151
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Qiao P, Sun B, Li H, Pan K, Tian G, Wang L, Zhou W. Surface Plasmon Resonance-Enhanced Visible-NIR-Driven Photocatalytic and Photothermal Catalytic Performance by Ag/Mesoporous Black TiO2
Nanotube Heterojunctions. Chem Asian J 2018; 14:177-186. [DOI: 10.1002/asia.201801428] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/05/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Panzhe Qiao
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
| | - Bojing Sun
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
| | - Haoze Li
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
| | - Kai Pan
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
| | - Guohui Tian
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
| | - Lei Wang
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
| | - Wei Zhou
- Key Laboratory of Functional Inorganic Material Chemistry; Ministry of Education of the People's Republic of China; Heilongjiang University; Harbin 150080 P. R. China
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152
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Abdelhameed M, Aly S, Lant JT, Zhang X, Charpentier P. Energy/Electron Transfer Switch for Controlling Optical Properties of Silicon Quantum Dots. Sci Rep 2018; 8:17068. [PMID: 30459354 PMCID: PMC6244374 DOI: 10.1038/s41598-018-35201-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/01/2018] [Indexed: 12/18/2022] Open
Abstract
The superior optical properties of Silicon Quantum Dots (SQDs) have made them of increasing interest for a variety of biological and opto-electronic applications. The surface functionalization of the SQDs with aromatic ligands plays a key role in controlling their optical properties due to the interaction of the ligands with the electronic wave function of SQDs. However, there is limited reports in literature describing the impact of spacer groups connecting the aromatic chromophore to SQDs on the optical properties of the SQDs. Herein, we report the synthesis of two SQDs assemblies (1.6 nm average diameter) functionalized with perylene-3,4,9,10-tetracarboxylic acid diimide (PDI) chromophore through N-propylurea and propylamine spacers. Depending on the nature of the spacer, the photophysical measurements provide clear evidence for efficient energy and/or electron transfer between the SQDs and PDI. Energy transfer was confirmed to be the operative process when propylurea spacer was used, in which the rate was estimated to be ~2 × 109 s-1. On the other hand, the propylamine spacer was found to facilitate electron transfer process within the SQDs assembly. To illustrate functionality, the water soluble SQD-N-propylurea-PDI assembly was proven to be nontoxic and efficient for fluorescent imaging of embryonic kidney HEK293 cells and human bone cancerous U2OS cells.
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Affiliation(s)
- Mohammed Abdelhameed
- Department of Chemical and Biochemical Engineering, Western University, London, Ontario, N6A 5B9, Canada
| | - Shawkat Aly
- Department of Mechanical and Materials Engineering, Western University, London, Ontario, N6A 5B9, Canada
| | - Jeremy T Lant
- Department of Biochemistry, Western University, London, Ontario, N6A 5B9, Canada
| | - Xiaoran Zhang
- Department of Chemical and Biochemical Engineering, Western University, London, Ontario, N6A 5B9, Canada
| | - Paul Charpentier
- Department of Chemical and Biochemical Engineering, Western University, London, Ontario, N6A 5B9, Canada.
- Department of Mechanical and Materials Engineering, Western University, London, Ontario, N6A 5B9, Canada.
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153
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Liu J, Chen K, Pan GM, Luo ZJ, Xie Y, Li YY, Lin YJ, Hao ZH, Zhou L, Ding SJ, Wang QQ. Largely enhanced photocatalytic hydrogen production rate of CdS/(Au-ReS 2) nanospheres by the dielectric-plasmon hybrid antenna effect. NANOSCALE 2018; 10:19586-19594. [PMID: 30324954 DOI: 10.1039/c8nr07013j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this study, we synthesized CdS/(Au-ReS2) nanospheres that have highly efficient photocatalytic hydrogen production activity induced by dielectric-plasmon hybrid antenna resonance. As the diameter (D) of ReS2 nanospheres consisting of 2D nanosheets increases from 114 ± 11 to 218 ± 25 nm, the resonance wavelength of the ReS2 dielectric antenna is tuned from 380 to 620 nm and the hydrogen production rate for the CdS/(Au-ReS2) nanospheres increases by more than 1.85 times and reaches a value as high as 3060 μmol g-1 h-1, with a 9% weight percentage of Au. Due to the enhancements of the local electromagnetic field and excitation energy transfer by the ReS2-Au dielectric-plasmon hybrid antenna, the hydrogen production rate for the CdS/(Au-ReS2) nanospheres (D = 218 ± 25 nm) is 797, 319, 105 and 12 times larger than that for pure ReS2, Au-ReS2, CdS, and CdS-ReS2, respectively. Additionally, the persistence and reusability measurements indicate a favorable stability of CdS/(Au-ReS2). These results provide a strategy to prepare a new class of dielectric-plasmon hybrid antennas consisting of 2D materials and metal nanoparticles, which have promise in applications ranging from photocatalysis to nonlinear optics.
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Affiliation(s)
- Jia Liu
- Department of Physics, Key Laboratory of Artificial Micro- and Nano-structures of the Ministry of Education, Wuhan University, Wuhan 430072, P. R. China.
