Synthesis and reaction temperature-tailored self-assembly of copper sulfide nanoplates

Nanostructured copper sulfides have attracted much attention due to their unique electronic and optical properties and potential applications in many areas. This article presents a high-temperature precursor-injection method to synthesize covellite copper sulfide (CuS) nanoplates by using oleylamine as capping ligands. The synthesized CuS nanoplates were found to be self-assembled into face-to-face one-dimensional columnar arrays with the longest column of 0.75 mu m. Further studies showed that the reaction temperature has strong effects on the size, size distribution and the self-assembly behaviors of the CuS nanoplates. The self-assembly behaviors were found to be tuned by the reaction temperature. In the range of 140-180 degrees C, the face-to-face self-assembly is formed over the entire substrate, whereas only edge-to-edge arrangements were observed at the reaction temperature of 200 degrees C. As the temperature further increases, the product exhibits a mixture of large and small nanocrystals and there is not any presence of self-assembly. The present study highlights the size-controlled synthesis of copper sulfide nanoplates and their self-assembly behaviors dependent on reaction temperature.