Rashba Spin鈥揙rbit Coupling Enhanced Carrier Lifetime in CH3NH3PbI3

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• 作者：Fan Zheng ; Liang Z. Tan ; Shi Liu ; Andrew M. Rappe
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：15
• 期：12
• 页码：7794-7800
• 全文大小：433K
• ISSN：1530-6992

文摘

Organometal halide perovskites are promising solar-cell materials for next-generation photovoltaic applications. The long carrier lifetime and diffusion length of these materials make them very attractive for use in light absorbers and carrier transporters. While these aspects of organometal halide perovskites have attracted the most attention, the consequences of the Rashba effect, driven by strong spin鈥搊rbit coupling, on the photovoltaic properties of these materials are largely unexplored. In this work, taking the electronic structure of CH₃NH₃PbI₃ (methylammonium lead iodide) as an example, we propose an intrinsic mechanism for enhanced carrier lifetime in three-dimensional (3D) Rashba materials. On the basis of first-principles calculations and a Rashba spin鈥搊rbit model, we demonstrate that the recombination rate is reduced due to the spin-forbidden transition. These results are important for understanding the fundamental physics of organometal halide perovskites and for optimizing and designing the materials with better performance. The proposed mechanism including spin degrees of freedom offers a new paradigm of using 3D Rashba materials for photovoltaic applications.