Surface-enhanced Raman scattering (SERS) holds significant potential across environmental monitoring, materials science, and biomedical applications. However, challenges regarding ultra-sensitive detection and repeatability are bottlenecks for practical applications, especially in terms of detection uniformity. In this study, we utilized surface acoustic waves (SAW) in conjunction with Raman spectroscopy to actively enrich 5 μL of 50 nm gold nanoparticles (AuNPs), thereby achieving innovative SERS-active sensing. This dynamic enrichment process enables the dense and uniform aggregation of AuNPs in droplets, thereby facilitating reliable ultrasensitive detection. The SAW system was further optimized through hydrophobic surface treatment. Using 4-mercaptobenzoic acid as a probe analyte, our SAW-SERS method successfully detected concentrations as low as 10⁻⁸ mol/L. The surface acoustic waves had the capability to significantly amplify Raman signal intensity up to 100 compared to conventional drying methodologies. This SAW-induced AuNP clustering technology offers a rapid, label-free SERS sensing method characterized by exceptional sensitivity and uniformity.

Organic–inorganic hybrid perovskites (OIHPs) have been widely used in fields such as solar cells, photodetectors, and light-emitting diodes due to their simple preparation by solution methods and excellent optoelectronic properties. In recent years, numerous scholars have delved deeply into the magneto-optical properties of perovskites and explored their potential applications in the magneto-optical field. Herein, we present the Faraday rotation characteristics of formamidinium lead bromide (Fabri₃) single crystals within the visible spectrum range. Firstly, FAPbBr₃ single crystals with high transparency and a size of 5.5 × 5.6 × 2 mm³ were prepared using the modified inverse temperature crystallization (MITC) method. The experimental results showed that the Verdet constant of FAPbBr₃ single crystal at 565 nm was up to 531.6 rad/(T·m). Furthermore, the FAPbBr₃ single crystal showed similar or an even higher Verdet constant when compared with the mature magneto-optical material TGG single crystal commonly used in the industry. The thermal simulation results of the FAPbBr₃ single crystal show low temperature dependence which achieves about 90% isolation transparency with a magnetic field of 0.35 T for 625 nm. This study demonstrates the outstanding Faraday rotation properties of FAPbBr₃ single crystals, thereby offering promising prospects for the development of perovskite materials in non-reciprocal devices such as optical isolators and optical circulators.