Spin–Orbit Coupling Is the Key to Promote Asynchronous Photoinduced Charge Transfer of Two-Dimensional Perovskites

Abstract

Two-dimensional (2D) perovskites are emerging as promising candidates for diverse optoelectronic applications because of low cost and excellent stability. In this work, we explore the electronic structures and interfacial properties of (4Tm) 2 PbI 4 with both the collinear and noncollinear DFT (PBE and HSE06) methods. The results evidently manifest that explicitly considering the spin–orbit coupling (SOC) effects is necessary to attain correct band alignment of (4Tm) 2 PbI 4 that agrees with recent experiments ( 31712613 Nat. Chem. 2019 11 1151 ; 32350477 Nature 2020 580 614 ). The subsequent time-domain noncollinear DFT-based nonadiabatic carrier dynamics simulations with the SOC effects reveal that the photoinduced electron and hole transfer processes are asymmetric and associated with different rates. The differences are mainly ascribed to considerably different nonadiabatic couplings in charge of the electron and hole transfer processes. Shortly, our current work sheds important light on the mechanism of the interfacial charge carrier transfer processes of (4Tm) 2 PbI 4 . The importance of the SOC effects on correctly aligning the band states of (4Tm) 2 PbI 4 may be generalized to similar organic–inorganic hybrid 2D perovskites having heavy Pb atoms.

Rational design of small molecule hole-transporting materials with a linear π-bridge for highly efficient perovskite solar cells

“…This computational setup was effective in several recent studies. [71][72][73] The DFT-D3 method proposed by Grimme et al is applied to describe the internal interaction between interfacial layers. [74][75][76] The optimization was not accomplished until residual forces were less than 0.01 eV Å À1 .…”

Generalized Ab Initio Nonadiabatic Dynamics Simulation Methods from Molecular to Extended Systems

“…141,142 We took one of the typical systems, namely, (4Tm) 2 PbI 4 , as our research object and explored the interfacial electron-transfer dynamics using density functional theory (Figure 9). 109 Analogously, special consideration was paid to the impacts of spin−orbit coupling effects. On the basis of our computational results, we can conclude that the spin−orbit coupling effects are necessary in the prediction of the correct interfacial properties of (4Tm) 2 PbI 4 .…”

“…Our recently developed GTSH approach at the time-domain TDDFT with collinear and noncollinear DFT methods are suitable for simulating much bigger systems, such as materials under the periodic boundary condition. Herein, we will discuss our latest progress on several important systems including transition-metal dichalcogenides (TMDs), perovskites, carbon nanotubes, etc. ,− In these complex systems, the photoinduced interfacial carrier dynamics are usually very important, which become a challenging task for both experimental and theoretical scientists.…”

“…In comparison with three-dimensional perovskites, two-dimensional ones usually have many advantages, such as the excellent stability, which have been widely used in various research fields. − Very recently, Dou et al synthesized a variety of perovskites, which exhibit very good charge-transfer abilities. , We took one of the typical systems, namely, (4Tm) 2 PbI 4 , as our research object and explored the interfacial electron-transfer dynamics using density functional theory (Figure ). Analogously, special consideration was paid to the impacts of spin–orbit coupling effects. On the basis of our computational results, we can conclude that the spin–orbit coupling effects are necessary in the prediction of the correct interfacial properties of (4Tm) 2 PbI 4 .…”

“…(Left) Structure of (4Tm) 2 PbI 4 and (right) projected density of states (PDOS) of (4Tm) 2 PbI 4 with different density functionals. Reprinted with permission from ref . Copyright 2021 American Chemical Society.…”