1
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Chan YH, Naik MH, Haber JB, Neaton JB, Louie SG, Qiu DY, da Jornada FH. Exciton-Phonon Coupling Induces a New Pathway for Ultrafast Intralayer-to-Interlayer Exciton Transition and Interlayer Charge Transfer in WS 2-MoS 2 Heterostructure: A First-Principles Study. NANO LETTERS 2024; 24:7972-7978. [PMID: 38888269 PMCID: PMC11229060 DOI: 10.1021/acs.nanolett.4c01508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 06/10/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024]
Abstract
Despite the weak, van der Waals interlayer coupling, photoinduced charge transfer vertically across atomically thin interfaces can occur within surprisingly fast, sub-50 fs time scales. An early theoretical understanding of charge transfer is based on a noninteracting picture, neglecting excitonic effects that dominate optical properties of such materials. We employ an ab initio many-body perturbation theory approach, which explicitly accounts for the excitons and phonons in the heterostructure. Our large-scale first-principles calculations directly probe the role of exciton-phonon coupling in the charge dynamics of the WS2/MoS2 heterobilayer. We find that the exciton-phonon interaction induced relaxation time of photoexcited excitons at the K valley of MoS2 and WS2 is 67 and 15 fs at 300 K, respectively, which sets a lower bound to the intralayer-to-interlayer exciton transfer time and is consistent with experiment reports. We further show that electron-hole correlations facilitate novel transfer pathways that are otherwise inaccessible to noninteracting electrons and holes.
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Affiliation(s)
- Yang-hao Chan
- Institute
of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Physic
Division, National Center of Theoretical Sciences, Taipei 10617, Taiwan
| | - Mit H. Naik
- Department
of Physics, University of California, Berkeley, California 94720-7300, United
States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Jonah B. Haber
- Department
of Physics, University of California, Berkeley, California 94720-7300, United
States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Jeffrey B. Neaton
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Department
of Physics, University of California, Berkeley, California 94720-7300, United
States
| | - Steven G. Louie
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Department
of Physics, University of California, Berkeley, California 94720-7300, United
States
| | - Diana Y. Qiu
- Department
of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, United States
| | - Felipe H. da Jornada
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
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2
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Hörmann M, Visentin F, Chakraborty SK, Nayak B, Sahoo PK, Cerullo G, Camargo FVA. Self-referencing for quasi shot-noise-limited widefield transient microscopy. OPTICS EXPRESS 2024; 32:21230-21242. [PMID: 38859482 DOI: 10.1364/oe.525581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 05/09/2024] [Indexed: 06/12/2024]
Abstract
Many applications of ultrafast and nonlinear optical microscopy require the measurement of small differential signals over large fields-of-view. Widefield configurations drastically reduce the acquisition time; however, they suffer from the low frame rates of two-dimensional detectors, which limit the modulation frequency, making the measurement sensitive to excess laser noise. Here we introduce a self-referenced detection configuration for widefield differential imaging. Employing regions of the field of view with no differential signal as references, we cancel probe fluctuations and increase the signal-to-noise ratio by an order of magnitude reaching noise levels only a few percent above the shot noise limit. We anticipate broad applicability of our method to transient absorption, stimulated Raman scattering and photothermal-infrared microscopies.
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3
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Wang J, Long R. Nuclear Quantum Effects Accelerate Charge Recombination but Boost the Stability of Inorganic Perovskites in Mild Humidity. NANO LETTERS 2024; 24:3476-3483. [PMID: 38445608 DOI: 10.1021/acs.nanolett.4c00245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Experiments have demonstrated that mild humidity can enhance the stability of the CsPbBr3 perovskite, though the underlying mechanism remains unclear. Utilizing ab initio molecular dynamics, ring polymer molecular dynamics, and non-adiabatic molecular dynamics, our study reveals that nuclear quantum effects (NQEs) play a crucial role in stabilizing the lattice rigidity of the perovskite while simultaneously shortening the charge carrier lifetime. NQEs reduce the extent of geometric disorder and the number of atomic fluctuations, diminish the extent of hole localization, and thereby improve the electron-hole overlap and non-adiabatic coupling. Concurrently, these effects significantly suppress phonon modes and slow decoherence. As a result, these factors collectively accelerate charge recombination by a factor of 1.42 compared to that in scenarios excluding NQEs. The resulting sub-10 ns recombination time scales align remarkably well with experimental findings. This research offers novel insight into how moisture resistance impacts the stability and charge carrier lifetime in all-inorganic perovskites.
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Affiliation(s)
- Jiao Wang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
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4
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Morabito F, Synnatschke K, Mehew JD, Varghese S, Sayers CJ, Folpini G, Petrozza A, Cerullo G, Tielrooij KJ, Coleman J, Nicolosi V, Gadermaier C. Long lived photogenerated charge carriers in few-layer transition metal dichalcogenides obtained from liquid phase exfoliation. NANOSCALE ADVANCES 2024; 6:1074-1083. [PMID: 38356640 PMCID: PMC10863726 DOI: 10.1039/d3na00862b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 11/26/2023] [Indexed: 02/16/2024]
Abstract
Semiconducting transition metal dichalcogenides are important optoelectronic materials thanks to their intense light-matter interaction and wide selection of fabrication techniques, with potential applications in light harvesting and sensing. Crucially, these applications depend on the lifetimes and recombination dynamics of photogenerated charge carriers, which have primarily been studied in monolayers obtained from labour-intensive mechanical exfoliation or costly chemical vapour deposition. On the other hand, liquid phase exfoliation presents a high throughput and cost-effective method to produce dispersions of mono- and few-layer nanosheets. This approach allows for easy scalability and enables the subsequent processing and formation of macroscopic films directly from the liquid phase. Here, we use transient absorption spectroscopy and spatiotemporally resolved pump-probe microscopy to study the charge carrier dynamics in tiled nanosheet films of MoS2 and WS2 deposited from the liquid phase using an adaptation of the Langmuir-Schaefer technique. We find an efficient photogeneration of charge carriers with lifetimes of several nanoseconds, which we ascribe to stabilisation at nanosheet edges. These findings provide scope for photocatalytic and photodetector applications, where long-lived charge carriers are crucial, and suggest design strategies for photovoltaic devices.
