Colloidal one-pot synthesis and characterization of Glycine capped Al(x) doped ZnS QDs for efficient UV light assisted photo-degradation of Stilbene 420 dye

Abstract

In thisstudy, successful synthesis and characterization of undoped and Al-doped ZnS quantum dots (QDs) capped with bio-friendly glycine (ZnSAl/Gly) are described. The synthesis is accomplished through a one-pot colloidal co-precipitation process, followed by the characterization of QDs using various analytical techniques.X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) showed the formation of cubic-faced ZnS QDs, with the crystal size decreasing as the amount of Al doping increased. A ZnS phase layer on the QDs surface was also demonstrated by Fourier-transform infrared spectroscopy (FTIR) measurements. Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDS) analysis was employed to examine the stoichiometry and shape of the synthesized QDs. Thermogravimetric analysis (TGA) showed a remarkable stability of Al-doped ZnS QDs over an extended period, enhancing their potential for a variety of applications. Measurements of the absorption band edge in the UV–Visible range demonstrated that Al ions were successfully incorporated into the ZnS lattice, causing a substantial red shift. This change, which caused the energy band gap to rise from 3.2 eV (ZnS/Gly) to 4.42 eV (ZnSAl1%/Gly), was attributed to the size confinement effect. The degradation of the Stilbene-420 dye under UV irradiation served as a test for the photodegradation capability of the synthesized QDs. The photodegradation efficiency of Al doping ranged from 60 % to 92 %, showing the induction of a significant number of crystalline structures with rising Al concentration. The Al-doped ZnS/Gly QDs are highly catalytic and photoactive, and they show great promise in the field of photoluminescence, medical and biological areas. Their potential for use as effective catalysts in waste water treatment methods is also remarkable.