Piezoelectric-driven self-powered sensor with tunable plasmonic hotspots for enhanced SERS performance

Electrically Modulated Surface-enhanced Raman spectroscopy (E-SERS) technology can effectively increase Raman signal intensity. Compared with conventional E-SERS, self-powered E-SERS sensors provide an electric field through energy conversion, which reduces the dependence on external power sources and thus facilitates the development of portable real sample detection. Herein, high-performance piezoelectric lead zirconate titanate (PZT) with dopamine-functionalized reduced graphene oxide (rGO@PDA) was embedded into a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) matrix, which was innovatively used for E-SERS technology. In particular, by applying external pressure to the PVDF-TrFE/PZT-rGO@PDA/Ag self-powered sensors, the surface localized electromagnetic field can be efficiently enhanced, which combines with the localized surface plasmon resonance (LSPR) effect of the Ag nanoparticles (NPs) to achieve highly tunable signal enhancement. As a proof-of-concept, voltage and current signals were generated by pressing the substrate, and Raman signal enhancement was also realized for molecules such as Rhodamine 6G (R6G) and Methyl Orange (MO). The self-powered sensor exhibits ultra-high sensitivity and excellent reproducibility for a wide range of probe molecules, especially thiram, with a low limit of detection (LOD) of 10^-12 M, determining a low variation of 8.5 %. Additionally, the substrate successfully detected 10^-7 M malachite green (MG) fungicide residue on fish skin and 10^-7 M sulfamonomethoxine (SMM) antibiotic residue in chicken breast by pressing, proving its great potential for application in food contaminant monitoring.