• crystal engineering;
  • iron;
  • nanostructures;
  • selenium;
  • solvothermal synthesis


Fe7Se8 polyhedra with high-index facets and Fe7Se8 nanorods can be selectively synthesized by a solvothermal reaction in a mixed solvent of diethylenetriamine (DETA) and deionized water (DIW). It is found that the morphologies of Fe7Se8 nanocrystals can be effectively controlled by adjusting the volume ratio of DETA and DIW. The unusual polyhedral crystals are bounded by two {001} and twelve {012} facets. The intrinsic properties of Fe7Se8 nanocrystals have been investigated. Magnetic measurements indicate that the obtained polyhedra and nanorods show a weak ferromagnetic ordering at room temperature. In particular, a new photoluminescence emission at 403 nm from the Fe7Se8 nanocrystals has been observed. The described solvothermal reaction in a mixed solvent may be extended to the synthesis of other transition-metal chalcogenide crystals with controlled shape, facets, and structure, which may bring new functionalities.