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ACS Appl Mater Interfaces. 2018 Aug 1;10(30):25401-25408. doi: 10.1021/acsami.8b07138. Epub 2018 Jul 20.

Unraveling the Mechanism of Photoinduced Charge-Transfer Process in Bilayer Heterojunction.

Jin H1, Li J1, Wei Y1, Dai Y2, Guo H1,3.

Author information

1
Shenzhen Key Laboratory of Advanced Thin Films and Applications, College of Physics and Energy , Shenzhen University , Shenzhen 518060 , People's Republic of China.
2
School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , People's Republic of China.
3
Centre for the Physics of Materials and Department of Physics , McGill University , Montréal H3A 2T8 , Canada.

Abstract

Charge transfer is a fundamental process that determines the performance of solar cell devices. Although great efforts have been made, the detailed mechanism of charge-transfer process across the two-dimensional van der Waals (vdW) heterostructure remains elusive. Here, on the basis of the ab initio nonadiabatic molecular dynamics simulation, we model the photoinduced charge-transfer dynamics at the InSe/InTe vdW heterostructures. Our results show that carriers can follow either the R-scheme or Z-scheme transfer path, depending on the coupling between the interlayer states at the band-edge positions. In addition, the charge-transfer dynamics can be effectively controlled by the external parameters, such as strains and interlayer stacking configurations. The predicated electron-hole recombination lifetime in the R-scheme transfer path is up to 1.4 ns, whereas it is shortened to 1.2 ps in the Z-scheme transfer path. The proposed R-scheme and Z-scheme are further verified by the quantum transport simulations on the basis of the density functional theory (DFT) method combined with nonequilibrium Green's functions (NEGF-DFT). The analysis reveals that the system dominated by the Z-scheme shows better performance, which can be attributed to the built-in electric field that facilitates the charge transfer. Our work may pave the way for the designing of next-generation devices for light detecting and harvesting.

KEYWORDS:

Two-dimensional heterostructure; Z-scheme; built-in electric field; charge-transfer dynamics; solar cell; type-II band alignment

PMID:
29987925
DOI:
10.1021/acsami.8b07138

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