National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, and Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Jan 15;265:120372. doi: 10.1016/j.saa.2021.120372. Epub 2021 Sep 8.
Photo-reduction of silver oxide and light-induced Ag nanoparticle (NP) generations have been applied for Surface-enhanced Raman spectroscopy (SERS) substrate fabricated for years. In this paper, we demonstrate a general method to enhance the SERS activity of conventional Ag NPs-based SERS substrates by performing Raman scattering measurement in a nitrogen ambient after a period of laser irradiation (photoactivation). The Raman characteristic peak intensity of carbonaceous impurities adsorbed on the surfaces of Ag NPs display an additional enhancement of 93 times after photoactivation in nitrogen ambient. A 3-fold extra Raman gain enhancement is also observed in the nitrogen-protected SERS measurement of R6G molecules. The extra SERS enhancement is attributed to the sub-nanometer scale near-field coupling between the Ag NPs and the photo-generated Ag clusters in the surface oxide layer of Ag NPs. This model is verified through the finite-difference time-domain (FDTD) simulations.
多年来，人们一直将银氧化物的光还原和光诱导的银纳米颗粒（NP）生成应用于表面增强拉曼光谱（SERS）基底的制备。在本文中，我们通过在激光辐照（光激活）一段时间后在氮气环境中进行拉曼散射测量，展示了一种增强常规基于 Ag NPs 的 SERS 基底 SERS 活性的通用方法。在氮气环境中光激活后，吸附在 Ag NPs 表面的碳质杂质的拉曼特征峰强度额外增强了 93 倍。在氮气保护的 R6G 分子的 SERS 测量中，也观察到拉曼增益额外增强了 3 倍。额外的 SERS 增强归因于 Ag NPs 表面氧化物层中 Ag NPs 和光生 Ag 团簇之间的亚纳米级近场耦合。该模型通过有限差分时域（FDTD）模拟得到验证。
