CdSe Colloidal Quantum Rings

Abstract

Atomically flat semiconductor nanostructures have sharp photoluminescence emission, short radiative lifetimes and a well-defined planar structure. However, these nanostructures lack the optical and electronic fine-tuning that justify extensive research in colloidal quantum dots. Here, we propose a heterostructure based on CdS nanoplatelets with laterally grown CdSe. Samples of two different thickness and varying ring width are synthesized by a one-pot method during which CdSe ring width is controlled by Se precursor amount. The CdSe dimensionality is continuously tuned from a 0D array of CdSe dots to a 1D CdSe quantum ring and finally a 2D CdSe nanoplatelet. Sample characterization shows that their optical properties are tunable by both structure thickness and CdSe ring width. This continuous tunability extends the emission range of nanoplatelet-based structures from 428 nm to 512 nm for 3 and 4 monolayers structures.