Oh Min Kyung, Yun Sukang, Kim Seong Kyu, Park Sungho
Department of Chemistry, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Anal Chim Acta. 2009 Sep 1;649(1):111-6. doi: 10.1016/j.aca.2009.07.025. Epub 2009 Jul 15.
Using a method of collecting nanoparticles at a water/hexane interface in a close-packed monolayer film and transferring such films onto a solid substrate, three-dimensional multilayer films of nanoparticles were formed. The packed nanoparticles were gold nanospheres (NS) with a 26 nm diameter or gold nanorods (NR) with a 31 nm diameter and 74 nm length. We investigated variations in the surface enhanced Raman scattering (SERS) intensities from such nanoparticle films as the layer compositions were changed. The films stacked with NR layers generated much higher SERS intensity than those of NS layers. The SERS intensities from both kinds of films increased as the number of layers were increased. However, when the NR layer and NS layer were stacked alternately, SERS intensity varied in a zigzag fashion. It was found that the structure of top layer plays a distinguishable role in generating strong SERS enhancement while the lower layers contribute to SERS with less dependency on structures. Interlayer coupling as well as intralayer coupling was considered in order to explain the observations.
采用在水/己烷界面以紧密堆积单层膜形式收集纳米颗粒并将此类膜转移到固体基质上的方法，形成了纳米颗粒的三维多层膜。堆积的纳米颗粒为直径26 nm的金纳米球（NS）或直径31 nm、长度74 nm的金纳米棒（NR）。我们研究了随着层组成的变化，此类纳米颗粒膜的表面增强拉曼散射（SERS）强度的变化。堆叠有NR层的膜产生的SERS强度比NS层的膜高得多。两种膜的SERS强度都随着层数的增加而增加。然而，当NR层和NS层交替堆叠时，SERS强度呈锯齿状变化。发现顶层结构在产生强烈的SERS增强方面起着显著作用，而较低层对SERS的贡献对结构的依赖性较小。为了解释这些观察结果，考虑了层间耦合以及层内耦合。
