Growth of copper sulfide dendrites and nanowires from elemental sulfur on TEM Cu grids under ambient conditions

Copper sulfide dendrites and subsequent uniform nanowires up to tens of micrometers long can be grown on carbon-coated transmission electron microscopy (TEM) Cu grids from elemental sulfur at room temperature under ambient conditions without any solvent and surfactants. TEM and high-resolution TEM studies demonstrated the morphology evolution of Cu2S from dendrites into ultra-long nanowires with increasing ageing time. The sulfur species influenced significantly the growth rate of Cu2S dendrites and nanowires, but the final morphology remained the same. The native oxide on the surface of Cu grids played a critical role in the formation of Cu2S dendrites and nanowires. The crystal structures and phase purity of Cu2S samples were confirmed by x-ray diffraction (XRD) and energy dispersive x-ray spectroscopy (EDX). A solid-liquid-solid growth model may be considered a potential mechanism in Cu2S morphology evolution on the basis of the experimental results. Most importantly, the present study provides a simple and environmentally friendly route for the growth of one-dimensional (1D) Cu2S on Cu substrate.