Oxidation Notably Accelerates Nonradiative Electron-Hole Recombination in MoS2 by Different Mechanisms: Time-Domain Ab Initio Analysis.,The Journal of Physical Chemistry Letters

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Oxidation Notably Accelerates Nonradiative Electron-Hole Recombination in MoS2 by Different Mechanisms: Time-Domain Ab Initio Analysis.
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2020-05-07 , DOI: 10.1021/acs.jpclett.0c01056
Xiaoli Wang ₁ , Run Long ₁

Affiliation

Two-dimensional transition metal dichalcogenides (TMDs) experience degradation in optoelectronic properties under ambient conditions. By performing nonadiabatic (NA) molecular dynamics simulations, we demonstrate that the MoS2 monolayer containing substitutional oxygen and oxygen adatom accelerates nonradiative electron-hole recombination by a factor of about 1.5 compared to perfect film but operates by different mechanisms. The substitutional oxygen creates no midgap states while enhancing NA coupling by increasing the overlap between electron and hole wave functions, accelerating electron-hole recombination. In contrast, electrons significantly populate the deep trap state created by the oxygen adatom because the trap is modestly delocalized and coupled strongly to free charges. The trap mediated instead of the direct pathway dominates the electron-hole recombination. The generated insights uncover the mechanisms for different types of defects on influencing charge dynamics in TMDs and suggest that the oxygen defects should be avoided for the design of high-performance optoelectronic devices.

中文翻译：

氧化通过不同机制显着加速MoS2中的非辐射电子-孔复合：时域从头算分析。

二维过渡金属二卤化物（TMD）在环境条件下的光电性能会下降。通过执行非绝热（NA）分子动力学模拟，我们证明了含有取代氧和氧原子的MoS2单层与非理想膜相比，可加速非辐射电子-空穴复合的速度约为1.5，但可通过不同的机理进行操作。取代氧不产生任何中间能隙态，同时通过增加电子和空穴波功能之间的重叠来增强NA耦合，加速电子-空穴复合。相比之下，电子会显着填充由氧原子形成的深陷阱态，因为陷阱会适度地离域并与自由电荷强烈耦合。介导的陷阱而不是直接途径主导了电子-空穴复合。所产生的见解揭示了影响TMDs中电荷动力学的不同类型缺陷的机理，并建议在设计高性能光电器件时应避免氧缺陷。

更新日期：2020-04-30

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