Zeng Huadong, Liu Xiangyue, Zhang Hong, Cheng Xinlu
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
Phys Chem Chem Phys. 2021 Jan 6;23(1):694-701. doi: 10.1039/d0cp04517a.
Shedding light on the dynamics of charge transfer is fundamental and important to understand the light-photocurrent power conversion in transition-metal dichalcogenide (TMD) heterostructures. Herein, based on time-dependent ab initio nonadiabatic molecular dynamics simulation, we studied the photoinduced carrier transfer dynamics in the WS2/WSe2 heterostructure and further analyzed the effects of stacking configuration and temperature. Our calculations show that the time scales of ultrafast hole transfer in the C7 and T stacking configurations are 35 fs and 30 fs, respectively, which are mainly caused by the adiabatic charge transfer mechanism. Meanwhile, the time scales of ultrafast electron transfer in the C7 and T stacking configurations are 12 fs and 40 fs, respectively, which are in good agreement with the experimental result. We also investigated in detail the photoinduced carrier transfer pathways of C7 and T stacking configurations, which appear to have some significant differences. In addition, we found that the temperature basically has no effect on the electron transfer dynamics of the WS2/WSe2 heterostructure; this is in excellent agreement with the experimental observation. In short, the reported findings can provide more in-depth insights into the photoinduced carrier transfer dynamics of TMD-based van der Waals heterostructures.
揭示电荷转移的动力学对于理解过渡金属二硫属化物（TMD）异质结构中的光-光电流功率转换至关重要。在此，基于含时从头算非绝热分子动力学模拟，我们研究了WS2/WSe2异质结构中的光致载流子转移动力学，并进一步分析了堆叠构型和温度的影响。我们的计算表明，C7和T堆叠构型中超快空穴转移的时间尺度分别为35飞秒和30飞秒，这主要是由绝热电荷转移机制引起的。同时，C7和T堆叠构型中超快电子转移的时间尺度分别为12飞秒和40飞秒，这与实验结果吻合良好。我们还详细研究了C7和T堆叠构型的光致载流子转移途径，它们似乎存在一些显著差异。此外，我们发现温度对WS2/WSe2异质结构的电子转移动力学基本没有影响；这与实验观察结果非常吻合。简而言之，所报道的研究结果可以为基于TMD的范德华异质结构的光致载流子转移动力学提供更深入的见解。
