Dealloying Ag–Al Alloy to Prepare Nanoporous Silver as a Substrate for Surface‐Enhanced Raman Scattering: Effects of Structural Evolution and Surface Modification |
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| Authors: | Dr Huajun Qiu Prof Zhonghua Zhang Prof Xirong Huang Prof Yinbo Qu |
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| Institution: | 1. Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education of China, Shandong University, Jinan 250100 (P.R. China), Fax: (+86)?531‐883‐65433;2. Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (P.R. China);3. Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jinan (P.R. China);4. State Key Laboratory of Microbial Technology of China, Shandong University, Jinan (P.R. China) |
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| Abstract: | Sensitive detection of molecules by using the surface‐enhanced Raman scattering (SERS) technique depends on the nanostructured metallic substrate and many efforts have been devoted to the preparation of SERS substrates with high sensitivity, stability, and reproducibility. Herein, we report on the fabrication of stable monolithic nanoporous silver (NPS) by chemical dealloying of Ag–Al precursor alloys with an emphasis on the effect of structural evolution on SERS signals. It was found that the dealloying conditions had great influence on the morphology (the ligament/pore size) and the crystallization status, which determined the SERS signal of rhodamine 6G on the NPS. NPS with small pores, low residual Al, and perfect crystallization gave high SERS signals. A high enhancement factor of 7.5×105 was observed on bare NPS obtained by dealloying Ag30Al70 in 2.5 wt % HCl at room temperature followed by 15 min aging at around 85 °C. After coating Ag nanoparticles on the NPS surface, the enhancement factor increased to 1.6×108 owing to strong near‐field coupling between the ligaments and nanoparticles. |
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| Keywords: | nanoparticles Raman spectroscopy silver size effects structural evolution |
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