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DOI	10.1039/c7ee03543h
	Identification of high-temperature exciton states and their phase-dependent trapping behaviour in lead halide perovskites
	Shi J.; Zhang H.; Li Y.; Jasieniak J.J.; Li Y.; Wu H.; Luo Y.; Li D.; Meng Q.
发表日期	2018
ISSN	17545692
起始页码	1460
结束页码	1469
卷号	11 期号:6
英文摘要	While lead halide perovskites have rapidly emerged as lucrative material candidates for optoelectronic applications, the crucial energy states and charge-carrier nature of these systems are yet to be fully understood, resulting in ongoing debates on the fundamental optical and material characters. In this work we probe the band-edge and sub-gap energy states within polycrystalline and single crystal perovskites to better understand their photophysical origins. Through temperature-, excitation intensity- and time-dependent optical measurements, we reveal the existence of both free and bound exciton contributions to the optoelectronic properties across a wide temperature region up to 300 K. The low-energy absorption and multiple-peak emission phenomena, whose physics origins have been highly controversial before, are caused by these exciton states. Furthermore, the trapping and recombination dynamics of these excitons is shown to be strongly dependent on the structural phase of the perovskite. The orthorhombic phase exhibits an ultrafast exciton trapping and distinct trap emissions, while the tetragonal phase gives low monomolecular recombination velocity and capture cross-sections (∼10-18 cm2). Within the multiphonon transition scenario, this suppression in charge trapping is caused by the increase in the charge capture activation energy due to a reduction in electron-lattice interactions within the inorganic framework, which can reasonably interpret the unexpectedly long carrier lifetime in these material systems. These findings provide a clearer understanding of the origins of the photophysical properties of perovskite materials, and the discovery of a high-temperature-stable bound exciton would bring the excitonic feature to be a concern for the perovskite energy conversion and utilization applications. © 2018 The Royal Society of Chemistry.
英文关键词	Activation energy; Carrier lifetime; Charge trapping; Energy conversion; High temperature applications; Lead compounds; Optical data processing; Perovskite; Single crystals; Capture cross sections; Electron-lattice interactions; Monomolecular recombination; Optoelectronic applications; Optoelectronic properties; Photophysical properties; Recombination dynamics; Transition scenarios; Excitons; absorption; activation energy; electron; energy; halide; high temperature; identification method; lead; optical property; perovskite; probe
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/190238
作者单位	Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese, Academy of Sciences, Beijing, 100049, China; Department of Materials Science and Engineering, Monash University, Clayton Victoria, 3800, Australia
推荐引用方式 GB/T 7714	Shi J.,Zhang H.,Li Y.,et al. Identification of high-temperature exciton states and their phase-dependent trapping behaviour in lead halide perovskites[J],2018,11(6).
APA	Shi J..,Zhang H..,Li Y..,Jasieniak J.J..,Li Y..,...&Meng Q..(2018).Identification of high-temperature exciton states and their phase-dependent trapping behaviour in lead halide perovskites.Energy & Environmental Science,11(6).
MLA	Shi J.,et al."Identification of high-temperature exciton states and their phase-dependent trapping behaviour in lead halide perovskites".Energy & Environmental Science 11.6(2018).