Effects of Zn precursors on solvothermal synthesis of Cu ₂ZnSnSe ₄ nanocrystals

Cu ₂ZnSnSe ₄ (CZTSe) has potential applications in thin film solar cells and thermoelectric devices. The synthesis of stoichiometric CZTSe nanocrystals by the solvothermal process is still a challenge. In this work, the effects of different Zn precursors on the synthesis of pure and stoichiometric CZTSe nanocrystals via a facile solvothermal process were explored. The products were characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and UV-vis spectroscopy. The present study showed that with the Zn(CH ₃COO) ₂ precursor pure and stoichiometric CZTSe nanocrystals were readily synthesized, while with the ZnCl ₂ precursor the synthesized nanocrystals were Zn-deficient and composed of CZTSe and Cu ₂SnSe ₃ phases. This result can be attributed to the chelating effect of the acetate anion in the solvothermal reaction.