1
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Tyson KH, Godfrey JR, Fraser JM, Knobel RG. Localized Gradual Photomediated Brightness and Lifetime Increase of Superacid-Treated Monolayer MoS 2. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39312628 DOI: 10.1021/acsami.4c00836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Monolayer semiconducting transition-metal dichalcogenides (S-TMDs) have been extensively studied as materials for next-generation optoelectronic devices due to their direct band gap and high exciton binding energy at room temperature. Under a superacid treatment of bis(trifluoromethane)sulfonimide (TFSI), sulfur-based TMDs such as MoS2 can emit strong photoluminescence (PL) with a photoluminescence quantum yield (PLQY) approaching unity. However, the magnitude of PL enhancement varies by more than 2 orders of magnitude in published reports. A major culprit behind the discrepancy is sulfur-based TMD's sensitivity to above-bandgap photostimulation. Here, we present a detailed study of how TFSI-treated MoS2 reacts to photostimulation with increasing PL occurring hours after continuous or pulsed laser exposure. The PL of TFSI-treated MoS2 is enhanced up to 74 times its initial intensity after 5 h of continuous exposure to 532 nm laser light. Photostimulation also enhances the PL of untreated MoS2 but with a much smaller enhancement. Caution should be taken when probing MoS2 PL spectra, as above-bandgap light can alter the resulting intensity and peak wavelength of the emission over time. The presence of air is verified to play a key role in the photostimulated enhancement effect. Additionally, the rise of PL intensity is mirrored by an increase in measured carrier lifetime of up to ∼400 ps, consistent with the suppression of nonradiative pathways. This work demonstrates why variations in PL intensity are observed across samples and provides an understanding of the changes in carrier lifetimes to better engineer next-generation optoelectronic devices.
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Affiliation(s)
- Kurt H Tyson
- Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - James R Godfrey
- Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - James M Fraser
- Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Robert G Knobel
- Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario K7L 3N6, Canada
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2
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Lim S, Kim TW, Park T, Heo YS, Yang S, Seo H, Suh J, Lee JU. Large-Scale Analysis of Defects in Atomically Thin Semiconductors using Hyperspectral Line Imaging. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400737. [PMID: 38874112 DOI: 10.1002/smll.202400737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 05/16/2024] [Indexed: 06/15/2024]
Abstract
Point defects play a crucial role in determining the properties of atomically thin semiconductors. This work demonstrates the controlled formation of different types of defects and their comprehensive optical characterization using hyperspectral line imaging (HSLI). Distinct optical responses are observed in monolayer semiconductors grown under different stoichiometries using metal-organic chemical vapor deposition. HSLI enables the simultaneous measurement of 400 spectra, allowing for statistical analysis of optical signatures at close to a centimeter scale. The study discovers that chalcogen-rich samples exhibit remarkable optical uniformity due to reduced precursor accumulation compared to the metal-rich case. The utilization of HSLI as a facile and reliable characterization tool pushes the boundaries of potential applications for atomically thin semiconductors in future devices.
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Affiliation(s)
- Seungjae Lim
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon, 16499, South Korea
| | - Tae Wan Kim
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon, 16499, South Korea
| | - Taejoon Park
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon, 16499, South Korea
| | - Yoon Seong Heo
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon, 16499, South Korea
| | - Seonguk Yang
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
- Department of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Hosung Seo
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon, 16499, South Korea
| | - Joonki Suh
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
- Department of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jae-Ung Lee
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon, 16499, South Korea
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3
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Li Z, Bretscher H, Rao A. Chemical passivation of 2D transition metal dichalcogenides: strategies, mechanisms, and prospects for optoelectronic applications. NANOSCALE 2024; 16:9728-9741. [PMID: 38700268 DOI: 10.1039/d3nr06296a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
The interest in obtaining high-quality monolayer transition metal dichalcogenides (TMDs) for optoelectronic device applications has been growing dramatically. However, the prevalence of defects and unwanted doping in these materials remain challenges, as they both limit optical properties and device performance. Surface chemical treatments of monolayer TMDs have been effective in improving their photoluminescence yield and charge transport properties. In this scenario, a systematic understanding of the underlying mechanism of chemical treatments will lead to a rational design of passivation strategies in future research, ultimately taking a step toward practical optoelectronic applications. We will therefore describe in this mini-review the strategies, progress, mechanisms, and prospects of chemical treatments to passivate and improve the optoelectronic properties of TMDs.
