Surface-enhanced Raman scattering (SERS) substrates based on chemical mechanism (CM) have received widespread attentions for the stable and repeatable signal output due to their excellent chemical stability, uniform molecular adsorption and controllable molecular orientation. However, it remains huge challenges to achieve the optimal SERS signal for diverse molecules with different band structures on the same substrate. Herein, we demonstrate a graphene oxide (GO) energy band regulation strategy through ferroelectric polarization to facilitate the charge transfer process for improving SERS activity. The Fermi level (E_f) of GO can be flexibly manipulated by adjusting the ferroelectric polarization direction or the temperature of the ferroelectric substrate. Experimentally, kelvin probe force microscopy (KPFM) is employed to quantitatively analyze the E_f of GO. Theoretically, the density functional theory calculations are also performed to verify the proposed modulation mechanism. Consequently, the SERS response of probe molecules with different band structures (R6G, CV, MB, PNTP) can be improved through polarization direction or temperature changes without the necessity to redesign the SERS substrate. This work provides a novel insight into the SERS substrate design based on CM and is expected to be applied to other two-dimensional materials.

Cavity array, with excellent optical capture capability, has received increasing attention for the surface‐enhanced Raman spectroscopy (SERS)‐active substrates. Here, we proposed molybdenum disulfide (MoS ₂ ) nanocavities growing on pyramid Si (PSi) composed of in situ reduced Au nanoparticles (AuNPs), which can form the multiscale cavities (MSCs), and is facile for the couple of the plasmon. We demonstrated that the PSi/MoS ₂ /Au MSCs can serve as highly sensitive, uniform, and stable SERS substrates for rhodamine 6G (R6G), crystal violet, and adenosine triphosphate detection, benefiting from the synergistic effect of the enhanced light trapping and the effective plasmonic couple. The couple of the plasmon in the MSCs is evidently proved by finite‐difference time domain simulation, showing the strong electromagnetic field is located around the cavity wall. Moreover, the excellent hydrophobicity of the PSi/MoS ₂ /AuNPs substrate endows it with the ability for the directional monitoring of organic pollutant in a mixture of oil and water. Finally, we demonstrated the MSCs with outstanding photocatalytic performance could achieve the renewable utilization by self‐cleaning, which was attributed to the fast electron transfer and effective light absorption. The proposed PSi/MoS ₂ /AuNPs MSC represents a robust mean using the plasmonic metal/semiconductor heterostructure for high‐performance SERS sensors and photodegradation.

Quantitative detection of trace small-sized nanoplastics (<100 nm) remains a significant challenge in surface-enhanced Raman scattering (SERS). To tackle this issue, we developed a hydrophobic CuO@Ag nanowire substrate and introduced a multiplex-feature analysis strategy based on the coffee ring effect. This substrate not only offers high Raman enhancement but also exhibits a high probability of detection (POD), enabling rapid and accurate identification of 50 nm polystyrene nanoplastics over a broad concentration range (1–10⁻¹⁰ wt%). Importantly, experimental results reveal a strong correlation between the coffee ring formation and the concentration of nanoplastic dispersion. By incorporating Raman signal intensity, coffee ring diameter, and POD as combined features, we established a machine learning-based mapping between nanoplastic concentration and coffee ring characteristics, allowing precise predictions of dispersion concentration. The mean squared error of these predictions is remarkably low, ranging from 0.21 to 0.54, representing a 19 fold improvement in accuracy compared to traditional linear regression-based methods. This strategy effectively integrates SERS with wettability modification techniques, ensuring high sensitivity and fingerprinting capabilities, while addressing the limitations of Raman signal intensity in accurately reflecting concentration changes at ultra-low levels, providing a new idea for precise SERS measurements of nanoplastics.

Regulation of hot spots exhibits excellent potential in many applications including nanolasers, energy harvesting, sensing, and subwavelength imaging. Here, hat‐shaped hierarchical nanostructures with different space curvatures have been proposed to enhance hot spots for facilitating surface‐enhanced Raman scattering (SERS) and plasmon‐driven catalysis applications. These novel nanostructures comprise two layers of metal nanoparticles separated by hat‐shaped MoS ₂ films. The fabrication of this hybrid structure is based on the thermal annealing and thermal evaporation of self‐assembled polystyrene spheres, which are convenient to control the metal particle size and the curvature of hat‐shaped nanostructures. Based on the narrow gaps produced by the MoS ₂ films and the curvature of space, the constructed platform exhibits superior SERS capability and achieves ultrasensitive detection for toxic molecules. Furthermore, the surface catalytic conversion of p‐nitrothiophenol (PNTP) to p, p′‐dimercaptobenzene (DMAB) was in situ monitored by the SERS substrate. The mechanism governing this regulation of hot spots is also investigated via theoretical simulations.