Blue Light-Emitting Diodes Enabled by Edge-Passivated MoS ₂ Quantum Sheets

Transition metal dichalcogenide (TMD) light-emitting diodes (LEDs) have attracted significant interest in recent years. Previously, defect passivation and heterostructure construction have been usually used to improve the electronic properties of the emitting layer. However, the effect of passivation is far from satisfactory due to the size and many-body effects of the TMD materials. Here, the edge dangling bonds of the intrinsic MoS₂ quantum sheets were passivated by heat treatment with tetrahydrofuran, which prevents the nonradiative recombination caused by edge relaxation and increases the absolute photoluminescence quantum yield (PLQY) to 39.9%. More importantly, blue LEDs with an emission wavelength of 455 nm and an external quantum efficiency (EQE) of 5.4% are fabricated based on edge-passivated MoS₂, which is the first report from TMD QD/QSs. The edge passivation of MoS₂ with high PLQY and EQE reveals an efficient approach for the development of highly efficient photonic applications.