investigating the effects of phosphorene nanotubes (pnts)-on-gold substrates on the enhancements of the sensitivity of spr biosensors

Surface plasmon resonance (spr) sensors have been widely considered for their sensitivity, accuracy, and appropriate response speed. this article simulates and analyzes the effects of phosphorene nanotubes (pnts) layer with various diameters and rolling directions on the structure of spr biosensor in the lumerical software environment. the main structure is based on the structure of kretschmann and the use of the bk7 prism, a gold (au) layer, and the end layer of phosphorene nanotubes. the proposed spr biosensor reflectance curves are obtained, analyzed, and compared for various modes of refractive index n = 1.33 and 1.339, resembling a neutral watery medium and a bacterial medium, respectively. the results show that the minimum reflection is achieved for 30 nm au at an spr resonance angle of θ = 71.59° while by adding phosphorene nanotubes, it is observed that at a diameter of 10.08 a and an armchair rolling direction, the configuration on the au layer becomes favorable. the minimum reflectance of 0.199 is observed for the armchair phosphorene nanotubes (10.08a) layer over 30 nm au. the combination also provides a sensitivity of 152°/riu for δn = 0.009 with a high detection accuracy of 0.079. the results demonstrate that the layer of phosphorene nanotubes has a positive effect on spr biosensors, and it can be used as a controlling factor in spr biosensors.