Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617 Taiwan (R.O.C.).
Nanoscale. 2015 Mar 7;7(9):3985-96. doi: 10.1039/c4nr05902f.
We have used a direct imprint-in-metal method that is cheap and rapid to prepare incident angle-tuned, broadband, ultrahigh-sensitivity plasmonic antennas from nanoparticles (NPs) and imprinted metal mirrors. By changing the angle of incidence, the nanoparticle-imprinted mirror antennas (NIMAs) exhibited broadband electromagnetic enhancement from the visible to the near-infrared (NIR) regime, making them suitable for use as surface-enhanced Raman scattering (SERS)-active substrates. Unlike other SERS-active substrates that feature various structures with different periods or morphologies, the NIMAs achieved broadband electromagnetic enhancement from single configurations. The enhancement of the electric field intensity in the NIMAs originated from coupling between the localized surface plasmon resonance of the NPs and the periodic structure-excited surface plasmon resonance (SPR) of the imprinted mirror. Moreover, the coupling wavelengths could be modulated because the SPR wavelength was readily tuned by changing the angle of the incident light. Herein, we demonstrate that such NIMAs are robust substrates for visible and NIR surface-enhanced resonance Raman scattering under multiple laser lines (532, 633, and 785 nm) of excitation. In addition, we have found that NIMAs are ultrasensitive SERS-active substrates that can detect analytes (e.g., rhodamine 6G) at concentrations as low as 10(-15) M.
我们使用了一种直接在金属上压印的廉价、快速方法，从纳米颗粒（NPs）和压印金属镜制备角度调谐、宽带、超高灵敏度等离子体天线。通过改变入射角，纳米颗粒压印镜天线（NIMA）在可见到近红外（NIR）范围内表现出宽带电磁增强，使其适合用作表面增强拉曼散射（SERS）活性衬底。与具有不同周期或形貌的各种结构的其他 SERS 活性衬底不同，NIMA 从单一配置实现了宽带电磁增强。NIMA 中的电场强度增强源于 NPs 的局域表面等离子体共振与压印镜的周期性结构激发表面等离子体共振（SPR）之间的耦合。此外，由于SPR 波长可以通过改变入射光的角度很容易地进行调谐，因此可以调制耦合波长。在此，我们证明了这些 NIMA 是在激发的多个激光线（532、633 和 785nm）下用于可见和近红外表面增强共振拉曼散射的坚固衬底。此外，我们发现 NIMA 是超灵敏的 SERS 活性衬底，能够以低至 10(-15) M 的浓度检测分析物（例如，若丹明 6G）。
