Highly-fluorescent alloyed quantum dots of CdSe1−xTex synthesized in paraffin liquid: gradient structure and promising bio-application

Abstract

By using paraffin liquid and oleic acid as the solvent and ligand, highly-fluorescent red to near-infrared (NIR)-emitting cadmium selenium telluride (CdSe_1−xTe_x) alloyed quantum dots (QDs) with photoluminescence quantum yield (PLQY) up to 70% were successfully prepared. The as-prepared CdSe_1−xTe_x QDs also demonstrated good optical stabilities against the temperature change and photobleaching due to their gradient “CdTe-rich core/CdSe-rich surface” quasi “core/shell” structure, which was confirmed by studying the alloying process of CdSe_1−xTe_x QDs. Moreover, the as-prepared red to NIR CdSe_1−xTe_x QDs were successfully incorporated into the carboxyl capped porous polystyrene (PS) microbeads to fabricate red to NIR-emitting microbeads with low in vitro cytotoxicity, and the biotinylated goat anti-mouse IgG could be specifically coupled to the optical encoded beads via mouse anti-human chorionic gonadotrophin connected to the carboxyl groups on the encoded microbeads successfully, which suggested promising application of CdSe_1−xTe_x QDs in multiplexed bioassays.