A Label-Free Surface Plasmon Resonance Biosensor for Chemical Sensing

In this work, we present a surface plasmon resonance (SPR) sensor based on a BK7 prism-silver (Ag)-aluminum phosphate (AlPO4\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${AlPO}_{4}$$\end{document})-2D material structure for the detection of various chemical compounds. To design this structure, Kretschmann configuration is used. The sensor's performance is analyzed using the transfer matrix method along with the angular interrogation technique at the wavelength of 633 nm. In the proposed sensor, Ag is used as metallic layers to generate the surface plasmon on the surface of prism. Also, it provides a sharp resonance dip that leads a high resolution. However, it has a problem with getting oxidized with the environment changes; therefore, AlPO4\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${AlPO}_{4}$$\end{document} is deposited on top of Ag to address this and enhance the sensor's performance. Moreover, 2D material is placed on AlPO4\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${AlPO}_{4}$$\end{document} to enhance the sensor's performance further due to their exceptional properties. Finally, to sense the chemical compounds, different refractive indices from 1.4021 to 1.4072 are considered, as demonstrated with analytes like n-butyl chloride, 2-methoxyethanol, cyclopentane, methyl isoamyl ketone, and tetrahydrofuran. Results exhibit a maximum sensitivity of 432.0697 degrees/RIU, a quality factor (QF) of 173.4662 RIU(-)1, and a detection accuracy (DA) of 0.7459 1/RIU through the detection of various chemical samples, demonstrating excellent improvements over existing methodologies. Additionally, the standard fabrication steps were explored for the experimental feasibility of the proposed sensor. Therefore, the proposed sensor can be used to enhance the sensor performance as well as stands as a novel platform for the biological and biomedical applications.