银纳米立方体对诺丹明分子的荧光增强或猝灭效应实验研究  

Experimental investigation of fluorescence enhancement or quenching of Rhodamine B molecules caused by silver nano-cubes

作　　者：易明芳[1] 张杰[1] 赵玉杰[1] 马业万[1] 朱德权[1] 祝祖送[1] 尤建村[1] 夏强胜[1] 

机构地区：[1]安庆师范学院物理与电气工程学院,安徽安庆246133

出　　处：《量子电子学报》2013年第5期513-519,共7页Chinese Journal of Quantum Electronics

基　　金：国家自然科学基金(11275006)资助项目

摘　　要：用乙二醇还原硝酸银,成功制备了平均边长约97 nm的银纳米立方体以用于诺丹明(RhB)分子的荧光实验。实验中,将探针分子RhB粉末掺杂于PMMA苯甲醚溶液中,制得不同厚度掺杂有RhB探针分子的PMMA薄膜,运用光谱技术和共焦显微技术研究了银纳米立方体与荧光分子的间隔、银纳米立方体不同浓度分布对RhB分子的荧光强度的影响。荧光光谱表明,荧光强度随PMMA厚度变薄而增强,当PMMA厚度为10 nm时,荧光增强因子最大,获得了56倍的荧光增强效果,而继续减小PMMA厚度时,其荧光增强因子又变小,说明发生了荧光猝灭效应。共焦荧光像则更直观地表现了银纳米立方体的浓度分布对荧光分子辐射增强的影响。因而,可通过调控银纳米立方体与荧光分子的距离及银纳米立方体的分布优化荧光增强因子以用于基于荧光的单分子探测,这一实验结果在生物成像和生物传感领域有潜在应用价值。Silver nano-cubes of about 97 nm side-length were synthesized by reducing AgNO3 with ethylene glycol （EG） and used to modulate fluorescence intensity of Rhodamine B （RhB）. The RhB （probe molecules） powder was dissolved into PMMA solution with different PMMA concentrations, which resulted in RhB doped PMMA films with different thickness. The distance between Ag nano-cubes and the fluorescence molecules and distribution of Ag nano-cubes has important influence on the fluorescence emission. The fluorescence spectrums show the enhancement and quenching effect with different thickness of PMMA film. The largest fluorescence enhancement factor （EF） is 56 for the structure of Ag nano-cubes absorbed on the RhB doped PMMA film as the thickness of PMMA is 10 am. The confocal-images also verified the fluorescence enhancement. The EF is influenced by the distribution of silver nano-cubes on the PMMA film from the confocal-images. So the biggest EF can be obtained by optimizing the distazlce between silver nano-cubes and the fluorescence molecules or by tuning the distribution of silver nano-cubes, which may be used to single molecule detection. The experiment results have potential application in fllm^o ~. bio-sensin~ or hin.lm~.;~

关 键 词：光谱学 增强荧光 表面等离子体激元 局域场增强 银纳米立方体 

分 类 号：O482.31[理学—固体物理]