Modeling of a fiber optic SPR biosensor employing Tin Selenide (SnSe) allotropes

We report an unique design of a fiber optic SPR biosensor in this study utilizing two-dimensional (2D) Tin Selenide (SnSe) allotropes not revealed before. Due to enhanced optical characteristics with 2D graphene-like structure of monolayer SnSe, recently it is getting much attraction by the researchers to use as a biomolecular recognition element (BRE) in sensor design. Sensitivity of the proposed fiber optic sensor with three sorts of monolayer allotropes of SnSe (alpha-SnSe, delta-SnSe and epsilon-SnSe) as a BRE is analyzed through wavelength interrogation scheme for sensing application. Results show that sensors with alpha-SnSe, delta-SnSe and epsilon-SnSe exhibit sensitivities of 3225 nm/RIU, 3300 nm/RIU and 3475 nm/RIU respectively. It is obvious that proposed sensor with improved sensitivity outperforms the conventional Ag-only based sensors having poor sensitivity of 1800 nm/RIU. Thus the proposed SnSe allotropes can be reasonable alternate of conventional BRE to design extremely high sensitive fiber optic SPR biosensors for DNA hybridization.