Study of Cu2ZnSnSe4 monograin formation in molten KI starting from binary chalcogenides

The present study deals with the possible chemical interactions of CuSe, SnSe, and ZnSe in molten KI as a flux material in vacuum ampoules. The aim is to find suitable preparation conditions for the synthesis of Cu2ZnSnSe4 monograin powders as an absorber material for solar cells. Impurities in the precursor materials and in the product powders were determined by inductively coupled plasma mass spectrometry. Differential thermal analysis was used to determine thermal effects. Phase composition in the mixtures of binary precursors and KI was determined by X-ray diffraction and Raman spectroscopy. It was found that no new compound was formed in the CuSe/KI, ZnSe/KI and SnSe/KI mixtures. The solubility of the binary chalcogenides in KI at 740 °C was determined.