Solution Synthesis of Nonequilibrium Zincblende MnS Nanowires

Uniform four-coordinate nonequilibrium MnS nanowires mainly in zincblende structure, other than the stable rock-salt phase, are reported for the first time. The MnS nanowires are grown via a solution-solid-solid model from the reaction of a Mn(II) source with dibenzyl disulfide in oleylamine at 180-200 °C catalyzed by Ag₂S nanocrystals in a body-centered cubic (bcc) fast-ionic phase transformed from their low-temperature monoclinic form. Investigations show that most of the zincblende MnS nanowires are grown along the ⟨112⟩ zone axis but a small proportion grow along the ⟨111⟩_ZB/⟨0001⟩_Wur axis with zincblende/defect-section and/or wurtzite/defect-section superlattices connected with the stems along the ⟨112⟩ direction. The nanowires have a tendency to grow straight at relatively low reaction temperature for short reaction times but twist at high temperature for long reaction times. Meanwhile, relatively high temperatures and long times favor the transition of the MnS nanowires in the zincblende phase to the corresponding thermodynamic ones in rock-salt form. Interestingly, even small increases in reaction pressure (1-2 atm) sensitively influence the growth of the MnS nanowires from zincblende to wurtzite form in the present catalytic system although low-pressure changes commonly do not have an obvious effect on condensed matter. In addition, the optical and magnetic properties of the zincblende MnS nanowires were studied, and they are varied largely from the bulk.