Feasibility of Halide Perovskite Material–Based Hybrid Surface Plasmon Resonance Biosensor for Formalin Detection: A Numerical Investigation

The recurring consumption of formalin, a notorious preservative, can lead to a variety of lethal diseases and cause significant morbidity, highlighting the pressing need for its precise detection in developing nations. Hence, in this article, a Kretschmann configuration–based hybrid surface plasmon resonance (SPR) biosensor is proposed and analyzed numerically for formalin detection. The sensor heterostructure consists of five monolayers, namely, BAK1 prism, WS₂, silver, FASnI₃ halide perovskite (HP), and 2D black phosphorous (BP). The influence of an additional metal oxide layer (ZnO, TiO₂, SiO₂, Al₂O₃, and MoO₃) over the metallic layer is also investigated w.r.t. major performance indicators such as sensitivity, detection accuracy, quality factor, and figure of merit. Here, BP and HP jointly act as biomolecular recognition elements. Chitosan serves as a probe to react with formalin, which acts as the target molecule. Using the attenuated total reflection (ATR) concept and Fresnel equations, we have employed angular interrogation and transfer matrix approaches to detect the concentration of formalin by monitoring the variations in the minimum reflectance and maximum transmittance attributors in relation to SPR angle and SPR frequency (SPRF), respectively. The simulation findings demonstrate a minimal variation in SPR angle and SPRF for improper formalin sensing, confirming its absence in liquid solution. In contrast, the aforesaid attributors show significantly measurable changes when formalin is properly sensed, confirming its presence. We demonstrate that adding MoO₃ over the Ag layer can enhance the detection accuracy of our primary HP-based SPR biosensor to a maximum of 55.6%. The finite difference time domain (FDTD) technique is utilized to examine the distribution of electric fields within this biosensor structure to showcase the distinct contributions of HP and metal oxide. In the end, our simulation work is validated by a comparative study of the performance parameters with a few of the previous works on formalin detection.