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 degrees 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 degrees 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%.