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Affiliation(s)
- Zhaojun Li
- Solid State Physics, Department of Materials Science and Engineering, Uppsala University, 75103 Uppsala, Sweden.
| | - Hope Bretscher
- The Max Planck Institute for the Structure and Dynamics of Matter, 22761, Hamburg, Germany
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE, Cambridge, UK
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4
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Li Z, Chen Z, Xiao L, Zhou X, Zhao C, Zhang Y. Extremely Enhanced Photoluminescence in MoS 2-Derived Quantum Sheets. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38470979 DOI: 10.1021/acsami.3c17934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Molybdenum disulfide (MoS2) quantum sheets (QSs) are attractive for applications due to their tunable energy band structures and optical and electronic properties. The photoluminescence quantum yield (PLQY) of MoS2 QSs achieved by mechanical and liquid exfoliation and chemical vapor deposition is low. Some studies have reported that chemical treatment and elemental doping can improve the PLQY of transition metal dichalcogenides (TMDs), but this is limited by complex instruments and reactions. In this study, a heat treatment method based on a polar solvent is reported to improve the PLQY and photoluminescence (PL) intensity of MoS2 QSs at room temperature. The absolute PLQY of treated MoS2 QSs is increased to 18.5%, and the PL intensity is increased by a factor of 64. This method is also effective for tungsten disulfide (WS2) QSs. The PL enhancement of QSs is attributed to oxidation of the edges. Such passivation/deformation of MoS2 QSs facilitates the radiative route rather than the nonradiative route, resulting in extreme enhancement of the PL. Our work could provide novel insights/routes toward the PL enhancement of TMD QSs.
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Affiliation(s)
- Zhangqiang Li
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zhexue Chen
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Liuyang Xiao
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xuanping Zhou
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Ce Zhao
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Yong Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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5
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Katiyar AK, Hoang AT, Xu D, Hong J, Kim BJ, Ji S, Ahn JH. 2D Materials in Flexible Electronics: Recent Advances and Future Prospectives. Chem Rev 2024; 124:318-419. [PMID: 38055207 DOI: 10.1021/acs.chemrev.3c00302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field.
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Affiliation(s)
- Ajit Kumar Katiyar
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Duo Xu
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Juyeong Hong
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Beom Jin Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Seunghyeon Ji
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jong-Hyun Ahn
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
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6
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Ahn B, Kim Y, Kim M, Yu HM, Ahn J, Sim E, Ji H, Gul HZ, Kim KS, Ihm K, Lee H, Kim EK, Lim SC. One-Step Passivation of Both Sulfur Vacancies and SiO 2 Interface Traps of MoS 2 Device. NANO LETTERS 2023; 23:7927-7933. [PMID: 37647420 DOI: 10.1021/acs.nanolett.3c01753] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Transition metal dichalcogenides (TMDs) benefit electrical devices with spin-orbit coupling and valley- and topology-related properties. However, TMD-based devices suffer from traps arising from defect sites inside the channel and the gate oxide interface. Deactivating them requires independent treatments, because the origins are dissimilar. This study introduces a single treatment to passivate defects in a multilayer MoS2 FET. By applying back-gate bias, protons from an H-TFSI droplet are injected into the MoS2, penetrating deeply enough to reach the SiO2 gate oxide. The characterizations employing low-temperature transport and deep-level transient spectroscopy (DLTS) studies reveal that the trap density of S vacancies in MoS2 drops to the lowest detection level. The temperature-dependent mobility plot on the SiO2 substrate resembles that of the h-BN substrate, implying that dangling bonds in SiO2 are passivated. The carrier mobility on the SiO2 substrate is enhanced by approximately 2200% after the injection.
