Tuning Photoluminescence Performance of Monolayer MoS₂ via H₂O₂ Aqueous Solution

We demonstrate a simple while very effective approach to tune the photoluminescence (PL) performance of monolayer MoS₂ by dipping into the H₂O₂ aqueous solution, which is a strong oxidizer that extracts electrons from the MoS₂ sheet within several seconds without damaging the crystal structure. During this process, the trion (electron-coupled exciton, X^?) is transformed into an exciton (X^o), and thus achieves a greatly enhanced PL performance. These results indicate a convenient way to tune and to control the PL luminescence from monolayer MoS₂ and thus lay a basis for the MoS₂-based optoelectronic application.