Multivariate optimization of optical properties of CdSe quantum dots obtained by a facile one-pot aqueous synthesis

This work presents a multivariate optimization of a simple, fast and reproducible one-pot procedure for the aqueous synthesis of cadmium selenide (CdSe) quantum dots (QDs) stabilized with mercaptosuccinic acid (MSA), aiming to improve their photoluminescence (PL) properties. A full factorial design and the Doehlert matrix were used to find optimal conditions for the MSA/Cd molar ratio (varied from 2 : 1 to 11 : 1), the Cd/Se molar ratio (varied from 1 : 1 to 8 : 1), the initial pH (varied from 3.0 to 12.0) and the synthesis temperature (varied from 15 to 90 °C). Response surfaces obtained by statistically validated equations were used and the optimal conditions were MSA/Cd molar ratio of 6 : 1, Cd/Se molar ratio of 8 : 1, pH 5.0 and temperature of 30 °C, under stirring for 60 min. The CdSe QDs obtained under these conditions presented an average diameter of 3.2 nm showing a cubic zinc blende structure and a relative quantum yield of up to 29.7%.