Enhanced Cu-Ni-TiO-BP Plasmonic Biosensor for Highly Sensitive Biomolecule Detection and SARS-CoV-2 Diagnosis

In this work, a bimetallic (Cu-Ni) prism-based surface plasmon resonance (SPR) sensor is presented. To enhance the interaction of bio-analytes with the sensing surface, a 2-D nanomaterial black phosphorous (BP) is used as it exhibits high biomolecule adsorption on its surface. Our investigation includes an assessment of key performance parameters such as sensitivity (S), full width at half maximum (FWHM), detection accuracy (DA), figure of merit (FoM), and penetration depth (PD). We meticulously optimized the thicknesses of the Copper, Nickel, and TiO2 layers to achieve optimal sensor performance. Our findings demonstrate that the highest sensitivity (S) is achieved with a configuration comprising a 25 nm layer of Cu, a 20 nm layer of Ni, a 1 nm layer of TiO2, and a monolayer of BP, resulting in a remarkable sensitivity (S) of 516°/RIU, with remarkable DA, FWHM, and FoM of 0.20/°, 6.15°, and 83.59/RIU, respectively. The incorporation of the TiO2 layer between the Ni and BP layers contributes to the enhanced sensitivity. Additionally, our proposed sensor configuration is well-suited for the detection of biomolecules within the refractive index (RI) range of 1.330–1.335. We further assessed the sensor’s capabilities in detecting the SARS-CoV-2 coronavirus, which exhibits RI values falling within the considered range (1.3348 and 1.3398). After optimizing the thickness of the metal layers, our sensor achieves an optimal sensitivity of 502°/RIU for SARS-CoV-2 virus detection. This configuration also maintains excellent DA, FWHM, and FoM values of 0.20/°, 4.9°, and 100.56/RIU, respectively.