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Affiliation(s)
- Floriana Morabito
- Area Science Park Basovizza S.S. 14 Km 163.5 34149 Trieste Italy
- Dipartimento di Fisica, Politecnico di Milano Piazza L. da Vinci 32 20133 Milano Italy
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia Via Rubattino 81 20134 Milan Italy
- CNR-IOM, Consiglio Nazionale delle Ricerche Istituto Officina dei Materiali Trieste Italy
| | - Kevin Synnatschke
- School of Physics, CRANN & AMBER Research Centres, Trinity College Dublin Dublin D02 Ireland
| | - Jake Dudley Mehew
- Catalan Institute of Nanoscience and Nanotechnology ICN2 UAB Campus Bellaterra (Barcelona) 08193 Spain
| | - Sebin Varghese
- Catalan Institute of Nanoscience and Nanotechnology ICN2 UAB Campus Bellaterra (Barcelona) 08193 Spain
| | - Charles James Sayers
- Dipartimento di Fisica, Politecnico di Milano Piazza L. da Vinci 32 20133 Milano Italy
| | - Giulia Folpini
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia Via Rubattino 81 20134 Milan Italy
| | - Annamaria Petrozza
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia Via Rubattino 81 20134 Milan Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano Piazza L. da Vinci 32 20133 Milano Italy
| | - Klaas-Jan Tielrooij
- Catalan Institute of Nanoscience and Nanotechnology ICN2 UAB Campus Bellaterra (Barcelona) 08193 Spain
- TU Eindhoven, Department of Applied Physics Den Dolech 2 5612 AZ Eindhoven The Netherlands
| | - Jonathan Coleman
- School of Physics, CRANN & AMBER Research Centres, Trinity College Dublin Dublin D02 Ireland
| | - Valeria Nicolosi
- School of Physics, CRANN & AMBER Research Centres, Trinity College Dublin Dublin D02 Ireland
| | - Christoph Gadermaier
- Dipartimento di Fisica, Politecnico di Milano Piazza L. da Vinci 32 20133 Milano Italy
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia Via Rubattino 81 20134 Milan Italy
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5
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Bange JP, Schmitt D, Bennecke W, Meneghini G, AlMutairi A, Watanabe K, Taniguchi T, Steil D, Steil S, Weitz RT, Jansen GSM, Hofmann S, Brem S, Malic E, Reutzel M, Mathias S. Probing electron-hole Coulomb correlations in the exciton landscape of a twisted semiconductor heterostructure. SCIENCE ADVANCES 2024; 10:eadi1323. [PMID: 38324690 PMCID: PMC10849592 DOI: 10.1126/sciadv.adi1323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024]
Abstract
In two-dimensional semiconductors, cooperative and correlated interactions determine the material's excitonic properties and can even lead to the creation of correlated states of matter. Here, we study the fundamental two-particle correlated exciton state formed by the Coulomb interaction between single-particle holes and electrons. We find that the ultrafast transfer of an exciton's hole across a type II band-aligned semiconductor heterostructure leads to an unexpected sub-200-femtosecond upshift of the single-particle energy of the electron being photoemitted from the two-particle exciton state. While energy relaxation usually leads to an energetic downshift of the spectroscopic signature, we show that this upshift is a clear fingerprint of the correlated interaction of the electron and hole parts of the exciton. In this way, time-resolved photoelectron spectroscopy is straightforwardly established as a powerful method to access electron-hole correlations and cooperative behavior in quantum materials. Our work highlights this capability and motivates the future study of optically inaccessible correlated excitonic and electronic states of matter.
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Affiliation(s)
- Jan Philipp Bange
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - David Schmitt
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Wiebke Bennecke
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Giuseppe Meneghini
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
| | | | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Daniel Steil
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Sabine Steil
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - R. Thomas Weitz
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- International Center for Advanced Studies of Energy Conversion (ICASEC), University of Göttingen, Göttingen, Germany
| | - G. S. Matthijs Jansen
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK
| | - Samuel Brem
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Ermin Malic
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Marcel Reutzel
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Stefan Mathias
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- International Center for Advanced Studies of Energy Conversion (ICASEC), University of Göttingen, Göttingen, Germany
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6
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Johnson AC, Georgaras JD, Shen X, Yao H, Saunders AP, Zeng HJ, Kim H, Sood A, Heinz TF, Lindenberg AM, Luo D, da Jornada FH, Liu F. Hidden phonon highways promote photoinduced interlayer energy transfer in twisted transition metal dichalcogenide heterostructures. SCIENCE ADVANCES 2024; 10:eadj8819. [PMID: 38266081 PMCID: PMC10807799 DOI: 10.1126/sciadv.adj8819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
Vertically stacked van der Waals (vdW) heterostructures exhibit unique electronic, optical, and thermal properties that can be manipulated by twist-angle engineering. However, the weak phononic coupling at a bilayer interface imposes a fundamental thermal bottleneck for future two-dimensional devices. Using ultrafast electron diffraction, we directly investigated photoinduced nonequilibrium phonon dynamics in MoS2/WS2 at 4° twist angle and WSe2/MoSe2 heterobilayers with twist angles of 7°, 16°, and 25°. We identified an interlayer heat transfer channel with a characteristic timescale of ~20 picoseconds, about one order of magnitude faster than molecular dynamics simulations assuming initial intralayer thermalization. Atomistic calculations involving phonon-phonon scattering suggest that this process originates from the nonthermal phonon population following the initial interlayer charge transfer and scattering. Our findings present an avenue for thermal management in vdW heterostructures by tailoring nonequilibrium phonon populations.
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Affiliation(s)
- Amalya C. Johnson
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Johnathan D. Georgaras
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Helen Yao
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Helen J. Zeng
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Hyungjin Kim
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Aditya Sood
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Tony F. Heinz
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Aaron M. Lindenberg
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Duan Luo
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Felipe H. da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Fang Liu
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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7
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Yang A, Luo J, Xie Z, Chen Q, Xie Q. Ab Initio Quantum Dynamics Simulation of the Impact of Graphene on the Carrier Lifetime of the ZnV 2O 6 Photocatalyst. J Phys Chem Lett 2024; 15:23-33. [PMID: 38127901 DOI: 10.1021/acs.jpclett.3c02387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
We used a nonadiabatic molecular dynamics simulation to determine the carrier dynamics of a graphene/ZnV2O6 heterostructure in the search for an effective photocatalyst material. The C-2p orbital promotes the wave function overlap, guiding electrons to move between graphene and ZnV2O6, successfully achieving good mixing with the valence and conduction bands in ZnV2O6 materials, which is conducive to supporting carrier migration. The overlap between graphene/ZnV2O6 electrons and hole wave functions is less than that of ZnV2O6, and there is small absolute nonadiabatic coupling. The charge separation caused by graphene increases the carrier lifetime and prevents nonradiative electron-hole recombination. This study reveals the microscopic mechanism of extending the carrier lifetime of ZnV2O6 by introducing graphene, providing useful insights for regulating the electronic structure, promoting electron transfer and ultrafast electron and hole transfer. This strategy provides design considerations for advanced photocatalytic materials.
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Affiliation(s)
- Anqi Yang
- Institute of New Type Optoelectronic Materials and Technology, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China
- Special and Key Laboratory of Guizhou Provincial Higher Education for Green Energy-Saving Materials, Guiyang 550025, China
| | - Jiaolian Luo
- Special and Key Laboratory of Guizhou Provincial Higher Education for Green Energy-Saving Materials, Guiyang 550025, China
- School of materials science and engineering, Guizhou Minzu University, Guiyang 550025, China
| | - Zhenyu Xie
- Special and Key Laboratory of Guizhou Provincial Higher Education for Green Energy-Saving Materials, Guiyang 550025, China
- Architectural Engineering College, Guizhou Minzu University, Guiyang 550025, China
| | - Qian Chen
- Institute of New Type Optoelectronic Materials and Technology, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China
- State Key Laboratory of Public Big Data, Guizhou University, Guiyang 550025, China
| | - Quan Xie
- Institute of New Type Optoelectronic Materials and Technology, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China
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8
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Hu C, Naik MH, Chan YH, Louie SG. Excitonic Interactions and Mechanism for Ultrafast Interlayer Photoexcited Response in van der Waals Heterostructures. PHYSICAL REVIEW LETTERS 2023; 131:236904. [PMID: 38134768 DOI: 10.1103/physrevlett.131.236904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 11/09/2023] [Indexed: 12/24/2023]
Abstract
Optical dynamics in van der Waals heterobilayers is of fundamental scientific and practical interest. Based on a time-dependent adiabatic GW approach, we discover a new many-electron (excitonic) channel for converting photoexcited intralayer to interlayer excitations and the associated ultrafast optical responses in heterobilayers, which is conceptually different from the conventional single-particle picture. We find strong electron-hole interactions drive the dynamics and enhance the pump-probe optical responses by an order of magnitude with a rise time of ∼300 fs in MoSe_{2}/WSe_{2} heterobilayers, in agreement with experiment.
