The capabilities of light-emitting diodes (LEDs) based on two-dimensional materials are restricted by efficiency roll-off, which is induced by exciton–exciton annihilation, at high current densities. Dielectric or strain engineering can be used to reduce exciton–exciton annihilation rates in monolayer transition metal dichalcogenides, but achieving electroluminescence in two-dimensional LEDs without efficiency roll-off is challenging. Here we describe pulsed LEDs that are based on intercalated transition metal dichalcogenides and offer suppressed exciton–exciton annihilation at high exciton generation rates. We intercalate oxygen plasma into few-layer molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂) to create LEDs with a suppressed efficiency roll-off in both photo-excitation and electro-injection luminescence at all exciton densities up to around 10²⁰ cm⁻² s⁻¹. We attribute this suppression to a reduced exciton Bohr radius and exciton diffusion coefficient, as extracted from optical spectroscopy measurements. LEDs based on intercalated MoS₂ and WS₂ operate at maximum external quantum efficiencies of 0.02% and 0.78%, respectively, at a generation rate of around 10²⁰ cm⁻² s⁻¹.

基于二维材料的发光二极管 （LED） 的能力受到高电流密度下由激子-激子湮没引起的效率滚降的限制。介电或应变工程可用于降低单层过渡金属硫化物中的激子-激子湮没速率，但在二维 LED 中实现电致发光而不产生效率滚降是具有挑战性的。在这里，我们描述了基于插层过渡金属二硫化物的脉冲 LED，并在高激子产生速率下提供抑制的激子-激子湮没。我们将氧等离子体嵌入到少层二硫化钼 （MoS₂） 和二硫化钨 （WS₂） 中，以制造在所有激子密度高达 10^{20 cm-2 s-1} 左右的光激发和电注入发光中具有抑制效率滚降的 LED。我们将这种抑制归因于从光谱测量中提取的激子玻尔半径和激子扩散系数的减小。基于插层 MoS₂ 和 WS₂ 的 LED 分别以 0.02% 和 0.78% 的最大外部量子效率运行，产生速率约为 10²⁰ cm⁻² s⁻¹。