Two-dimensional transition metal dichalcogenides mediated long range surface plasmon resonance biosensors

Abstract

Two-dimensional transition metal dichalcogenides (TMDCs), as promising alternative plasmon supporting materials to graphene, exhibit potential applications in sensing. Here, we propose a TMDCs-mediated long range surface plasmon resonance (LRSPR) imaging biosensor, which shows tremendous improvements in both imaging sensitivity (2) and detection accuracy (10) as compared to conventional surface plasmon resonance (cSPR) biosensors. It is found that the imaging sensitivity of the LRSPR biosensor can be enhanced by the integration of TMDC layers, which is different from the previously reported graphene-mediated cSPR imaging sensor, whose imaging sensitivity decreases with the number of graphene layers. This imaging sensitivity enhancement effect for the TMDCs-mediated LRSPR sensor originates from the propagating nature of the LRSPR at both interfaces of sensing medium/gold and gold/cytop layer (with a matching refractive index as sensing medium). By tuning the thickness of gold film and cytop layer, it is possible to achieve optimized imaging sensitivity for LRSPR sensors with any known integrated number of TMDC layers and an analyte refractive index. The proposed TMDCs-mediated LRSPR imaging sensor could provide potential applications in chemical sensing and biosensing.