Preparation, Optimization and Characterization of CuInS2 quantum dots by a D-optimal Design

Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated the literature. Response surface methodology (RSM) in combination with D-optimal design was applied to optimize the synthesis and evaluate the PL intensity as the response which described by a reduced quadratic equation. The relationship between the PL intensity and independent variables (ligand/precursor, reaction time, reaction temperature, pH, and precursors ratio) was investigated using reduced quadratic polynomial equations. The produced QDs in the optimum condition were analyzed by UV-Vis, FE-SEM, and FTIR. The results showed that the nanoparticles have a high PL intensity and a red shift in both emission and absorbtion spectra which is a splendid point for their applications specially in bioimaging. The interaction between variables was not significant and the temperature was the most effective variable of PL intensity. A good agreement between predicted model and experimental data confirmed the correlated model.