Cyclic microwave-assisted synthesis of CuFeS2 nanoparticles using biomolecules as sources of sulfur and complexing agent

•Chalcopyrite CuFeS2 is one of I–III–VI2 compounds.•Biomolecules, sources of sulfur and complexing agent, enable us to synthesize it.•The material for lithium-ion batteries, solar cells and thermoelectric devices.

Copper iron sulfide (CuFeS2) nanoparticles were successfully synthesized by a 300 W cyclic microwave radiation, exposing onto ethylene glycol containing Cu(CH3COO)2, FeCl3·6H2O or FeCl2·4H2O and l-cysteine biomolecules. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectrometry and X-ray photoelectron spectroscopy (XPS) revealed the presence of pure tetragonal chalcopyrite CuFeS2 nanoparticles with valence states of Cu+, Fe3+ and S2− and four Raman shifts at 215.0–218.6, 280.2–281.4, 394.4–394.9 and 472.2–473.4 cm−1. A formation mechanism of the products was also proposed according to the experimental results.