1
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Jahn YM, Alboteanu G, Mordehai D, Ya'akobovitz A. Strain engineering of the mechanical properties of two-dimensional WS 2. NANOSCALE ADVANCES 2024; 6:4062-4070. [PMID: 39114146 PMCID: PMC11302181 DOI: 10.1039/d3na00990d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 06/26/2024] [Indexed: 08/10/2024]
Abstract
Tuning the physical properties of two-dimensional (2D) materials is crucial for their successful integration into advanced applications. While strain engineering demonstrated an efficient means to modulate the electrical and optical properties of 2D materials, tuning their mechanical properties has not been carried out. Here we applied compressive strain through the buckling metrology to 2D tungsten disulfide (WS2), which demonstrated mechanical softening manifested by the reduction of its effective Young's modulus. Raman modes analysis of the strained WS2 also showed strain-dependent vibrational modes softening and revealed its Grüneisen parameter (γ E2g = 0.29) and its shear deformation potential (β E2g = 0.56) - both are similar to the values of other 2D materials. In parallel, we conducted a molecular dynamic simulation that confirmed the validity of continuum mechanics modeling in the nanoscale and revealed that due to sequential atomic-scale buckling events in compressed WS2, it shows a mechanical softening. Therefore, by tuning the mechanical properties of WS2 we shed light on its fundamental physics, thus making it an attractive candidate material for high-end applications, such as tunable sensors and flexible optoelectronic devices.
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Affiliation(s)
- Yarden Mazal Jahn
- Department of Mechanical Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev Israel
| | - Guy Alboteanu
- Department of Mechanical Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev Israel
| | - Dan Mordehai
- Faculty of Mechanical Engineering, Technion Israel Institute of Technology Haifa Israel
| | - Assaf Ya'akobovitz
- Department of Mechanical Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev Israel
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2
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Wang X, Niu G, Jiang J, Sui L, Zeng X, Liu X, Zhang Y, Wu G, Yuan K, Yang X. Modulating Carrier Dynamics in PdSe 2: The Role of Pressure in Electronic and Phononic Interactions. NANO LETTERS 2024; 24:9058-9064. [PMID: 39007901 DOI: 10.1021/acs.nanolett.4c02300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
PdSe2 is a puckered transition metal dichalcogenide that has been reported to undergo a two-dimensional to three-dimensional structural transition under pressure. Here, we investigated the electronic and phononic evolution of PdSe2 under high pressure using pump-probe spectroscopy. We observed the electronic intraband and interband transitions occurring in the d orbitals of Pd, revealing the disappearance of the Jahn-Teller effect under high pressure. Furthermore, we found that the decay rates of interband recombination and intraband relaxation lifetimes change at 3 and 7 GPa, respectively. First-principles calculations suggest that the bandgap closure slows the decay rate of interband recombination after 3 GPa, while the saturation of phonon-phonon scattering is the main reason for the relatively constant intraband relaxation lifetime. Our work provides a novel perspective for understanding the evolution of the electron and modulation of the carrier dynamics by phonons under pressure.
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Affiliation(s)
- Xiaowei Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Guangming Niu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Jutao Jiang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Laizhi Sui
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xiangyu Zeng
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Xin Liu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Science College, Dalian Maritime University, Dalian 116026, China
| | - Yutong Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Wei X, Wang Z, Wang Z, Lu Y, Ji Q, Liu W. Unveiling Spatiotemporal Diffusion of Hot Carriers Influenced by Spatial Nonuniform Hot Phonon Bottleneck Effect in Monolayer MoS 2. NANO LETTERS 2024. [PMID: 39038297 DOI: 10.1021/acs.nanolett.4c02059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
The exceptional semiconducting properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) have made them highly promising for the development of future electronic and optoelectronic devices. Extensive studies of TMDs are partly associated with their ability to generate 2D-confined hot carriers above the conduction band edges, enabling potential applications that rely on such transient excited states. In this work, room-temperature spatiotemporal hot carrier dynamics in monolayer MoS2 is studied by transient absorption microscopy (TAM), featuring an initial ultrafast expansion followed by a rapid negative diffusion, and ultimately a slow long-term expansion of the band edge C-excitons. We provide direct experimental evidence to identify the abnormal negative diffusion process as a spatial contraction of the hot carriers resulting from spatial variation in the hot phonon bottleneck effect due to the Gaussian intensity distribution of the pump laser beam.
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Affiliation(s)
- Xiaofan Wei
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zihan Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ziyu Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yue Lu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qingqing Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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4
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Liu B, Michail E, He G, Sfeir MY, Forrest SR. Ultrafast Dynamics of Bloch Surface Wave Polaritons in Large-Area 2D Semiconductor Monolayers at Room Temperature. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2404286. [PMID: 38924714 DOI: 10.1002/adma.202404286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 06/18/2024] [Indexed: 06/28/2024]
Abstract
The dynamics of strongly coupled polariton systems integrated with 2D transition metal dichalcogenides (TMDs) is key to enabling efficient coherent processes and achieving high-performance TMD-based polaritonic devices, such as ultralow-threshold polariton lasers and ultrafast optical switches. However, there has been a lack of a comprehensive understanding of the excited state dynamics in TMD-based polariton systems. In this work, ultrafast pump-probe optical spectroscopy is used to investigate the room temperature dynamics of the polariton systems consisting of TMD monolayer excitons strongly coupled with Bloch surface waves (BSWs) supported by all-dielectric photonic structures. The transient response is found for both above-exciton energy pumping and polariton-resonant pumping. The excited state population and ultrafast coherent coupling of the exciton reservoir and lower polariton (LP) branch are observed for resonant pumping. Moreover, it is found that the transient response of the LP first decays on a short-time scale of 0.15-0.25 ps compared to the calculated intrinsic lifetime of 0.11-0.20 ps, and is followed by a longer decay (>100 ps) due to the dynamical evolution of the exciton reservoir. The results provide a fundamental understanding of the dynamics of TMD-based polariton systems while showing the potential for achieving efficient coherent optical processes for device applications.
