纳米银颗粒表面增强荧光效应与其覆盖率的关联  

Correlation of surface enhanced fluorescence and coverage for silver nanoparticles

作　　者：刘岩[1] 张崇磊[1] 陈平[1] 林列[1] 母国光[1] 

机构地区：[1]南开大学现代光学研究所,天津300071

出　　处：《光电子．激光》2012年第2期379-385,共7页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(60508004;60778043);天津市科技支撑重点项目(08ZCDFGX09400)资助项目

摘　　要：实验上获得了纳米银颗粒对光敏剂二氢卟吩f-甲醚(CPD4)的荧光增强效应,基于纳米银颗粒覆盖率对表面增强荧光效应的影响,初步探讨了荧光增强的物理增强机制。不同覆盖率纳米银基底表面吸附的CPD4的增强荧光结果显示,在低颗粒覆盖率时(<30%),激发效率和激发态分子衰减速率不依赖于覆盖率变化;当颗粒覆盖率大于30%接近40%时,激发效率和激发态分子衰减速率都得到提高。实验和理论结果均表明,相比于单个银纳米颗粒,颗粒覆盖率增加提高了颗粒间电磁耦合效应,能够产生更强的表面增强荧光效应。In this paper, we focus on the fluorescence enhancement effect of photosensitizer cholorin fehter （CPD4） which was adsorbed on the surface with varied silver nanopartides coverages. Substrates with varied coverages 9f silver nanoparticles （NPs） were prepared through the self-assembly method. The measurements of fluorescence images and the spectra of adsorbed fluorophores on silver NPs substrate were performed by the laser scanning confocal microscopy. The results show that the excitation rate and the total decay rate of admolecule are independent of the nanoparticles coverage when the coverage is lower （〈30 %）, and they dramatically increase when the coverage approaches 40 %, which demonstrates that the interparticle electromagnetic coupling is strong enough to enhance both the excitation rate and radiation rate. The experimental results and theoretical analysis both indicate that the strong interparticle electromagnetic coupling induced by dense arrangement of nanoparticles leads to stronger fluorescence compared with individual silver nanoparticles.

关 键 词：表面增强荧光 银纳米颗粒 局域表面等离子体共振 颗粒覆盖率 

分 类 号：O439[机械工程—光学工程]