Spin–Orbit Interactions Greatly Accelerate Nonradiative Dynamics in Lead Halide Perovskites,ACS Energy Letters

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Spin–Orbit Interactions Greatly Accelerate Nonradiative Dynamics in Lead Halide Perovskites
ACS Energy Letters ( IF 19.3 ) Pub Date : 2018-08-16 00:00:00 , DOI: 10.1021/acsenergylett.8b01226
Wei Li ₁ , Liujiang Zhou ₂ , Oleg V. Prezhdo ₃ , Alexey V. Akimov ₄

Affiliation

In this work, we study the role of spin–orbit coupling (SOC) in nonradiative relaxation of hot electrons and holes in methylammonium lead perovskite, MAPbI₃. For this purpose, we have developed the nonadiabatic molecular dynamics method with two-component spinor wave functions that are solutions of the relativistic Kohn–Sham (KS) equations. We find that SOC enhances contributions of Pb(p_x) and Pb(p_y) orbitals to the conduction and valence bands. As a result, the KS orbitals become more sensitive to nuclear motions, leading to the increased nonadiabatic couplings. Consequently, SOC greatly speeds up the electron and hole relaxation, making the computed relaxation time scales consistent with available experiments. We suggest that the fast hot carrier relaxation facilitated by the SOC allows rapid transition into the long-lived triplet state that extends charge-carrier lifetime and helps achieve high-efficiency perovskite solar cells.

中文翻译：

自旋-轨道相互作用极大地加速了卤化钙钛矿中的非辐射动力学。

在这项工作中，我们研究了自旋轨道耦合（SOC）在热辐射电子和空穴中钙钛矿型甲基铵铅MAPbI _3的非辐射弛豫中的作用。为了这个目的，我们开发了具有两组分自旋波函数的非绝热分子动力学方法，该方法是相对论的Kohn-Sham（KS）方程的解。我们发现SOC增强了Pb（p _x）和Pb（p _y）到导带和价带的轨道。结果，KS轨道对核运动变得更加敏感，从而导致非绝热耦合增加。因此，SOC极大地加快了电子和空穴的弛豫速度，使计算出的弛豫时间尺度与可用实验一致。我们建议，由SOC促进的快速热载流子松弛允许快速过渡到长寿命的三重态，这延长了电荷载流子的寿命并有助于实现高效率的钙钛矿太阳能电池。

更新日期：2018-08-16

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