Black Phosphorus Based SPR Biosensor for Formaldehyde Detection

A surface plasmon resonance (SPR) biosensor implementing Kretschmann configuration is proposed to enhance performance in detecting formalin in liquid. Slight changes are done in the metal layer by varying between gold (Au) and silver (Ag) as metal layer and Black Phosphorus (BP) as 2D semiconductor layer and to observe the best performing combination. In the case of this theoretical analysis, a rigorous simulation has been done for the result and output. To achieve the most effective possible combination, BP layer thickness is altered. Among them Ag and BP with Indium Phosphide (InP) layer showed overall best performance showing maximum detection accuracy. Moreover, comparisons are made between FWHM, Sensitivity, and Figure of Merit (FoM). The combination of the materials helped to obtain better values of the performance parameters of the device. To assess the device's performance, the angular interrogation technique is employed. Transfer matrix method (TMM) is implemented to avoid prediction and obtain more accurate results. The proposed sensor will help in detecting formalin for the aqueous sensing medium more accurately.