National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani 12120, Thailand.
Sci Rep. 2016 Dec 13;6:39115. doi: 10.1038/srep39115.
Limitations of achieving highly sensitive and stable surface-enhanced Raman scattering (SERS) substrate greatly concern the suitable method for fabrication of large-area plasmonic nanostructures. Herein we report a simple approach using template-based synthesis to create a highly ordered two-dimensional array of gold-silver alloy nanowires, followed by the controlled dealloying process. This particular step of mild acid etching (15%v/v nitric acid for 5 min) allowed the formation of Raman hot spots on the nanowire tips while maintaining the integrity of highly active alloy composition and rigid nanowire array structure. Full consideration of SERS substrate performance was accomplished using 4-mercaptobenzoic acid (4-MBA) as a probe molecule. Exceedingly higher SERS signal (150-fold) can be achieved with respect to typical gold film substrate. Moreover, an excellent stability of SERS substrate was also determined for over 3 months storage time. In contrast to the previous studies which stability improvement was accomplished at a cost of sensitivity reduction, the simultaneous improvement of sensitivity and stability makes the controlled dealloying process an excellent choice of SERS substrate fabrication. In addition, uniformity and reproducibility studies indicated satisfactory results with the acceptable values of relative standard deviation.
实现高灵敏度和稳定的表面增强拉曼散射 (SERS) 基底的局限性极大地关注适合制造大面积等离子体纳米结构的方法。在此，我们报告了一种使用基于模板的合成来创建高度有序的金-银合金纳米线二维阵列的简单方法，然后进行可控的脱合金化过程。这一特定的温和酸蚀刻步骤（15%v/v 硝酸蚀刻 5 分钟）允许在纳米线尖端形成拉曼热点，同时保持高活性合金成分和刚性纳米线阵列结构的完整性。使用 4-巯基苯甲酸（4-MBA）作为探针分子充分考虑了 SERS 基底的性能。与典型的金膜基底相比，可获得高得多的 SERS 信号（150 倍）。此外，SERS 基底的稳定性也被确定可以超过 3 个月的储存时间。与之前的研究不同，这些研究是在降低灵敏度的代价下提高稳定性的，灵敏度和稳定性的同时提高使得可控脱合金化过程成为 SERS 基底制造的一个极好的选择。此外，均匀性和可重复性研究表明，相对标准偏差的可接受值表明结果令人满意。
