纳米颗粒银层的电沉积机理及SERS效应

Electrodeposition Mechanism and Surface-enhanced Raman Spectroscopic Effect of Nano-sized Silver Layer

研究了大面积均匀平整的纳米颗粒银层电沉积的机理,优化了制备工艺,探索了其在表面增强拉曼光谱检测中的应用.结果表明,该纳米颗粒银层的电沉积随着电极电势的负移,逐步由连续成核转向瞬时成核机理,在电流密度为1.0 A/dm^(2),阴阳极面积比为1∶10,以及20~30℃条件下,银层具有更强的表面增强效应.XRD测试表明,(111)晶面为银电沉积层的择优取向面;扫描电子显微镜表征表明,银的颗粒尺度为6~11 nm.该电沉积层作为表面增强拉曼光谱的活性基底,具有灵敏度高及检测限低的特点,对罗丹明6G分子的检测限低至1.0×10-12mol/L,同时在大范围内的拉曼增强效果均匀,展现了良好的应用前景.

The electrodeposition mechanism of nano-sized silver layer with large area uniformity and smoothness was studied,the corresponding preparation process was optimized,and its application in surfaceenhanced Raman spectroscopy(SERS)was explored. The result shows that the nucleation mechanism of electrodeposition transitions gradually from progressive one to instantaneous one with negative shift of electrode potential and the best effect of SERS was achieved under such conditions,current density is 1.0 A/dm^(2),area ratio of cathode to anode is 1∶10,electrodeposition temperature is 20—30 ℃. Under ideal conditions,the silver grains are oriented along the(111)plane,with the diameters mainly distributing between 6—11 nm from scanning electron microscopy. The prepared coating can be used as SERS active substrate with high sensitivity and low limit of detection(LOD),the LOD of R6G was determined to below 1.0×10-12 mol/L,the coating also can realize uniform Raman enhancement effect on a large scale at the same time,which shows great potential for alpplication.