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Affiliation(s)
- Byungwook Ahn
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yoonsok Kim
- Department of Physics, Hanyang University, Seoul 04763, Republic of Korea
- Institute of Plasma Technology, Korea Institute of Fusion Energy, Gunsan 54004, Republic of Korea
| | - Meeree Kim
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyang Mi Yu
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jaehun Ahn
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Eunji Sim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyunjin Ji
- Department of Electrical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Hamza Zad Gul
- Department of Electrical Engineering, Namal University, 30 km Talagang Road, Mianwali 42250, Pakistan
| | - Keun Soo Kim
- Department of Physics and Graphene Research Institute, Sejong University, Seoul 05006, Republic of Korea
| | - Kyuwook Ihm
- Nano & Interface Research Team, Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Hyoyoung Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Eun Kyu Kim
- Department of Physics, Hanyang University, Seoul 04763, Republic of Korea
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fabrication Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
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7
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Xu N, Hong D, Liang B, Qiu L, Tian Y, Li S. Lattice Vacancy Induced Energy Renormalization of Photonic Quasiparticles in Two-Dimensional Semiconductors. ACS NANO 2023; 17:16904-16911. [PMID: 37603694 DOI: 10.1021/acsnano.3c03996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Coulomb interactions among dense charges and quasiparticle energy renormalization are at the center of quantum science because they significantly reshape the fundamental electronic and photonic properties of materials. While lattice vacancies are ubiquitous in solid materials, their physical effect on the Coulomb interaction among quasiparticles is normally weak and negligible. Here we show that in atomically thin semiconductors the presence of lattice vacancies emerges as an important but unexplored origin for the nontrivial renormalization of quasiparticle binding energies, due to the subtle modification of overall dielectric functions at low dimensionality. Such a renormalization effect leads to unusual reduction in the energy scales of photonic quasiparticles and red shifts of photoluminescence as the density of lattice vacancies increases. With strict configurative form factors derived, a dielectric screening model is also established for the generalized trilayer systems to capture the fine modification in the energy scales of quasiparticles and to elucidate the dielectric functions versus realistic Bohr lengths. This finding highlights the essential but commonly neglected role of lattice vacancies and deciphers the longstanding enigma of unpredictable photoluminescent line shifts in low-dimensional systems.
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Affiliation(s)
- Ning Xu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Daocheng Hong
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Binxi Liang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Lipeng Qiu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Yuxi Tian
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Songlin Li
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
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8
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Dziobek-Garrett R, Imperiale CJ, Wilson MWB, Kempa TJ. Photon Upconversion in a Vapor Deposited 2D Inorganic-Organic Semiconductor Heterostructure. NANO LETTERS 2023. [PMID: 37191568 DOI: 10.1021/acs.nanolett.3c00380] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Energy transfer processes may be engineered in van der Waals heterostructures by taking advantage of the atomically abrupt, Å-scale, and topologically tailorable interfaces within them. Here, we prepare heterostructures comprised of 2D WSe2 monolayers interfaced with dibenzotetraphenylperiflanthene (DBP)-doped rubrene, an organic semiconductor capable of triplet fusion. We fabricate these heterostructures entirely through vapor deposition methods. Time-resolved and steady-state photoluminescence measurements reveal rapid subnanosecond quenching of WSe2 emission by rubrene and fluorescence from guest DBP molecules at 612 nm (λexc = 730 nm), thus providing clear evidence of photon upconversion. The dependence of the upconversion emission on excitation intensity is consistent with a triplet fusion mechanism, and maximum efficiency (linear regime) of this process occurs at threshold intensities as low as 110 mW/cm2, which is comparable to the integrated solar irradiance. This study highlights the potential for advanced optoelectronic applications employing vdWHs which leverage strongly bound excitons in monolayer TMDs and organic semiconductors.
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Affiliation(s)
| | | | - Mark W B Wilson
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Thomas J Kempa
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Materials Science & Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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9
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Li Q, Alfrey A, Hu J, Lydick N, Paik E, Liu B, Sun H, Lu Y, Wang R, Forrest S, Deng H. Macroscopic transition metal dichalcogenides monolayers with uniformly high optical quality. Nat Commun 2023; 14:1837. [PMID: 37005420 PMCID: PMC10067954 DOI: 10.1038/s41467-023-37500-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 03/19/2023] [Indexed: 04/04/2023] Open
Abstract
The unique optical properties of transition metal dichalcogenide (TMD) monolayers have attracted significant attention for both photonics applications and fundamental studies of low-dimensional systems. TMD monolayers of high optical quality, however, have been limited to micron-sized flakes produced by low-throughput and labour-intensive processes, whereas large-area films are often affected by surface defects and large inhomogeneity. Here we report a rapid and reliable method to synthesize macroscopic-scale TMD monolayers of uniform, high optical quality. Using 1-dodecanol encapsulation combined with gold-tape-assisted exfoliation, we obtain monolayers with lateral size > 1 mm, exhibiting exciton energy, linewidth, and quantum yield uniform over the whole area and close to those of high-quality micron-sized flakes. We tentatively associate the role of the two molecular encapsulating layers as isolating the TMD from the substrate and passivating the chalcogen vacancies, respectively. We demonstrate the utility of our encapsulated monolayers by scalable integration with an array of photonic crystal cavities, creating polariton arrays with enhanced light-matter coupling strength. This work provides a pathway to achieving high-quality two-dimensional materials over large areas, enabling research and technology development beyond individual micron-sized devices.
