Laser-assisted synthesis of magnetic Fe/Fe2O3 core: carbon-shell nanoparticles in organic solvents

This work provides a new approach for the solution laser synthesis of magnetic Fe/Fe2O3 nanoparticles (15–25 nm average size), as well as core–shell nanoparticles consisting of crystalline Fe/Fe2O3 cores (5–15 nm average size), and amorphous carbon-shells. Laser irradiation of iron pentacarbonyl, Fe(CO)5, in different organic solvents (toluene, tetrahydrofuran, dimethyl sulphoxide, and acetonitrile) using the 532- and 355-nm wavelengths was investigated. The mechanism operating in the laser synthesis involves photodecomposition of Fe(CO)5 and the formation of iron and/or an iron oxide core surrounded by a carbon-shell depending on the nature of the solvent. In the case of toluene as a solvent, a magnetic Fe/Fe2O3 core surrounded by a carbon-shell was formed, while in the other solvents investigated (tetrahydrofuran, dimethyl sulphoxide, and acetonitrile), both Fe and Fe2O3 nanoparticles were formed without carbon-shells. Characterization techniques including X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy were used to determine the composition and morphology of the laser-synthesized magnetic Fe/Fe2O3 nanoparticles and the core–shell nanoparticles. In addition, the data revealed that the Fe/Fe2O3-nanoparticles produced in all the solvents used except tetrahydrofuran had good magnetic properties.