785 nm 激光诱导银纳米三角片聚集表面增强拉曼散射效应

摘要

为实现表面增强拉曼散射（ SERS）光谱的强信号快速检测分析，报道了通过785 nm激光诱导银纳米三角片（ Ag-NPRs）聚集的方法。采用配体辅助化学还原法制备了AgNPRs，其边长约为80 nm，表面等离子体吸收峰出现在约774 nm处，对785 nm光产生有效吸收。在785 nm光辐照下，AgNPRs逐渐聚集，对巯基苯甲酸的SERS信号逐渐增强，其源于AgNPRs吸收的光转化为热而引起的AgNPRs聚集。其增强因子高达109。为快速获得强SERS信号，激发光功率需大于250 mW。%Surface enhanced Raman spectroscopy ( SERS ) is an ultrasensitive vibrational spectroscopic tech-nique to detect molecules .At present , adding salts is a main way to induce nanoparticles aggregation to get gi-ant enhancement .However , this method needs more procedures and salts may etch nanoparticles .Here an ef-fective and simple method is reported to enhance SERS effect by the aggregation of silver nanoprisms ( Ag-NPRs) induced by 785 nm laser .Silver nanoprisms were prepared by ligand-assisted chemical reductions method.AgNO3 were reduced by NaBH4 in the presence of trisodium citrate, poly(vinylpyrrolidone) and H2 O2 .The edge of silver nanoprisms is about 80 nm.Surface plasmon band of silver nanoprisms is around 774 nm which could effectively absorb 785 nm laser .When laser irradiating silver nanoprisms during the detection of Raman spectra , these nanoprisms gradually aggregated and SERS spectra of analytes ( 4-mercaptobenzoic acid, 4-MBA) were gradually enhanced .And enhancement factor of Raman spectra ~109 is obtained by this method.Due to the huge magnitude of SERS in the near infrared region ( excitation wavelength 785 nm) , this technique has the potential in the field of biochemical tests .