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Affiliation(s)
- Bin Liu
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Evripidis Michail
- Department of Physics, Graduate Center, City University of New York, New York, NY, 10016, USA
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
| | - Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, NY, 10016, USA
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, NY, 10016, USA
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
| | - Stephen R Forrest
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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5
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Jeffries WR, Jawaid AM, Vaia RA, Knappenberger KL. Thickness-dependent electronic relaxation dynamics in solution-phase redox-exfoliated MoS2 heterostructures. J Chem Phys 2024; 160:144707. [PMID: 38597312 DOI: 10.1063/5.0200398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 03/20/2024] [Indexed: 04/11/2024] Open
Abstract
Electronic relaxation dynamics of solution-phase redox-exfoliated molybdenum disulfide (MoS2) monolayer and multilayer ensembles are described. MoS2 was exfoliated using polyoxometalate (POM) reductants. This process yields a colloidal heterostructure consisting of MoS2 2D sheet multilayers with surface-bound POM complexes. Using two-dimensional electronic spectroscopy, transient bleaching and photoinduced absorption signals were detected at excitation/detection energies of 1.82/1.87 and 1.82/1.80 eV, respectively. Approximate 100-fs bandgap renormalization (BGR) and subsequent defect- and phonon-mediated relaxation on the picosecond timescale were resolved for several MoS2 thicknesses spanning from 1 to 2 L to ∼20 L. BGR rates were independent of sample thickness and slightly slower than observations for chemical vapor deposition-grown MoS2 monolayers. However, defect-mediated relaxation accelerated ∼10-fold with increased sample thicknesses. The relaxation rates increased from 0.33 ± 0.05 to 1.2 ± 0.1 and 3.1 ± 0.4 ps-1 for 1-2 L, 3-4 L, and 20 L fractions. The thicknesses-dependent relaxation rates for POM-MoS2 heterostructures were modeled using a saturating exponential function that showed saturation at thirteen MoS2 layers. The results suggest that the increased POM surface coverage leads to larger defect density in the POM-MoS2 heterostructure. These are the first descriptions of the influence of sample thickness on electronic relaxation rates in solution-phase redox-exfoliated POM-MoS2 heterostructures. Outcomes of this work are expected to impact the development of solution-phase exfoliation of 2D metal-chalcogenide heterostructures.
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Affiliation(s)
- William R Jeffries
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ali M Jawaid
- Air Force Research Laboratory, 2941 Hobson Way, Wright Patterson Air Force Base, Dayton, Ohio 45433, USA
| | - Richard A Vaia
- Air Force Research Laboratory, 2941 Hobson Way, Wright Patterson Air Force Base, Dayton, Ohio 45433, USA
| | - Kenneth L Knappenberger
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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6
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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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7
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Walsh CP, Malizia JP, Sutton SC, Papanikolas JM, Cahoon JF. Monolayer-like Exciton Recombination Dynamics of Multilayer MoSe 2 Observed by Pump-Probe Microscopy. NANO LETTERS 2024; 24:1431-1438. [PMID: 38252694 DOI: 10.1021/acs.nanolett.3c04754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Transition metal dichalcogenides (TMDCs) have garnered considerable interest over the past decade as a class of semiconducting layered materials. Most studies on the carrier dynamics in these materials have focused on the monolayer due to its direct bandgap, strong photoluminescence, and strongly bound excitons. However, a comparative understanding of the carrier dynamics in multilayer (e.g., >10 layers) flakes is still absent. Recent computational studies have suggested that excitons in bulk TMDCs are confined to individual layers, leading to room-temperature stable exciton populations. Using this new context, we explore the carrier dynamics in MoSe2 flakes that are between ∼16 and ∼125 layers thick. We assign the kinetics to exciton-exciton annihilation (EEA) and Shockley-Read-Hall recombination of free carriers. Interestingly, the average observed EEA rate constant (0.003 cm2/s) is nearly independent of flake thickness and 2 orders of magnitude smaller than that of an unencapsulated monolayer (0.33 cm2/s) but very similar to values observed in encapsulated monolayers. Thus, we posit that strong intralayer interactions minimize the effect of layer thickness on recombination dynamics, causing the multilayer to behave like the monolayer and exhibit an apparent EEA rate intrinsic to MoSe2.
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Affiliation(s)
- Cullen P Walsh
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jason P Malizia
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Sarah C Sutton
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - John M Papanikolas
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - James F Cahoon
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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8
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Chi Z, Wei Z, Zhang G, Chen H, Weng YX. Determining Band Splitting and Spin-Flip Dynamics in Monolayer MoS 2. J Phys Chem Lett 2023; 14:9640-9645. [PMID: 37870497 DOI: 10.1021/acs.jpclett.3c02431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Femtosecond helicity-resolved pump-probe spectroscopy is performed to study the spin and valley dynamics in monolayer (ML) MoS2. Both the bright to dark intravalley exciton transition (∼50 fs) and the reverse transition process (<50 fs) are directly monitored. It suggests that the bright exciton state of ML MoS2 is lower in energy than the dark one, which is also confirmed by observing the temperature-dependent co-polarized photobleaching dynamics of A and B excitons. Furthermore, the band splitting in the conduction band of ML MoS2 with a value of 15 ± 0.3 meV is determined by fitting the temperature-dependent ratios of the population in bright and dark states using the Boltzmann distribution law. Such minor band splitting allows the phonon-mediated intravalley spin-flip to even occur from the lower to the upper conduction band within tens of femtoseconds, which will have non-negligible effects on the performance of these ML MoS2-based optoelectronic and photonic devices.
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Affiliation(s)
- Zhen Chi
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physics and Electronics, International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, Henan University, Kaifeng 475004, China
| | - Zheng Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hailong Chen
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yu-Xiang Weng
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Yagodkin D, Kumar A, Ankerhold E, Richter J, Watanabe K, Taniguchi T, Gahl C, Bolotin KI. Probing the Formation of Dark Interlayer Excitons via Ultrafast Photocurrent. NANO LETTERS 2023; 23:9212-9218. [PMID: 37788809 PMCID: PMC10603811 DOI: 10.1021/acs.nanolett.3c01708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/15/2023] [Indexed: 10/05/2023]
Abstract
Optically dark excitons determine a wide range of properties of photoexcited semiconductors yet are hard to access via conventional time-resolved spectroscopies. Here, we develop a time-resolved ultrafast photocurrent technique (trPC) to probe the formation dynamics of optically dark excitons. The nonlinear nature of the trPC makes it particularly sensitive to the formation of excitons occurring at the femtosecond time scale after the excitation. As a proof of principle, we extract the interlayer exciton formation time of 0.4 ps at 160 μJ/cm2 fluence in a MoS2/MoSe2 heterostructure and show that this time decreases with fluence. In addition, our approach provides access to the dynamics of carriers and their interlayer transport. Overall, our work establishes trPC as a technique to study dark excitons in various systems that are hard to probe by other approaches.
