A strategy for building ring-like deposit surface-enhanced Raman scattering (SERS) sensors with the coffee ring effect through the functional modification of the silica nanoparticle surface encapsulated by free-tagged Ag nanoparticles is addressed along with their applications in the SERS-based detection and degradation of target species, including paraquat, diquat, and their free radicals. The nanogap formed by two interparticles with SERS hotspots provides a gigantic amplification signal for the Raman scattering intensity of the analyte molecule located approximately at the hotspots. The enhanced Raman spectrum signals of these target analytes were achieved through the hotspot region of the surface plasmon resonance (SPR) located on the embankment formed by self-aggregation of SiO₂@Ag nanoparticles due to the coffee ring effect. Meanwhile, the intrinsic properties of Ag nanoparticles embedded onto the silica surface were applied to photocatalytically degrade the target analytes by harvesting energy from sunlight. The SERS sensor detected the analytes down to 10^–9 M in the aqueous solution.

中文翻译：

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构建具有咖啡环效应的环状自聚集 SERS 传感器，用于除草剂百草枯和敌草快的超灵敏检测和光催化降解

通过对自由标记的 Ag 纳米颗粒封装的二氧化硅纳米颗粒表面进行功能修饰，构建具有咖啡环效应的环状沉积表面增强拉曼散射 (SERS) 传感器的策略及其在基于 SERS 检测中的应用得到解决目标物种的降解，包括百草枯、敌草快及其自由基。由两个具有 SERS 热点的粒子间形成的纳米间隙为大约位于热点处的分析物分子的拉曼散射强度提供了巨大的放大信号。这些目标分析物的增强拉曼光谱信号是通过位于 SiO _{2自聚集形成的堤坝上的表面等离子体共振 (SPR) 的热点区域实现的}@Ag 纳米颗粒由于咖啡环效应。同时，将嵌入二氧化硅表面的银纳米粒子的固有特性应用于通过从阳光中收集能量来光催化降解目标分析物。SERS 传感器检测到水溶液中低至 10 ^{–9 M 的分析物。}