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Qian W, Qi P, Dai Y, Shi B, Tao G, Liu H, Zhang X, Xiang D, Fang Z, Liu W. Strongly Localized Moiré Exciton in Twisted Homobilayers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305200. [PMID: 37649150 DOI: 10.1002/smll.202305200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/14/2023] [Indexed: 09/01/2023]
Abstract
Artificially molding exciton flux is the cornerstone for developing promising excitonic devices. In the emerging hetero/homobilayers, the spatial separated charges prolong exciton lifetimes and create out-plane dipoles, facilitating electrically control exciton flux on a large scale, and the nanoscale periodic moiré potentials arising from twist-angle or/and lattice mismatch can substantially alter exciton dynamics, which are mainly proved in the heterostructures. However, the spatially indirect excitons dynamics in homobilayers without lattice mismatch remain elusive. Here the nonequilibrium dynamics of indirect exciton in homobilayers are systematically investigated. The homobilayers with slightly twist-angle can induce a deep moiré potential (>50 meV) in the energy landscape of indirect excitons, resulting in a strongly localized moiré excitons insulating the transport dynamics from phonons and disorder. These findings provide insights into the exciton dynamics and many-body physics in moiré superlattices modulated energy landscape, with implications for designing excitonic devices operating at room temperature.
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Affiliation(s)
- Wenqi Qian
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Pengfei Qi
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Yuchen Dai
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Beibei Shi
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Guangyi Tao
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Haiyi Liu
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Xubin Zhang
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Dong Xiang
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Zheyu Fang
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Weiwei Liu
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
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Diroll BT, Guzelturk B, Po H, Dabard C, Fu N, Makke L, Lhuillier E, Ithurria S. 2D II-VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration. Chem Rev 2023; 123:3543-3624. [PMID: 36724544 DOI: 10.1021/acs.chemrev.2c00436] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The field of colloidal synthesis of semiconductors emerged 40 years ago and has reached a certain level of maturity thanks to the use of nanocrystals as phosphors in commercial displays. In particular, II-VI semiconductors based on cadmium, zinc, or mercury chalcogenides can now be synthesized with tailored shapes, composition by alloying, and even as nanocrystal heterostructures. Fifteen years ago, II-VI semiconductor nanoplatelets injected new ideas into this field. Indeed, despite the emergence of other promising semiconductors such as halide perovskites or 2D transition metal dichalcogenides, colloidal II-VI semiconductor nanoplatelets remain among the narrowest room-temperature emitters that can be synthesized over a wide spectral range, and they exhibit good material stability over time. Such nanoplatelets are scientifically and technologically interesting because they exhibit optical features and production advantages at the intersection of those expected from colloidal quantum dots and epitaxial quantum wells. In organic solvents, gram-scale syntheses can produce nanoparticles with the same thicknesses and optical properties without inhomogeneous broadening. In such nanoplatelets, quantum confinement is limited to one dimension, defined at the atomic scale, which allows them to be treated as quantum wells. In this review, we discuss the synthetic developments, spectroscopic properties, and applications of such nanoplatelets. Covering growth mechanisms, we explain how a thorough understanding of nanoplatelet growth has enabled the development of nanoplatelets and heterostructured nanoplatelets with multiple emission colors, spatially localized excitations, narrow emission, and high quantum yields over a wide spectral range. Moreover, nanoplatelets, with their large lateral extension and their thin short axis and low dielectric surroundings, can support one or several electron-hole pairs with large exciton binding energies. Thus, we also discuss how the relaxation processes and lifetime of the carriers and excitons are modified in nanoplatelets compared to both spherical quantum dots and epitaxial quantum wells. Finally, we explore how nanoplatelets, with their strong and narrow emission, can be considered as ideal candidates for pure-color light emitting diodes (LEDs), strong gain media for lasers, or for use in luminescent light concentrators.