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Affiliation(s)
- Qiuyang Li
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Adam Alfrey
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jiaqi Hu
- Applied Physics Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nathanial Lydick
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eunice Paik
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Bin Liu
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Haiping Sun
- Michigan Center for Materials Characterization, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yang Lu
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ruoyu Wang
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Stephen Forrest
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
- Applied Physics Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hui Deng
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
- Applied Physics Program, University of Michigan, Ann Arbor, MI, 48109, USA.
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10
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Li Z, Rashvand F, Bretscher H, Szydłowska BM, Xiao J, Backes C, Rao A. Understanding the Photoluminescence Quenching of Liquid Exfoliated WS 2 Monolayers. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:21681-21688. [PMID: 36605783 PMCID: PMC9806825 DOI: 10.1021/acs.jpcc.2c05284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 11/24/2022] [Indexed: 06/17/2023]
Abstract
Monolayer transition metal dichalcogenides (TMDs) are being investigated as active materials in optoelectronic devices due to their strong excitonic effects. While mechanical exfoliation (ME) of monolayer TMDs is limited to small areas, these materials can also be exfoliated from their parent layered materials via high-volume liquid phase exfoliation (LPE). However, it is currently considered that LPE-synthesized materials show poor optoelectronic performance compared to ME materials, such as poor photoluminescence quantum efficiencies (PLQEs). Here we evaluate the photophysical properties of monolayer-enriched LPE WS2 dispersions via steady-state and time-resolved optical spectroscopy and benchmark these materials against untreated and chemically treated ME WS2 monolayers. We show that the LPE materials show features of high-quality semiconducting materials such as very small Stokes shift, smaller photoluminescence line widths, and longer exciton lifetimes than ME WS2. We reveal that the energy transfer between the direct-gap monolayers and in-direct gap few-layers in LPE WS2 dispersions is a major reason for their quenched PL. Our results suggest that LPE TMDs are not inherently highly defective and could have a high potential for optoelectronic device applications if improved strategies to purify the LPE materials and reduce aggregation could be implemented.
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Affiliation(s)
- Zhaojun Li
- Cavendish
Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
- Molecular
and Condensed Matter Physics, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Farnia Rashvand
- Institute
for Physical Chemistry, Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Hope Bretscher
- Cavendish
Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
| | - Beata M. Szydłowska
- Institute
for Physical Chemistry, Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - James Xiao
- Cavendish
Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
| | - Claudia Backes
- Institute
for Physical Chemistry, Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Akshay Rao
- Cavendish
Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
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11
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Kiriya D, Lien DH. Superacid Treatment on Transition Metal Dichalcogenides. NANO EXPRESS 2022. [DOI: 10.1088/2632-959x/ac87c2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Superacids are strong acids with an acidity higher than pure sulfuric acid. Recently, superacid treatment of monolayer transition metal dichalcogenide (TMDC) flakes, such as MoS2 and WS2, has shown a dramatic enhancement of optical properties, such as photoluminescence (PL) intensity. The superacid molecule is bis(trifluoromethane)sulfonimide (TFSI). In this review paper, we summarize and discuss the recent works and the current understanding of the TFSI treatment, and finally, we describe the outlook of the treatment on monolayer TMDCs.
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12
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Feng J, Li Y, Li J, Feng Q, Xin W, Liu W, Xu H, Liu Y. Engineering Relaxation-Paths of C-Exciton for Constructing Band Nesting Bypass in WS 2 Monolayer. NANO LETTERS 2022; 22:3699-3706. [PMID: 35481760 DOI: 10.1021/acs.nanolett.2c00509] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transition-metal dichalcogenides exhibit strong photon absorption characteristics in the band nesting region (denoted as C-exciton) due to intrinsic van Hove singularities despite being atomically thin. However, because of unique parallel band structure and ineluctably unfavorable recombination process, only a small fraction of the hot carriers from C-excitons are converted into optically active band-edge excitons via inherent relaxation-paths. The resultant photoluminescence quantum yield (PLQY) is severely suppressed for the resonant excitation of C-exciton. To overcome this limitation, we have designed double type-I band alignments to construct a band nesting bypass in a monolayer WS2/CdS quantum dot heterostructure for cooling the C-excitons. Transient optical measurements confirmed that the hot carriers from the C-excitons were effectively transferred from WS2 to CdS with an efficiency of 50% and subsequently back to the WS2 band-edge to form A-excitons over an ultrafast subpicosecond time scale, accompanied by a record high PLQY of ∼11.1% for near-resonance C-exciton excitation.
