化学学报 ›› 2015, Vol. 73 ›› Issue (1): 41-46.DOI: 10.6023/A14100734 上一篇    下一篇

研究论文

介孔SiO2薄膜与金银合金薄膜相结合的大面积、高性能SERS基底

刘德龙a, 逯丹凤a, 赵乔a, 陈晨a, 祁志美a,b   

  1. a 中国科学院电子学研究所传感技术国家重点实验室 北京 100190;
    b 国民核生化灾害防护国家重点实验室 北京 102205
  • 收稿日期:2014-10-23 出版日期:2015-01-14 发布日期:2014-12-15
  • 通讯作者: 逯丹凤 E-mail:dflu@mail.ie.ac.cn
  • 基金资助:

    项目受国家重大科学仪器设备开发项目(No. 2011YQ0301240802)、国家自然科学基金(No. 61377064)、北京市自然科学基金(No. 3131001)和国民核生化灾害防护国家重点实验室开放基金(No. SKLNBC2014-11)资助.

Large-area High-performance SERS Substrates Prepared with a Combination of Mesoporous Silica Film and AuAg Alloy film

Liu Delonga, Lu Danfenga, Zhao Qiaoa, Chen Chena, Qi Zhimeia,b   

  1. a State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190;
    b State Key Laboratory of NBC Protection for Civilian, Beijing 102205
  • Received:2014-10-23 Online:2015-01-14 Published:2014-12-15
  • Supported by:

    Project supported by the Major National Scientific Instrument and Equipment Development Project of China (No. 2011YQ0301240802), the National Natural Science Foundation of China (No. 61377064), the Beijing Natural Science Foundation (No. 3131001) and the State Key Laboratory of NBC Protection for Civilian (No. SKLNBC2014-11).

通过对涂布在金银合金薄膜表面的硅基凝胶膜进行高温热处理首次制备出均匀的大面积表面增强拉曼散射(Surface Enhanced Raman Scattering, SERS)基底. 利用扫描电子显微镜观测到由硅基凝胶膜经高温脱模形成的介孔二氧化硅薄膜具有表面开口结构, 基底的X射线能量色散(EDX)谱揭示了高温热处理引起金银合金薄膜中的银原子流失, 从而导致薄膜的纳米构造. 通过测试基底对Nile blue (NB)和Crystal violet (CV)拉曼活性分子的SERS光谱, 观测到在玻璃衬底与50 nm厚的金银合金薄膜之间插入20 nm厚金薄膜能够显著提高基底的SERS增强因子. 测试了基底在水溶液样品(50 nmol·L-1 CV)中的浸渍时间对SERS信号的影响, 结果指出SERS信号随浸渍时间的增加而增强并在30 min后达到稳定, 15 min浸渍时间对应的SERS信号强度达到其稳定值的85%. 比对实验指出CV的SERS光谱与其溶液的常规拉曼光谱的峰位完全一致, 揭示了介孔二氧化硅薄膜能够有效阻止SERS基底的金属成份对待测分子拉曼指纹谱的干扰. 实验还证明了这种新型SERS基底对水溶液中NB的探测下限可达1 nmol·L-1.

关键词: 金银合金薄膜, 介孔二氧化硅薄膜, SERS基底, 大面积, 高性能, 探测下限

Uniform large-area and high-performance surface enhanced Raman scattering (SERS) substrates were prepared for the first time by using a simple three-step method. The method contains sputtering deposition of an AuAg alloy layer on the glass sheet and subsequent dip-coating of a sol-gel copolymer-templated silica film on the alloy layer and finally thermal treatment of the double-layer coated glass sheet in air at 450 ℃ for several hours. The thermal treatment leads to formation of the mesoporous silica (MS) film. The scanning electron microscope images show that the top layer of MS has the open-pore structure that facilitates rapid diffusion of small molecules into the film. The energy dispersive X-ray (EDX) spectroscopy analyses indicate that the thermal treatment of the substrate results in the loss of Ag atoms in the AuAg alloy film accompanied with the nanostructure formation in the film. The systematic measurements of SERS spectra for Nile blue (NB) and Crystal violet (CV) demonstrate that the insertion of a 20-nm-thick gold layer between the glass sheet and a 50-nm-thick AuAg alloy film can effectively increase the SERS enhancement factor of the substrate. Dependence of the SERS signal on the substrate immersion time was investigated with an aqueous solution of 50 nmol·L-1 CV, and the findings indicate that the intensity of SERS signal increases with increasing the immersion time up to 30 min after which the signal becomes stable. The SERS signal intensity detected 15 min after immersion is 85% of its stable value. The position of each peak in the SERS spectrum for the adsorbed CV molecules is perfectly identical to that in the conventional Raman spectrum obtained with the aqueous CV solution, giving a sign that the MS film enables to prevent the metal from interfering the positions of SERS peaks. The experimental results demonstrate that such novel SERS substrates have the detection limit of 1 nmol·L-1 NB.

Key words: AuAg alloy film, mesoporous silica film, SERS substrate, large area, high performance, detection limit