Self-Assembly of Water-Soluble Glutathione Thiol-Capped n-Hematite–p–XZn-Ferrites (X = Mg, Mn, or Ni): Experiment and Theory

Abstract

A facile bioapproach has been developed to fabricate nonfluorescent Fe2O3–XZnFe2O4 (X = Mg, Mn, or Ni) hematite core–ferrite shell structures. Major efforts are focused on the self-organization process of water-soluble glutathione (GSH) onto hematite core–ferrite shell nanoparticles, for example, by altering the electron–hole recombination and unpaired–paired spin change using X–Zn codoping. The X–Zn codoping enhances the fluorescence response intensity of Fe2O3 core–XZnFe2O4 shell structure. The relative ligand-to-metal 2p(O2–) → 3d(Fe3+) charge transfer located in visible region (755 nm) changes to 2p(O2–) → −SH charge transfer located in near-infrared region (785 nm), when [FeO6] octahedra complexs with thiol (−SH) group of GSH. These results help to enhance the current understanding about the mechanism for the tunable emission of Fe2O3–XZnFe2O4 in the visible–near-infrared range and its self-assembly behavior.