Synthesis and reaction pathway investigation of chalcopyrite CuInSe2 nanoparticles for one-pot method

•Highly dispersed chalcopyrite CISe nanoparticles were successfully synthesized.•The phase formation sequence was CuSe → CISe.•The valence of Se in solid intermediates was from −1 to −2.•The amorphous In–Se secondary phase existed in early solid intermediates.•The possible reaction pathway of CISe nanoparticles was proposed.

Highly dispersed and near stoichiometric chalcopyrite CuInSe2 nanoparticles were successfully synthesized via a facile and rapid one-pot method. For understanding the reaction pathway, the solid intermediates obtained at different stages of CuInSe2 nanoparticles synthesis process were investigated in detail by powder X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), energy dispersive spectroscopy (EDS) and Raman spectroscopy. The XRD patterns showed that the phase formation sequence was CuSe → CuInSe2. The XPS results indicated that the valences of Cu and Se in CuSe were +1 and −1, respectively. The chemical composition of the solid intermediates revealed the presence of the solid-state In–Se secondary phases in the synthesis process. However, no XRD signals or Raman signals of the solid-state In–Se secondary phase were observed. Based on the experimental results, the possible reaction pathway was proposed.

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