纳米银粒子对表面吸附罗丹明B的光谱学性质的影响及电解质效应研究

基于贵金属纳米粒子的局域场增强效应,利用透射电子显微镜、紫外-可见分光光度计和荧光分光光度计等分析手段研究了纳米银粒子对表面吸附罗丹明B的光谱学性质的影响以及罗丹明B-纳米银体系中加入电解质离子后,电解质离子与纳米银、染料分子间的相互关系和作用.研究结果表明,当罗丹明B溶液的浓度小于0.6 μmol·L－1时,微量纳米银可使其荧光强度略增加,继续增加纳米银浓度则造成荧光强度下降.当罗丹明B溶液的浓度高于0.6 μmol·L－1时,纳米银总是引起溶液的荧光强度下降.KNO3、KCl、Ca(NO3)2、MgCl2和CaCl2电解质可造成纳米银粒子不同程度的聚集和生长.引起的纳米银粒子的聚集程度关系为:CaCl2>MgCl2>KCl>Ca(NO3)2>KNO3.随着电解质加入量的增加,溶液的荧光强度先下降,而后又逐渐增强,直至达到定值.各电解质对罗丹明B-Ag溶液的荧光强度影响强弱关系为Ca(NO3)2>CaCl2>MgCl2>Cl>KNO3.

Effects of Silver Nanoparticles on Spectroscopy Properties of Rhodamine B and Electrolyte Effect

Based on the local field enhancement of noble metals,the effect of silver nanoparticles on spectroscopy properties of rhodamine B was investigated by transmission electron microscopy and UV-Visible spectroscopy and spectrofluorophotometer.Furthermore,the interactions among electrolyte ions and silver nano-particles and rhodamine B were studied.The results indicate that the fluorescence of rhodamine B increased first and then decreased when the silver nanoparticles were added into the 0.6 μmol·L－1 rhodamine B.The fluorescence of rhodamine B always decreased when the concentration of rhodamine B is over 0.6 μmol·L－1.The electrolytes,including KNO3,KCl,Ca(NO3)2,MgCl2and CaCl2,led to the formation of large particles and aggregates in the solution.The effect order of electrolytes on the aggregates of silver nanoparticles is CaCl2>MgCl2>KCl>Ca(NO3)2>KNO3.With the increasing of the electrolyte content,the fluorescence intensity decreased first and then increased until to the constant value.The dependence of electrolytes on the fluorescence intensity of the rhodamine B -Ag solution follows the order of Ca(NO3)2>CaCl2>MgCl2>KCl>KNO3.