Gold coated iron phosphide core–shell structures

Core–shell particles Fe 2 P@Au have been prepared beginning with Fe 2 P nanorods, nanocrosses and nanobundles prepared from the solvothermal decomposition of H 2 Fe 3 (CO) 9 (μ 3 -P t Bu). Iron phosphide structures can be produced from a single-source organometallic precursor with morphological control by varying the surfactant conditions to yield fiber bundles and dumbbell-shaped bundles ranging from nanometers to microns. Derivatization of the surfaces with γ-aminobutyric acid was used to attach Au nanoparticle seeds to the surface of the Fe 2 P nanoparticles followed by completion of the Au shell by reduction with formaldehyde or aqueous HAuCl 4 /CO, with the latter giving somewhat better results. Shell thickness ranged from an incomplete, partially coated Au shell to a thickness of 65 ± 21 nm by varying the amount of gold decorated precursor particles. Increasing the thicknesses of the Au shells produced a redshift in the plasmonic resonance of the resulting structures as was observed previously for FeO x @Au.