Crucial role of anions on arrangement of Cu₂S nanocrystal superstructures

Both of the arrays of Cu₂S nanowires and the superlattices of Cu₂S nanoparticles are obtained by the solventless thermolysis of copper thiolate in the presence of laurate. For the first time, the types of anions in the reaction system, which are generally neglected in previous studies, are found to determine the structure of the final assembly products. Furthermore, experimental results shows in the presence of Cl^- ions, Cl^- ions participate in the self-assembly process and promote the formation of Cu₂S nanowire arrays. Finally, the content of Cl- ions is gradually decreased with assembly reaction proceeding. Therefore, duiring the process, Cl^- ions play a role of 'catassembly' in the formation of Cu₂S nanocrystal superstructures. The arrays of Cu₂S nanowires and the superlattice of Cu₂S nanoparticles are fabricated by classic solventless thermolysis reaction of copper thiolate. Anions are found to play the key role in the arrangement of Cu₂S nanocrystal superstructures. In the presence of Cl^- ions, Cu₂S nanowire arrays are prepared; otherwise superlattices of Cu₂S nanoparticles are produced.