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DOI	10.1021/acs.jpcc.0c06345
	Discerning between Exciton and Free-Carrier Behaviors in Ruddlesden-Popper Perovskite Quantum Wells through Kinetic Modeling of Photoluminescence Dynamics
	Spitha N.; Kohler D.D.; Hautzinger M.P.; Li J.; Jin S.; Wright J.C.
发表日期	2020
ISSN	19327447
起始页码	17430
结束页码	17439
卷号	124 期号:31
英文摘要	Two-dimensional (2D) Ruddlesden-Popper (RP)-layered lead halide perovskites have recently emerged as a more stable alternative to their three-dimensional (3D) counterparts while also exhibiting intriguing photophysical properties. Although time-resolved photoluminescence (TRPL) is an excellent diagnostic tool for the photophysics of these luminescent semiconductors, the most common approaches to analyzing TRPL transients do not discriminate between the mechanisms responsible for charge carrier dynamics, namely, the behavior of excitons, which is more relevant for optoelectronic applications, and the behavior of electrons and holes, which is most relevant for solar conversion. Here, we develop a kinetic approach to systematically resolve exciton and free-carrier dynamics across a series of (PEA)2(CH3NH3)n-1PbnI3n+1 RP perovskite single crystals (PEA = phenethylammonium, n = 1, 2, 3, 4, and ∞). Our approach uses repetitive excitation that builds up a steady state of free carriers, even when the exciton binding energies are large. Within the time scale of a TRPL experiment, the rapid changes in the total photoexcited carrier density cause the carrier dynamics to change from exciton-dominated to free-carrier-dominated, as expected from the Saha equilibrium. Thus, despite only measuring excitonic emission, we can analyze the dynamic and steady-state dynamics of the TRPL transients to also resolve the dynamics of free carriers. We obtain an Arrhenius-like relationship between the exciton dissociation rate constant and the exciton binding energy (determined by the quantum well thickness, n) and compare the trends of the exciton annihilation and the electron-hole recombination rate constants as a function of n. Moreover, we examine the influence of excitation power and trap filling on the observed value of each parameter. The computational framework developed for this study provides more insights into the photophysics of the 2D-RP perovskites and can be used more generally to obtain a mechanistic understanding of semiconductor carrier dynamics. Copyright © 2020 American Chemical Society.
scopus关键词	Binding energy; Dissociation; Dynamics; Excited states; Excitons; Lead compounds; Perovskite; Photoluminescence; Photophysics; Rate constants; Charge carrier dynamics; Computational framework; Electron hole recombination rate; Exciton-binding energy; Optoelectronic applications; Photophysical properties; Semiconductor carrier dynamics; Time-resolved photoluminescence; Semiconductor quantum wells
来源期刊	Journal of Physical Chemistry C
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/176846
作者单位	Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
推荐引用方式 GB/T 7714	Spitha N.,Kohler D.D.,Hautzinger M.P.,et al. Discerning between Exciton and Free-Carrier Behaviors in Ruddlesden-Popper Perovskite Quantum Wells through Kinetic Modeling of Photoluminescence Dynamics[J],2020,124(31).
APA	Spitha N.,Kohler D.D.,Hautzinger M.P.,Li J.,Jin S.,&Wright J.C..(2020).Discerning between Exciton and Free-Carrier Behaviors in Ruddlesden-Popper Perovskite Quantum Wells through Kinetic Modeling of Photoluminescence Dynamics.Journal of Physical Chemistry C,124(31).
MLA	Spitha N.,et al."Discerning between Exciton and Free-Carrier Behaviors in Ruddlesden-Popper Perovskite Quantum Wells through Kinetic Modeling of Photoluminescence Dynamics".Journal of Physical Chemistry C 124.31(2020).