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Affiliation(s)
- Chen Hu
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Mit H Naik
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yang-Hao Chan
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Institute of Atomic and Molecular Sciences, Academia Sinica, and Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
| | - Steven G Louie
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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9
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Policht VR, Mittenzwey H, Dogadov O, Katzer M, Villa A, Li Q, Kaiser B, Ross AM, Scotognella F, Zhu X, Knorr A, Selig M, Cerullo G, Dal Conte S. Time-domain observation of interlayer exciton formation and thermalization in a MoSe 2/WSe 2 heterostructure. Nat Commun 2023; 14:7273. [PMID: 37949848 PMCID: PMC10638375 DOI: 10.1038/s41467-023-42915-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023] Open
Abstract
Vertical heterostructures of transition metal dichalcogenides (TMDs) host interlayer excitons with electrons and holes residing in different layers. With respect to their intralayer counterparts, interlayer excitons feature longer lifetimes and diffusion lengths, paving the way for room temperature excitonic optoelectronic devices. The interlayer exciton formation process and its underlying physical mechanisms are largely unexplored. Here we use ultrafast transient absorption spectroscopy with a broadband white-light probe to simultaneously resolve interlayer charge transfer and interlayer exciton formation dynamics in a MoSe2/WSe2 heterostructure. We observe an interlayer exciton formation timescale nearly an order of magnitude (~1 ps) longer than the interlayer charge transfer time (~100 fs). Microscopic calculations attribute this relative delay to an interplay of a phonon-assisted interlayer exciton cascade and thermalization, and excitonic wave-function overlap. Our results may explain the efficient photocurrent generation observed in optoelectronic devices based on TMD heterostructures, as the interlayer excitons are able to dissociate during thermalization.
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Affiliation(s)
- Veronica R Policht
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy.
- NRC Postdoc residing at U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC, 20375, USA.
| | - Henry Mittenzwey
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany.
| | - Oleg Dogadov
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Manuel Katzer
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Andrea Villa
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Qiuyang Li
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY, 10027, USA
| | | | - Aaron M Ross
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Francesco Scotognella
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, 10129, Italy
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY, 10027, USA
| | - Andreas Knorr
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Malte Selig
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
- CNR-IFN, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Stefano Dal Conte
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy.
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10
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Sayers C, Genco A, Trovatello C, Conte SD, Khaustov VO, Cervantes-Villanueva J, Sangalli D, Molina-Sanchez A, Coletti C, Gadermaier C, Cerullo G. Strong Coupling of Coherent Phonons to Excitons in Semiconducting Monolayer MoTe 2. NANO LETTERS 2023; 23:9235-9242. [PMID: 37751559 PMCID: PMC10603802 DOI: 10.1021/acs.nanolett.3c01936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 09/19/2023] [Indexed: 09/28/2023]
Abstract
The coupling of the electron system to lattice vibrations and their time-dependent control and detection provide unique insight into the nonequilibrium physics of semiconductors. Here, we investigate the ultrafast transient response of semiconducting monolayer 2H-MoTe2 encapsulated with hBN using broadband optical pump-probe microscopy. The sub-40 fs pump pulse triggers extremely intense and long-lived coherent oscillations in the spectral region of the A' and B' exciton resonances, up to ∼20% of the maximum transient signal, due to the displacive excitation of the out-of-plane A1g phonon. Ab initio calculations reveal a dramatic rearrangement of the optical absorption of monolayer MoTe2 induced by an out-of-plane stretching and compression of the crystal lattice, consistent with an A1g -type oscillation. Our results highlight the extreme sensitivity of the optical properties of monolayer TMDs to small structural modifications and their manipulation with light.
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Affiliation(s)
| | - Armando Genco
- Dipartimento
di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - Chiara Trovatello
- Dipartimento
di Fisica, Politecnico di Milano, 20133 Milano, Italy
- Department
of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | | | - Vladislav O. Khaustov
- Center
for Nanotechnology Innovation @ NEST, Istituto
Italiano di Tecnologia, 56127 Pisa, Italy
- Scuola
Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Jorge Cervantes-Villanueva
- Institute
of Materials Science (ICMUV), University
of Valencia, Catedrático Beltrán 2, E-46980 Valencia, Spain
| | - Davide Sangalli
- Division
of Ultrafast Processes in Materials (FLASHit), Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, 00016 Monterotondo, Scalo, Italy
| | - Alejandro Molina-Sanchez
- Institute
of Materials Science (ICMUV), University
of Valencia, Catedrático Beltrán 2, E-46980 Valencia, Spain
| | - Camilla Coletti
- Center
for Nanotechnology Innovation @ NEST, Istituto
Italiano di Tecnologia, 56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | | | - Giulio Cerullo
- Dipartimento
di Fisica, Politecnico di Milano, 20133 Milano, Italy
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11
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Zheng F, Wang LW. Multiple k-Point Nonadiabatic Molecular Dynamics for Ultrafast Excitations in Periodic Systems: The Example of Photoexcited Silicon. PHYSICAL REVIEW LETTERS 2023; 131:156302. [PMID: 37897744 DOI: 10.1103/physrevlett.131.156302] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/22/2023] [Accepted: 08/18/2023] [Indexed: 10/30/2023]
Abstract
With the rapid development of ultrafast experimental techniques for the research of carrier dynamics in solid-state systems, a microscopic understanding of the related phenomena, particularly a first-principle calculation, is highly desirable. Nonadiabatic molecular dynamics (NAMD) offers a real-time direct simulation of the carrier transfer or carrier thermalization. However, when applied to a periodic supercell, there is no cross-k-point transitions during the NAMD simulation. This often leads to a significant underestimation of the transition rate with the single-k-point band structure in a supercell. In this work, based on the surface hopping scheme used for NAMD, we propose a practical method to enable the cross-k transitions for a periodic system. We demonstrate our formalism by showing that the hot electron thermalization process by the multi-k-point NAMD in a small silicon supercell is equivalent to such simulation in a large supercell with a single Γ point. The simulated hot carrier thermalization process of the bulk silicon is compared with the recent ultrafast experiments, which shows excellent agreements. We have also demonstrated our method for the hot carrier coolings in the amorphous silicons and the GaAlAs_{2} solid solutions with the various cation distributions.
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Affiliation(s)
- Fan Zheng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Lin-Wang Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083, China
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12
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Pang J, Peng S, Hou C, Zhao H, Fan Y, Ye C, Zhang N, Wang T, Cao Y, Zhou W, Sun D, Wang K, Rümmeli MH, Liu H, Cuniberti G. Applications of Graphene in Five Senses, Nervous System, and Artificial Muscles. ACS Sens 2023; 8:482-514. [PMID: 36656873 DOI: 10.1021/acssensors.2c02790] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Graphene remains of great interest in biomedical applications because of biocompatibility. Diseases relating to human senses interfere with life satisfaction and happiness. Therefore, the restoration by artificial organs or sensory devices may bring a bright future by the recovery of senses in patients. In this review, we update the most recent progress in graphene based sensors for mimicking human senses such as artificial retina for image sensors, artificial eardrums, gas sensors, chemical sensors, and tactile sensors. The brain-like processors are discussed based on conventional transistors as well as memristor related neuromorphic computing. The brain-machine interface is introduced for providing a single pathway. Besides, the artificial muscles based on graphene are summarized in the means of actuators in order to react to the physical world. Future opportunities remain for elevating the performances of human-like sensors and their clinical applications.
