Solution-phase synthesis and morphology-controlled mechanism of flower-like indium sulfide hierarchitectures

Flower-like In₂S₃ hierarchical nanostructures were successfully prepared via a facile solution-phase route, using In(NO₃)₃ as processor and C₂H₅NS as sulfur source. Our experimental results demonstrated that the morphology of the product can be easily modified by tuning the precursor ratio. The molar ratio of In(NO₃)₃/C₂H₅NS plays a crucial role in the morphology of In₂S₃ hierarchitectures. With the ratio increasing from 1:1.5 to 1:6, the flower-like In₂S₃ crystals exhibited various morphologies and different sizes. X-ray diffraction (XRD) patterns of the flowers revealed the cubic structure of In₂S₃; morphological studies examined by scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the synthesized In₂S₃ nanostructure was flower-like hierarchitecture assembled by nanoflakes. Density functional theory (DFT) calculation results indicate that the adsorption of C₂H₅NS can affectively and selectively reduce the surface energy of In₂S₃ facet, stabilize the corresponding crystal facet. The results indicate that there is a synergistic effect between C₂H₅NS protecting the crystal facet and the nucleation rate for C₂H₅NS to tune the growth of In₂S₃ nanoplates. Therefore, the morphology of flower-like In₂S₃ crystals can be controlled by adjusting the C₂H₅NS concentration in the mixed solvent.