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

ChenYu Xu1, Lei Wang1, Lin Cui1, BingRong Gao1, HaiYu Wang1
1State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, China

Tóm tắt

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.

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Tài liệu tham khảo

Plekhanov V G. Lead halides: Electronic properties and applications. Prog Mater Sci, 2004, 49: 787–886

Lin D Y, Guo B C, Dai Z Y, et al. PbI2 single crystal growth and its optical property study. Crystals, 2019, 9: 589

Zhu X H, Wei Z R, Jin Y R, et al. Growth and characterization of a PbI2 single crystal used for gamma ray detectors. Cryst Res Technol, 2007, 42: 456–459

Sun H, Liu Y, Gao X, et al. Bendable 3D-structure X-ray photo-detectors based on pure PbI2 single crystal. Semicond Sci Technol, 2021, 36: 035022

Hassan M, Matuchova M, Zdansky K. Performance of lead iodide nuclear radiation detectors with the introduction of rare earth elements. Open Phys, 2006, 4: 117–123

Fang H H, Yang J, Adjokatse S, et al. Band-edge exciton fine structure and exciton recombination dynamics in single crystals of layered hybrid perovskites. Adv Funct Mater, 2020, 30: 1907979

Kahmann S, Duim H, Fang H H, et al. Photophysics of two-dimensional perovskites: Learning from metal halide substitution. Adv Funct Mater, 2021, 31: 2103778

Wei H, Huang J. Halide lead perovskites for ionizing radiation detection. Nat Commun, 2019, 10: 1066

Li H, He Y, Li W, et al. Perovskite dimensional evolution through cations engineering to tailor the detection limit in hard X-ray response. Small, 2022, 18: 2203884

Zheng W, Zhang Z, Lin R, et al. High-crystalline 2D layered PbI2 with ultrasmooth surface: Liquid-phase synthesis and application of high-speed photon detection. Adv Electron Mater, 2016, 2: 1600291

Tan M, Hu C, Lan Y, et al. 2D lead dihalides for high-performance ultraviolet photodetectors and their detection mechanism investigation. Small, 2017, 13: 1702024

Beckmann P A. A review of polytypism in lead iodide. Cryst Res Technol, 2010, 45: 455–460

Matsui T, Yamamoto T, Nishihara T, et al. Compositional engineering for thermally stable, highly efficient perovskite solar cells exceeding 20% power conversion efficiency with 85°C/85% 1000 h stability. Adv Mater, 2019, 31: 1806823

Yang W S, Noh J H, Jeon N J, et al. High-performance photovoltaic perovskite layers fabricated through intramolecular exchange. Science, 2015, 348: 1234–1237

Jung M, Shin T J, Seo J, et al. Structural features and their functions in surfactant-armoured methylammonium lead iodide perovskites for highly efficient and stable solar cells. Energy Environ Sci, 2018, 11: 2188–2197

Wu C G, Chiang C H, Tseng Z L, et al. High efficiency stable inverted perovskite solar cells without current hysteresis. Energy Environ Sci, 2015, 8: 2725–2733

Roldán-Carmona C, Gratia P, Zimmermann I, et al. High efficiency methylammonium lead triiodide perovskite solar cells: The relevance of non-stoichiometric precursors. Energy Environ Sci, 2015, 8: 3550–3556

Barrit D, Sheikh A D, Munir R, et al. Hybrid perovskite solar cells: In situ investigation of solution-processed PbI2 reveals metastable precursors and a pathway to producing porous thin films. J Mater Res, 2017, 32: 1899–1907

Tong G, Son D Y, Ono L K, et al. Removal of residual compositions by powder engineering for high efficiency formamidinium-based perovskite solar cells with operation lifetime over 2000 h. Nano Energy, 2021, 87: 106152

Zhang Z Y, Chen X, Wang H Y, et al. Elucidating the band structure and free charge carrier dynamics of pure and impurities doped CH3NH3PbI3−xClx perovskite thin films. Phys Chem Chem Phys, 2015, 17: 30084–30089

Park B, Kedem N, Kulbak M, et al. Understanding how excess lead iodide precursor improves halide perovskite solar cell performance. Nat Commun, 2018, 9: 3301

Zheng W, Zheng B, Jiang Y, et al. Probing and manipulating carrier interlayer diffusion in van der Waals multilayer by constructing type-I heterostructure. Nano Lett, 2019, 19: 7217–7225

Zhang D, Liu Y, He M, et al. Room temperature near unity spin polarization in 2D van der Waals heterostructures. Nat Commun, 2020, 11: 4442

Liu X, Ha S T, Zhang Q, et al. Whispering gallery mode lasing from hexagonal shaped layered lead iodide crystals. ACS Nano, 2015, 9: 687–695

Wang L, Wu C F, Wang H Y, et al. Internal structure-mediated ultrafast energy transfer in self-assembled polymer-blend dots. Nanoscale, 2013, 5: 7265–7270

Sun Y, Zhou Z, Huang Z, et al. Band structure engineering of interfacial semiconductors based on atomically thin lead iodide crystals. Adv Mater, 2019, 31: 1806562

Wang R, Li S, Wang P, et al. PbI2 nanosheets for photodetectors via the facile cooling thermal supersaturation solution method. J Phys Chem C, 2019, 123: 9609–9616

Zhao L Y, Wang H, Wang H Y, et al. Ultrafast modulation of valley dynamics in multiple WS2-Ag gratings strong coupling system. PhotoniX, 2022, 3: 5

Yue Y Y, Wang H Y, Wang L, et al. Direct observation of room-temperature intravalley coherent coupling processes in monolayer MoS2. Laser Photonics Rev, 2021, 16: 2100343

Zheng S W, Wang L, Wang H Y, et al. Observation of quantum-confined exciton states in monolayer WS2 quantum dots by ultrafast spectroscopy. Nanoscale, 2021, 13: 17093–17100

Wang L, Wang Z, Wang H Y, et al. Slow cooling and efficient extraction of C-exciton hot carriers in MoS2 monolayer. Nat Commun, 2017, 8: 13906

Wang L, Li Q, Wang H Y, et al. Ultrafast optical spectroscopy of surface-modified silicon quantum dots: Unraveling the underlying mechanism of the ultrabright and color-tunable photoluminescence. Light Sci Appl, 2015, 4: e245

Qi P, Luo Y, Shi B, et al. Phonon scattering and exciton localization: Molding exciton flux in two dimensional disorder energy landscape. eLight, 2021, 1: 6

Shen C, Wang G. Excitonic effects on layer- and strain-dependent optoelectronic properties of PbI2. Appl Surf Sci, 2019, 470: 143–149

Sim S, Park J, Song J G, et al. Exciton dynamics in atomically thin MoS2: Interexcitonic interaction and broadening kinetics. Phys Rev B, 2013, 88: 075434

Zhao W, Su R, Huang Y, et al. Transient circular dichroism and exciton spin dynamics in all-inorganic halide perovskites. Nat Commun, 2020, 11: 5665