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154
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Sun J, Hu H, Zheng D, Zhang D, Deng Q, Zhang S, Xu H. Light-Emitting Plexciton: Exploiting Plasmon-Exciton Interaction in the Intermediate Coupling Regime. ACS NANO 2018; 12:10393-10402. [PMID: 30222317 DOI: 10.1021/acsnano.8b05880] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The interaction between plasmons in metal nanostructures and excitons in layered materials attracts recent interests due to its fascinating properties inherited from the two constituents, e.g., the high tunability on its spectral or spatial properties from the plasmonic component, and the large optical nonlinearity or light emitting properties from the excitonic counterpart. Here, we demonstrate light-emitting plexcitons from the coupling between the neutral excitons in monolayer WSe2 and highly confined nanocavity plasmons in the nanocube-over-mirror system. We observe, simultaneously, an anticrossing dispersion curve of the hybrid system in the dark-field scattering spectrum and a 1700 times enhancement in the photoluminescence. We attribute the large photoluminescence enhancement to the increased local density of states by both the plasmonic and excitonic constituents in the intermediate coupling regime. In addition, increasing the confinement of the hybrid systems is achieved by shrinking down the size of the hot spot within the gap between the nanocube and the metal film. Numerical calculations reproduce the experimental observations and provide the effective number of excitons taking part in the interaction. This highly compact system provides a room temperature testing platform for quantum cavity electromagnetics at the deep subwavelength scale.
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Affiliation(s)
- Jiawei Sun
- The Institute for Advanced Studies , Wuhan University , Wuhan 430072 , China
| | - Huatian Hu
- The Institute for Advanced Studies , Wuhan University , Wuhan 430072 , China
| | - Di Zheng
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education , Wuhan University , Wuhan 430072 , China
| | - Daxiao Zhang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education , Wuhan University , Wuhan 430072 , China
| | - Qian Deng
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education , Wuhan University , Wuhan 430072 , China
| | - Shunping Zhang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education , Wuhan University , Wuhan 430072 , China
| | - Hongxing Xu
- The Institute for Advanced Studies , Wuhan University , Wuhan 430072 , China
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education , Wuhan University , Wuhan 430072 , China
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155
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Garoli D, Mosconi D, Miele E, Maccaferri N, Ardini M, Giovannini G, Dipalo M, Agnoli S, De Angelis F. Hybrid plasmonic nanostructures based on controlled integration of MoS 2 flakes on metallic nanoholes. NANOSCALE 2018; 10:17105-17111. [PMID: 30179242 DOI: 10.1039/c8nr05026k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Here, we propose an easy and robust strategy for the versatile preparation of hybrid plasmonic nanopores by means of controlled deposition of single flakes of MoS2 directly on top of metallic holes. The device is realized on silicon nitride membranes and can be further refined by TEM or FIB milling to achieve the passing of molecules or nanometric particles through a pore. Importantly, we show that the plasmonic enhancement provided by the nanohole is strongly accumulated in the 2D nanopore, thus representing an ideal system for single-molecule sensing and sequencing in a flow-through configuration. Here, we also demonstrate that the prepared 2D material can be decorated with metallic nanoparticles that can couple their resonance with the nanopore resonance to further enhance the electromagnetic field confinement at the nanoscale level. This method can be applied to any gold nanopore with a high level of reproducibility and parallelization; hence, it can pave the way to the next generation of solid-state nanopores with plasmonic functionalities. Moreover, the controlled/ordered integration of 2D materials on plasmonic nanostructures opens a pathway towards new investigation of the following: enhanced light emission; strong coupling from plasmonic hybrid structures; hot electron generation; and sensors in general based on 2D materials.
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Affiliation(s)
- Denis Garoli
- Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
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156
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Tai KL, Huang GM, Huang CW, Tsai TC, Lee SK, Lin TY, Lo YC, Wu WW. Observing phase transformation in CVD-grown MoS 2via atomic resolution TEM. Chem Commun (Camb) 2018; 54:9941-9944. [PMID: 30116815 DOI: 10.1039/c8cc05129a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We utilized in situ transmission electron microscopy to observe phase transformation in CVD-grown MoS2. Significantly, the reaction was performed under electron irradiation through appropriate control of the electron dose and exposure time. Moreover, we proposed a new route between the 2H and 1T phases that involved the higher energy states TS1/TS2.
