Water-soluble quantum dot/carboxylic-poly (vinyl alcohol) conjugates: Insights into the roles of nanointerfaces and defects toward enhancing photoluminescence behavior

Abstract

The synthesis of quantum dots (QDs) using wet chemistry with photoluminescent (PL) properties suitable to be used as biomarkers is a challenge yet to be overcome. Thus, this study demonstrates that the optical properties of aqueous colloidal semiconductor QDs can be engineered by altering the stoichiometric ratio of reagents achieving PL behavior comparable to systems using core–shell heterostructures. Here, it is reported the “bottom-up” approach for preparing quantum dot-polymer conjugates. A straightforward one-pot synthesis of CdSe nanocrystals was conducted using carboxylic functionalized poly (vinyl alcohol) as capping ligand by methods of aqueous colloidal chemistry at room temperature. Different molar ratios of reagents (Cd2+:Se2−) were prepared for investigating the effect on the kinetics of nucleation and growth of colloidal quantum dots (CQD) and their respective influence on the density of defects. These systems were characterized by UV–vis Spectroscopy, Photoluminescence Spectroscopy, and Transmission Electron Microscopy. Small QDs were produced with average particle size of 2.9 nm. The results have showed the influence of the ratio of the reagents on the photoluminescent behavior of the CQDs. Thus, a relatively facile colloidal route was developed for synthesizing water-soluble quantum dots-polymer conjugates that may potentially offer countless choices in nanotechnology for biomedical applications.