Ultrasonic and microwave assisted extraction as rapid and efficient techniques for plant mediated synthesis of quantum dots: green synthesis, characterization of zinc telluride and comparison study of some biological activities

Abstract

In this study, a simple, rapid, and efficient plant-mediated green approach was presented for the synthesis of stable and ultra-small zinc telluride quantum dots (ZnTe QDs) using the aqueous extract of the Ficus johannis plant. Two modern techniques, namely ultrasonic and microwave techniques, were applied to prepare the plant extracts, which were then used as stabilizing precursors in the synthesis of ZnTe QDs. The synthesized samples were characterized via different techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible absorption, photoluminescence and Fourier transform infrared spectroscopy. The TEM images confirmed the formation of ultra-small nanoparticles with an average size of 8 nm. According to the optical characterization, a wide absorption band around 390 nm and an intense emission peak at 463 nm clarified the successful synthesis of ZnTe QDs. After synthesis and characterization, the antioxidant, antimicrobial, and antifungal potentials of the as-prepared QDs as well as the plant extracts were examined by different tests, comparatively. In addition, the determination of the total phenolic and flavonoid contents of the as-prepared samples was carried out. Moreover, the toxicity of the samples was investigated by Artemia uramiana from their brine shrimp lethality potentials. In the cytotoxicity tests, the inhibition of root growth was considered as an indicator to evaluate the cytotoxicities of the samples.