Jiang Jizhou, Zou Jing, Wee Andrew Thye Shen, Zhang Wenjing
SZU-NUS Collaborative Innovation Center for Optoelectronic Science &Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore.
Sci Rep. 2016 Sep 30;6:34599. doi: 10.1038/srep34599.
Surface-enhanced Raman scattering (SERS) substrates with high activity and stability are desirable for SERS sensing. Here, we report a new single atomic layer graphitic-CN (S-g-CN) and Ag nanoparticles (NPs) hybrid as high-performance SERS substrates. The SERS mechanism of the highly stable S-g-CN/Ag substrates was systematically investigated by a combination of experiments and theoretical calculations. From the results of XPS and Raman spectroscopies, it was found that there was a strong interaction between S-g-CN and Ag NPs, which facilitates the uniform distribution of Ag NPs over the edges and surfaces of S-g-CN nanosheets, and induces a charge transfer from S-g-CN to the oxidizing agent through the silver surface, ultimately protecting Ag NPs from oxidation. Based on the theoretical calculations, we found that the net surface charge of the Ag atoms on the S-g-CN/Ag substrates was positive and the Ag NPs presented high dispersibility, suggesting that the Ag atoms on the S-g-CN/Ag substrates were not likely to be oxidized, thereby ensuring the high stability of the S-g-CN/Ag substrate. An understanding of the stability mechanism in this system can be helpful for developing other effective SERS substrates with long-term stability.
具有高活性和稳定性的表面增强拉曼散射（SERS）基底对于SERS传感而言是很理想的。在此，我们报道了一种新型的单原子层石墨相氮化碳（S-g-CN）与银纳米颗粒（NPs）的杂化物作为高性能SERS基底。通过实验和理论计算相结合的方式，系统地研究了高度稳定的S-g-CN/Ag基底的SERS机制。从X射线光电子能谱（XPS）和拉曼光谱的结果来看，发现S-g-CN与Ag NPs之间存在强烈的相互作用，这有利于Ag NPs在S-g-CN纳米片的边缘和表面均匀分布，并通过银表面诱导电荷从S-g-CN转移到氧化剂上，最终保护Ag NPs不被氧化。基于理论计算，我们发现S-g-CN/Ag基底上Ag原子的净表面电荷为正，且Ag NPs具有高分散性，这表明S-g-CN/Ag基底上的Ag原子不太可能被氧化，从而确保了S-g-CN/Ag基底的高稳定性。了解该体系中的稳定性机制有助于开发其他具有长期稳定性的有效SERS基底。
