Synthesis, characterization, shape evolution, and optical properties of copper sulfide hexagonal bifrustum nanocrystals
文摘
The hexagonal bifrustum-shaped copper sulfide (CuS) nanocrystals were selectively and facilely synthesized by a hydrothermal method for the first time at 120?°C. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, ultraviolet–visible (UV–Vis) spectroscopy, and photoluminescence spectroscopy. The results showed that the CuS hexagonal bifrustum nanocrystal was bounded by two top hexagons with edge length of about 50-0?nm and twelve lateral trapezoids with a base of about 100?nm and that the length of each hexagonal bifrustum was about 250?nm. Tetradecylamine (TDA), as an effective capping agent, was found to be critical for this special shape. Using different amounts of TDA, two kinds of CuS hexagonal bifrustum nanocrystals were obtained: “lender hexagonal bifrustum-and “pancake hexagonal bifrustum.-Furthermore, we studied the formation mechanism of hexagonal bifrustum, which is related to the intrinsic crystalline structure of CuS and Ostwald ripening. And, the results revealed that the CuS nanocrystal evolved from hexagonal plate to hexagonal bifrustum and finally to hexagonal bipyramid as the heating time increased. The UV–Vis absorption spectrum showed that these CuS hexagonal bifrustum nanocrystals exhibited strong absorption in the near-infrared region and had a potential application for photothermal therapy and photocatalysis.