Li Zhongbo, Sun Kexi, Du Zhaofang, Chen Bensong, He Xuan
College of Light-Textile Engineering and Art, Anhui Agricultural University, Hefei 230036, China.
Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China.
Nanomaterials (Basel). 2018 Apr 23;8(4):265. doi: 10.3390/nano8040265.
Here we report a low-cost synthetic approach for the direct fabrication of large-area Au nanourchin arrays on indium tin oxide (ITO) via a facile galvanic-cell-reaction-driven deposition in an aqueous solution of chloroauric acid and poly(vinyl pyrrolidone) (PVP). The homogeneous Au nanourchins are composed of abundant sharp nanotips, which can served as nanoantennas and increase the local electromagnetic field enhancement dramatically. Finite element theoretical calculations confirm the strong electromagnetic field can be created around the sharp nanotips and located in the nanogaps between adjacent tips of the Au nanourchins. In addition, the interparticle nanogaps between the neighboring Au nanourchins may create additional hotspots, which can induce the higher electromagnetic field intensity. By using rhodamine 6G as a test molecule, the large-area Au nanourchin arrays on ITO exhibit active, uniform, and reproducible surface-enhanced Raman scattering (SERS) effect. To trial their practical application, the Au nanourchin arrays are utilized as SERS substrates to detect 3,3’,4,4’-tetrachlorobiphenyl (PCB-77) one congener of polychlorinated biphenyls (PCBs) as a notorious class of persistent organic pollutants. The characteristic Raman peaks can be still identified when the concentration of PCB-77 is down to 5 × 10 M.
在此，我们报道了一种低成本的合成方法，可通过在氯金酸和聚乙烯吡咯烷酮（PVP）水溶液中进行简便的原电池反应驱动沉积，在氧化铟锡（ITO）上直接制备大面积的金纳米海胆阵列。均匀的金纳米海胆由大量尖锐的纳米尖端组成，这些纳米尖端可作为纳米天线，显著增强局部电磁场。有限元理论计算证实，在尖锐的纳米尖端周围以及相邻金纳米海胆尖端之间的纳米间隙中可产生强电磁场。此外，相邻金纳米海胆之间的粒子间纳米间隙可能会产生额外的热点，从而导致更高的电磁场强度。通过使用罗丹明6G作为测试分子，ITO上的大面积金纳米海胆阵列表现出活性、均匀且可重复的表面增强拉曼散射（SERS）效应。为了测试它们的实际应用，金纳米海胆阵列被用作SERS基底来检测3,3′,4,4′-四氯联苯（PCB - 77），它是多氯联苯（PCBs）这一臭名昭著的持久性有机污染物类别中的一种同系物。当PCB - 77的浓度低至5×10⁻⁸ M时，仍可识别出特征拉曼峰。
