Lau Guanghua, Li Yi, Zhang Yongfan, Lin Wei
State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of China.
Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen, Fujian 361005, People's Republic of China.
J Chem Phys. 2024 Mar 28;160(12). doi: 10.1063/5.0200098.
As typical representatives of group III chalcogenides, InSe, α-In2Se3, and β'-In2Se3 have drawn considerable interest in the domain of photoelectrochemistry. However, the microscopic mechanisms of carrier dynamics in these systems remain largely unexplored. In this work, we first reveal that hot electrons in the three systems have different cooling rate stages and long-lived hot electrons, through the utilization of density functional theory calculations and nonadiabatic molecular dynamics simulations. Furthermore, the ferroelectric polarization of α-In2Se3 weakens the nonadiabatic coupling of the nonradioactive recombination, successfully competing with the narrow bandgap and slow dephasing process, and achieving both high optical absorption efficiency and long carrier lifetime. In addition, we demonstrate that the ferroelectric polarization of α-In2Se3 not only enables the formation of the double type-II band alignment in the InSe/α-In2Se3/InSe heterostructure, with the top and bottom InSe sublayers acting as acceptors and donors, respectively, but also eliminates the hindrance of the built-in electric field at the interface, facilitating an ultrafast interlayer carrier transfer in the heterojunction. This work establishes an atomic mechanism of carrier dynamics in InSe, α-In2Se3, and β'-In2Se3 and the regulatory role of the ferroelectric polarization on the charge carrier dynamics, providing a guideline for the design of photoelectronic materials.
作为III族硫属化物的典型代表，InSe、α-In2Se3和β'-In2Se3在光电化学领域引起了广泛关注。然而，这些体系中载流子动力学的微观机制在很大程度上仍未被探索。在这项工作中，我们首先通过利用密度泛函理论计算和非绝热分子动力学模拟揭示了这三种体系中的热电子具有不同的冷却速率阶段和长寿命热电子。此外，α-In2Se3的铁电极化削弱了非辐射复合的非绝热耦合，成功地与窄带隙和缓慢的退相过程竞争，实现了高光学吸收效率和长载流子寿命。此外，我们证明α-In2Se3的铁电极化不仅能够在InSe/α-In2Se3/InSe异质结构中形成双II型能带排列，顶部和底部的InSe子层分别作为受体和供体，而且还消除了界面处内建电场的阻碍，促进了异质结中的超快层间载流子转移。这项工作建立了InSe、α-In2Se3和β'-In2Se3中载流子动力学的原子机制以及铁电极化对电荷载流子动力学的调控作用，为光电子材料的设计提供了指导。
