Mathematical modeling of surface plasmon and detection of DNA hybridization using novel SPR sensor

In this article, we have proposed a novel Kretschmann's configuration-based surface plasmon resonance (SPR) sensor structure with gold (Au) or silver (Ag) and perovskite material, to detect the change in refractive index (RI) due to Deoxyribonucleic acid (DNA) hybridization. The proposed SPR sensor structure consists of SF01/Cr₂O₃/(Au/Ag)/perovskite/graphene/analyteslayer. Each layer of the proposed structure is judiciously optimized by observing the minimum reflectance (R_min→0), and FWHM (width) value using Fresnel reflection, and transfer matrix method (TMM). Moreover, we have developed a mathematical model to calculate the surface plasmon generation and quality factor for the graphene layer due to the injection of electrons to the upper sub-band from the lower sub-band of graphene, which helps to understand the interaction with the analyte sample. Reflectance spectra demonstrate a significant shift in resonance angle for ssDNA and dsDNA. Furthermore, we have analyzed the performance parameters and observed outstanding sensitivity, remarkable percentage change in quality factor, extraordinary percentage change in figure of merit (FoM), and dip figure of merit (DFoM) in the case of silver (Ag) in contrast to gold (Au) using CsSnI₃ perovskite material layer. The enhancement of performance parameters is due to better interaction of graphene with the free charge carriers of DNA, which leads to molecular mass or weight change during the hybridization. Therefore, the proposed SPR sensor might be a prominent biosensor for detecting DNA hybridization.