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Affiliation(s)
- Kuo-Lun Tai
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Guan-Min Huang
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Chun-Wei Huang
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Tsung-Chun Tsai
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Shih-Kuang Lee
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Ting-Yi Lin
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Yu-Chieh Lo
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Wen-Wei Wu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan. and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan and Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
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157
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158
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Bertolazzi S, Gobbi M, Zhao Y, Backes C, Samorì P. Molecular chemistry approaches for tuning the properties of two-dimensional transition metal dichalcogenides. Chem Soc Rev 2018; 47:6845-6888. [PMID: 30043037 DOI: 10.1039/c8cs00169c] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Two-dimensional (2D) semiconductors, such as ultrathin layers of transition metal dichalcogenides (TMDs), offer a unique combination of electronic, optical and mechanical properties, and hold potential to enable a host of new device applications spanning from flexible/wearable (opto)electronics to energy-harvesting and sensing technologies. A critical requirement for developing practical and reliable electronic devices based on semiconducting TMDs consists in achieving a full control over their charge-carrier polarity and doping. Inconveniently, such a challenging task cannot be accomplished by means of well-established doping techniques (e.g. ion implantation and diffusion), which unavoidably damage the 2D crystals resulting in degraded device performances. Nowadays, a number of alternatives are being investigated, including various (supra)molecular chemistry approaches relying on the combination of 2D semiconductors with electroactive donor/acceptor molecules. As yet, a large variety of molecular systems have been utilized for functionalizing 2D TMDs via both covalent and non-covalent interactions. Such research endeavours enabled not only the tuning of the charge-carrier doping but also the engineering of the optical, electronic, magnetic, thermal and sensing properties of semiconducting TMDs for specific device applications. Here, we will review the most enlightening recent advancements in experimental (supra)molecular chemistry methods for tailoring the properties of atomically-thin TMDs - in the form of substrate-supported or solution-dispersed nanosheets - and we will discuss the opportunities and the challenges towards the realization of novel hybrid materials and devices based on 2D semiconductors and molecular systems.
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Affiliation(s)
- Simone Bertolazzi
- Université de Strasbourg, CNRS, ISIS, 8 alleé Gaspard Monge, 67000 Strasbourg, France.
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159
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Vasileiadis T, Waldecker L, Foster D, Da Silva A, Zahn D, Bertoni R, Palmer RE, Ernstorfer R. Ultrafast Heat Flow in Heterostructures of Au Nanoclusters on Thin Films: Atomic Disorder Induced by Hot Electrons. ACS NANO 2018; 12:7710-7720. [PMID: 29995378 DOI: 10.1021/acsnano.8b01423] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We study the ultrafast structural dynamics, in response to electronic excitations, in heterostructures composed of size-selected Au nanoclusters on thin-film substrates with the use of femtosecond electron diffraction. Various forms of atomic motion, such as thermal vibrations, thermal expansion, and lattice disordering, manifest as distinct and quantifiable reciprocal-space observables. In photoexcited supported nanoclusters, thermal equilibration proceeds through intrinsic heat flow between their electrons and their lattice and extrinsic heat flow between the nanoclusters and their substrate. For an in-depth understanding of this process, we have extended the two-temperature model to the case of 0D/2D heterostructures and used it to describe energy flow among the various subsystems, to quantify interfacial coupling constants and to elucidate the role of the optical and thermal substrate properties. When lattice heating of Au nanoclusters is dominated by intrinsic heat flow, a reversible disordering of atomic positions occurs, which is absent when heat is injected as hot substrate phonons. The present analysis indicates that hot electrons can distort the lattice of nanoclusters, even if the lattice temperature is below the equilibrium threshold for surface premelting. Based on simple considerations, the effect is interpreted as activation of surface diffusion due to modifications of the potential energy surface at high electronic temperatures. We discuss the implications of such a process in structural changes during surface chemical reactions.
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Affiliation(s)
| | - Lutz Waldecker
- Fritz-Haber-Institut , Faradayweg 4-6 , 14195 Berlin , Germany
| | - Dawn Foster
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy , University of Birmingham , Edgbaston , Birmingham B15 2TT , United Kingdom
| | - Alessandra Da Silva
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy , University of Birmingham , Edgbaston , Birmingham B15 2TT , United Kingdom
| | - Daniela Zahn
- Fritz-Haber-Institut , Faradayweg 4-6 , 14195 Berlin , Germany
| | - Roman Bertoni
- Fritz-Haber-Institut , Faradayweg 4-6 , 14195 Berlin , Germany
| | - Richard E Palmer
- College of Engineering , Swansea University , Bay Campus, Fabian Way, Swansea SA1 8EN , United Kingdom
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160
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Sharma CH, Surendran AP, Varghese A, Thalakulam M. Stable and scalable 1T MoS 2 with low temperature-coefficient of resistance. Sci Rep 2018; 8:12463. [PMID: 30127378 PMCID: PMC6102259 DOI: 10.1038/s41598-018-30867-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 08/07/2018] [Indexed: 11/09/2022] Open
Abstract
Monolithic realization of metallic 1T and semiconducting 2H phases makes MoS2 a potential candidate for future microelectronic circuits. A method for engineering a stable 1T phase from the 2H phase in a scalable manner and an in-depth electrical characterization of the 1T phase is wanting at large. Here we demonstrate a controllable and scalable 2H to 1T phase engineering technique for MoS2 using microwave plasma. Our method allows lithographically defining 1T regions on a 2H sample. The 1T samples show excellent temporal and thermal stability making it suitable for standard device fabrication techniques. We conduct both two-probe and four-probe electrical transport measurements on devices with back-gated field effect transistor geometry in a temperature range of 4 K to 300 K. The 1T samples exhibit Ohmic current-voltage characteristics in all temperature ranges without any dependence to the gate voltage, a signature of a metallic state. The sheet resistance of our 1T MoS2 sample is considerably lower and the carrier concentration is a few orders of magnitude higher than that of the 2H samples. In addition, our samples show negligible temperature dependence of resistance from 4 K to 300 K ruling out any hoping mediated or activated electrical transport.
