Hydrothermal synthesis of BiSe nanosheets by using gallic acid as a reductant.

In this work, a simple and reproducible hydrothermal synthesis was employed to synthesize two-dimensional BiSe nanosheets by using gallic acid as a reductant. Meanwhile, the effects of the amounts of gallic acid and sodium hydroxide and the surfactant Triton X-100 on phase composition and morphology of the obtained BiSe were also studied. The results reveal that gallic acid could effectively reduce Se to Se and gave rise to the formation of BiSe. Additionally, keeping the reaction conditions of molar ratio of gallic acid to the precursor elements (Bi + Se) at 1 to 1 (or higher) and using strong alkaline solutions were the key factors to synthesize high purity crystalline BiSe nanosheets. Furthermore, flower-like BiSe composed of nanosheets with a dozen nanometer thickness could be easily fabricated by adding appropriate amounts of Triton X-100. This work provides a novel approach for synthesis of ultra-thin BiSe nanosheets in a controllable manner.