Photodegradation in the Presence of Zinc Selenide Nanoparticles

Quantum dot fabrication as ZnSe has been of great interest in recent decades due to its electrical, optical properties, and potential use in technology, biology, and medicine. Quantum dots (QDs) has shown extraordinary contributions due to its optical properties in optoelectrical devices, solar cells, photocatalytic activities, light-emitting diodes (LEDs), sensors, beam expanders among other contributions. Furthermore, previous studies have shown that ZnSe QDs show excellent photocatalytic activity in the degradation of contaminating dyes. Based on these considerations, the present research was focused on the synthesis, characterization, and modification of the QDs surface with different ligands. The presence of an organic cover (as thiols) on the QDs surface can affect its optical properties as fluorescence and absorbance. The objectives of this work were: I) synthesize nanoparticles with a size smaller than 10 nanometers (nm) in an aqueous medium with different thiols (L-glutathione, N-acetyl-L-cysteine, 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA), II) characterize zinc selenide (ZnSe) nanoparticles by different spectroscopy methods, and III) determine the point of zero charges IV) photodegradation of dyes in the presence of ZnSe quantum dots. Quantum Dots were synthesized in aqueous phase via reflux system. Precursors of Zinc (as zinc acetate dihydrate) and thiol compounds were mixed into a two-neck flask at temperature of 100 °C. As-synthesized nanocrystals were purified and precipitated with 2-propanol and resuspended in deionized water. Nanoparticles evidenced fluorescence peaks at 468 nm, 455 nm, 448 nm, and 397 nm for quantum dots covered with L-glutathione, N-acetyl-L-cysteine, 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA), respectively. Quantum dots evidenced remarkable optical properties and high stability in aqueous medium. Nanoparticles of ZnSe will be used to photodegrade organic contaminants.