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Affiliation(s)
- Jiying Feng
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Yuanzheng Li
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Jixiu Li
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Qiushi Feng
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Wei Xin
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Weizhen Liu
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Haiyang Xu
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Yichun Liu
- Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
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Huang L, Krasnok A, Alú A, Yu Y, Neshev D, Miroshnichenko AE. Enhanced light-matter interaction in two-dimensional transition metal dichalcogenides. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:046401. [PMID: 34939940 DOI: 10.1088/1361-6633/ac45f9] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 12/16/2021] [Indexed: 05/27/2023]
Abstract
Two-dimensional (2D) transition metal dichalcogenide (TMDC) materials, such as MoS2, WS2, MoSe2, and WSe2, have received extensive attention in the past decade due to their extraordinary electronic, optical and thermal properties. They evolve from indirect bandgap semiconductors to direct bandgap semiconductors while their layer number is reduced from a few layers to a monolayer limit. Consequently, there is strong photoluminescence in a monolayer (1L) TMDC due to the large quantum yield. Moreover, such monolayer semiconductors have two other exciting properties: large binding energy of excitons and valley polarization. These properties make them become ideal materials for various electronic, photonic and optoelectronic devices. However, their performance is limited by the relatively weak light-matter interactions due to their atomically thin form factor. Resonant nanophotonic structures provide a viable way to address this issue and enhance light-matter interactions in 2D TMDCs. Here, we provide an overview of this research area, showcasing relevant applications, including exotic light emission, absorption and scattering features. We start by overviewing the concept of excitons in 1L-TMDC and the fundamental theory of cavity-enhanced emission, followed by a discussion on the recent progress of enhanced light emission, strong coupling and valleytronics. The atomically thin nature of 1L-TMDC enables a broad range of ways to tune its electric and optical properties. Thus, we continue by reviewing advances in TMDC-based tunable photonic devices. Next, we survey the recent progress in enhanced light absorption over narrow and broad bandwidths using 1L or few-layer TMDCs, and their applications for photovoltaics and photodetectors. We also review recent efforts of engineering light scattering, e.g., inducing Fano resonances, wavefront engineering in 1L or few-layer TMDCs by either integrating resonant structures, such as plasmonic/Mie resonant metasurfaces, or directly patterning monolayer/few layers TMDCs. We then overview the intriguing physical properties of different van der Waals heterostructures, and their applications in optoelectronic and photonic devices. Finally, we draw our opinion on potential opportunities and challenges in this rapidly developing field of research.
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Affiliation(s)
- Lujun Huang
- School of Engineering and Information Technology, University of New South Wales, Canberra, ACT, 2600, Australia
| | - Alex Krasnok
- Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States of America
| | - Andrea Alú
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY 10031, United States of America
- Physics Program, Graduate Center, City University of New York, New York, NY 10016, United States of America
| | - Yiling Yu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - Dragomir Neshev
- ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Andrey E Miroshnichenko
- School of Engineering and Information Technology, University of New South Wales, Canberra, ACT, 2600, Australia
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Liu M, Ma L, Xie K, Zeng P, Wei S, Zhang F, Li C, Wang F. Efficiently Improved Photoluminescence in Cesium Lead Halide Perovskite Nanocrystals by Using Bis(trifluoromethane)sulfonimide. J Phys Chem Lett 2022; 13:1519-1525. [PMID: 35133165 DOI: 10.1021/acs.jpclett.2c00010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) have attracted enormous attention because of their great potential for optoelectronic applications, such as light-emitting diodes (LEDs). However, the photoluminescence and surface ligands of CsPbX3 NCs have a great impact on their device applications. Herein, we report a molecular superacid of bis(trifluoromethane)sulfonimide (TFSI), which could boost the photoluminescence in the metal halide perovskite nanocrystals. In particular, the photoluminescence quantum yield (PLQY) of CsPbI3 nanocrystals could be greatly improved from 28.6% to near 100% with the superacid treatment. The improved PLQY in CsPbX3 nanocrystals is mainly contributed from the surface passivation based on the characterizations. The CsPbX3 nanocrystals were further modified with PMMA, which could greatly improve their stability while preserving high photoluminescence and good dispersion. The use of superacid combined with a polymer for improving the photoluminescence and stability in CsPbX3 provides an alternative strategy for optoelectronics.
