银粒子的表面修饰及荧光表面增强效应

采用表面化学修饰制备了Ag-SiO2核-壳纳米粒子,发现SiO2包裹壳层形状随其厚度而改变,包裹初期SiO2壳层依托银核的形状生长,随着壳层厚度增加则趋于热力学稳定的球状。银纳米粒子的表面等离子体共振可由SiO2包裹壳层厚度调变,银核吸收谱峰随壳层厚度增大而红移。Ag-SiO2核-壳纳米粒子可极大增强罗丹明6G的荧光强度,且表面增强效应与壳层的厚度密切相关。

Fluorescence Surface-Enhancement Effect of Ag-SiO2 Core-Shell Nanoparticles

Ag-SiO_2 core-shell nanoparticles were prepared by surface modification of silver nanoparticles.It was found that the shape of the shell varied with its thickness.In the early stage,the SiO_2 shell grows according to the shape of the silver particles,then tends to grow into a thermodynamic stable geometry.The surface plasmon resonance of the silver core can be altered by the thickness of the SiO_2 shell,which shows a red shift of the absorption band of the silver core with increasing of the shell thickness.The fluorescence of Rhodamine 6G is largely enhanced in the presence of the Ag-SiO_2 nanoparticles,largely depending on the thickness of the SiO_2 shell.