CdSe@CdS dot@platelet nanocrystals possess, similar to 2 orders of magnitude lower probability for initiating PL blinking at the single-nanocrystal level than the dot-shaped counterparts do.