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Affiliation(s)
- Jinbo Pang
- Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong, Institute for Advanced Interdisciplinary Research (iAIR), University of Jinan, Jinan 250022, China
| | - Songang Peng
- High-Frequency High-Voltage Device and Integrated Circuits R&D Center and Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Chongyang Hou
- Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong, Institute for Advanced Interdisciplinary Research (iAIR), University of Jinan, Jinan 250022, China
| | - Hongbin Zhao
- State Key Laboratory of Advanced Materials for Smart Sensing, GRINM Group Co. Ltd., Xinwai Street 2, Beijing 100088, People's Republic of China
| | - Yingju Fan
- School of Chemistry and Chemical Engineering, University of Jinan, Shandong, Jinan 250022, China
| | - Chen Ye
- School of Chemistry and Chemical Engineering, University of Jinan, Shandong, Jinan 250022, China
| | - Nuo Zhang
- School of Chemistry and Chemical Engineering, University of Jinan, Shandong, Jinan 250022, China
| | - Ting Wang
- State Key Laboratory of Biobased Material and Green Papermaking and People's Republic of China School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, No. 3501 Daxue Road, Jinan 250353, People's Republic of China
| | - Yu Cao
- Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology (Ministry of Education) and School of Electrical Engineering, Northeast Electric Power University, Jilin 132012, China
| | - Weijia Zhou
- Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong, Institute for Advanced Interdisciplinary Research (iAIR), University of Jinan, Jinan 250022, China
| | - Ding Sun
- School of Electrical and Computer Engineering, Jilin Jianzhu University, Changchun 130118, P. R. China
| | - Kai Wang
- School of Electrical Engineering, Weihai Innovation Research Institute, Qingdao University, Qingdao 266000, China
| | - Mark H Rümmeli
- Leibniz Institute for Solid State and Materials Research Dresden, Dresden, D-01171, Germany.,College of Energy, Soochow Institute for Energy and Materials Innovations, and Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou 215006, China.,Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie Sklodowskiej 34, Zabrze 41-819, Poland.,Institute for Complex Materials, IFW Dresden, 20 Helmholtz Strasse, Dresden 01069, Germany.,Center for Energy and Environmental Technologies, VŠB-Technical University of Ostrava, 17. Listopadu 15, Ostrava 708 33, Czech Republic
| | - Hong Liu
- Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong, Institute for Advanced Interdisciplinary Research (iAIR), University of Jinan, Jinan 250022, China.,State Key Laboratory of Crystal Materials, Center of Bio & Micro/Nano Functional Materials, Shandong University, 27 Shandanan Road, Jinan 250100, China
| | - Gianaurelio Cuniberti
- Institute for Materials Science and Max Bergmann Center of Biomaterials and Center for Advancing Electronics Dresden, Technische Universität Dresden, Dresden 01069, Germany
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13
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Smejkal V, Trovatello C, Li Q, Dal Conte S, Marini A, Zhu X, Cerullo G, Libisch F. Photonic effects in the non-equilibrium optical response of two-dimensional semiconductors. OPTICS EXPRESS 2023; 31:107-115. [PMID: 36606945 DOI: 10.1364/oe.479518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Transient absorption spectroscopy is a powerful tool to monitor the out-of-equilibrium optical response of photoexcited semiconductors. When this method is applied to two-dimensional semiconductors deposited on different substrates, the excited state optical properties are inferred from the pump-induced changes in the transmission/reflection of the probe, i.e., ΔT/T or ΔR/R. Transient optical spectra are often interpreted as the manifestation of the intrinsic optical response of the monolayer, including effects such as the reduction of the exciton oscillator strength, electron-phonon coupling or many-body interactions like bandgap renormalization, trion or biexciton formation. Here we scrutinize the assumption that one can determine the non-equilibrium optical response of the TMD without accounting for the substrate used in the experiment. We systematically investigate the effect of the substrate on the broadband transient optical response of monolayer MoS2 (1L-MoS2) by measuring ΔT/T and ΔR/R with different excitation photon energies. Employing the boundary conditions given by the Fresnel equations, we analyze the transient transmission/reflection spectra across the main excitonic resonances of 1L-MoS2. We show that pure interference effects induced by the different substrates explain the substantial differences (i.e., intensity, peak energy and exciton linewidth) observed in the transient spectra of the same monolayer. We thus demonstrate that the substrate strongly affects the magnitude of the exciton energy shift and the change of the oscillator strength in the transient optical spectra. By highlighting the key role played by the substrate, our results set the stage for a unified interpretation of the transient response of optoelectronic devices based on a broad class of TMDs.
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14
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Sood A, Haber JB, Carlström J, Peterson EA, Barre E, Georgaras JD, Reid AHM, Shen X, Zajac ME, Regan EC, Yang J, Taniguchi T, Watanabe K, Wang F, Wang X, Neaton JB, Heinz TF, Lindenberg AM, da Jornada FH, Raja A. Bidirectional phonon emission in two-dimensional heterostructures triggered by ultrafast charge transfer. NATURE NANOTECHNOLOGY 2023; 18:29-35. [PMID: 36543882 DOI: 10.1038/s41565-022-01253-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 10/04/2022] [Indexed: 06/17/2023]
Abstract
Photoinduced charge transfer in van der Waals heterostructures occurs on the 100 fs timescale despite weak interlayer coupling and momentum mismatch. However, little is understood about the microscopic mechanism behind this ultrafast process and the role of the lattice in mediating it. Here, using femtosecond electron diffraction, we directly visualize lattice dynamics in photoexcited heterostructures of WSe2/WS2 monolayers. Following the selective excitation of WSe2, we measure the concurrent heating of both WSe2 and WS2 on a picosecond timescale-an observation that is not explained by phonon transport across the interface. Using first-principles calculations, we identify a fast channel involving an electronic state hybridized across the heterostructure, enabling phonon-assisted interlayer transfer of photoexcited electrons. Phonons are emitted in both layers on the femtosecond timescale via this channel, consistent with the simultaneous lattice heating observed experimentally. Taken together, our work indicates strong electron-phonon coupling via layer-hybridized electronic states-a novel route to control energy transport across atomic junctions.
