Role of Dielectric Drag in Polaron Mobility in Lead Halide Perovskites
Role of Dielectric Drag in Polaron Mobility in Lead Halide Perovskites
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DOI：
10.1021/acsenergylett.7b00717
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发表时间：
2017-11-01
影响因子：
22
通讯作者：
Zhu, X. -Y.
中科院分区：
文献类型：
--
作者：
Bonn, Mischa;Miyata, Kiyoshi;Zhu, X. -Y.
杂化有机-无机卤化铅钙钛矿（HOIPs）以其优异的载流子寿命和扩散长度而备受关注。这些特性归因于在高极性和动态环境中通过极化子形成有效地筛选载流子。极化子的形成至少在一定程度上解释了中等载流子迁移率，但计算的迁移率略高于实验值。在这里，我们讨论一个以前被忽视的因素，可以潜在地解释这种差异：介电阻力的影响。虽然卤化铅亚晶格的光学声子模式主要负责极化子的形成，但周围偶极子的缓慢取向弛豫增加了移动电荷的介电阻力。基于在千兆赫到太赫兹频率范围内测量的介电函数，我们讨论了这种介电阻力的作用，以及我们如何根据其晶体-液体对偶性来理解hops中独特的载流子物理。
Hybrid organic-inorganic lead halide perovskites (HOIPs) have attracted much attention because of their remarkable carrier lifetimes and diffusion lengths. These properties have been attributed to the efficient screening of charge carriers via polaron formation in the highly polar and dynamic environment. Polaron formation explains, at least in part, the moderate charge carrier mobility, but the calculated mobilities are somewhat higher than experimental values. Here we discuss a factor that has been previously overlooked and can potentially account for the discrapency: the effect of dielectric drag. While optical phonon modes of the lead halide sublattice are mainly responsible for polaron formation, slower orientational relaxation of surrounding dipoles adds a dielectric drag to the moving charge. We discuss the role of this dielectric drag based on the measured dielectric function in the gigahertz to terahertz frequency range and how we can understand the unique carrier physics in HOIPs in view of its crystal-liquid duality.