Sensitivity enhancement of surface plasmon resonance sensors with 2D franckeite nanosheets

As a latest novel two-dimensional (2D) material with naturally occurring van der Waals heterostructure, franckeite has the unique advantages compared with the artificial stacking heterostructures. Herein, we propose a surface plasmon resonance (SPR) sensor with 2D franckeite nanosheets to improve the sensitivity. In this structure, franckeite is covered on the surface of 50 nm silver film, so that the SPR sensitivity is related to the thickness of the franckeite overlayer. The sensitivity as high as 188 degrees/RIU in theory has been obtained, which is a 62% increasing compared with the conventional SPR biosensor. Moreover, an additional film of graphene is considered for the virtue of bio-compatible, and the sensitivity of the franckeite-graphene heterostructures is furthermore improved. As an air-stable 2D material, we believe that 2D franckeite nanosheets could have potential applications in the field of chemical and biological sensors in the future.