Hollow plasmonic nanostructures with built-in and accessible electromagnetic hotspots such as nanorattles, obtained through a galvanic replacement reaction, have received wide attention in chemical and biological sensing and targeted drug delivery. In this study, we investigate the surface enhanced Raman scattering (SERS) activity of plasmonic nanorattles obtained through different degrees of galvanic replacement of Au@Ag nanocubes. We found that the SERS efficacy of the nanorattles is governed by the plasmon extinction intensity, localized surface plasmon resonance (LSPR) wavelength of the nanostructures with respect to the excitation source and intensity of the electromagnetic field at the hotspot, with the latter playing a determining role. Finite-difference time-domain (FDTD) simulations showed excellent agreement with the experimental findings that an optimal degree of galvanic replacement is critical for maximum SERS enhancement. The rational design and synthesis of the plasmonic nanorattles based on these findings can make these nanostructures highly attractive for SERS-based chemical and biological sensing and bioimaging.

中文翻译：

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具有内置电磁热点的等离激元纳米ra的结构依赖性SERS活性

通过电置换反应获得的具有内置且可接近的电磁热点（例如纳米ra）的空心等离激元纳米结构在化学和生物传感以及靶向药物递送中受到了广泛关注。在这项研究中，我们研究了通过不同程度的Au @ Ag纳米立方体的电流置换获得的等离激元纳米ra的表面增强拉曼散射（SERS）活性。我们发现纳米ra的SERS功效受等离子体消光强度，相对于激发源的纳米结构的局部表面等离子体共振（LSPR）波长和热点处的电磁场强度的控制，后者起着决定性作用角色。时域有限差分（FDTD）模拟与实验发现极好吻合，实验发现最佳的电流置换对最大程度地增强SERS至关重要。基于这些发现的等离子体纳米nano的合理设计和合成可以使这些纳米结构对基于SERS的化学和生物传感以及生物成像具有高度的吸引力。