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Affiliation(s)
- Chithra H Sharma
- School of Physics, Indian Institute of Science Education & Research Thiruvananthapuram, Kerala, 695551, India
| | - Ananthu P Surendran
- School of Physics, Indian Institute of Science Education & Research Thiruvananthapuram, Kerala, 695551, India
| | - Abin Varghese
- School of Physics, Indian Institute of Science Education & Research Thiruvananthapuram, Kerala, 695551, India
| | - Madhu Thalakulam
- School of Physics, Indian Institute of Science Education & Research Thiruvananthapuram, Kerala, 695551, India.
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161
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Xu H, Han D, Bao Y, Cheng F, Ding Z, Tan SJR, Loh KP. Observation of Gap Opening in 1T' Phase MoS 2 Nanocrystals. NANO LETTERS 2018; 18:5085-5090. [PMID: 29998735 DOI: 10.1021/acs.nanolett.8b01953] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDs) manifest in various polymorphs, which deliver different electronic properties; the most prominent among them include the semiconducting 2H phase and metallic 1T (or distorted 1T' phase) phase. Alkali metal intercalation or interface strain has been used to induce semiconductor-to-metal transition in a monolayer MoS2 sheet, leading to exotic quantum states or improved performance in catalysis. However, the direct growth of 1T or 1T' phase MoS2 is challenging due to its metastability. Here, we report MBE growth of isolated 1T' and 2H MoS2 nanocrystals on a Au substrate; these nanocrystals can be differentiated unambiguously by their electronic states using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). By studying the initial stages of nucleation during molecular beam epitaxy (MBE) of MoS2, we could identify atomic clusters (30-50 atoms) with intralayer stacking corresponding to 1T' and 2H separately, which suggests a deterministic growth mechanism from initial nuclei. Furthermore, a topological insulator type behavior was observed for the 1T' MoS2 crystals, where an energy gap opening of 80 meV was measured by STS in the basal plane at 5 K, with the edge of the nanocrystals remaining metallic.
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Affiliation(s)
- Hai Xu
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 117543 , Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore 117546 , Singapore
| | - Dong Han
- State Key Laboratory of Luminescence and Applications , Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences , Changchun 130033 , People's Republic of China
| | - Yang Bao
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 117543 , Singapore
| | - Fang Cheng
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 117543 , Singapore
| | - Zijing Ding
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore 117546 , Singapore
| | - Sherman J R Tan
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 117543 , Singapore
- NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore 117456 , Singapore
| | - Kian Ping Loh
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 117543 , Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore 117546 , Singapore
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162
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Hu Y, Zhang H, Chong WK, Li Y, Ke Y, Ganguly R, Morris SA, You L, Yu T, Sum TC, Long Y, Fan HJ. Molecular Engineering toward Coexistence of Dielectric and Optical Switch Behavior in Hybrid Perovskite Phase Transition Material. J Phys Chem A 2018; 122:6416-6423. [DOI: 10.1021/acs.jpca.8b05693] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuzhong Hu
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Hongbo Zhang
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Wee Kiang Chong
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Yongxin Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Yujie Ke
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
| | - Rakesh Ganguly
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Samuel Alexander Morris
- Facility for Analysis, Characterisation, Testing and Simulation (FACT), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - Lu You
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
| | - Ting Yu
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Tze Chien Sum
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Yi Long
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
| | - Hong Jin Fan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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163
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Liu H, Wu R, Tian L, Kong Y, Sun Y. Synergetic photocatalytic effect between 1 T@2H-MoS 2 and plasmon resonance induced by Ag quantum dots. NANOTECHNOLOGY 2018; 29:285402. [PMID: 29671406 DOI: 10.1088/1361-6528/aabf56] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Semiconductor phase transitions and plasma noble metal quantum dots (QDs) for visible-light-driven photocatalysts have attracted significant research interest. In this study, novel microwave hydrothermal and photo-reduction methods are proposed to synthesise a visible-light-driven plasma photocatalytic 1T@2H-MoS2/Ag composite. Photoelectrochemical results show that the introduction of the 1T phase and Ag significantly enhances the light response range and charge separation. The 1T phase can act as a co-catalyst to provide a high electron concentration. Ag QDs can effectively improve the light absorption and catalytic effect. The synergistic effect between the 1T@2H-MoS2 microspheres and localised surface plasmon resonance of the Ag QDs can effectively enhance the photocatalytic activity of 1T@2H-MoS2/Ag. The developed 1T@2H-MoS2/Ag composite is superior, not only with respect to a visible-light photocatalytic degradation of conventional dyes, but also in the photocatalytic reduction of Cr(VI). Compared with 2H-MoS2, the catalytic efficiency of 1T@2H-MoS2/Ag for Cr(VI) and MB is increased by 81% and 41%, respectively. This study demonstrates that the introduction of 1T-MoS2 and Ag QDs can significantly enhance the catalytic properties of 2H-MoS2. The microwave and photo-reduction technologies can be employed as green, safe, simple, and rapid methods for the synthesis of noble metal plasma composites.