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Affiliation(s)
- Aditya Sood
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
| | - Jonah B Haber
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
| | | | - Elizabeth A Peterson
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Elyse Barre
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Johnathan D Georgaras
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | | | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Marc E Zajac
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Emma C Regan
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Graduate Group in Applied Science and Technology, University of California Berkeley, Berkeley, CA, USA
| | - Jie Yang
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Feng Wang
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
| | - Xijie Wang
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Jeffrey B Neaton
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoScience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Tony F Heinz
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Aaron M Lindenberg
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
| | - Felipe H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
| | - Archana Raja
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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15
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Yoon Y, Zhang Z, Qi R, Joe AY, Sailus R, Watanabe K, Taniguchi T, Tongay S, Wang F. Charge Transfer Dynamics in MoSe 2/hBN/WSe 2 Heterostructures. NANO LETTERS 2022; 22:10140-10146. [PMID: 36485010 DOI: 10.1021/acs.nanolett.2c04030] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ultrafast charge transfer processes provide a facile way to create interlayer excitons in directly contacted transition metal dichalcogenide (TMD) layers. More sophisticated heterostructures composed of TMD/hBN/TMD enable new ways to control interlayer exciton properties and achieve novel exciton phenomena, such as exciton insulators and condensates, where longer lifetimes are desired. In this work, we experimentally study the charge transfer dynamics in a heterostructure composed of a 1 nm thick hBN spacer between MoSe2 and WSe2 monolayers. We observe the hole transfer from MoSe2 to WSe2 through the hBN barrier with a time constant of 500 ps, which is over 3 orders of magnitude slower than that between TMD layers without a spacer. Furthermore, we observe strong competition between the interlayer charge transfer and intralayer exciton-exciton annihilation processes at high excitation densities. Our work opens possibilities to understand charge transfer pathways in TMD/hBN/TMD heterostructures for the efficient generation and control of interlayer excitons.
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Affiliation(s)
- Yoseob Yoon
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Zuocheng Zhang
- Department of Physics, University of California, Berkeley, California94720, United States
| | - Ruishi Qi
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Andrew Y Joe
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Renee Sailus
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona85287, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona85287, United States
| | - Feng Wang
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
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16
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Zhao X, Vasenko AS, Prezhdo OV, Long R. Anion Doping Delays Nonradiative Electron-Hole Recombination in Cs-Based All-Inorganic Perovskites: Time Domain ab Initio Analysis. J Phys Chem Lett 2022; 13:11375-11382. [PMID: 36454707 DOI: 10.1021/acs.jpclett.2c03072] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Using time-domain density functional theory combined with nonadiabatic (NA) molecular dynamics, we demonstrate that composition engineering of the X-site anions has a strong influence on the nonradiative electron-hole recombination and thermodynamic stability of cesium-based all-inorganic perovskites. Partial substitution of iodine(I) with bromine (Br) and acetate (Ac) anions reduces the NA electron-vibrational coupling by minimizing the overlap between the electron and hole wave functions and suppressing atomic fluctuations. The doping also widens the energy gap to further reduce the NA coupling and to enhance the open-circuit voltage of perovskite solar cells. These factors increase the charge carrier lifetime by an order of magnitude and improve structural stability in the series CsPbI1.88BrAc0.12 > CsPbI2Br > CsPbI3. The fundamental atomistic insights into the influence of anion doping on the photophysical properties of the all-inorganic lead halide perovskites guide the design of efficient optoelectronic materials.
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Affiliation(s)
- Xi Zhao
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, People's Republic of China
| | - Andrey S Vasenko
- HSE University, 101000Moscow, Russia
- I. E. Tamm Department of Theoretical Physics, P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991Moscow, Russia
| | - Oleg V Prezhdo
- Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California90089, United States
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, People's Republic of China
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17
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Lin CY, Lee MP, Chang YM, Tseng YT, Yang FS, Li M, Chen JY, Chen CF, Tsai MY, Lin YC, Ueno K, Yamamoto M, Lo ST, Lien CH, Chiu PW, Tsukagoshi K, Wu WW, Lin YF. Diffused Beam Energy to Dope van der Waals Electronics and Boost Their Contact Barrier Lowering. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41156-41164. [PMID: 36037311 DOI: 10.1021/acsami.2c07679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Contact engineering of two-dimensional semiconductors is a central issue for performance improvement of micro-/nanodevices based on these materials. Unfortunately, the various methods proposed to improve the Schottky barrier height normally require the use of high temperatures, chemical dopants, or complex processes. This work demonstrates that diffused electron beam energy (DEBE) treatment can simultaneously reduce the Schottky barrier height and enable the direct writing of electrical circuitry on van der Waals semiconductors. The electron beam energy projected into the region outside the electrode diffuses into the main channel, producing selective-area n-type doping in a layered MoTe2 (or MoS2) field-effect transistor. As a result, the Schottky barrier height at the interface between the electrode and the DEBE-treated MoTe2 channel is as low as 12 meV. Additionally, because selective-area doping is possible, DEBE can allow the formation of both n- and p-type doped channels within the same atomic plane, which enables the creation of a nonvolatile and homogeneous MoTe2 p-n rectifier with an ideality factor of 1.1 and a rectification ratio of 1.3 × 103. These results indicate that the DEBE method is a simple, efficient, mask-free, and chemical dopant-free approach to selective-area doping for the development of van der Waals electronics with excellent device performances.
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Affiliation(s)
- Che-Yi Lin
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
- Institute of Nanoscience, National Chung Hsing University, Taichung 40227, Taiwan
| | - Mu-Pai Lee
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yuan-Ming Chang
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
- Institute of Nanoscience, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yi-Tang Tseng
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Feng-Shou Yang
- Institute of Electronic Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Mengjiao Li
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
- Institute of Nanoscience, National Chung Hsing University, Taichung 40227, Taiwan
| | - Jiann-Yeu Chen
- Department of Material Science and Engineering and i-Center for Advanced Science and Technology (i-CAST), National Chung Hsing University, Taichung 40227, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ciao-Fen Chen
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Meng-Yu Tsai
- Institute of Electronic Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yi-Chun Lin
- Instrument Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Keiji Ueno
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Mahito Yamamoto
- Department of Pure and Applied Physics, Kansai University, Osaka 564-8680, Japan
| | - Shun-Tsung Lo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Chen-Hsin Lien
- Institute of Electronic Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Po-Wen Chiu
- Institute of Electronic Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kazuhito Tsukagoshi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Ibaraki, Japan
| | - Wen-Wei Wu
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yen-Fu Lin
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
- Institute of Nanoscience, National Chung Hsing University, Taichung 40227, Taiwan
- Department of Material Science and Engineering and i-Center for Advanced Science and Technology (i-CAST), National Chung Hsing University, Taichung 40227, Taiwan
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18
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Ghosh A, Ball B, Pal S, Sarkar P. Ultrafast Charge Transfer and Delayed Recombination in Graphitic-CN/WTe 2 van der Waals Heterostructure: A Time Domain Ab Initio Study. J Phys Chem Lett 2022; 13:7898-7905. [PMID: 35980156 DOI: 10.1021/acs.jpclett.2c02196] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In search of an efficient solar energy harvester, we herein performed a time domain density functional study coupled with nonadiabatic molecular dynamics (NAMD) simulation to gain atomistic insight into the charge carrier dynamics of a graphitic carbon nitride (g-CN)-tungsten telluride (WTe2) van der Waals heterostructure. Our NAMD study predicted ultrafast electron (589 fs) and hole-transfer (807 fs) dynamics in g-CN/WTe2 heterostructure and a delayed electron-hole recombination process (2.404 ns) as compared to that of the individual g-CN (3 ps) and WTe2 (0.55 ps) monolayer. The ultrafast charge transfer is due to strong electron-phonon coupling during the charge-transfer process while comparatively weak electron-phonon coupling, sufficient band gap, comparatively lower nonadiabatic coupling (NAC), and fast decoherence time slow down the electron-hole recombination process. The NAMD results of exciton relaxation dynamics are valuable for insightful understanding of charge carrier dynamics and in designing photovoltaic devices based on organic-inorganic 2D van der Waals heterostructures.
