Ultra-Sensitive and Selective Surface Plasmon Resonance using Ag Metal, Carbon Nanotube, and Selenium Based Biosensors for the Detection of Ascorbic Acid

In this work, we present a novel surface plasmon resonance (SPR) sensor for ascorbic acid detection based on a borosilicate crown (BK7) prism coated with a multilayer structure made of ferric oxide (Fe2O3), silver (Ag), and carbon nanotube (CNT). The SPR sensor improves sensitivity and selectivity for ascorbic acid detection by taking advantage of the special optical characteristics of the multilayer construction. The CNT layer offers increased surface area and biocompatibility, and the Ag layer acts as a plasmonic material to promote surface plasmons. The performance of the sensor is improved by the addition of selenium (Se) and Fe2O3 layers, which provide further capabilities like photoconductivity and magnetic manipulation, respectively. Numerical analysis at the operating wavelength of 633 nm is conducted using the transfer matrix approach. For the proposed SPR sensor at room temperature, the performance characteristics, including sensitivity (274.37 degree (°)/RIU), figure of merit (40.60 RIU−1), and detection accuracy (0.189°−1), are computed. The proposed SPR sensor could be very useful in to detect ascorbic acid in the visible range.