Department of Chemical and Materials Engineering, Vanung University, 1, Van Nung Road, Shuei-Wei Li, Chung-Li City, Taiwan.
Langmuir. 2010 Jul 6;26(13):11512-7. doi: 10.1021/la100235x.
We develop an easy and effective pathway to improve surface-enhanced Raman scattering (SERS) effects of probe molecules of Rhodamine 6G (R6G) adsorbed on electrochemically prepared roughened Ag substrates. In general SERS studies, SERS-active metal substrates are first prepared. Then probe molecules are adsorbed on them to evaluate the relative SERS effects. In this study, we employ electrochemical oxidation-reduction cycle (ORC) treatments in 0.1 M KCl solutions containing probe molecules of 2 x 10(-5) M R6G to prepare R6G-adsorbed SERS-active Ag substrates for one step. Encouragingly, based on this strategy, the SERS intensity of adsorbed R6G can be increased by 1 order of magnitude, as compared with that of R6G adsorbed on a roughened Ag substrate beforehand, which was generally shown in the literature. Moreover, this improved SERS effect based on this strategy is also effective for 2 x 10(-9) M probe molecules, which is at a level of single molecule detection based on Ag colloids. It is also effective for probe molecules of ClO(4)(-) with low Raman cross section and for other electrochemically prepared SERS-active substrates of Au. Further analyses indicate that the increase in SERS activity in this new method is most likely due to the incorporation of more chloride ions into the substrate.
我们开发了一种简便有效的途径，以提高吸附在电化学制备的粗糙 Ag 基底上的 Rhodamine 6G（R6G）探针分子的表面增强拉曼散射（SERS）效应。在一般的 SERS 研究中，首先制备 SERS 活性金属基底。然后将探针分子吸附在它们上面，以评估相对 SERS 效应。在这项研究中，我们采用电化学氧化还原循环（ORC）处理，在含有 2x10(-5) M R6G 的探针分子的 0.1 M KCl 溶液中，一步制备 R6G 吸附的 SERS 活性 Ag 基底。令人鼓舞的是，基于这种策略，吸附的 R6G 的 SERS 强度可以增加一个数量级，与文献中通常显示的预先吸附在粗糙 Ag 基底上的 R6G 的 SERS 强度相比。此外，这种基于该策略的改进 SERS 效应对于 2x10(-9) M 的探针分子也是有效的，这是基于 Ag 胶体的单分子检测水平。它对于具有低拉曼截面的 ClO(4)(-)探针分子以及其他电化学制备的 SERS 活性 Au 基底也是有效的。进一步的分析表明，在这种新方法中 SERS 活性的增加很可能是由于更多的氯离子掺入到基底中。