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Affiliation(s)
- Haiyang Liu
- School of Physics Science and Technology, Xinjiang University, Xinjiang 830046, People's Republic of China
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164
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Shang B, Ma P, Fan J, Jiao L, Liu Z, Zhang Z, Chen N, Cheng Z, Cui X, Zheng W. Stabilized monolayer 1T MoS 2 embedded in CoOOH for highly efficient overall water splitting. NANOSCALE 2018; 10:12330-12336. [PMID: 29947394 DOI: 10.1039/c8nr04218g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The complicated synthesis procedure and the unstable nature of 1T MoS2 vastly impede its practical application although it has shown a high performance for many different applications. Herein, we have synthesized ultrastable 1T phase MoS2 embedded in CoOOH by a facile one-pot strategy and achieved a high overall water splitting activity. The amorphous CoOOH in this heterostructure not only exhibits high oxygen evolution reaction activity, but also anchors and stabilizes the 1T MoS2 as vertically aligned single layers. This novel method gives new insight into developing stable and active atomically thin transition metal dichalcogenide heterostructures.
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Affiliation(s)
- Bo Shang
- State Key Laboratory of Automotive Simulation and Control, Department of Materials Science and Key Laboratory of Automobile Materials of MOE, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
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165
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166
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Dong R, Zhang T, Feng X. Interface-Assisted Synthesis of 2D Materials: Trend and Challenges. Chem Rev 2018; 118:6189-6235. [DOI: 10.1021/acs.chemrev.8b00056] [Citation(s) in RCA: 378] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Renhao Dong
- Department of Chemistry and Food Chemistry & Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Tao Zhang
- Department of Chemistry and Food Chemistry & Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Xinliang Feng
- Department of Chemistry and Food Chemistry & Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
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167
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Recent development on MoS2-based photocatalysis: A review. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2018. [DOI: 10.1016/j.jphotochemrev.2017.12.002] [Citation(s) in RCA: 284] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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168
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Shi W, Wang Z. Mechanical and electronic properties of Janus monolayer transition metal dichalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:215301. [PMID: 29638217 DOI: 10.1088/1361-648x/aabd59] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The mechanical and electronic properties of Janus monolayer transition metal dichalcogenides MXY (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W; X/Y = S, Se, Te) were investigated using density functional theory. Results show that breaking the out-of-plane structural symmetry can be used to tune the electronic and mechanical behavior of monolayer transition metal dichalcogenides. The band gaps of monolayer WXY and MoXY are in the ranges of 0.16-1.91 and 0.94-1.69 eV, respectively. A semiconductor to metallic phase transition occurred in Janus monolayer MXY (M = Ti, Zr and Hf). The monolayers MXY (M = V, Nb, Ta and Cr) show metallic characteristics, which show no dependence on the structural symmetry breaking. The mechanical properties of MXY depended on the composition. Monolayer MXY (M = Mo, Ti, Zr, Hf and W) showed brittle characteristic, whereas monolayer CrXY and VXY are with ductile characteristic. The in-plane stiffness of pristine and Janus monolayer MXY are in the range between 22 and 158 N m-1. The tunable electronic and mechanical properties of these 2D materials would advance the development of ultra-sensitive detectors, nanogenerators, low-power electronics, and energy harvesting and electromechanical systems.
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Affiliation(s)
- Wenwu Shi
- School of Electronics Science and Engineering, Center for Public Security Technology, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
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169
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Reshmi S, Akshaya MV, Satpati B, Basu PK, Bhattacharjee K. Structural stability of coplanar 1T-2H superlattice MoS 2 under high energy electron beam. NANOTECHNOLOGY 2018; 29:205604. [PMID: 29498935 DOI: 10.1088/1361-6528/aab3c3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Coplanar heterojunctions composed of van der Waals layered materials with different structural polymorphs have drawn immense interest recently due to low contact resistance and high carrier injection rate owing to low Schottky barrier height. Present research has largely focused on efficient exfoliation of these layered materials and their restacking to achieve better performances. We present here a microwave assisted easy, fast and efficient route to induce high concentration of metallic 1T phase in the original 2H matrix of exfoliated MoS2 layers and thus facilitating the formation of a 1T-2H coplanar superlattice phase. High resolution transmission electron microscopy (HRTEM) investigations reveal formation of highly crystalline 1T-2H hybridized structure with sharp interface and disclose the evidence of surface ripplocations within the same exfoliated layer of MoS2. In this work, the structural stability of 1T-2H superlattice phase during HRTEM measurements under an electron beam of energy 300 keV is reported. This structural stability could be either associated to the change in electronic configuration due to induction of the restacked hybridized phase with 1T- and 2H-regions or to the formation of the surface ripplocations. Surface ripplocations can act as an additional source of scattering centers to the electron beam and also it is possible that a pulse train of propagating ripplocations can sweep out the defects via interaction from specific areas of MoS2 sheets.
