Hot-exciton effects on exciton diffusion and circular polarization dynamics in a single PbI2 nanoflake

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外文摘要：As one of the emerging two-dimensional lead halide materials,lead iodide(PbI2)nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient perovskite solar cells.However,the underlying photophysical properties such as hot-exciton-related carrier dynamics remain unclear for PbI2 nanosheets.Here,we report the exciton dynamics of a single PbI2 nanoflake prepared by an aqueous solution method.Through a three-dimensional(3D)diffusion model,we obtain the exciton annihilation radius and diffusion coefficient of a single PbI2 nanoflake under non-resonant and resonant excitation conditions of band-edge exciton state.As initial exciton densities increase,we find the carrier recombination mechanism for a single PbI2 nanoflake gradually changes from exciton-exciton annihilation to free-carrier recombination.Finally,we reveal the room-temperature circular polarization of a single PbI2 nanoflake is due to free-carrier recombination with a band-edge exciton dissociation time of～120 fs under the resonant excitation condition.

外文关键词：

single PbI2 nanoflakeexciton diffusionroom-temperature circular polarizationultrafast spectroscopy

作者：

XU ChenYu、WANG Lei、CUI Lin、GAO BingRong、WANG HaiYu

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作者单位：

State Key Laboratory of Integrated Optoelectronics,College of Electronic Science and Engineering,Jilin University,Changchun 130012,China

基金：

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaChina Postdoctoral Science Foundation

项目编号：

62175088619278142177308721603083219030352016M590259

出版年：

2024

DOI：

10.1007/s11431-022-2249-1

中国科学:技术科学(英文版)

中国科学院

中国科学:技术科学(英文版)

CSTPCDEI

影响因子：1.056

ISSN：1674-7321

年,卷(期)：2024.67(1)

参考文献量36