High Yield CdS Nanowires Synthesized by Solvothermal Routes and Novel Diauxic Growth Mechanism

摘要

The CdS nanowires were synthesized by a solvothermal method in ethylenediamine solvent both at short time (2 h) and longer time (more than 12 h). The nanowires had an average diameter of ca. 26 nm with a length of ca. 1-3 μm at 200℃ for 2 h and ～43 nm in diameter and ～4-6 μm in length at 200℃ for 12 h, respectively. These CdS nanowires were in crystalline wurtzite structure, and their crystal growth direction was [0001]. An interesting phenomenon was found that the nanowires synthesized at 2 h broken into nanorods with increasing reaction time. These broken nanorods grew into nanowires at 12 h again. More than 12 h, the diauxic growth nanowires become longer and little thicker without other obvious changes. Based on a series of experimental results, it was revealed that the formation of CdS nanowires followed a novel diauxic growth processes during the hydrothermal synthesis: (1) the formation of nanowhiskers on chrysanthemum-like nanostructure as seeds for 1-D nanostructure, (2) transformation of nanowhiskers into the CdS nanorods on the surface of chrysanthemum-like nanostructures, (3) growth of CdS nanowires from CdS nanorods, (4) broken of CdS nanowire into short CdS nanorods and (5) diauxic growth of CdS nanowires from CdS nanorods preferentially along the c-axis again.