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Affiliation(s)
- S Reshmi
- Department of Physics, Indian Institute of Space Science and Technology (IIST), Thiruvananthapuram 695 547, Kerala, India
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170
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Agarwal A, Vitiello MS, Viti L, Cupolillo A, Politano A. Plasmonics with two-dimensional semiconductors: from basic research to technological applications. NANOSCALE 2018; 10:8938-8946. [PMID: 29741546 DOI: 10.1039/c8nr01395k] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Herein, we explore the main features and the prospect of plasmonics with two-dimensional semiconductors. Plasmonic modes in each class of van der Waals semiconductors have their own peculiarities, along with potential technological capabilities. Plasmons of transition-metal dichalcogenides share features typical of graphene, due to their honeycomb structure, but with damping processes dominated by intraband rather than interband transitions, unlike graphene. Spin-orbit coupling strongly affects the plasmonic spectrum of buckled honeycomb lattices (silicene and germanene), while the anisotropic lattice of phosphorene determines different propagation of plasmons along the armchair and zigzag directions. Black phosphorus is also a suitable material for ultrafast plasmonics, for which the active plasmonic response can be initiated by photoexcitation with femtosecond pulses. We also review existing applications of plasmonics with two-dimensional materials in the fields of thermoplasmonics, biosensing, and plasma-wave Terahertz detection. Finally, we consider the capabilities of van der Waals heterostructures for innovative low-loss plasmonic devices.
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Affiliation(s)
- Amit Agarwal
- Department of Physics, Indian Institute of Technology Kanpur, 208016, Kanpur, India.
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171
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Zhang X, Lai Z, Ma Q, Zhang H. Novel structured transition metal dichalcogenide nanosheets. Chem Soc Rev 2018; 47:3301-3338. [PMID: 29671441 DOI: 10.1039/c8cs00094h] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ultrathin two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have attracted considerable attention owing to their unique properties and great potential in a wide range of applications. Great efforts have been devoted to the preparation of novel-structured TMD nanosheets by engineering their intrinsic structures at the atomic scale. Until now, a lot of new-structured TMD nanosheets, such as vacancy-containing TMDs, heteroatom-doped TMDs, TMD alloys, 1T'/1T phase and in-plane TMD crystal-phase heterostructures, TMD heterostructures and Janus TMD nanosheets, have been prepared. These materials exhibit unique properties and hold great promise in various applications, including electronics/optoelectronics, thermoelectrics, catalysis, energy storage and conversion and biomedicine. This review focuses on the most recent important discoveries in the preparation, characterization and application of these new-structured ultrathin 2D layered TMDs.
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Affiliation(s)
- Xiao Zhang
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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172
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Devi MM, Dolai N, Sreehala S, Jaques YM, Mishra RSK, Galvao DS, Tiwary CS, Sharma S, Biswas K. Morphology controlled graphene-alloy nanoparticle hybrids with tunable carbon monoxide conversion to carbon dioxide. NANOSCALE 2018; 10:8840-8850. [PMID: 29714367 DOI: 10.1039/c7nr09688g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Selective oxidation of CO to CO2 using metallic or alloy nanoparticles as catalysts can solve two major problems of energy requirements and environmental pollution. Achieving 100% conversion efficiency at a lower temperature is a very important goal. This requires sustained efforts to design and develop novel supported catalysts containing alloy nanoparticles. In this regard, the decoration of nanoalloys with graphene, as a support for the catalyst, can provide a novel structure due to the synergic effect of the nanoalloys and graphene. Here, we demonstrate the effect of nano-PdPt (Palladium-Platinum) alloys having different morphologies on the catalytic efficiency for the selective oxidation of CO. Efforts were made to prepare different morphologies of PdPt alloy nanoparticles with the advantage of tuning the capping agent (PVP - polyvinyl pyrollidone) and decorating them on graphene sheets via the wet-chemical route. The catalytic activity of the G-PdPt hybrids with an urchin-like morphology has been found to be superior (higher % conversion at 135 °C lower) to that with a nanoflower morphology. The above experimental observations are further supported by molecular dynamics (MD) simulations.
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Affiliation(s)
- M Manolata Devi
- Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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173
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Hwang DY, Choi KH, Suh DH. A vacancy-driven phase transition in MoX 2 (X: S, Se and Te) nanoscrolls. NANOSCALE 2018; 10:7918-7926. [PMID: 29670959 DOI: 10.1039/c7nr08634b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Atomically thin MoX2 (MoS2, MoSe2 and MoTe2) exhibits semiconducting, metallic, and semi-metallic properties associated with different polymorphic phases such as 2H, 1T and distorted 1T (1T'), respectively. The phase transitions from 2H to 1T for TMDs have been reported, but the mechanism for the formation and fraction control of 1T and 1T' phases in phase transition processes has never been reported because the 1T and 1T' phases are very unstable even at room temperature. To solve the problem of the thermal instability in the 1T and 1T' phases and investigate the mechanism, we design and synthesize nanoscrolls of MoX2 which have two key attributes, bending strain for phase transition and van der Waals forces as the self-stabilizing energy for thermal stability at high temperature and then investigate the mechanism of phase transition in the synthesized nanoscrolls by an increase in temperature. It turns out that the phase transition of the 2H to the 1T phase is driven by the transition metal Mo vacancy in the XY plane and that of the 1T to the 1T' phase is induced by the chalcogen X vacancy in the Z plane. In addition, each phase itself and fractions of the 2H, 1T and 1T' phases in nanoscrolls can be freely controlled by inducing vacancies of transition metal and chalcogen with increasing temperature.
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Affiliation(s)
- Da Young Hwang
- Division of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791, Republic of Korea.
