Efficient all-optical MoS2/Au hybrid plasmon-exciton competitive response towards selective gas sensors

Abstract

In this study, we explore the realization of the optical concept of hybrid surface plasmon resonance (SPR) and lossy mode resonance (LMR), which facilitates plasmonic hot electron transfer from an Au thin film to MoS2 layers coated on a polymer optical fiber. The purpose of this experiment is to address the selective detection of humidity and volatile organic compounds in ambient conditions. By altering the properties of the surrounding environment, we can induce changes in the resonance dip wavelength stemming from the surface plasmon and lossy modes of the Au/MoS2 bilayer thin film coated on the optical fiber, acting as the transducing medium. Comparative experimental studies of transmitted light through the coated fiber reveal evidence of plasmon-enhanced charge injection from Au to a sensing surface, which relies on the competitive behavior of environment-induced conformational charge transfer. This provides substantial sensing enhancement towards optical devices based on hot-electrons technology. By optimizing the Au thickness and the MoS2 synthesis period, we obtained the most enhanced sensing performance, with a sensitivity of − 1.21 Δλ/RH% and a correlation factor of R2 = 0.99.