SERS活性表面荧光增强或淬灭的机制研究

利用银胶和银镜两种SERS活性表面,对吸附分子的荧光增强或淬灭机制进行了实验和理论研究.结果表明,荧光增强或淬灭主要取决于局域电磁场增强和分子到金属表面无辐射能量转移过程的竞争效应.当满足吸收共振增强和辐射共振增强时,荧光被增强,反之荧光被淬灭.荧光增强最大一般只为10—10²倍,远小于喇曼截面的增强. 关键词：

FLUORESCENCE ENHANCEMENT OR QUENCHING OF MOLECULE AT SERS ACTIVE SURFACES

Molecular fluorescence spectra of dye adsorbed on silver colliod and silver mirror were studied. Acriding Orange was used as sample in the experiment. We have found that the enhancement or quenching are depend on the competition of two processes, i.e., local field enhancement and non-radiation energy transfer from the molecule to metal surface. The fluorescence is enhanced when enhanced absorption and enhanced emission conditions are achieved. However, molecular fluorescence is far less enhanced then Raman. Theoretical calculation shows that peak enhencement of fluorescence intensity will be 10-10². It agrees with the experimental value for Acriding Orenge adsorbed on silver mirror.