Self-Assembly of Two Kinds of Nanoparticles and Their Surface Enhanced Raman Spectroscopic Study
HUANG Cai-feng1, SHEN Hong-xia2，HUANG Jie1, YAO Jian-lin1*, GU Ren-ao1*
1. Department of Chemistry, Chemical Engineering and Materials Sciences, Soochow University, Suzhou 215123, China 2. Department of Biology and Chemistry, Jiaxing College，Jiaxing 314001，China
Abstract：Two kinds of nanoparticles (gold nanoparticles and Au core Pt shell nanoparticles) on silicon surfaces which were silanization were electrostatically self-assembled. The density of nanoparticles was controlled by changing the time of the substrate immersed in colloids. The substrate was characterized by scanning electron microscope (SEM), and the results indicated that Au and Au@Pt particles were dispersed on the substrate with mono/submonolayers. The authors used pyridine (Py) as a probing molecule, and surface enhanced Raman spectroscopy (SERS) effect was investigated on pure Au and Au-Au@Pt mixed nanoparticle surfaces under the excitation line of 632.8 nm. The results revealed that there is a significant shift of the two characteristic peaks of Py, but the enhancement factors of Au dropped off precipitously with the introduction of the Au@Pt nanoparticles. The authors attributed this effect to the introduction of metal d-states from the metal, which would serve effectively to quench the surface plasmon excitation necessary for large (electromagnetic) enhancements in Raman spectroscopy.
[1] Colvin V L, Goldstein A N, Alivisatos A P. J . Am. Chem. Soc., 1992, 114 : 5221. [2] Ogawa S, Fan F R, Bard A J. J. Phys. Chem., 1995, 99: 11182. [3] Ogawa S, Hu K, Fan F R, et al. J. Phys. Chem. B, 1997, 101: 5707. [4] Wang H, Levin C S, Halas N J. J. Am. Chem. Soc., 2005, 127: 14992. [5] Gao M X, Lin X M, Ren B. Chem. J. Chin. Univ-Chin., 2008, 29: 959. [6] Fendler J H. Chem. Mat., 1996, 8: 1616. [7] Freeman R G, Grabar K C, Allison K J, et al. Science, 1995, 267: 1629. [8] Chumanov G, Sokolov K, Gregory B W, et al. J. Phys. Chem., 1995, 99: 9466. [9] HUANG Jie, YAO Jian-lin, GU Ren-ao(黄 洁, 姚建林, 顾仁敖). Acta Chem. Sin.(化学学报), 2007, 65: 2505. [10] Frens G. J. Nature Phys. Sci., 1973, 241: 20. [11] Lu L H, Wang H S, Xi S Q, et al. Journal of Material Chem., 2002, 12(2): 156. [12] Grabar K C, Smith P C, Musick M D, et al. J. Am. Chem. Soc., 1996, 118: l148. [13] Moskovits M J. Raman Spectrosc, 2005, 36: 1143. [14] Creighton J A, Blatchford C G, Albrecht M G. J. Chem. Soc., Faraday Trans., 1979, 75: 790. [15] Cai W B, She C X, Ren B, et al. J. Chem. Soc., Faraday Trans., 1998, 94: 3127. [16] Xu & Kll. Chem. Phys. Chem., 2003, 4: 1001. [17] Furtak T E, Kester J. Phys. Rev. Lett., 1980, 45: 1652.
