Synthesis and magnetic properties of CuCr2S4 chalcospinel nanocrystals using single-source precursors

Magnetic thiospinel CuCr₂S₄ nanocrystals (NCs) have been synthesized via hot-injection (HI) method using metal-complexes of diethyl dithiocarbamate (DDTC) and 1-dodecanethiol (1-DDT) as the precursors. The single-source precursor's effect on the composition, crystallinity, and structure of the products is studied. Moreover, the influence of various process parameters, such as reaction time and temperature, capping ligand, and precursor on the crystalline phase, shape, and size of the NCs is systematically investigated. The morphological changes and magnetic properties of the NCs are also examined. The synthesized materials have been analyzed and characterized using X-ray diffraction, TEM, HRTEM, HAADF-STEM, and EDS-STEM. The results reveal the formation of uniform NCs of CuCr₂S₄ along with appearance of a trace amount of sulfur. The presence of sulfur in the structure of the organic ligand DDTC likely facilitates formation of the sulfur impurity. Our results indicate that controlling the formation of pure-phase nanoparticles using metal-DDTC precursors is more challenging than using simple metal salts reported earlier. Nevertheless, this work is the first successful effort in preparing NCs of CuCr₂S₄ employing single-source precursors.