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Affiliation(s)
- Denis Yagodkin
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Abhijeet Kumar
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Elias Ankerhold
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Johanna Richter
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, 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
| | - Cornelius Gahl
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Kirill I. Bolotin
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
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10
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Wang T, Hopper TR, Mondal N, Liu S, Yao C, Zheng X, Torrisi F, Bakulin AA. Hot Carrier Cooling and Trapping in Atomically Thin WS 2 Probed by Three-Pulse Femtosecond Spectroscopy. ACS NANO 2023; 17:6330-6340. [PMID: 36939760 PMCID: PMC10100566 DOI: 10.1021/acsnano.2c10479] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Transition metal dichalcogenides (TMDs) have shown outstanding semiconducting properties which make them promising materials for next-generation optoelectronic and electronic devices. These properties are imparted by fundamental carrier-carrier and carrier-phonon interactions that are foundational to hot carrier cooling. Recent transient absorption studies have reported ultrafast time scales for carrier cooling in TMDs that can be slowed at high excitation densities via a hot-phonon bottleneck (HPB) and discussed these findings in the light of optoelectronic applications. However, quantitative descriptions of the HPB in TMDs, including details of the electron-lattice coupling and how cooling is affected by the redistribution of energy between carriers, are still lacking. Here, we use femtosecond pump-push-probe spectroscopy as a single approach to systematically characterize the scattering of hot carriers with optical phonons, cold carriers, and defects in a benchmark TMD monolayer of polycrystalline WS2. By controlling the interband pump and intraband push excitations, we observe, in real-time (i) an extremely rapid "intrinsic" cooling rate of ∼18 ± 2.7 eV/ps, which can be slowed with increasing hot carrier density, (ii) the deprecation of this HPB at elevated cold carrier densities, exposing a previously undisclosed role of the carrier-carrier interactions in mediating cooling, and (iii) the interception of high energy hot carriers on the subpicosecond time scale by lattice defects, which may account for the lower photoluminescence yield of TMDs when excited above band gap.
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Affiliation(s)
- Tong Wang
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Thomas R. Hopper
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Navendu Mondal
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Sihui Liu
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Chengning Yao
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Xijia Zheng
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Felice Torrisi
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
- Dipartimento
di Fisica e Astronomia, Universita’
di Catania & CNR-IMM (Catania Universita’), Via S. Sofia 64, 95123 Catania, Italy
| | - Artem A. Bakulin
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
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11
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Wang ZM, Yao CB, Wang LY, Wang X, Jiang CH, Yin HT. Charge Mobility and Strain Engineering in Two-Step MS-Grown MoS 2/Seed Layer Heterointerface and Photo-Excitation Mechanism. ACS APPLIED MATERIALS & INTERFACES 2023; 15:17364-17376. [PMID: 36973948 DOI: 10.1021/acsami.3c00706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) materials have potential application and wide development prospects in photoelectron and spintronic devices. However, the properties of different growth conditions are challenging to study in the future. This, in turn, hinders further research into 2D materials and the manufacture of high-quality devices. A comprehensive understanding of the ultrafast laser spectroscopy and dynamics that take into account the substrate-transition metal dichalcogenide (TMD) interaction is lacking. Here, the strain effect is elucidated by systematically investigating the interfacial interaction between different substrates and MoS2. The strain and interface engineering of MoS2/seeds layer heterointerface and light-matter coupling are discussed in the Raman and photoluminescence spectra. The dramatic enhanced PL originates from the phase transition of MoS2 on different substrates and electron-hole pairs dissociated by exciton screening effect. Finite-difference time-domain simulation confirmed that the electric field, magnetic field, and polarization field of the heterojunction system changed after the strain was applied. In addition, based on the dependence of physical parameters of MoS2, the relative numerical changes of physical parameters of MoS2 films on different substrates as well as the photoelectric transfer, strain, and charge doping levels on the surface or interface will provide a direction for optimizing the selection of various devices.
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Affiliation(s)
- Ze-Miao Wang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Cheng-Bao Yao
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Li-Yuan Wang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Xue Wang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Cai-Hong Jiang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Hai-Tao Yin
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
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12
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M CS, Pippia G, Tanghe I, Martín-García B, Rousaki A, Vandenabeele P, Schiettecatte P, Moreels I, Geiregat P. Charge Carrier Dynamics in Colloidally Synthesized Monolayer MoX 2 Nanosheets. J Phys Chem Lett 2023; 14:2620-2626. [PMID: 36888728 DOI: 10.1021/acs.jpclett.3c00278] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Transition metal dichalcogenides (TMDs) are nanostructured semiconductors with prospects in optoelectronics and photocatalysis. Several bottom-up procedures to synthesize such materials have been developed yielding colloidal transition metal dichalcogenides (c-TMDs). Where such methods initially yielded multilayered sheets with indirect band gaps, recently, also the formation of monolayered c-TMDs became possible. Despite these advances, no clear picture on the charge carrier dynamics in monolayer c-TMDs exists to date. Here, we show through broadband and multiresonant pump-probe spectroscopy, that the carrier dynamics in monolayer c-TMDs are dominated by a fast electron trapping mechanism, universal to both MoS2 and MoSe2, contrasting hole-dominated trapping in their multilayered counterparts. Through a detailed hyperspectral fitting procedure, sizable exciton red shifts are found and assigned to static shifts originating from both interactions with the trapped electron population and lattice heating. Our results pave the way to optimizing monolayer c-TMDs via passivation of predominantly the electron-trap sites.
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Affiliation(s)
- Chandra Sekhar M
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
- NoLIMITS Center for Non-Linear Microscopy and Spectroscopy, Ghent University, 9000 Ghent, Belgium
| | - Gabriele Pippia
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
- Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Ivo Tanghe
- NoLIMITS Center for Non-Linear Microscopy and Spectroscopy, Ghent University, 9000 Ghent, Belgium
- Photonics Research Group, Ghent University, 9000 Ghent, Belgium
| | - Beatriz Martín-García
- CIC nanoGUNE, Tolsa Hirbidea 76, E-20018 Donostia-San Sebastian, Spain
- IKERBASQUE Basque Foundation for Science, 48009 Bilbao, Spain
| | | | - Peter Vandenabeele
- Department of Chemistry, Ghent University, 9000 Ghent, Belgium
- Department of Archaeology, Ghent University, 9000 Ghent, Belgium
| | - Pieter Schiettecatte
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Iwan Moreels
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
- Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
- NoLIMITS Center for Non-Linear Microscopy and Spectroscopy, Ghent University, 9000 Ghent, Belgium
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13
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Wang X, Niu G, Jiang J, Sui L, Zeng X, Liu X, Zhang Y, Wu G, Yuan K, Yang X. Anomalous Dynamics of Defect-Assisted Phonon Recycling in Few-Layer Mo 0.5W 0.5S 2. J Phys Chem Lett 2022; 13:10395-10403. [PMID: 36318176 DOI: 10.1021/acs.jpclett.2c02935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Alloying has emerged as a new strategy to tune the function of 2D transition metal dichalcogenides (TMDCs). However, the lack of research on the electrical and structural properties of these alloys limits their practical applications. Here, femtosecond transient absorption spectroscopy with pump pulse tunability is performed to elucidate the ultrafast carrier dynamics in the few-layer Mo0.5W0.5S2 prepared by the liquid phase exfoliation method. An anomalous rebleaching of the ground state is observed at high pump fluence by 3.1 eV excitation. We ascribe this rebleaching of the ground state to the mechanism that the carriers trapped in the defect are thermally excited back to the untrapped exciton state due to the phonon recycling, which hinders the dissipation of nonradiative energy, through comparative experiments and global analysis. Our findings demonstrate a novel energy transfer channel assisted by defect in few-layer TMDCs which is critical for their advanced applications.
