The effect of phase interface on the synthesis of SnS2-Cu2S

•Opto-crystalline character of the composition of Cu2S and S2Sn was considered.•The formation Cu2SnS3 is strongly related to phase separation at interface.•The entanglement of phases is strongly due to the chemical bond competition.•The suggested fluctuation region is approved by PL spectra.•Reconstruction and cluster formation is evident by formation of flat-spiral flowers.

Optical character of crystal structure of the composition of two different semiconducting metallic sulfides, Cu2S and S2Sn, in pure phase formation of the ternary chalcogenide Cu2SnS3 was considered. Because of the difficulties related to the phase separation at the definite Eutectic temperature for the composite formation, which is evident in optical absorption fluctuations, solvothermal synthesis in the intermediate temperature range 180–220 °C seems convenient where tetragonal crystal structure is investigated by XRD. Absorption fluctuations below E = Eg were more pronounced for the lower limit case (180 °C) reflected in a sharp peak located at 1.48 eV on S1 as seen in UV-PL measurement. The characteristic behavior of the interface, resulting in the reconstruction and cluster formation due to the offset of bond rupturing displacement of atomic positions, is in favor of aggregation instead of agglomeration, which is evident by formation of small flat-spiral flowers in SEM images.

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