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Affiliation(s)
- Atish Ghosh
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India
| | - Biswajit Ball
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India
| | - Sougata Pal
- Department of Chemistry, University of Gour Banga, Malda 732103, India
| | - Pranab Sarkar
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India
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19
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Electronic gap characterization at mesoscopic scale via scanning probe microscopy under ambient conditions. Nat Commun 2022; 13:4648. [PMID: 35941143 PMCID: PMC9359982 DOI: 10.1038/s41467-022-32439-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/29/2022] [Indexed: 11/08/2022] Open
Abstract
Electronic gaps play an important role in the electric and optical properties of materials. Although various experimental techniques, such as scanning tunnelling spectroscopy and optical or photoemission spectroscopy, are normally used to perform electronic band structure characterizations, it is still challenging to measure the electronic gap at the nanoscale under ambient conditions. Here we report a scanning probe microscopic technique to characterize the electronic gap with nanometre resolution at room temperature and ambient pressure. The technique probes the electronic gap by monitoring the changes of the local quantum capacitance via the Coulomb force at a mesoscopic scale. We showcase this technique by characterizing several 2D semiconductors and van der Waals heterostructures under ambient conditions.
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20
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Wang B, Chu W, Wu Y, Casanova D, Saidi WA, Prezhdo OV. Electron-Volt Fluctuation of Defect Levels in Metal Halide Perovskites on a 100 ps Time Scale. J Phys Chem Lett 2022; 13:5946-5952. [PMID: 35732502 DOI: 10.1021/acs.jpclett.2c01452] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metal halide perovskites (MHPs) have gained considerable attention due to their excellent optoelectronic performance, which is often attributed to unusual defect properties. We demonstrate that midgap defect levels can exhibit very large and slow energy fluctuations associated with anharmonic acoustic motions. Therefore, care should be taken classifying MHP defects as deep or shallow, since shallow defects may become deep and vice versa. As a consequence, charges from deep levels can escape into bands, and light absorption can be extended to longer wavelengths, improving material performance. The phenomenon, demonstrated with iodine vacancy in CH3NH3PbI3 using a machine learning force field, can be expected for a variety of defects and dopants in many MHPs and other soft inorganic semiconductors. Since large-scale anharmonic motions can be precursors to chemical decomposition, a known problem with MHPs, we propose that materials that are stiffer than MHPs but softer than traditional inorganic semiconductors, such as Si and TiO2, may simultaneously exhibit excellent performance and stability.
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Affiliation(s)
- Bipeng Wang
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Weibin Chu
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Yifan Wu
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - David Casanova
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
- Basque Foundation for Science, IKERBASQUE, Bilbao, 48009 Euskadi, Spain
| | - Wissam A Saidi
- Department of Mechanical Engineering & Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Oleg V Prezhdo
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, United States
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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21
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Cinquanta E, Sardar S, Huey WLB, Vozzi C, Goldberger JE, D’Andrea C, Gadermaier C. Dynamics of Two Distinct Exciton Populations in Methyl-Functionalized Germanane. NANO LETTERS 2022; 22:1183-1189. [PMID: 35050634 PMCID: PMC8832397 DOI: 10.1021/acs.nanolett.1c04357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Methyl-substituted germanane is an emerging material that has been proposed for novel applications in optoelectronics, photoelectrocatalysis, and biosensors. It is a two-dimensional semiconductor with a strong above-gap fluorescence associated with water intercalation. Here, we use time-resolved photoluminescence spectroscopy to understand the mechanism causing this fluorescence. We show that it originates from two distinct exciton populations. Both populations recombine exponentially, accompanied by the thermally activated transfer of exciton population from the shorter- to the longer-lived type. The two exciton populations involve different electronic levels and couple to different phonons. The longer-lived type of exciton migrates within the disordered energy landscape of localized recombination centers. These outcomes shed light on the fundamental optical and electronic properties of functionalized germanane, enabling the groundwork for future applications in optoelectronics, light harvesting, and sensing.
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Affiliation(s)
- Eugenio Cinquanta
- Istituto
di Fotonica e Nanotecnologie, Consiglio
Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Samim Sardar
- Center
for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70, Milano 20133, Italy
| | - Warren L. B. Huey
- Department
of Chemistry and Biochemistry, The Ohio
State University, Columbus, Ohio 43210, United States
| | - Caterina Vozzi
- Istituto
di Fotonica e Nanotecnologie, Consiglio
Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Joshua E. Goldberger
- Department
of Chemistry and Biochemistry, The Ohio
State University, Columbus, Ohio 43210, United States
| | - Cosimo D’Andrea
- Center
for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70, Milano 20133, Italy
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Christoph Gadermaier
- Center
for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70, Milano 20133, Italy
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano 20133, Italy
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22
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Ghods S, Esfandiar A, Iraji zad A, Vardast S. Enhanced Photoresponse and Wavelength Selectivity by SILAR-Coated Quantum Dots on Two-Dimensional WSe 2 Crystals. ACS OMEGA 2022; 7:2091-2098. [PMID: 35071897 PMCID: PMC8771979 DOI: 10.1021/acsomega.1c05591] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
High-performance photodetectors play crucial roles as an essential tool in many fields of science and technology, such as photonics, imaging, spectroscopy, and data communications. Demands for desired efficiency and low-cost new photodetectors through facile manufacturing methods have become a long-standing challenge. We used a simple successive ionic layer adsorption and reaction (SILAR) method to synthesize CdS, CdSe, and PbS nanoparticles directly grown on WSe2 crystalline flakes. In addition to the excellent wavelength selectivity for (30 nm) CdS, (30 nm) CdSe, and (6 nm) PbS/WSe2 heterostructures, the hybrid devices presented an efficient photodetector with a photoresponsivity of 48.72 A/W, a quantum efficiency of 71%, and a response time of 2.5-3.5 ms. Considering the energy band bending structure and numerical simulation data, the electric field distribution at interfaces and photocarrier generation/recombination rates have been studied. The introduced fabrication strategy is fully compatible with the semiconductor industry process, and it can be used as a novel method for fabricating wavelength-tunable and high-performance photodetectors toward innovative optoelectronic applications.
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Affiliation(s)
- Soheil Ghods
- Department
of Physics, Sharif University of Technology, Tehran 11155-9161, Iran
| | - Ali Esfandiar
- Department
of Physics, Sharif University of Technology, Tehran 11155-9161, Iran
| | - Azam Iraji zad
- Department
of Physics, Sharif University of Technology, Tehran 11155-9161, Iran
- Institute
for Nanoscience and Nanotechnology, Sharif
University of Technology, Tehran 11155-9161, Iran
| | - Sajjad Vardast
- Department
of Electrical Engineering, Sharif University
of Technology, Tehran 11155-9161, Iran
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23
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Wang B, Chu W, Prezhdo OV. Interpolating Nonadiabatic Molecular Dynamics Hamiltonian with Inverse Fast Fourier Transform. J Phys Chem Lett 2022; 13:331-338. [PMID: 34978830 DOI: 10.1021/acs.jpclett.1c03884] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nonadiabatic (NA) molecular dynamics (MD) allows one to investigate far-from-equilibrium processes in nanoscale and molecular materials at the atomistic level and in the time domain, mimicking time-resolved spectroscopic experiments. Ab initio NAMD is limited to about 100 atoms and a few picoseconds, due to computational cost of excitation energies and NA couplings. We develop a straightforward methodology that can extend ab initio quality NAMD to nanoseconds and thousands of atoms. The ab initio NAMD Hamiltonian is sampled and interpolated along a trajectory using a Fourier transform, and then, it is used to perform NAMD with known algorithms. The methodology relies on the classical path approximation, which holds for many materials and processes. To achieve a complete ab initio quality description, the trajectory can be obtained using an ab initio trained machine learning force field. The method is demonstrated with charge carrier trapping and relaxation in hybrid organic-inorganic and all-inorganic metal halide perovskites that exhibit complex dynamics and are actively studied for optoelectronic applications.