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174
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Kim UJ, Lee H, Lee W, Jeong HY, Kim H, Han GH, Lee HS, Park Y, Roh YG, Lee YH, Lee E, Hwang SW. Misorientation-Angle-Dependent Phase Transformation in van der Waals Multilayers via Electron-Beam Irradiation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706864. [PMID: 29573499 DOI: 10.1002/adma.201706864] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/21/2018] [Indexed: 06/08/2023]
Abstract
Misorientation-angle dependence on layer thickness is an intriguing feature of van der Waals materials, which causes stark optical gain and electrical transport modulation. However, the influence of misorientation angle on phase transformation is not determined yet. Herein, this phenomenon in a MoS2 multilayer via in situ electron-beam irradiation is reported. An AA'-stacked MoS2 bilayer undergoes structural transformation from the 2H semiconducting phase to the 1T' metallic phase, similar to a MoS2 monolayer, which is confirmed via in situ transmission electron microscopy. Moreover, non-AA' stacking, which has no local AA' stacking order in the Moiré pattern, does not reveal such a phase transformation. While a collective sliding motion of chalcogen atoms easily occurs during the transformation in AA' stacking, in non-AA' stacking it is suppressed by the weak van der Waals strength and by the chalcogen atoms interlocked at different orientations, which disfavor their kinetics by the increased entropy of mixing.
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Affiliation(s)
- Un Jeong Kim
- Imaging Device Lab., Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
| | - Hyangsook Lee
- AE Group, Platform Technology Laboratory, Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Woojin Lee
- CAE Group, Platform Technology Laboratory, Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
| | - Hye Yun Jeong
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Hyun Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Gang Hee Han
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Hyo Sug Lee
- CAE Group, Platform Technology Laboratory, Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
| | - Yeonsang Park
- Imaging Device Lab., Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
| | - Young-Geun Roh
- Imaging Device Lab., Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Eunha Lee
- AE Group, Platform Technology Laboratory, Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
| | - Sung Woo Hwang
- Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea
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175
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Yu Y, Nam GH, He Q, Wu XJ, Zhang K, Yang Z, Chen J, Ma Q, Zhao M, Liu Z, Ran FR, Wang X, Li H, Huang X, Li B, Xiong Q, Zhang Q, Liu Z, Gu L, Du Y, Huang W, Zhang H. High phase-purity 1T′-MoS2- and 1T′-MoSe2-layered crystals. Nat Chem 2018; 10:638-643. [DOI: 10.1038/s41557-018-0035-6] [Citation(s) in RCA: 563] [Impact Index Per Article: 93.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 03/01/2018] [Indexed: 11/09/2022]
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176
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Li D, Xiao Z, Mu S, Wang F, Liu Y, Song J, Huang X, Jiang L, Xiao J, Liu L, Ducharme S, Cui B, Hong X, Jiang L, Silvain JF, Lu Y. A Facile Space-Confined Solid-Phase Sulfurization Strategy for Growth of High-Quality Ultrathin Molybdenum Disulfide Single Crystals. NANO LETTERS 2018; 18:2021-2032. [PMID: 29351373 DOI: 10.1021/acs.nanolett.7b05473] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Single-crystal transition metal dichalcogenides (TMDs) and TMD-based heterojunctions have recently attracted significant research and industrial interest owing to their intriguing optical and electrical properties. However, the lack of a simple, low-cost, environmentally friendly, synthetic method and a poor understanding of the growth mechanism post a huge challenge to implementing TMDs in practical applications. In this work, we developed a novel approach for direct formation of high-quality, monolayer and few-layer MoS2 single crystal domains via a single-step rapid thermal processing of a sandwiched reactor with sulfur and molybdenum (Mo) film in a confined reaction space. An all-solid-phase growth mechanism was proposed and experimentally/theoretically evidenced by analyzing the surface potential and morphology mapping. Compared with the conventional chemical vapor deposition approaches, our method involves no complicated gas-phase reactant transfer or reactions and requires very small amount of solid precursors [e.g., Mo (∼3 μg)], no carrier gas, no pretreatment of the precursor, no complex equipment design, thereby facilitating a simple, low-cost, and environmentally friendly growth. Moreover, we examined the symmetry, defects, and stacking phase in as-grown MoS2 samples using simultaneous second-harmonic-/sum-frequency-generation (SHG/SFG) imaging. For the first time, we observed that the SFG (peak intensity/position) polarization can be used as a sensitive probe to identify the orientation of TMDs' crystallographic axes. Furthermore, we fabricated ferroelectric programmable Schottky junction devices via local domain patterning using the as-grown, single-crystal monolayer MoS2, revealing their great potential in logic and optoelectronic applications. Our strategy thus provides a simple, low-cost, and scalable path toward a wide variety of TMD single crystal growth and novel functional device design.