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Affiliation(s)
- Xiaowei Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Guangming Niu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Jutao Jiang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Laizhi Sui
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xiangyu Zeng
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Xin Liu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Science College, Dalian Maritime University, Dalian 116026, China
| | - Yutong Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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14
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Nayyar N, Le D, Turkowski V, Rahman TS. Electron-phonon interaction and ultrafast photoemission from doped monolayer MoS 2. Phys Chem Chem Phys 2022; 24:25298-25306. [PMID: 36226502 DOI: 10.1039/d2cp02905g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We have examined the effect of electron-phonon coupling on photoluminescence and ultrafast response of electron doped monolayer MoS2, using a combination of density functional theory, time dependent density functional theory, and many-body theory. For small doping (∼1-3%) of interest here, the electron-phonon coupling parameter is modest (∼0.1-0.2) but its effect on the emissive properties and response of the system to femtosecond (fs) laser pulses is striking. We find an ultrafast (fs) relaxation of the electronic subsystem as well as a high fluence of visible light emission induced by electron phonon interaction. Together with high carrier mobility, these features of monolayer MoS2 may be relevant for optoelectronic technologies.
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Affiliation(s)
- Neha Nayyar
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Duy Le
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Volodymyr Turkowski
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
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15
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Park C, Ahn S, Cha JH, Hong W, Jin HJ, Yang SY, Cho YH, Choi SY. Spatially isolated neutral excitons via clusters on trilayer MoS 2. NANOSCALE 2022; 14:4304-4311. [PMID: 35244667 DOI: 10.1039/d2nr00391k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In spite of having a large exciton binding energy, two-dimensional (2D) transition metal dichalcogenides (TMDs) are limited as light-emitting materials because the spectral weight of neutral excitons decreases exponentially with increasing the excitation density. That is, neutral excitons easily transfer to trions, and exciton-exciton annihilation (EEA) occurs due to the strengthening of exciton kinetic energy in the layered structure. In here, we come up with an isolated neutral exciton system, maintaining its high spectral weight when the carrier density increased, which is achieved via MoS2 clusters on a MoS2 trilayer directly synthesized by metal-organic chemical vapor deposition (MOCVD). While increasing the excitation density, trions are decomposed by spatial confinement at the saturation level of its full width at half maximum (FWHM), and simultaneously the spectral weight of neutral excitons restarts to increase. Furthermore, we reveal the causality relationship between trions and B excitons, providing a keen insight into organic interactions among radiative recombination processes in 2D TMDs.
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Affiliation(s)
- Cheolmin Park
- School of Electrical Engineering, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Seonghun Ahn
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Jun-Hwe Cha
- School of Electrical Engineering, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Woonggi Hong
- School of Electrical Engineering, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Hyeok Jun Jin
- School of Electrical Engineering, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Sang Yoon Yang
- School of Electrical Engineering, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Yong-Hoon Cho
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Sung-Yool Choi
- School of Electrical Engineering, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
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16
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Zhu J, Zhou L, Zhu Y, Huang J, Hou L, Shen J, Dai S, Li C. Stable Bismuth-Doped Lead Halide Perovskite Core-Shell Nanocrystals by Surface Segregation Effect. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2104399. [PMID: 34837312 DOI: 10.1002/smll.202104399] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/09/2021] [Indexed: 05/20/2023]
Abstract
Lead halide perovskite nanocrystals (NCs) exhibit excellent optoelectronic performance, however, the broad application is limited by their poor stability. Herein, a strategy for stable core-shell structured bismuth-doped lead halide perovskite NCs is reported. The stable core-shell perovskite NCs are prepared based on heterovalent substitutions and surface segregation effect. Core-shell features are revealed through advanced characterization and structure analyses. Meanwhile, the transfer of carriers between the core and the shell is observed by ultrafast transient absorption spectroscopy. The core-shell structured perovskite NCs exhibit outstanding structure stability and retain 97% of the original photocatalytic efficiency after cycle experiments under moisture ambient and light irradiation. Such a core-shell structure constructs gradient energy levels. These findings are expected to facilitate the development of stable lead halide perovskite devices.
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Affiliation(s)
- Jingrun Zhu
- Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, Frontier Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Lihui Zhou
- Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Yihua Zhu
- Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, Frontier Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Jianfei Huang
- Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Lu Hou
- Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, Frontier Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Jianhua Shen
- Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, Frontier Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Sheng Dai
- Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Chunzhong Li
- Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, Frontier Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
- School of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
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17
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Wang Y, Iyikanat F, Rostami H, Bai X, Hu X, Das S, Dai Y, Du L, Zhang Y, Li S, Lipsanen H, García de Abajo FJ, Sun Z. Probing Electronic States in Monolayer Semiconductors through Static and Transient Third-Harmonic Spectroscopies. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107104. [PMID: 34743375 DOI: 10.1002/adma.202107104] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/23/2021] [Indexed: 05/06/2023]
Abstract
Electronic states and their dynamics are of critical importance for electronic and optoelectronic applications. Here, various relevant electronic states in monolayer MoS2 , such as multiple excitonic Rydberg states and free-particle energy bands are probed with a high relative contrast of up to ≥200 via broadband (from ≈1.79 to 3.10 eV) static third-harmonic spectroscopy (THS), which is further supported by theoretical calculations. Moreover, transient THS is introduced to demonstrate that third-harmonic generation can be all-optically modulated with a modulation depth exceeding ≈94% at ≈2.18 eV, providing direct evidence of dominant carrier relaxation processes associated with carrier-exciton and carrier-phonon interactions. The results indicate that static and transient THS are not only promising techniques for the characterization of monolayer semiconductors and their heterostructures, but also a potential platform for disruptive photonic and optoelectronic applications, including all-optical modulation and imaging.