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Affiliation(s)
- Bipeng Wang
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Weibin Chu
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Oleg V Prezhdo
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, United States
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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24
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Zhan J, Yang J, Xie X, Prezhdo OV, Li W. Interplay of structural fluctuations and charge carrier dynamics is key for high performance of hybrid lead halide perovskites. Inorg Chem Front 2022. [DOI: 10.1039/d2qi01482c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Interplay of organic cation rotation and inorganic lattice fluctuation maintains the high performance of hybrid organic–inorganic perovskites.
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Affiliation(s)
- Juan Zhan
- School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, China
| | - Jack Yang
- School of Material Science and Engineering, Materials and Manufacturing Futures Institute, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Xiaoyin Xie
- School of Chemistry and Chemical Engineering, Hubei Polytechnic University, Huangshi, 435003, China
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Wei Li
- School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, China
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25
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Ab initio Nonadiabatic Dynamics of Semiconductor Nanomaterials via Surface Hopping Method. CHINESE J CHEM PHYS 2022. [DOI: 10.1063/1674-0068/cjcp2111247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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26
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Saha D, Lodha S. First-principles based simulations of electronic transmission in ReS 2/WSe 2 and ReS 2/MoSe 2 type-II vdW heterointerfaces. Sci Rep 2021; 11:23455. [PMID: 34873179 PMCID: PMC8648936 DOI: 10.1038/s41598-021-02704-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 11/18/2021] [Indexed: 11/10/2022] Open
Abstract
Electronic transmission in monolayer ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 and ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 based van der Waals (vdW) heterointerfaces are studied here. Since ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2/WSe\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 and ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2/MoSe\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 type-II vdW heterostructures are suitable for near infrared (NIR)/short-wave infrared (SWIR) photodetection, the role of interlayer coupling at the heterointerfaces is examined in this work. Besides, a detailed theoretical study is presented employing density functional theory (DFT) and nonequilibrium Green’s function (NEGF) combination to analyse the transmission spectra of the two-port devices with ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2/WSe\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 and ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2/MoSe\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 channels and compare the near-equilibrium conductance values. Single layer distorted 1T ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 exhibits formation of parallel chains of ‘Re’-‘Re’ bonds, leading to in-plane anisotropy. Owing to this structural anisotropy, the charge carrier transport is very much orientation dependent in ReS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2. Therefore, this work is further extended to investigate the role of clusterized ‘Re’ atoms in electronic transmission.
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Affiliation(s)
- Dipankar Saha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India. .,Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology Shibpur, Howrah, 711103, India.
| | - Saurabh Lodha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India
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27
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Yang J, Jiang S, Xie J, Jiang H, Xu S, Zhang K, Shi Y, Zhang Y, Zeng Z, Fang G, Wang T, Su F. Identifying the Intermediate Free-Carrier Dynamics Across the Charge Separation in Monolayer MoS 2/ReSe 2 Heterostructures. ACS NANO 2021; 15:16760-16768. [PMID: 34549939 DOI: 10.1021/acsnano.1c06822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Van der Waals heterostructures composed of different two-dimensional films offer a unique platform for engineering and promoting photoelectric performances, which highly demands the understanding of photocarrier dynamics. Herein, large-scale vertically stacked heterostructures with MoS2 and ReSe2 monolayers are fabricated. Correspondingly, the carrier dynamics have been thoroughly investigated using different ultrafast spectroscopies, including Terahertz (THz) emission spectroscopy, time-resolved THz spectroscopy (TRTS), and near-infrared optical pump-probe spectroscopy (OPPS), providing complementary dynamic information for the out-of-plane charge separation and in-plane charge transport at different stages. The initial charge transfer (CT) within the first 170 fs, generating a transient directional current, is directly demonstrated by the THz emissions. Furthermore, the TRTS explicitly unveils an intermediate free-carrier relaxation pathway, featuring a pronounced augmentation of THz photoconductivity compared to the isolated ReSe2 layer, which likely contains the evolution from immigrant hot charged free carriers to bounded interlayer excitons (∼0.7 ps) and the surface defect trapping (∼13 ps). In addition, the OPPS reveals a distinct enhancement in the saturable absorption along with long-lived dynamics (∼365 ps), which originated from the CT and interlayer exciton recombination. Our work provides comprehensive insight into the photocarrier dynamics across the charge separation and will help with the development of optoelectronic devices based on ReSe2-MoS2 heterostructures.
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Affiliation(s)
- Jin Yang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Shaolong Jiang
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiafeng Xie
- GBA branch of Aerospace Information Research Institute, Chinese Academy of Sciences, Guangzhou 510700, China
| | - Huachao Jiang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Shujuan Xu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Kai Zhang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Yuping Shi
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Yanfeng Zhang
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Zhi Zeng
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Guangyou Fang
- GBA branch of Aerospace Information Research Institute, Chinese Academy of Sciences, Guangzhou 510700, China
| | - Tianwu Wang
- GBA branch of Aerospace Information Research Institute, Chinese Academy of Sciences, Guangzhou 510700, China
| | - Fuhai Su
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
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28
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Zimmermann JE, Axt M, Mooshammer F, Nagler P, Schüller C, Korn T, Höfer U, Mette G. Ultrafast Charge-Transfer Dynamics in Twisted MoS 2/WSe 2 Heterostructures. ACS NANO 2021; 15:14725-14731. [PMID: 34520661 DOI: 10.1021/acsnano.1c04549] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional transition metal dichalcogenides offer a fascinating platform for creating van der Waals heterojunctions with exciting physical properties. Because of their typical type-II band alignment, photoexcited electrons and holes can separate via interfacial charge transfer. Furthermore, the relative crystallographic alignment of the individual layers in these heterostructures represents an important degree of freedom. Based on both effects, various fascinating ideas for applications in optoelectronics and valleytronics have been suggested. Despite its utmost importance for the design and efficiency of potential devices, the nature and the dynamics of ultrafast charge transfer are not yet well understood. This is mainly because the charge transfer can be surprisingly fast, usually faster than the temporal resolution of previous experimental approaches. Here, we apply time- and polarization-resolved second-harmonic imaging microscopy to investigate the charge-transfer dynamics for three MoS2/WSe2 heterostructures with different stacking angles at a previously unattainable time resolution of ≈10 fs. For 1.70 eV excitation energy, electron transfer from WSe2 to MoS2 is found to depend considerably on the stacking angle with the fastest transfer time observed to be as short as 12 fs. At 1.85 eV excitation energy, ultrafast hole transfer from MoS2 to hybridized states at the Γ-point and to the K-points of WSe2 has to be considered. Surprisingly, the corresponding decay dynamics show only a minor stacking-angle dependence indicating that radiative recombination of momentum-space indirect Γ-K excitons becomes the dominant decay route for all samples.