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Affiliation(s)
- Mengyuan Liu
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Le Ma
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Kehan Xie
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Piaopiao Zeng
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Shijing Wei
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Feng Zhang
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Chao Li
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
| | - Feijiu Wang
- Henan Key Laboratory of Photovoltaic Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
- Center for Topological Functional Materials, Henan University, 1 Jinming Road, Kaifeng 475004, P.R. China
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Pain SL, Grant NE, Murphy JD. Room Temperature Enhancement of Electronic Materials by Superacid Analogues. ACS NANO 2022; 16:1260-1270. [PMID: 34978794 DOI: 10.1021/acsnano.1c09085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Treatment with the superacid bis(trifluoromethanesulfonyl)amide (sometimes known as TFSA, TFSI, or HNTf2) enhances the properties of a wide range of optoelectronic materials, resulting in longer effective carrier lifetimes and higher photoluminescence quantum yields. We have conducted a multimaterial study treating both crystalline silicon and transition metal dichalcogenide (TMDC) monolayers and few-layer flakes with solutions formed from TFSA and a range of compounds with related chemical structures with different Lewis acidities, in order to elucidate the factors underpinning the TFSA-related class of enhancement treatments. We adopt dichloromethane (DCM) as a common solvent as it provides good results at room temperature and is potentially less hazardous than TFSA-dichloroethane (DCE) heated to ∼100 °C, which has been used previously. Kelvin probe experiments on silicon demonstrate that structurally similar chemicals give passivating films with substantially different charge levels, with the higher levels of charge associated with the presence of CF3SO2 groups resulting in longer effective lifetimes due to an enhancement in field-effect passivation. Treatment with all analogue solutions used results in enhanced photoluminescence in MoS2 and WS2 compared to untreated controls. Importantly we find that MoS2 and WS2 can be enhanced by analogues to TFSA that lack sulfonyl groups, meaning an alternative mechanism to that proposed in computational reports for TFSA enhancement must apply.
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Affiliation(s)
- Sophie L Pain
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Nicholas E Grant
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - John D Murphy
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
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Zhao Y, Gobbi M, Hueso LE, Samorì P. Molecular Approach to Engineer Two-Dimensional Devices for CMOS and beyond-CMOS Applications. Chem Rev 2021; 122:50-131. [PMID: 34816723 DOI: 10.1021/acs.chemrev.1c00497] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two-dimensional materials (2DMs) have attracted tremendous research interest over the last two decades. Their unique optical, electronic, thermal, and mechanical properties make 2DMs key building blocks for the fabrication of novel complementary metal-oxide-semiconductor (CMOS) and beyond-CMOS devices. Major advances in device functionality and performance have been made by the covalent or noncovalent functionalization of 2DMs with molecules: while the molecular coating of metal electrodes and dielectrics allows for more efficient charge injection and transport through the 2DMs, the combination of dynamic molecular systems, capable to respond to external stimuli, with 2DMs makes it possible to generate hybrid systems possessing new properties by realizing stimuli-responsive functional devices and thereby enabling functional diversification in More-than-Moore technologies. In this review, we first introduce emerging 2DMs, various classes of (macro)molecules, and molecular switches and discuss their relevant properties. We then turn to 2DM/molecule hybrid systems and the various physical and chemical strategies used to synthesize them. Next, we discuss the use of molecules and assemblies thereof to boost the performance of 2D transistors for CMOS applications and to impart diverse functionalities in beyond-CMOS devices. Finally, we present the challenges, opportunities, and long-term perspectives in this technologically promising field.
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Affiliation(s)
- Yuda Zhao
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000 Strasbourg, France.,School of Micro-Nano Electronics, ZJU-Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, 310027 Hangzhou, People's Republic of China
| | - Marco Gobbi
- Centro de Fisica de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 Donostia-San Sebastián, Spain.,CIC nanoGUNE, E-20018 Donostia-San Sebastian, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Luis E Hueso
- CIC nanoGUNE, E-20018 Donostia-San Sebastian, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Paolo Samorì
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000 Strasbourg, France
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