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Affiliation(s)
- Benjamin T Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Burak Guzelturk
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Hong Po
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Corentin Dabard
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Ningyuan Fu
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Lina Makke
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Emmanuel Lhuillier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, 75005 Paris, France
| | - Sandrine Ithurria
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
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Yu J, Hu S, Gao H, Delikanli S, Liu B, Jasieniak JJ, Sharma M, Demir HV. Observation of Phonon Cascades in Cu-Doped Colloidal Quantum Wells. NANO LETTERS 2022; 22:10224-10231. [PMID: 36326236 DOI: 10.1021/acs.nanolett.2c03427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Electronic doping has endowed colloidal quantum wells (CQWs) with unique optical and electronic properties, holding great potential for future optoelectronic device concepts. Unfortunately, how photogenerated hot carriers interact with phonons in these doped CQWs still remains an open question. Here, through investigating the emission properties, we have observed an efficient phonon cascade process (i.e., up to 27 longitudinal optical phonon replicas are revealed in the broad Cu emission band at room temperature) and identified a giant Huang-Rhys factor (S ≈ 12.4, more than 1 order of magnitude larger than reported values of other inorganic semiconductor nanomaterials) in Cu-doped CQWs. We argue that such an ultrastrong electron-phonon coupling in Cu-doped CQWs is due to the dopant-induced lattice distortion and the dopant-enhanced density of states. These findings break the widely accepted consensus that electron-phonon coupling is typically weak in quantum-confined systems, which are crucial for optoelectronic applications of doped electronic nanomaterials.
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Affiliation(s)
- Junhong Yu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang621900, People's Republic of China
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore639798, Singapore
| | - Sujuan Hu
- School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou510275, People's Republic of China
| | - Huayu Gao
- School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou510275, People's Republic of China
| | - Savas Delikanli
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara06800, Turkey
| | - Baiquan Liu
- School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou510275, People's Republic of China
| | - Jacek J Jasieniak
- ARC Centre of Excellence in Exciton Science, Department of Materials Science and Engineering, Monash University, Clayton Campus, Melbourne, Victoria3800, Australia
| | - Manoj Sharma
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore639798, Singapore
- ARC Centre of Excellence in Exciton Science, Department of Materials Science and Engineering, Monash University, Clayton Campus, Melbourne, Victoria3800, Australia
| | - Hilmi Volkan Demir
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore639798, Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara06800, Turkey
- School of Physical and Mathematical Sciences, Division of Physics and Applied Physics, Nanyang Technological University, Singapore639798, Singapore
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Yu J, Han Y, Zhang H, Ding X, Qiao L, Hu J. Excimer Formation in the Non-Van-Der-Waals 2D Semiconductor Bi 2 O 2 Se. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204227. [PMID: 35781340 DOI: 10.1002/adma.202204227] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/21/2022] [Indexed: 06/15/2023]
Abstract
The layered semiconductor Bi2 O2 Se is a promising new-type 2D material that holds layered structure via electrostatic forces instead of van der Waals (vdW) attractions. Aside from the huge success in device performance, the non-vdW nature in Bi2 O2 Se with a built-in interlayer electric field has also provided an appealing platform for investigating unique photoexcited carrier dynamics. Here, experimental evidence for the observation of excimers in multilayer Bi2 O2 Se nanosheets via transient absorption spectroscopy is presented. It is found that the excimer formation is the primary decay pathway of photoexcited excitons and three-stage excimer dynamics with corresponding time scales are established. Excitation-fluence-dependent excimer dynamics further suggest that the excimer is diffusive and its formation can be simply described as excitons relaxed to an excimer geometry. This work indicates the outstanding promise of unique excitonic processes in Bi2 O2 Se, which may motivate novel device designs.
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Affiliation(s)
- Junhong Yu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Yadong Han
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Hang Zhang
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Xiang Ding
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Liang Qiao
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Jianbo Hu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
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Yu J, Han Y, Zhang H, Misochko OV, Nakamura KG, Hu J. Attosecond-Resolved Coherent Control of Lattice Vibrations in Thermoelectric SnSe. J Phys Chem Lett 2022; 13:2584-2590. [PMID: 35289629 DOI: 10.1021/acs.jpclett.2c00426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Manipulating lattice vibrations is the cornerstone to achieving ultralow thermal conductivity in thermoelectrics. Although spatial control by novel material designs has been recently reported, temporal manipulation, which can shape thermoelectric properties under nonequilibrium conditions, remains largely unexplored. Here, taking SnSe as a representative, we have demonstrated that in the ultrafast pump-pump-probe spectroscopy, electronic and lattice coherences inherited from optical excitations can be exploited independently to manipulate phonon oscillations in a highly selective manner. Specifically, when the pump-pump delay time (tmod) is in the electronic coherence time range, the amplitude, frequency, and lifetime of all phonon modes are simultaneously following the optical cycle. While extending tmod into the lattice coherence time range, the amplitude of each coherent phonon mode can be selectively manipulated according to its intrinsic period without changing the frequency and lifetime. This work opens up exciting avenues to temporally and discriminatorily manipulate phononic processes in thermoelectric materials.
