An innovative chalcogenide transfer agent for improved aqueous quantum dot synthesis†
Abstract
An innovative approach to chalcogenide precursor synthesis and their subsequent use for the production of CdX (X = S, Se, Te) quantum dots (QDs) in water under scalable and intensified continuous flow conditions is introduced. Herein, tris(2-carboxyethyl)phosphine (TCEP) is identified as a novel, efficient and water-soluble vehicle for chalcogenide transfer to form CdX QDs under aqueous conditions. A comprehensive exploration of critical process parameters, including pH, chalcogen excess, and residence time, utilizing a Design of Experiments (DoE) approach is reported. Reaction kinetics are investigated in real-time using a combination of in situ Raman spectroscopy and in-line 31P NMR spectroscopy. The conversion of TCEP into TCEPX (X = S, Se, Te) species is seamlessly adapted to continuous flow conditions. TCEP
X precursors are subsequently employed in the synthesis of CdX QDs. Scalability trials are successfully demonstrated, with experiments conducted at flow rates of up to 80 mL min−1 using a commercially available mesofluidic flow reactor with favorable metrics. Furthermore, biocompatible and aqueous CdSe/ZnS core–shell QDs are for the first time prepared in flow within a fully concatenated process. These results emphasize the potential for widespread biological or industrial applications of this novel protocol.
- This article is part of the themed collections: 2024 Chemical Science Covers and Celebrating the scientific accomplishments of RSC Fellows