Zhou Qun, Chao Yanwen, Li Yan, Xu Wei, Wu Ying, Zheng Junwei
Organic Synthesis Laboratory of Jiangsu Province, Department of Chemistry, Suzhou University, Suzhou 215123, P. R. China.
Chemphyschem. 2007 Apr 23;8(6):921-5. doi: 10.1002/cphc.200600776.
Surface-enhanced Raman scattering under near-IR excitation is investigated for p-aminothiophenol (PATP) molecules that are either adsorbed on an electrochemically roughened silver electrode or embedded in an Au/PATP/Ag molecular junction assembled on an indium-doped tin oxide electrode. The contribution from chemical enhancement can be amplified relative to the contribution from electromagnetic enhancement, because the energy of the near-IR excitation is far from the surface plasmon resonance of the nanosized metal particles. The energy required for the charge-transfer process for the Au/PATP/Ag molecular junction is much lower than that of the PATP molecules adsorbed on the electrochemically roughened silver electrode. Coadsorption of chloride ions on the metal nanoparticles may result in an alteration of the local Fermi level of the metal nanoparticles, thus leading to better energy matching between the energy level of the interconnecting PATP molecules and the Fermi level of the metal nanoparticles.
研究了在近红外激发下，对氨基硫酚（PATP）分子的表面增强拉曼散射，这些分子要么吸附在电化学粗糙化的银电极上，要么嵌入在组装在氧化铟锡电极上的Au/PATP/Ag分子结中。相对于电磁增强的贡献，化学增强的贡献可以被放大，因为近红外激发的能量远离纳米尺寸金属颗粒的表面等离子体共振。Au/PATP/Ag分子结的电荷转移过程所需的能量远低于吸附在电化学粗糙化银电极上的PATP分子的能量。金属纳米颗粒上氯离子的共吸附可能导致金属纳米颗粒的局部费米能级发生变化，从而使相互连接的PATP分子的能级与金属纳米颗粒的费米能级之间实现更好的能量匹配。
