Gum Arabic Microgels as Template for in Situ Metal-Sulfide Based Quantum Dots Preparation and Their Thermal, Spectroscopic, Optical, and Magnetic Characterization

Abstract

Here, gum arabic (GA) microgel in 5-50 mu m size range was used as a template for in situ quantum dot (QD) preparation. The in situ synthesis of metal sulfide quantum dots (QDs) such as CdS, PbS, CuS, ZnS, CoS, and MnS was accomplished by the absorption of the corresponding metal ions from aqueous solutions and then in situ precipitation with S2- treatments within GA microgels. Transmission electron microscopy (TEM) confirmed the existence of the evenly distributed QDs within GA microgel matrices for each of the prepared QDs. All the fabricated GA-QD composites have shown excellent semiconducting behaviors with relatively larger band gap values of 4.87 eV, 4.60 eV, 6.71 eV, 4.81 eV, 3.68 eV, 5.2 eV, and 4.0 eV for CdS, PbS, ZnS, CuS, CoS, MoS, and MnS, respectively. The results revealed that CdS and ZnS are found to be the most efficient florescence materials amongst the all QDs with 630 and 70 cd/cm(2) fluorescence intensities, respectively. Moreover, the magnetic susceptibility study suggests that Mn(IV), Co(III), and Mo(IV), have mononuclear octahedral geometries whereas Zn(II), Cd(II), and Pb(II) show binuclear geometries.