Magnetic Iron Sulfide Nanoparticles for Potential Applications in Gas Sensing

The crystal structure and phase transformations of iron sulfide nanomaterials have interesting properties that can be utilized in solar cells, biological and other applications. Iron (III) complexes piperidine (1) and tetrahydroquinoline (2) dithiocarbamate have been synthesized and subsequently utilized as single source precursors for the preparation of iron sulfide nanoparticles by solvothermal and pyrolysis methods. The powder X-ray diffraction (p-XRD) studies gave crystalline information of the iron sulfide nanoparticles which were dependent on the reaction conditions. Only the greigite phase (Fe3S4) was obtained when the solvothermal method was used during the synthesis. The pyrolysis method gave a mixture of pyrite (FeS2) and pyrrhotite phases when complex (1) was used while complex (2) gave pure pyrrhotite. Well interconnected microstructures and nanoflakes-like structures were obtained by scanning electron microscopy imaging. Furthermore, magnetic properties of the as-synthesized nanoparticles displayed ferromagnetic and antiferromagnetic behaviour, typical of greigite and pyrrhotite nanoparticles respectively. A direct band gap of 2.70 eV was obtained according to optical absorption studies.