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Affiliation(s)
- Jonas E Zimmermann
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - Marleen Axt
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - Fabian Mooshammer
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93053 Regensburg, Germany
| | - Philipp Nagler
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93053 Regensburg, Germany
| | - Christian Schüller
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93053 Regensburg, Germany
| | - Tobias Korn
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - Ulrich Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - Gerson Mette
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
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29
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Mangan SM, Zhou G, Chu W, Prezhdo OV. Dependence between Structural and Electronic Properties of CsPbI 3: Unsupervised Machine Learning of Nonadiabatic Molecular Dynamics. J Phys Chem Lett 2021; 12:8672-8678. [PMID: 34472856 DOI: 10.1021/acs.jpclett.1c02361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Using unsupervised machine learning on the trajectories from a nonadiabatic molecular dynamics simulation with time-dependent Kohn-Sham density functional theory, we elucidated the structural parameters with the largest influence on nonradiative recombination of charge carriers in CsPbI3, which forms the basis for solar energy and optoelectronic applications. The I-I-I angles between PbI6 octahedra, followed by the Cs-I distance, have the strongest impact on the bandgap and the nonadiabatic coupling. The importance of the Cs-I distance is unexpected, because Cs does not contribute to electron and hole wave functions. The nonadiabatic coupling is most influenced by static properties, which is also surprising, given its explicit dependence on atomic velocities.
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Affiliation(s)
- Spencer M Mangan
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - Guoqing Zhou
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Weibin Chu
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Oleg V Prezhdo
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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30
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Zheng SW, Wang HY, Wang L, Luo Y, Gao BR, Sun HB. Observation of robust charge transfer under strain engineering in two-dimensional MoS 2-WSe 2 heterostructures. NANOSCALE 2021; 13:14081-14088. [PMID: 34477689 DOI: 10.1039/d1nr02014e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Strain is one of the effective ways to modulate the band structure of monolayer transition metal dichalcogenides (TMDCs), which has been reported in theoretical and steady-state spectroscopic studies. However, the strain effects on the charge transfer processes in TMDC heterostructures have not been experimentally addressed thus far. Here, we systematically investigate the strain-mediated transient spectral evolutions corresponding to excitons at band-edge and higher energy states for monolayer MoS2 and monolayer WSe2. It is demonstrated that Γ and K valleys in monolayer WSe2 and monolayer MoS2 present different strain responses, according to the broadband femtosecond pump-probe experimental results. It is further observed that the resulting band offset changes tuned by applied tensile strains in MoS2-WSe2 heterostructures would not affect the band-edge electron transfer profiles, where only monolayer WSe2 is excited. From a flexible optoelectronic applications perspective, the robust charge transfer under strain engineering in TMDC heterostructures is very advantageous.
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Affiliation(s)
- Shu-Wen Zheng
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
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31
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Wang B, Chu W, Tkatchenko A, Prezhdo OV. Interpolating Nonadiabatic Molecular Dynamics Hamiltonian with Artificial Neural Networks. J Phys Chem Lett 2021; 12:6070-6077. [PMID: 34170705 DOI: 10.1021/acs.jpclett.1c01645] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nonadiabatic (NA) molecular dynamics (MD) allows one to study far-from-equilibrium processes involving excited electronic states coupled to atomic motions. While NAMD involves expensive calculations of excitation energies and NA couplings (NACs), ground-state properties require much less effort and can be obtained with machine learning (ML) at a fraction of the ab initio cost. Application of ML to excited states and NACs is more challenging, due to costly reference methods, many states, and complex geometry dependence. We developed a NAMD methodology that avoids time extrapolation of excitation energies and NACs. Instead, under the classical path approximation that employs a precomputed ground-state trajectory, we use a small fraction (2%) of the geometries to train neural networks and obtain excited-state energies and NACs for the remaining 98% of the geometries by interpolation. Demonstrated with metal halide perovskites that exhibit complex MD, the method provides nearly two orders of computational savings while generating accurate NAMD results.
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Affiliation(s)
- Bipeng Wang
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Weibin Chu
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Alexandre Tkatchenko
- Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Oleg V Prezhdo
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, United States
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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32
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Lloyd LT, Wood RE, Mujid F, Sohoni S, Ji KL, Ting PC, Higgins JS, Park J, Engel GS. Sub-10 fs Intervalley Exciton Coupling in Monolayer MoS 2 Revealed by Helicity-Resolved Two-Dimensional Electronic Spectroscopy. ACS NANO 2021; 15:10253-10263. [PMID: 34096707 DOI: 10.1021/acsnano.1c02381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The valley pseudospin at the K and K' high-symmetry points in monolayer transition metal dichalcogenides (TMDs) has potential as an optically addressable degree of freedom in next-generation optoelectronics. However, intervalley scattering and relaxation of charge carriers leads to valley depolarization and limits practical applications. In addition, enhanced Coulomb interactions lead to pronounced excitonic effects that dominate the optical response and initial valley depolarization dynamics but complicate the interpretation of ultrafast spectroscopic experiments at short time delays. Employing broadband helicity-resolved two-dimensional electronic spectroscopy (2DES), we observe ultrafast (∼10 fs) intervalley coupling between all A and B valley exciton states that results in a complete breakdown of the valley index in large-area monolayer MoS2 films. These couplings and subsequent dynamics exhibit minimal excitation fluence or temperature dependence and are robust toward changes in sample grain size and inherent strain. Our observations strongly suggest that this direct intervalley coupling on the time scale of optical excitation is an inherent property of large-area MoS2 distinct from dynamic carrier or exciton scattering, phonon-driven processes, and multiexciton effects. This ultrafast intervalley coupling poses a fundamental challenge for exciton-based valleytronics in monolayer TMDs and must be overcome to fully realize large-area valleytronic devices.
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Affiliation(s)
- Lawson T Lloyd
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Ryan E Wood
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Fauzia Mujid
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Siddhartha Sohoni
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Karen L Ji
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Po-Chieh Ting
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jacob S Higgins
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jiwoong Park
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
| | - Gregory S Engel
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
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33
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Qiao L, Fang WH, Long R, Prezhdo OV. Elimination of Charge Recombination Centers in Metal Halide Perovskites by Strain. J Am Chem Soc 2021; 143:9982-9990. [PMID: 34155882 DOI: 10.1021/jacs.1c04442] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Metal halide perovskites exhibit enhanced photoluminescence and long-lived carriers in experiments under strain. Using ab initio nonadiabatic molecular dynamics, we demonstrate that compressive and tensile strain can eliminate charge recombination centers created by defect states, by shifting traps from bandgap into bands. A compressive strain enhances coupling of Pb-s and I-p orbitals, pushes the valence band (VB) up in energy, and moves the trap state due to iodine interstitial (Ii) into the VB. The strain distorts the system and breaks the I-dimer responsible for the Ii trap. A tensile strain increases Pb-Pb distance, weakens overlap of Pb-p orbitals, and pushes the conduction band (CB) down in energy. The trap state created by replacement of iodine with methylammonium (MAI) is moved into the CB. Application of strain to the defective systems not only eliminates midgap traps but also creates moderate disorder that reduces overlap of electron and hole wave functions, activates phonon modes accelerating coherence loss within the electronic subsystem, and extends carrier lifetimes even beyond those in pristine MAPbI3. Our investigation rationalizes the high performance of perovskites solar cells under strain and reveals how strain passivates Ii and MAI defects in MAPbI3, providing a new nonchemical strategy for defect control and engineering.
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Affiliation(s)
- Lu Qiao
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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