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Affiliation(s)
- Yadong Wang
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Fadil Iyikanat
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
| | - Habib Rostami
- Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, Stockholm, 10691, Sweden
| | - Xueyin Bai
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Xuerong Hu
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Susobhan Das
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Yunyun Dai
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Luojun Du
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Yi Zhang
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - Shisheng Li
- International Center for Young Scientists (ICYS), National Institute for Materials Science, Tsukuba, 305-0044, Japan
| | - Harri Lipsanen
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Zhipei Sun
- Department of Electronics and Nanoengineering, Aalto University, Espoo, 02150, Finland
- QTF Centre of Excellence, Department of Applied Physics, Aalto University, Espoo, 02150, Finland
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18
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Xu YJ, Liu HY, Chen HL. Direct observation of electron-vibration coupling at MXene-solvent interface. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2108135] [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]
Affiliation(s)
- Yan-jun Xu
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - He-yuan Liu
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hai-long Chen
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
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19
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Zhao WQ, Zou JW, Qu SZ, Qin PL, Chen XB, Ding SJ, Ma L, Wang QQ. Plasmon-Mediated 2D/2D Phase Junction for Improved Photocatalytic Hydrogen Generation Activity. ACS APPLIED MATERIALS & INTERFACES 2021; 13:44440-44450. [PMID: 34499478 DOI: 10.1021/acsami.1c13074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A phase junction fabricated by two crystalline phases of the same semiconductor is a promising photocatalyst with efficient charge transfer and separation. However, the weak light absorption and uncontrolled phase junction interface limit the generation and separation of photogenerated carriers. Herein, a two-dimensional (2D)/2D phase junction was prepared by growing orthorhombic WO3 ultrathin nanosheets on hexagonal WO3 nanosheets through a one-step hydrothermal method. The orthorhombic/hexagonal WO3 possesses large-area phase junction interfaces, rich reactive sites, and built-in electric field, which greatly accelerate the photogenerated charge separation and transfer. Thus, the orthorhombic/hexagonal WO3 displayed excellent photocatalytic hydrogen generation activity from water splitting under light irradiation (λ > 420 nm), which is 2.16 and 2.85 times those of orthorhombic and hexagonal WO3 phase components. Furthermore, Au nanoparticles (about 4.5 nm in diameter) were deposited on both orthorhombic and hexagonal WO3 nanosheets to form a plasmon-mediated phase junction. The hybrids exhibit prominent visible-light absorption and efficient charge transfer, leading to a further improved photocatalytic hydrogen generation activity. Further characterization studies demonstrate that superior photoactivity arises from the excellent visible-light-harvesting ability, appropriate band structure, and high-efficiency and multichannel transferring processes of photogenerated carriers.
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Affiliation(s)
- Wen-Qin Zhao
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, P. R. China
| | - Jing-Wen Zou
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, P. R. China
| | - Shu-Zhou Qu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, P. R. China
| | - Ping-Li Qin
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, P. R. China
| | - Xiang-Bai Chen
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, P. R. China
| | - Si-Jing Ding
- School of Mathematics and Physics, China University of Geosciences (Wuhan), Wuhan 430074, P. R. China
| | - Liang Ma
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, P. R. China
| | - Qu-Quan Wang
- Department of Physics, Wuhan University, Wuhan 430072, P. R. China
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20
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Ding B, Li X, Zhou W, Zhang G, Gao H. Anomalous strain effect on the thermal conductivity of low-buckled two-dimensional silicene. Natl Sci Rev 2021; 8:nwaa220. [PMID: 34691724 PMCID: PMC8433080 DOI: 10.1093/nsr/nwaa220] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/19/2020] [Accepted: 08/03/2020] [Indexed: 11/13/2022] Open
Abstract
The thermal conductivity of two-dimensional materials, such as graphene, typically decreases when tensile strain is applied, which softens their phonon modes. Here, we report an anomalous strain effect on the thermal conductivity of monolayer silicene, a representative low-buckled two-dimensional (LB-2D) material. ReaxFF-based molecular dynamics simulations are performed to show that biaxially stretched monolayer silicene exhibits a remarkable increase in thermal conductivity, by as much as 10 times the freestanding value, with increasing applied strain in the range of [0, 0.1], which is attributed to increased contributions from long-wavelength phonons. A further increase in strain in the range of [0.11, 0.18] results in a plateau of the thermal conductivity in an oscillatory manner, governed by a unique dynamic bonding behavior under extreme loading. This anomalous effect reveals new physical insights into the thermal properties of LB-2D materials and may provide some guidelines for designing heat management and energy conversion devices based on such materials.
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Affiliation(s)
- Bin Ding
- Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore
| | - Xiaoyan Li
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Wuxing Zhou
- School of Materials Science and Engineering & Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Gang Zhang
- Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore
| | - Huajian Gao
- Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, Singapore 637457, Singapore
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21
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Nazemi M, Panikkanvalappil SR, Liao CK, Mahmoud MA, El-Sayed MA. Role of Femtosecond Pulsed Laser-Induced Atomic Redistribution in Bimetallic Au-Pd Nanorods on Optoelectronic and Catalytic Properties. ACS NANO 2021; 15:10241-10252. [PMID: 34032116 DOI: 10.1021/acsnano.1c02347] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Utilizing solar energy for chemical transformations has attracted a growing interest in promoting the clean and modular chemical synthesis approach and addressing the limitations of conventional thermocatalytic systems. Under light irradiation, noble metal nanoparticles, particularly those characterized by localized surface plasmon resonance, commonly known as plasmonic nanoparticles, generate a strong electromagnetic field, excited hot carriers, and photothermal heating. Plasmonic nanoparticles enabling efficient absorption of light in the visible range have moderate catalytic activities. However, the catalytic performance of a plasmonic nanoparticle can be significantly enhanced by incorporating a highly catalytically active metal domain onto its surface. In this study, we demonstrate that femtosecond laser-induced atomic redistribution of metal domains in bimetallic Au-Pd nanorods (NRs) can enhance its photocurrent response by 2-fold compared to parent Au-Pd NRs. We induce structure changes on Au-Pd NRs by irradiating them with a femtosecond pulsed laser at 808 nm to precisely redistribute Pd atoms on AuNR surfaces, resulting in modified electronic and optical properties and, thereby, enhanced catalytic activity. We also investigate the trade-off between the effect of light absorption and catalytic activity by optimizing the structure and composition of bimetallic Au-Pd nanoparticles. This work provides insight into the design of hybrid plasmonic-catalytic nanostructures with well-tailored geometry, composition, and structure for solar-fuel-based applications.
