Plasmonic Signal Amplification Through a V2O5–Nickel Foam Interface for Precision Refractive Index Biosensing

This study theoretically investigates a surface plasmon resonance (SPR) sensor that includes a CaF2 prism. Silver (Ag) and vanadium pentoxide/nickel (V2O5/Ni) foam layers for the detection of analytes with refractive indices (RIs) between 1.33 and 1.35. The transfer matrix method (TMM) was used to analyze the optical response of the sensor at a wavelength of 633 nm. The plasmonic interaction was significantly enhanced by the addition of a V2O5/Ni foam layer, resulting in sharper reflectivity curves and increased sensitivity. Various parameters, such as sensitivity, detection accuracy (DA), figure of merit (FoM), and penetration depth (PD), were obtained at the optimized Ag thickness. The maximum sensitivity of 398.95 °/RIU was attained at an Ag thickness of 46 nm with an RI of 1.34. The proposed sensor is suitable for chemical and biomedical sensing applications, such as disease diagnosis and biomolecular detection, owing to its exceptional capacity to detect minute changes in the RI.