Three-dimensional (3D) plasmonic nanostructures with nanoparticles that can be tuned have got a lot of attention in surface-enhanced Raman scattering (SERS) due to the unique 3D plasmonic coupling. Here, two nanoparticles, gold nanosphere (AuNS) and gold nanooctahedra (AuNO), were used to construct 3D hybrid SERS substrates to investigate the effect of nanoparticle spatial position on the SERS performance of the 3D nanostructure and to obtain 3D substrates with high SERS activity. And more hybrid combination possibilities were tested to explore the variation trend of hot spots generated when the nanoparticles were near. First, two-dimensional (2D) planar substrates were prepared using the air–liquid interface-assisted self-assembly method, to examine the effect of nanoparticle size on SERS performance. Then, 3D hybrid SERS substrates were further prepared layer by layer to discuss the effect of different combination methods within three layers on SERS performance. The optimized 3D hybrid substrate with the sandwich structure of AuNS/AuNO/AuNS performed the strongest SERS enhancement effect, whose intensity was 4.1 and 1.9 times that of AuNS/AuNS/AuNS and AuNO/AuNO/AuNO, respectively, and had good reproducibility (relative standard deviation (RSD) of 1.08%). Furthermore, the thiram molecular result showed that the prepared AuNS/AuNO/AuNS had good linear relationship (R² of 0.991) and good molecule detection sensitivity (the minimum detection volume of thiram is 100 ppb), which demonstrated the great potential of the 3D hybrid SERS substrates in practical analysis.

中文翻译：

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3D混合SERS基板的制备优化与应用

由于独特的 3D 等离子体耦合，具有可调谐纳米粒子的三维 (3D) 等离子体纳米结构在表面增强拉曼散射 (SERS) 中引起了广泛关注。本文采用金纳米球 (AuNS) 和金纳米八面体 (AuNO) 两种纳米颗粒构建 3D 杂化 SERS 基底，以研究纳米颗粒空间位置对 3D 纳米结构的 SERS 性能的影响，并获得具有高 SERS 活性的 3D 基底. 并测试了更多混合组合的可能性，以探索纳米粒子靠近时产生的热点的变化趋势。首先，使用气液界面辅助自组装方法制备二维（2D）平面基板，以检查纳米颗粒尺寸对 SERS 性能的影响。然后，进一步逐层制备3D混合SERS衬底，讨论三层内不同组合方法对SERS性能的影响。优化后的具有AuNS/AuNO/AuNS夹层结构的3D杂化衬底表现出最强的SERS增强效果，其强度分别是AuNS/AuNS/AuNS和AuNO/AuNO/AuNO的4.1倍和1.9倍，并且具有良好的重现性（相对标准偏差 (RSD) 为 1.08%)。此外，福美双分子结果表明，制备的AuNS/AuNO/AuNS具有良好的线性关系（分别是AuNS/AuNS/AuNS和AuNO/AuNO/AuNO的9倍，重现性好（相对标准偏差（RSD）为1.08%）。此外，福美双分子结果表明，制备的AuNS/AuNO/AuNS具有良好的线性关系（分别是AuNS/AuNS/AuNS和AuNO/AuNO/AuNO的9倍，重现性好（相对标准偏差（RSD）为1.08%）。此外，福美双分子结果表明，制备的AuNS/AuNO/AuNS具有良好的线性关系（R ²为0.991）和良好的分子检测灵敏度（福美双的最小检测体积为100 ppb），证明了3D混合SERS底物在实际分析中的巨大潜力。