Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea.
Los Alamos National Laboratory, Center for Integrated Nanotechnologies (CINT), Los Alamos, NM 87545, USA.
Int J Mol Sci. 2021 Nov 11;22(22):12191. doi: 10.3390/ijms222212191.
In this work, we develop a Ag@AlO@Ag plasmonic core-shell-satellite (PCSS) to achieve highly sensitive and reproducible surface-enhanced Raman spectroscopy (SERS) detection of probe molecules. To fabricate PCSS nanostructures, we employ a simple hierarchical dewetting process of Ag films coupled with an atomic layer deposition (ALD) method for the AlO shell. Compared to bare Ag nanoparticles, several advantages of fabricating PCSS nanostructures are discovered, including high surface roughness, high density of nanogaps between Ag core and Ag satellites, and nanogaps between adjacent Ag satellites. Finite-difference time-domain (FDTD) simulations of the PCSS nanostructure confirm an enhancement in the electromagnetic field intensity (hotspots) in the nanogap between the Ag core and the satellite generated by the AlO shell, due to the strong core-satellite plasmonic coupling. The as-prepared PCSS-based SERS substrate demonstrates an enhancement factor (EF) of 1.7 × 10 and relative standard deviation (RSD) of ~7%, endowing our SERS platform with highly sensitive and reproducible detection of R6G molecules. We think that this method provides a simple approach for the fabrication of PCSS by a solid-state technique and a basis for developing a highly SERS-active substrate for practical applications.
在这项工作中，我们开发了一种 Ag@AlO@Ag 等离子体核壳卫星（PCSS），以实现对探针分子的高灵敏度和可重现的表面增强拉曼光谱（SERS）检测。为了制备 PCSS 纳米结构，我们采用了一种简单的分层去湿 Ag 薄膜工艺，并结合原子层沉积（ALD）方法来制备 AlO 壳。与裸 Ag 纳米颗粒相比，制备 PCSS 纳米结构有几个优势，包括高表面粗糙度、Ag 核和 Ag 卫星之间纳米间隙的高密度，以及相邻 Ag 卫星之间的纳米间隙。PCSS 纳米结构的时域有限差分（FDTD）模拟证实，由于强核卫星等离子体耦合，Ag 核和卫星之间的 AlO 壳产生的电磁场强度（热点）增强。所制备的基于 PCSS 的 SERS 基底表现出 1.7×10 的增强因子（EF）和~7%的相对标准偏差（RSD），使我们的 SERS 平台能够对 R6G 分子进行高灵敏度和可重现的检测。我们认为，这种方法为采用固态技术制备 PCSS 提供了一种简单的方法，并为开发用于实际应用的高 SERS 活性基底奠定了基础。
