银纳米线蚀刻及其表面等离激元特性

Etching of silver nanowires and its surface-plasmon

采用电子扫描显微镜(SEM)表征过氧化氢(H_2O_2)蚀刻的银纳米线表面形貌,采用紫外-可见(UV-vis)吸收光谱、荧光光谱以及拉曼光谱研究蚀刻后银纳米线的表面等离激元特性。结果表明:H_2O_2可有效蚀刻银纳米线表面形貌,与未蚀刻的银纳米线相比,蚀刻后的银纳米线平均直径减小,表面形成纳米凹槽以及立方状的银纳米粒子,银纳米线表面等离激元共振吸收峰强度增大,并呈现宽化。由于蚀刻后的银纳米线光电耦合增强,导致表面的电磁场强度增大,对罗丹明B(RB)探针分子的荧光辐射增强16.8倍,对RB探针分子的拉曼散射信号增强约6.2×105倍。这对于纳米金属表面增强光谱具有积极的应用意义。

Using H_2O_2 acid, the surface of silver nanowires（AgNWs） was etched after being prepared by chemical method, and the morphologies of smooth AgNWs and etched AgNWs were both characterized by scanning electron microscopy（SEM）. Employing UV-vis spectrum, Fluorescent spectrum and Raman spectrum, the surface plasmons of smooth AgNWs and etched AgNWs were both analyzed. The SEM results show that the mean diameters of AgNWs are significantly reduced after being etched, and more nanogaps and nanocubes form on the surfaces of AgNWs that are etched. The UV-vis spectrum shows that the surface-plasmon resonance（SPR） peak of AgNWs is broaden after the nanowires are etched, which result is due to the stronger coupling of surface plasmon, and Fluorescent spectrum and Raman spectrum of RB are both enhanced since the stronger electromagnetic field effect around etched AgNWs. These results may be significant for the application of surface enhanced spectrum.