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DOI	10.1039/c8ee03369b
	Large polaron formation and its effect on electron transport in hybrid perovskites
	Zheng F.; Wang L.-W.
发表日期	2019
ISSN	17545692
起始页码	1219
结束页码	1230
卷号	12 期号:4
英文摘要	Many experiments have indicated that a large polaron may be formed in hybrid perovskites, and its existence is proposed to screen the carrier-carrier and carrier-defect scattering, thus contributing to the long lifetime of the carriers. However, a detailed theoretical study of the large polaron and its effect on carrier transport at the atomic level is still lacking. In particular, how strong is the large polaron binding energy? How does its effect compare with the effect of dynamic disorder caused by the A-site molecular rotation? And how does the inorganic sublattice vibration impact the motion of the large polaron? All of these questions are largely unanswered. In this work, using CH3NH3PbI3 as an example, we implement a tight-binding model fitted from density-functional theory to describe the electron large polaron ground state and to understand the large polaron formation and transport at its strong-coupling limit. We find that the formation energy of the large polaron is around -12 meV for the case without dynamic disorder, and -55 meV by including dynamic disorder. By performing the explicit time-dependent wavefunction evolution of the polaron state, together with the rotations of CH3NH3+ and vibrations of the PbI3- sublattice, we studied the diffusion constant and mobility of the large polaron state driven by the dynamic disorder and the sublattice vibration. Two effects of the inorganic sublattice vibrations are found: on one hand, the vibration of the sublattice provides an additional driving force for carrier mobility; on the other hand, the large polaron polarization further localizes the electron, reducing its mobility. Overall, the effect of the large polaron is to slow down the electron mobility by roughly a factor of two. We believe that both dynamic disorder due to rotation of the organic molecule, and large polaron effects induced by the polarization and vibration of the inorganic sublattice, play important roles for the electronic structure and carrier dynamics of the system. © 2019 The Royal Society of Chemistry.
英文关键词	Binding energy; Chemical bonds; Density functional theory; Electron transport properties; Electronic structure; Ground state; Induced polarization logging; Molecular dynamics; Perovskite; Polarization; Rotation; Stereochemistry; Diffusion constant; Electron transport; Formation energies; Molecular rotations; Organic molecules; Polaron formation; Sublattice vibrations; Tight binding model; Polarons; chemical binding; electron; experimental study; molecular analysis; perovskite; polarization; scattering; theoretical study
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/189950
作者单位	Joint Center for Artificial Photosynthesis, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
推荐引用方式 GB/T 7714	Zheng F.,Wang L.-W.. Large polaron formation and its effect on electron transport in hybrid perovskites[J],2019,12(4).
APA	Zheng F.,&Wang L.-W..(2019).Large polaron formation and its effect on electron transport in hybrid perovskites.Energy & Environmental Science,12(4).
MLA	Zheng F.,et al."Large polaron formation and its effect on electron transport in hybrid perovskites".Energy & Environmental Science 12.4(2019).