A general strategy for enhancing the photoluminescence of TMD quantum sheets†

Abstract

Two-dimensional transition metal dichalcogenide (TMD) quantum sheets (QSs) with intrinsic characteristics promise new research topics and applications. However, their absolute photoluminescence quantum yield (PLQY) is far from being satisfactory. Herein, we report a general PL enhancement strategy based on passivation with polar solvent. The edge-passivated TMD QSs demonstrate solid-state fluorescence with high PLQYs. The material diversity of the passivation strategy is testified by using tungsten disulfide (WS₂), molybdenum diselenide (MoSe₂), bismuth selenide (Bi₂Se₃), and tungsten diselenide (WSe₂) as examples. Particularly, the passivated WS₂ QSs (P-WS₂ QSs) in poly(methyl methacrylate) exhibit an exceedingly high PLQY of 27.7% compared with that (4.1%) of the intrinsic WS₂ QSs. Furthermore, the P-WS₂ QSs are utilized in commercial light-emitting diodes (LEDs), enabling white-light emission which can be filtered into a sharp, blue emission, thus they function as highly luminescent blue LEDs. Note that the intrinsic WS₂ QSs are almost inert to commercial LEDs, which in turn indicates the unique contribution of the P-WS₂ QSs. Our work highlights the great potential of passivated TMD QSs in applications such as LEDs.