Highly efficient plasmon-driven catalysis and excellent surface-enhanced Raman spectroscopy (SERS) performance are proportional to the square of the local electromagnetic field (hot spot). However, a proven way to realize the enhancement in intensity and density of “hot spot” still needs to be investigated. Here, we report on multilayered Ag nanoparticle (Ag NP)/graphene coupled to an underlying Cu film system (MAgNP-CuF) which can be used as an effective SERS substrates realizing ultra-sensitive detection for toxic molecules and in situ monitoring the plasmon-driven reaction for p-nitrothiophenol (PNTP) to p,p′-dimercaptobenzene (DMAB) conversion. The mechanism of ultra-sensitive SERS response and catalytic reaction is investigated via Ag NP/graphene layer-dependent experiments combined with theoretical simulations. The research found that the intensity and density of “hot spot” can be effectively manipulated by the number of plasmonic layers, and the bottom Cu film could also reflect the scattered and excitation beam and would further enhance the Raman signals. Moreover, the MAgNP-CuF exhibits outstanding performance in stability and reproducibility. We believe that this concept of multilayered plasmonic structures would be widely used not only in the field of SERS but also in the wider research in photocatalysis.

中文翻译：

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通过在光激发下控制Ag NP /石墨烯层来操纵表面增强拉曼光谱（SERS）活性和等离激元驱动的催化效率

高效等离激元驱动的催化作用和出色的表面增强拉曼光谱（SERS）性能与局部电磁场（热点）的平方成正比。但是，仍然需要研究一种行之有效的方法来实现“热点”的强度和密度的增强。在这里，我们报道了与底层铜膜系统（MAgNP-CuF）耦合的多层银纳米粒子（Ag NP）/石墨烯，可以用作有效的SERS底物，实现对有毒分子的超灵敏检测并原位监测等离子体对硝基苯硫酚（PNTP）转化为对，p'-二巯基苯（DMAB）的反应。通过Ag NP /石墨烯层相关实验和理论模拟，研究了超敏SERS反应和催化反应的机理。研究发现，可以通过等离激元层的数量有效地控制“热点”的强度和密度，并且底部的铜膜也可以反射散射和激发束，并进一步增强拉曼信号。而且，MAgNP-CuF在稳定性和再现性方面表现出优异的性能。我们相信，这种多层等离激元结构的概念将不仅在SERS领域中得到广泛应用，而且将在光催化领域中得到更广泛的研究。