Wang Haoyang, Wang Jun, Chen Huamin, Fu Xinhai, Fu Jiaqi, Huang Yanqi, Zhang Yang
Fujian Key Laboratory of Functional Marine Sensing Materials, College of Material and Chemical Engineering, Minjiang University, Fuzhou, 350108, China.
Fujian Key Laboratory of Functional Marine Sensing Materials, College of Material and Chemical Engineering, Minjiang University, Fuzhou, 350108, China.
Talanta. 2025 May 15;287:127624. doi: 10.1016/j.talanta.2025.127624. Epub 2025 Jan 23.
In this study, we develop a filter paper-supported Ag nanowire (AgNWs) substrate coated with a tunable layer of zeolitic imidazolate framework-67 (ZIF-67) metal-organic framework (MOF) for surface-enhanced Raman scattering (SERS) applications. The thickness of the ZIF-67 layer is precisely controlled by adjusting the soaking time, allowing us to investigate the influence of MOF thickness on SERS performance using probes with different sizes. Sensitivity for large, impenetrable molecules such as thiram and rhodamine 6G (R6G) are primarily governed by localized surface plasmon resonance (LSPR), while smaller, penetrable molecules like 4-mercaptobenzoic acid (4-MBA) exhibit enhanced sensitivity driven by charge transfer (CT) effects due to their ability to penetrate the MOF layer. A finite-difference time-domain (FDTD) simulation reveals that the porous structure of ZIF-67 facilitates electric field propagation to the probe, maintaining significant LSPR effects even beyond 200 nm from the AgNWs. Practical applicability is demonstrated using a wiping mode to detect thiram spiked on apple surfaces, with reliable linear detection achieved across a wide range of concentrations. This study underscores the potential of MOF-based hybrid SERS substrates for real-world applications, leveraging the complementary roles of CT and electromagnetic (EM) mechanisms to enhance sensitivity.
在本研究中，我们开发了一种由滤纸支撑的银纳米线（AgNWs）基底，其上涂覆有可调谐的沸石咪唑酯骨架-67（ZIF-67）金属有机框架（MOF）层，用于表面增强拉曼散射（SERS）应用。通过调整浸泡时间精确控制ZIF-67层的厚度，这使我们能够使用不同尺寸的探针研究MOF厚度对SERS性能的影响。对于诸如福美双和罗丹明6G（R6G）等较大的、不可穿透的分子，其灵敏度主要由局部表面等离子体共振（LSPR）决定，而像4-巯基苯甲酸（4-MBA）这样较小的、可穿透的分子，由于它们能够穿透MOF层，表现出由电荷转移（CT）效应驱动的增强灵敏度。时域有限差分（FDTD）模拟表明，ZIF-67的多孔结构有助于电场向探针传播，即使在距AgNWs超过200 nm的距离处仍保持显著的LSPR效应。通过擦拭模式检测苹果表面添加的福美双，证明了其实际适用性，在很宽的浓度范围内实现了可靠的线性检测。本研究强调了基于MOF的混合SERS基底在实际应用中的潜力，利用CT和电磁（EM）机制的互补作用来提高灵敏度。