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Affiliation(s)
- Mohammadreza Nazemi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Sajanlal R Panikkanvalappil
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02210, United States
| | - Chih-Kai Liao
- Department of Biomedical Engineering and Chemical Engineering, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Mahmoud A Mahmoud
- Department of Biomedical Engineering and Chemical Engineering, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Mostafa A El-Sayed
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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22
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Gao L, Hu Z, Lu J, Liu H, Ni Z. Defect-related dynamics of photoexcited carriers in 2D transition metal dichalcogenides. Phys Chem Chem Phys 2021; 23:8222-8235. [PMID: 33875990 DOI: 10.1039/d1cp00006c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDs) exhibit enormous potential in the field of optoelectronics. The high performance of TMD materials and optoelectronic devices significantly depends on processes involved in photoelectric conversion, including photo-excitation, relaxation, transportation, and recombination. Remarkably, inevitable defects in materials prolong or shorten the characteristic time of these processes and even bring about new photoelectric conversion channels, namely, the defect-related relaxation pathways of photoexcited carriers tailor the performance of photoelectric applications. In recent years, there have been numerous investigations in exploring the variant transient signals caused by defects in TMDs utilizing ultrafast spectroscopies. They have the capability in providing an accurate and overall representation of ultrafast processes owing to the subtle temporal resolution. The defect-related mechanisms occurring in different time scales (from femtosecond (fs) to microsecond (μs)) play influential roles throughout the relaxation process of photoexcited species. Herein, we review the defect-related relaxation mechanisms of photoexcited species in TMDs according to the time scale utilizing ultrafast spectroscopy techniques. By interpreting and summarizing the defect-related transient signals, we furnish the direction in material design and performance optimization.
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Affiliation(s)
- Lei Gao
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
| | - Zhenliang Hu
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
| | - Junpeng Lu
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
| | - Hongwei Liu
- Jiangsu Key Lab on Opto-Electronic Technology, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Zhenhua Ni
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
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23
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Liu F, Wang Z, Weng Y, Shi R, Ma W, Chen Y. Black Phosphorus Quantum Dots Modified CdS Nanowires with Efficient Charge Separation for Enhanced Photocatalytic H
2
Evolution. ChemCatChem 2021. [DOI: 10.1002/cctc.202001847] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Fulai Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics & CAS, Key Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Yuxiang Weng
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
- Beijing National Laboratory for Condensed Matter Physics & CAS, Key Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Rui Shi
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Wangjing Ma
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Yong Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
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24
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Chi Z, Chen HH, Chen Z, Chen HL. Unveiling defect-mediated carrier dynamics in few-layer MoS2 prepared by ion exchange method via ultrafast Vis-NIR-MIR spectroscopy. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp2007123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Zhen Chi
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China
| | - Hui-hui Chen
- Department of Materials Physics and Chemistry, Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology Institution, Beijing 100081, China
| | - Zhuo Chen
- Department of Materials Physics and Chemistry, Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology Institution, Beijing 100081, China
| | - Hai-long Chen
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
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25
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Cheng Y, Kong X, Chang Y, Feng Y, Zheng R, Wu X, Xu K, Gao X, Zhang H. Spatiotemporally Synchronous Oxygen Self-Supply and Reactive Oxygen Species Production on Z-Scheme Heterostructures for Hypoxic Tumor Therapy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1908109. [PMID: 32022983 DOI: 10.1002/adma.201908109] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Indexed: 06/10/2023]
Abstract
Photodynamic therapy (PDT) efficacy has been severely limited by oxygen (O2 ) deficiency in tumors and the electron-hole separation inefficiency in photosensitizers, especially the long-range diffusion of O2 toward photosensitizers during the PDT process. Herein, novel bismuth sulfide (Bi2 S3 )@bismuth (Bi) Z-scheme heterostructured nanorods (NRs) are designed to realize the spatiotemporally synchronous O2 self-supply and production of reactive oxygen species for hypoxic tumor therapy. Both narrow-bandgap Bi2 S3 and Bi components can be excited by a near-infrared laser to generate abundant electrons and holes. The Z-scheme heterostructure endows Bi2 S3 @Bi NRs with an efficient electron-hole separation ability and potent redox potentials, where the hole on the valence band of Bi2 S3 can react with water to supply O2 for the electron on the conduction band of Bi to produce reactive oxygen species. The Bi2 S3 @Bi NRs overcome the major obstacles of conventional photosensitizers during the PDT process and exhibit a promising phototherapeutic effect, supplying a new strategy for hypoxic tumor elimination.
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Affiliation(s)
- Yan Cheng
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
| | - Xiangpeng Kong
- College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, 330000, Jiangxi, China
| | - Yun Chang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
| | - Yanlin Feng
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
- University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Runxiao Zheng
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
- University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Xiaqing Wu
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
- University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Keqiang Xu
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
- University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Xingfa Gao
- College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, 330000, Jiangxi, China
| | - Haiyuan Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, China
- University of Science and Technology of China, Hefei, 230026, Anhui, China
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26
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Chi Z, Chen H, Zhao Q, Weng YX. Observation of the hot-phonon effect in monolayer MoS 2. NANOTECHNOLOGY 2020; 31:235712. [PMID: 32097893 DOI: 10.1088/1361-6528/ab79ad] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Femtosecond transient absorption measurements have been performed to study the pump wavelength- and fluence-dependent hot carrier relaxation dynamics in monolayer MoS2. The relaxation process of the photoinduced carriers monitored within hundreds of femtoseconds after photoexcitation is demonstrated to be achieved through the carrier-phonon scattering mechanism. It is observed that an efficient hot-phonon effect can slow down the relaxation rate by around three times with the injected carrier density changing from 1 × 1012 to 3 × 1013 cm-2. A pronounced increase in the hot carrier relaxation time with decreasing temperature is further detected, which is attributed to the decreased phonon occupancy at lower temperature.
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Affiliation(s)
- Zhen Chi
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China. Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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27
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Chai Y, Liu X, Wu B, Liu L, Wang Z, Weng Y, Wang C. In Situ Switching of Photoinduced Electron Transfer Direction by Regulating the Redox State in Fullerene-Based Dyads. J Am Chem Soc 2020; 142:4411-4418. [DOI: 10.1021/jacs.9b13376] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yongqiang Chai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolong Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Bo Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Liping Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuxiang Weng
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunru Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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28
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Liu H, Wang C, Zuo Z, Liu D, Luo J. Direct Visualization of Exciton Transport in Defective Few-Layer WS 2 by Ultrafast Microscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906540. [PMID: 31773833 DOI: 10.1002/adma.201906540] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/03/2019] [Indexed: 06/10/2023]
Abstract
As defects usually limit the exciton diffusion in 2D transition metal dichalcogenides (TMDCs), the interaction knowledge of defects and exciton transport is crucial for achieving efficient TMDC-based devices. A direct visualization of defect-modulated exciton transport is developed in few-layer WS2 by ultrafast transient absorption microscopy. Atomic-scale defects are introduced by argon plasma treatment and identified by aberration-corrected scanning transmission electron microscopy. Neutral excitons can be captured by defects to form bound excitons in 7.75-17.88 ps, which provide a nonradiative relaxation channel, leading to decreased exciton lifetime and diffusion coefficient. The exciton diffusion length of defective sample has a drastic reduction from 349.44 to 107.40 nm. These spatially and temporally resolved measurements reveal the interaction mechanism between defects and exciton transport dynamics in 2D TMDCs, giving a guideline for designing high-performance TMDC-based devices.
