Interdisciplinary Research Center for Renewable Energy and Power System (IRC-REPS), King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia.
Interdisciplinary Research Center for Hydrogen and Energy Storage (IRC-HES), King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia.
Chem Asian J. 2021 Jul 5;16(13):1807-1819. doi: 10.1002/asia.202100386. Epub 2021 Jun 8.
A new route has been developed to design plasmonic pollen grain-like nanostructures (PGNSs) as surface-enhanced Raman scattering (SERS)-active substrate. The nanostructures consisting of silver (Ag) and gold (Au) nanoparticles along with zinc oxide (ZnO) nanoclusters as spacers were found highly SERS-active. The morphology of PGNSs and those obtained in the intermediate stage along with each elemental evolution has been investigated by a high-resolution field emission scanning electron microscopy. The optical band gaps and crystal structure have been identified by UV-vis absorption and X-ray powder diffraction (XRD) measurements, respectively. For PGNSs specimen, three distinct absorption bands related to constituent elements Ag, Au, and ZnO were observed, whereas XRD peaks confirmed the existence of Ag, Au, and ZnO within the composition of PGNSs. SERS-activity of PGNSs was confirmed using Rhodamine 6G (R6G) as Raman-active dyes. Air-cooled solid-state laser kits of 532 nm were used as excitation sources in SERS measurements. SERS enhancement factor was estimated for PGNSs specimen and was found as high as 3.5×10 . Finite difference time domain analysis was carried out to correlate the electromagnetic (EM) near-field distributions with the experiment results achieved under this investigation. EM near-field distributions at different planes were extracted for s-, p- and 45° of incident polarizations. EM near-field distributions for such nanostructures as well as current density distributions under different circumstances were demonstrated and plausible scenarios were elucidated given SERS enhancements. Such generic fabrication route as well as correlated investigation is not only indispensable to realize the potential of SERS applications but also unveil the underneath plasmonic characteristics of complex SERS-active nanostructures.
一种新的途径已经被开发出来，用于设计等离子体花粉粒状纳米结构（PGNSs）作为表面增强拉曼散射（SERS）活性衬底。研究发现，由银（Ag）和金（Au）纳米粒子以及氧化锌（ZnO）纳米团簇作为间隔物组成的纳米结构具有很高的 SERS 活性。通过高分辨率场发射扫描电子显微镜研究了 PGNSs 的形态以及中间阶段获得的纳米结构以及每个元素的演变。通过紫外-可见吸收和 X 射线粉末衍射（XRD）测量分别确定了光学带隙和晶体结构。对于 PGNSs 样品，观察到与组成元素 Ag、Au 和 ZnO 相关的三个明显吸收带，而 XRD 峰则证实了 PGNSs 成分中存在 Ag、Au 和 ZnO。使用罗丹明 6G（R6G）作为拉曼活性染料证实了 PGNSs 的 SERS 活性。在 SERS 测量中使用 532nm 的风冷固态激光套件作为激发源。对 PGNSs 样品的 SERS 增强因子进行了估计，发现高达 3.5×10。进行了有限差分时域分析，以将电磁场（EM）近场分布与本研究中获得的实验结果相关联。对于不同的平面提取了 s-、p-和 45°的入射偏振的 EM 近场分布。展示了这种纳米结构的 EM 近场分布以及在不同情况下的电流密度分布，并根据 SERS 增强解释了可能的情况。这种通用的制造途径以及相关的研究不仅对于实现 SERS 应用的潜力是必不可少的，而且还揭示了复杂 SERS 活性纳米结构的潜在等离子体特性。
