银薄层控制金纳米四足体的重塑和等离激元调谐

Controlled reshaping and plasmon tuning of gold nanotetrapods using the thin layer of Ag

探究了溶液中不同温度以及不同溶液成分(I-的引入)对金纳米四足体(GNTPs)重塑过程的影响,表明了GNTPs的重塑机制为Ostwald熟化,即弱结合的表面Au原子在高凸曲率区域溶解和在凹区域重新沉积。这种重塑过程可以随时通过镀银薄层在几秒内阻止,GNTPs的形貌可以在最大程度上得到很好的稳定,从而也可以防止其光学性质的演变。在此基础上,通过紫外可见近红外(UV-Vis-NIR)吸收光谱和基于同步辐射的小角X射线散射(SAXS)进一步研究了GNTPs/Ag的稳定性,并通过表面增强拉曼散射(SERS)光谱证实了GNTPs/Ag的光学响应。

The effects of different temperatures and different solution components(introduction of I-)on the gold nanotetrapods(GNTPs)reshaping process were investigated,revealing that the GNTPs reshaping mechanism is Ostwald ripening,that is,the dissolution of weakly bound surface atoms of Au at areas with high convex curvature and re-deposition at concave areas.This reshaping process can be stopped at any time in a few seconds by a thin layer of silver coating,and the morphology of GNTPs can be well stabilized to the greatest extent,thereby also preventing the evolution of optical properties.On this basis,the stability of GNTPs/Ag was further investigated by ultraviolet-visible-near-infrared(UV-Vis-NIR)absorption spectroscopy and synchrotron-based small-angle X-ray scattering(SAXS),as well as GNTPs/Ag results in an optical response,which is demonstrated by surface-enhanced Raman scattering(SERS)spectroscopy.