Multiple Families of Magic-Sized CdSe Nanocrystals with Strong Bandgap Photoluminescence via Noninjection One-Pot Syntheses

Abstract

Three families of colloidal CdSe magic-sized nanocrystals (MSNs) exhibiting bright bandgap photoluminescence (PL) with narrow full width at half-maximum (fwhm) on the order of ca. 10 nm were synthesized in pure form. This noninjection one-pot synthetic approach uses cadmium acetate dihydrate (Cd(OAc)2·2H2O) and elemental selenium as Cd and Se source compounds, respectively, while a fatty acid as surface ligands and 1-octadecene (ODE) as the reaction medium. All of these chemicals were loaded at room temperature in a reaction flask, with low acid-to-Cd and high Cd-to-Se feed molar ratios; the growth of the CdSe MSNs was carried out at 120 −240 °C. This synthetic approach allows long growth/annealing periods at high temperature and thus results in high-quality CdSe MSNs exhibiting strong bandgap PL; furthermore, this ready approach features high synthetic reproducibility and large-scale production. The reason for the low acid-to-Cd feed molar ratio is argued to be related to the low activity of the Cd precu...