Single crystalline zinc structures synthesized spontaneously in solution

Abstract

We report a method for the synthesis of Zn structures with a variety of morphologies through a spontaneous solution phase reaction without application of an electropotential under ambient conditions. We also describe, in detail, the influence of several experimental conditions on the morphology and microstructure of the Zn structures. The morphology of the Zn structures transitioned from hexagonal disks to dendritic forms as the reaction temperature was increased due to an increase in the driving force for Zn structure formation (over a temperature range from room temperature, 22 °C, to 95 °C). The size of the Zn structures was controlled by adjusting the concentration of zinc acetate dihydrate added to the reaction solution. When the concentration of zinc salt was reduced, smaller Zn structures were synthesized. Control experiments revealed that the aluminium layer, ammonia additions, and ammonia concentration were key factors for the formation of Zn metal structures. A zinc ion complex, Zn(NH₃)₄²⁺, played a critical role in the formation of the Zn structures. Zn nanowires were synthesized in the presence of a 1.5 μm thick Al layer substrate. Based on these observations, we propose possible formation mechanisms for the spontaneous assembly of the various Zn structures.