Two-dimensional (2D) amorphous antimony (III) trisulfide nanosheets: Synthesis, photoelectronic property and their transformation to crystalline 1D micro/nanorods

Two-dimensional (2D) crystal materials have attracted intensive research interest because of their multi functionality. However, the 2D nanosheets (NSs) of amorphous semiconductors are far less explored. We demonstrate here the colloidal synthesis of 2D amorphous antimony (III) trisulfide (Sb2S3) NSs in the mixture solution of different long-chain primary amines. These organic amines act as soft template to define the 2D growth through the coordination of metal cations with amine group. The resultant NSs exhibit distinct 2D characteristic with the thickness of 2-4 nm and the length x width dimensions ranging from several hundreds of nanometer to one to several micrometers. Their photoelectronic property has been evaluated in the indium tin oxide (ITO)/Sb2S3/ITO model device, showing fast temporal photoresponse and photoswitch ability. Through a solid-state thermal-annealing process, the amorphous NSs can be converted to 1D crystalline micro/nanorods, which is due to the high structural anisotropy of crystal phase (stibnite). TG-DSC thermal analysis reveals that the amorphous-crystalline phase transformation is companied by the desorption and/or decomposition of organic surfactant molecules and the S loss.