Robust B-exciton emission at room temperature in few-layers of MoS(2):Ag nanoheterojunctions embedded into a glass matrix

Tailoring the photoluminescence (PL) properties in two-dimensional (2D) molybdenum disulfide (MoS(2)) crystals using external factors is critical for its use in valleytronic, nanophotonic and optoelectronic applications. Although significant effort has been devoted towards enhancing or manipulating the excitonic emission in MoS(2) monolayers, the excitonic emission in few-layers MoS(2) has been largely unexplored. Here, we put forward a novel nano-heterojunction system, prepared with a non-lithographic process, to enhance and control such emission. It is based on the incorporation of few-layers MoS(2) into a plasmonic silver metaphosphate glass (AgPO(3)) matrix. It is shown that, apart from the enhancement of the emission of both A- and B-excitons, the B-excitonic emission dominates the PL intensity. In particular, we observe an almost six-fold enhancement of the B-exciton emission, compared to control MoS(2) samples. This enhanced PL at room temperature is attributed to an enhanced exciton–plasmon coupling and it is supported by ultrafast time-resolved spectroscopy that reveals plasmon-enhanced electron transfer that takes place in Ag nanoparticles-MoS(2) nanoheterojunctions. Our results provide a great avenue to tailor the emission properties of few-layers MoS(2), which could find application in emerging valleytronic devices working with B excitons.