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Affiliation(s)
- Huan Liu
- State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, P. R. China
| | - Chong Wang
- State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, P. R. China
| | - Zhengguang Zuo
- State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, P. R. China
| | - Dameng Liu
- State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, P. R. China
| | - Jianbin Luo
- State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, P. R. China
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29
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Wei R, Tian X, Yang L, Yang D, Ma Z, Guo H, Qiu J. Ultrafast and large optical nonlinearity of a TiSe 2 saturable absorber in the 2 μm wavelength region. NANOSCALE 2019; 11:22277-22285. [PMID: 31570910 DOI: 10.1039/c9nr06374a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The non-equilibrium state of correlated electron materials is crucial for both scientific research and practical applications in optoelectronic and photonic devices. Because of the weak optical nonlinearity of most materials even under a dense optical excitation, it is desirable to achieve a significant nonlinear optical response with ultrafast and large optical nonlinearity utilizing a common material. Here, an ultrafast response and large optical nonlinearity induced by non-equilibrium electrons in typical transition metal dichalcogenides, TiSe2, are investigated in the 1.55-2.0 μm wavelength region. Significantly, we observe an ultrafast transient dynamics of 491 femtoseconds as well as a large optical nonlinearity with a saturable coefficient of -0.17 cm GW-1 (1.55 μm) and -0.10 cm GW-1 (2.0 μm). Upon increasing pump fluence, TiSe2 exhibits an enhanced bleaching response amplitude up to 563%. Furthermore, a stable Q-switched fiber laser in the 2.0 μm wavelength region is achieved by employing the TiSe2-saturable absorber. The findings offer the potential design to enhance the optical nonlinearity via non-equilibrium electrons for advanced photonic devices.
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Affiliation(s)
- Rongfei Wei
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
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30
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Zhou P, Tanghe I, Schiettecatte P, van Thourhout D, Hens Z, Geiregat P. Ultrafast carrier dynamics in colloidal WS2 nanosheets obtained through a hot injection synthesis. J Chem Phys 2019; 151:164701. [DOI: 10.1063/1.5124898] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Pengshang Zhou
- Physics and Chemistry of Nanostructures Group, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
| | - Ivo Tanghe
- Physics and Chemistry of Nanostructures Group, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
- Photonics Research Group, Department of Information Technology, Ghent University, Technologiepark-Zwijnaarde 126, 9052 Ghent, Belgium
| | - Pieter Schiettecatte
- Physics and Chemistry of Nanostructures Group, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
| | - Dries van Thourhout
- Photonics Research Group, Department of Information Technology, Ghent University, Technologiepark-Zwijnaarde 126, 9052 Ghent, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures Group, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures Group, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
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31
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Chi Z, Chen H, Zhao Q, Weng YX. Ultrafast carrier and phonon dynamics in few-layer 2H-MoTe 2. J Chem Phys 2019; 151:114704. [PMID: 31542040 DOI: 10.1063/1.5115467] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By using femtosecond pump-probe spectroscopy with broadband detection from near-infrared to midinfrared, the carrier and phonon dynamics in few-layer 2H-MoTe2 after ultrafast excitation have been investigated in detail. Immediately following the photoexcitation, an ultrafast relaxation of the generated hot carriers by releasing phonons is observed within hundreds of femtoseconds. The subsequent electron-hole recombination with a time constant of ∼1.5 ps is clearly identified and demonstrated to be mediated through a defect-assisted process. Furthermore, we confirm that the observed redshift of the exciton resonance energy on longer time scales arises from the ultrafast thermalization of the 2H-MoTe2 lattice caused by the transfer of electronic excitation to the phonon system. As a result, the thermalization dynamics of the lattice within 2 ps and the following cooling process of the phonon system on the 100 ps time scale are directly monitored.
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Affiliation(s)
- Zhen Chi
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Hailong Chen
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Zhao
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Yu-Xiang Weng
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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32
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Liu F, Shi R, Wang Z, Weng Y, Che C, Chen Y. Direct Z‐Scheme Hetero‐phase Junction of Black/Red Phosphorus for Photocatalytic Water Splitting. Angew Chem Int Ed Engl 2019; 58:11791-11795. [DOI: 10.1002/anie.201906416] [Citation(s) in RCA: 194] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Fulai Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Rui Shi
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics & CAS Key Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Yuxiang Weng
- Beijing National Laboratory for Condensed Matter Physics & CAS Key Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Chi‐Ming Che
- State Key Laboratory of Synthetic Chemistry & Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR P. R. China
| | - Yong Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
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33
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Liu F, Shi R, Wang Z, Weng Y, Che C, Chen Y. Direct Z‐Scheme Hetero‐phase Junction of Black/Red Phosphorus for Photocatalytic Water Splitting. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906416] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Fulai Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Rui Shi
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics & CAS Key Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Yuxiang Weng
- Beijing National Laboratory for Condensed Matter Physics & CAS Key Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Chi‐Ming Che
- State Key Laboratory of Synthetic Chemistry & Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR P. R. China
| | - Yong Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & HKU-CAS Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
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34
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Goswami T, Rani R, Hazra KS, Ghosh HN. Ultrafast Carrier Dynamics of the Exciton and Trion in MoS 2 Monolayers Followed by Dissociation Dynamics in Au@MoS 2 2D Heterointerfaces. J Phys Chem Lett 2019; 10:3057-3063. [PMID: 31117684 DOI: 10.1021/acs.jpclett.9b01022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Many-body states like excitons, biexcitons, and trions play an important role in optoelectronic and photovoltaic applications in 2D materials. Herein, we studied carrier dynamics of excitons and trions in monolayer MoS2 deposited on a SiO2/Si substrate, before and after Au NP deposition, using femtosecond transient absorption spectroscopy. Luminescence measurements confirm the presence of both an exciton and trion in MoS2, which are drastically quenched after deposition of Au NPs, indicating electron transfer from photoexcited MoS2 to Au. Ultrafast study reveals that photogenerated free carriers form excitons with a time scale of ∼500 fs and eventually turn into trions within ∼1.2 ps. Dissociation of excitons and trions has been observed in the presence of Au, with time scales of ∼600 fs and ∼3.7 ps, respectively. Understanding the formation and dissociation dynamics of the exciton and trion in monolayer MoS2 is going to help immensely to design and develop many new 2D devices.
