Synthesis and luminescence characteristics of DHLA-capped PbSe quantum dots with biocompatibility

In this work, we report a facile aqueous route to prepare PbSe QDs with strong photoluminescent and near-infrared (NIR) emission using dihydrolipoic acid (DHLA) as the capping ligands. It was found that the synthesis parameters including the molar ratio of DHLA/Pb, the pH value and the reaction time have considerable influence on photoluminescent intensity (PL) of the PbSe QDs. The as-synthesized DHLA-capped PbSe QDs were characterized by high-resolution transmission electron microscopy (HRTEM), energy-dispersive analysis of X-ray (EDX) and X-ray diffraction (XRD), the results indicated that the QDs were about 8.0 ± 0.2 nm in size and had good monodisperse and a rock salt crystalline structure. Also, there was DHLA on the surface of QDs, which was confirmed by Fourier transform infrared (FT-IR) spectrometry. The PbSe QDs exhibited optimal PL intensity when Pb:Se:DHLA = 1:0.6:1 in weak alkaline aqueous. The as-synthesized QDs kept highly PL intensities when stored in the dark in normal air environment during the period of 60 days. In addition, the biocompatibility of these QDs was measured by hemolytic test, which indicated that DHLA-stabilized QDs are biocompatible. It is important for QDs as biomarkers in biological detection and diagnosis.

► DHLA-capped PbSe QDs were first successfully synthesized in aqueous solution.
► The as-synthesized PbSe QDs exhibit higher photoluminescent intensity under the optimum conditions.
► The as-synthesized PbSe QDs have been demonstrated good biocompatibility by the hemolysis experiments.