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.