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Affiliation(s)
- Junhong Yu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
| | - Yadong Han
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
| | - Hang Zhang
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
| | - Oleg V Misochko
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
- Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region, Russia
| | - Kazutaka G Nakamura
- Materials and Structures Laboratory, Tokyo Institute of Technology, R3-10, 4259 Nagatsuta, Yokohama 226-8503, Japan
| | - Jianbo Hu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
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Han Y, Yu J, Zhang H, Xu F, Peng K, Zhou X, Qiao L, Misochko OV, Nakamura KG, Vanacore GM, Hu J. Photoinduced Ultrafast Symmetry Switch in SnSe. J Phys Chem Lett 2022; 13:442-448. [PMID: 34990128 DOI: 10.1021/acs.jpclett.1c03704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Layered tin selenide (SnSe) has recently emerged as a high-performance thermoelectric material with the current record for the figure of merit (ZT) observed in the high-temperature Cmcm phase. So far, access to the Cmcm phase has been mainly obtained via thermal equilibrium methods based on sample heating or application of external pressure, thus restricting the current understanding only to ground-state conditions. Here, we investigate the ultrafast carrier and phononic dynamics in SnSe. Our results demonstrate that optical excitations can transiently switch the point-group symmetry of the crystal from Pnma to Cmcm at room temperature in a few hundreds of femtoseconds with an ultralow threshold for the excitation carrier density. This nonequilibrium Cmcm phase is found to be driven by the displacive excitation of coherent Ag phonons and, given the absence of low-energy thermal phonons, exists in SnSe with the status of 'cold lattice with hot carriers'. Our findings provide an important insight for understanding the nonequilibrium thermoelectric properties of SnSe.
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Affiliation(s)
- Yadong Han
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Junhong Yu
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Hang Zhang
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Fang Xu
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Kunlin Peng
- College of Physics and Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing, 401331, China
| | - Xiaoyuan Zhou
- College of Physics and Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing, 401331, China
| | - Liang Qiao
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Oleg V Misochko
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia
| | - Kazutaka G Nakamura
- Materials and Structures Laboratory, Tokyo Institute of Technology, R3-10, 4259 Nagatsuta, Yokohama, 226-8503, Japan
| | - Giovanni M Vanacore
- Department of Materials Science, University of Milano-Bicocca, Via Cozzi 55, Milano, 20121, Italy
| | - Jianbo Hu
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
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Yu J, Han Y, Wang L, Xu F, Zhang H, Yu Y, Wu Q, Hu J. Visualizing Nonlinear Phononics in Layered ReSe 2. J Phys Chem Lett 2021; 12:5178-5184. [PMID: 34037407 DOI: 10.1021/acs.jpclett.1c01172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nonlinear phononics has recently been demonstrated as a viable approach for dynamically modifying materials' properties. Conventionally, nonlinearity in the lattice dynamics is introduced via the "ionic" Raman scattering, in which infrared-active phonons (i.e., coherent ionic vibrations) serve as the intermediate state for transferring energy to Raman-active phonons. Here we report that it is also possible to achieve phononic nonlinearity through the "electronic" route, a process that relies on excited electronic states to initiate energy exchange among Raman-active phonons. Taking layered ReSe2 as a model system, we use coherent phonon spectroscopy with a pump energy larger than the band gap to follow lattice dynamics and observe the nonlinear coupling between both Raman-active intralayer atomic oscillations and interlayer breathing modes. In addition, we show that such nonlinear phononic coupling is highly dependent on the environment temperature. This work, which demonstrates a different and novel mechanism, may enrich the toolkit for controlling material properties by means of nonlinear phononics.
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Affiliation(s)
- Junhong Yu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Yadong Han
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Longyu Wang
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Fang Xu
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Hang Zhang
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Yuying Yu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Qiang Wu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Jianbo Hu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
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