Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
Langmuir. 2012 Oct 9;28(40):14441-9. doi: 10.1021/la302795r. Epub 2012 Sep 25.
The effective number of surface-enhanced Raman spectroscopy (SERS) active hot spots on plasmonic nanostructures is the most crucial factor in ensuring high sensitivity in SERS sensing platform. Here we demonstrate a chemical etching method to increase the surface roughness of one-dimensional Ag nanowires, targeted at creating more SERS active hot spots along Ag nanowire's longitudinal axis for increased SERS detection sensitivity. Silver nanowires were first synthesized by the conventional polyol method and then subjected to chemical etching by NH(4)OH and H(2)O(2) mixture. The surfaces of silver nanowires were anisotropically etched off to create miniature "beads on a string" features with increased surface roughness while their crystallinity was preserved. Mapping of single-nanowire SERS measurements showed that the chemical etching method has overcome the limitation of conventional one-dimensional Ag nanowires with limited SERS active area at the tips to produce etched Ag nanowires with an increase in Raman hot spots and polarization-independent SERS signals across tens of micrometers length scale.
表面增强拉曼光谱（SERS）活性热点的有效数量是确保 SERS 传感平台高灵敏度的最关键因素。在这里，我们展示了一种化学蚀刻方法来增加等离子体纳米结构一维 Ag 纳米线的表面粗糙度，旨在沿 Ag 纳米线的纵轴创建更多的 SERS 活性热点，以提高 SERS 检测灵敏度。首先通过传统的多元醇法合成银纳米线，然后用 NH（4）OH 和 H（2）O（2）混合物进行化学蚀刻。银纳米线的表面被各向异性地蚀刻掉，形成具有增加的表面粗糙度的微型“串珠”特征，同时保持其结晶度。单纳米线 SERS 测量的映射表明，化学蚀刻方法克服了传统一维 Ag 纳米线的局限性，即尖端处的 SERS 活性面积有限，从而产生了具有增加的拉曼热点和偏振无关 SERS 信号的蚀刻 Ag 纳米线，横跨数十微米的长度尺度。