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Affiliation(s)
- Tanmay Goswami
- Institute of Nano Science and Technology , Mohali , Punjab 160062 , India
| | - Renu Rani
- Institute of Nano Science and Technology , Mohali , Punjab 160062 , India
| | | | - Hirendra N Ghosh
- Institute of Nano Science and Technology , Mohali , Punjab 160062 , India
- Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai 400085 , India
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35
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Li J, Qin R, Yan L, Chi Z, Yu Z, Li N, Hu M, Chen H, Shan G. Plasmonic Light Illumination Creates a Channel To Achieve Fast Degradation of Ti3C2Tx Nanosheets. Inorg Chem 2019; 58:7285-7294. [DOI: 10.1021/acs.inorgchem.9b00329] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jiebo Li
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, China
| | - Ruzhan Qin
- School of Instrumentation Science and Optoelectronics Engineering, Beihang University, Beijing, 100191, China
| | - Li Yan
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Zhen Chi
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhihao Yu
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing, 100871, China
| | - Naitao Li
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100191, China
| | - Mingjun Hu
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Hailong Chen
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guangcun Shan
- School of Instrumentation Science and Optoelectronics Engineering, Beihang University, Beijing, 100191, China
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36
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Zhu Q, Li S, Wang Q, Qi Y, Li X, Sun X, Li JG. Grafting of terbium(iii) complexes onto layered rare-earth hydroxide nanosheets to fabricate novel optical fiber temperature sensors. NANOSCALE 2019; 11:2795-2804. [PMID: 30675610 DOI: 10.1039/c8nr08900k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Optical sensors of temperature possess the unique advantages of contactless measurement and large-scale imaging. Developments have been rapidly made in optical fiber sensors due to their high sensitivity, short response time, and electromagnetic immunity, and being easy to handle and light weight. Therefore, novel optical sensors of temperature based on optical fibers were fabricated to explore their application in special environments, such as poisonous, sparkless, currentless, and gelid ones. The present study is the first report of successful intercalation of neutral Y(iii) complexes in situ into the gallery of Y/Eu binary layered rare-earth hydroxides by hydrothermal processing without replacing the nitrate ions. The swollen layered rare-earth hydroxides were then exfoliated into ultrathin nanosheets ∼2 nm thick through dispersion in formamide. Grafting of Tb(iii) complexes onto the exfoliated nanosheets yielded novel temperature sensor films <100 nm thick, which exhibited color emissions from green to pink tunable through temperatures ranging from 77 to 360 K under ultraviolet excitation. Due to the highly sensitive and temperature-dependent emission, an optical fiber-based temperature sensor was fabricated by employing these novel allochroic films, which showed luminescence that could reversibly undergo repeated thermocycles. These optical fiber sensors have the potential to open up new fields in material functionalities via nanostructure manipulation and functionalized optical fiber engineering.
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Affiliation(s)
- Qi Zhu
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning 110819, China.
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37
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Du Y, Wang Z, Chen H, Wang HY, Liu G, Weng Y. Effect of trap states on photocatalytic properties of boron-doped anatase TiO2 microspheres studied by time-resolved infrared spectroscopy. Phys Chem Chem Phys 2019; 21:4349-4358. [DOI: 10.1039/c8cp06109b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photocatalytic hydrogen and oxygen evolution switching effect in the water splitting of two boron-doped anatase TiO2 microspheres was elucidated from the viewpoint of trap states.
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Affiliation(s)
- Yijie Du
- The Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences
- Beijing 100190
- China
- School of Physical Sciences, University of Chinese Academy of Sciences
- Beijing 100049
| | - Zhuan Wang
- The Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences
- Beijing 100190
- China
| | - Hailong Chen
- The Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences
- Beijing 100190
- China
| | - Hao-Yi Wang
- The Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences
- Beijing 100190
- China
| | - Gang Liu
- Shenyang National Laboratory for Materials Science Institute of Metal Research, Chinese Academy of Sciences
- Shenyang 110016
- China
- School of Materials Science and Engineering, University of Science and Technology of China
- Shenyang 110016
| | - Yuxiang Weng
- The Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences
- Beijing 100190
- China
- School of Physical Sciences, University of Chinese Academy of Sciences
- Beijing 100049
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Shang MH, Hou H, Zheng J, Yang Z, Zhang J, Wei S, Duan X, Yang W. Elimination of S Vacancy as the Cause for the n-Type Behavior of MoS 2 from the First-Principles Perspective. J Phys Chem Lett 2018; 9:6032-6037. [PMID: 30230842 DOI: 10.1021/acs.jpclett.8b02591] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Molybdenum disulfide (2H-MoS2) based low-dimensional nanostructure materials have great potential for applications in electronic and optoelectronic devices. However, some of the properties such as the origin of the native n-type electrical conductivity (EC) observed in these materials still remain elusive. Here, the defect properties in the 2H-MoS2 bulk system are systematically investigated by first-principles calculation to address these issues. We find that the S vacancy VS with low formation energy cannot be the origin of n-type EC owing to its deep defect levels within the valence band region. All other donor defects such as antisite MoS or Mo interstitial MoI also have deep levels that can trap electrons leading to depressed EC. SMo and SI could be the origin of the p-type EC in 2H-MoS2, but the concentrations are expected to be rather low due to their high formation energies and can only be enhanced under S-rich/Mo-poor conditions. These results provide the underlying insights on the defect properties 2H-MoS2 and explain well the experimental observations.
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Affiliation(s)
- Ming-Hui Shang
- Institute of Material , Ningbo University of Technology , Ningbo 315016 , P. R. China
- Graduate School of Advanced Integration Science , Chiba University , Chiba 263-8522 , Japan
| | - Huilin Hou
- Institute of Material , Ningbo University of Technology , Ningbo 315016 , P. R. China
| | - Jinju Zheng
- Institute of Material , Ningbo University of Technology , Ningbo 315016 , P. R. China
| | - Zuobao Yang
- Institute of Material , Ningbo University of Technology , Ningbo 315016 , P. R. China
| | - Jing Zhang
- Faculty of Science , Ningbo University , Ningbo 315211 , P. R. China
| | - Shihao Wei
- Faculty of Science , Ningbo University , Ningbo 315211 , P. R. China
| | - Xiangmei Duan
- Faculty of Science , Ningbo University , Ningbo 315211 , P. R. China
| | - Weiyou Yang
- Institute of Material , Ningbo University of Technology , Ningbo 315016 , P. R. China
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