Solvothermal crystal growth of CuSbQ2 (Q=S, Se) and the correlation between macroscopic morphology and microscopic structure

A low temperature solvothermal method has been successfully used for preparation of two semiconductor compounds CuSbQ2 (Q=S(1), Se(2)) by the reactions of Cu, Sb and S(or Se) powders in 1,2-diaminopropane at 160 °C for 10 days. The crystal structure of 2 was determined first time using single crystal X-ray diffraction analyses. The structures of 1 and 2 are discussed in the view of covalent bonds and weak interactions. Double CuSbQ2 layers are assembled to a 3-D network structure by Cu⋯Sb and Q⋯Sb secondary bonds. In contrast with the isostructure of the two materials, the crystal morphology of them is quite different, brick-like crystals for CuSbS2 and plank-like crystals for CuSbSe2. The phenomenon is related to their different inter-planar interactions. Semiconductor properties of the microcrystal samples are measured and the band gaps of 1 and 2 are 1.38 and 1.05 eV, respectively.