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Affiliation(s)
- Dawei Li
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
| | - Zhiyong Xiao
- Department of Physics and Astronomy , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
- Nebraska Center for Materials and Nanoscience , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0299 , United States
| | - Sai Mu
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6124 , United States
| | - Fei Wang
- Department of Mechanical and Materials Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588 , United States
| | - Ying Liu
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
| | - Jingfeng Song
- Department of Physics and Astronomy , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
- Nebraska Center for Materials and Nanoscience , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0299 , United States
| | - Xi Huang
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
| | - Lijia Jiang
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
| | - Jun Xiao
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
| | - Lei Liu
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
| | - Stephen Ducharme
- Department of Physics and Astronomy , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
- Nebraska Center for Materials and Nanoscience , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0299 , United States
| | - Bai Cui
- Nebraska Center for Materials and Nanoscience , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0299 , United States
- Department of Mechanical and Materials Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588 , United States
| | - Xia Hong
- Department of Physics and Astronomy , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
- Nebraska Center for Materials and Nanoscience , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0299 , United States
| | - Lan Jiang
- School of Mechanical Engineering , Beijing Institute of Technology , Beijing 100081 , China
| | - Jean-Francois Silvain
- Institut de Chimie de la Matière Condensée de Bordeaux , Avenue du Docteur Albert Schweitzer F-33608 Pessac Cedex , France
| | - Yongfeng Lu
- Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States
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177
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Wen X, Xu W, Zhao W, Khurgin JB, Xiong Q. Plasmonic Hot Carriers-Controlled Second Harmonic Generation in WSe 2 Bilayers. NANO LETTERS 2018; 18:1686-1692. [PMID: 29376381 DOI: 10.1021/acs.nanolett.7b04707] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Modulating second harmonic generation (SHG) by a static electric field through either electric-field-induced SHG or charge-induced SHG has been well documented. Nonetheless, it is essential to develop the ability to dynamically control and manipulate the nonlinear properties, preferably at high speed. Plasmonic hot carriers can be resonantly excited in metal nanoparticles and then injected into semiconductors within 10-100 fs, where they eventually decay on a comparable time scale. This allows one to rapidly manipulate all kinds of characteristics of semiconductors, including their nonlinear properties. Here we demonstrate that plasmonically generated hot electrons can be injected from plasmonic nanostructure into bilayer (2L) tungsten diselenide (WSe2), breaking the material inversion symmetry and thus inducing an SHG. With a set of pump-probe experiments we confirm that it is the dynamic separation electric field resulting from the hot carrier injection (rather than a simple optical field enhancement) that is the cause of SHG. Transient absorption measurement further substantiate the plasmonic hot electrons injection and allow us to measure a rise time of ∼120 fs and a fall time of 1.9 ps. Our study creates opportunity for the ultrafast all-optical control of SHG in an all-optical manner that may enable a variety of applications.
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Affiliation(s)
- Xinglin Wen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
| | - Weigao Xu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
| | - Weijie Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
| | - Jacob B Khurgin
- Department of Electrical and Computer Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Qihua Xiong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
- NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering , Nanyang Technological University , Singapore , 639798
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178
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Zhang Z, Jiang X, Liu B, Guo L, Lu N, Wang L, Huang J, Liu K, Dong B. IR-Driven Ultrafast Transfer of Plasmonic Hot Electrons in Nonmetallic Branched Heterostructures for Enhanced H 2 Generation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30. [PMID: 29327486 DOI: 10.1002/adma.201705221] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/08/2017] [Indexed: 06/07/2023]
Abstract
The ultrafast transfer of plasmon-induced hot electrons is considered an effective kinetics process to enhance the photoconversion efficiencies of semiconductors through strong localized surface plasmon resonance (LSPR) of plasmonic nanostructures. Although this classical sensitization approach is widely used in noble-metal-semiconductor systems, it remains unclear in nonmetallic plasmonic heterostructures. Here, by combining ultrafast transient absorption spectroscopy with theoretical simulations, IR-driven transfer of plasmon-induced hot electron in a nonmetallic branched heterostructure is demonstrated, which is fabricated through solvothermal growth of plasmonic W18 O49 nanowires (as branches) onto TiO2 electrospun nanofibers (as backbones). The ultrafast transfer of hot electron from the W18 O49 branches to the TiO2 backbones occurs within a timeframe on the order of 200 fs with very large rate constants ranging from 3.8 × 1012 to 5.5 × 1012 s-1 . Upon LSPR excitation by low-energy IR photons, the W18 O49 /TiO2 branched heterostructure exhibits obviously enhanced catalytic H2 generation from ammonia borane compared with that of W18 O49 nanowires. Further investigations by finely controlling experimental conditions unambiguously confirm that this plasmon-enhanced catalytic activity arises from the transfer of hot electron rather than from the photothermal effect.
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Affiliation(s)
- Zhenyi Zhang
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Xiaoyi Jiang
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Benkang Liu
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Lijiao Guo
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Na Lu
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Li Wang
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Jindou Huang
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Kuichao Liu
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Bin Dong
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Nationalities University, 18 Liaohe West Road, Dalian, 116600, P. R. China
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179
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Kim S, Maassen J, Lee J, Kim SM, Han G, Kwon J, Hong S, Park J, Liu N, Park YC, Omkaram I, Rhyee JS, Hong YK, Yoon Y. Interstitial Mo-Assisted Photovoltaic Effect in Multilayer MoSe 2 Phototransistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1705542. [PMID: 29369423 DOI: 10.1002/adma.201705542] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/26/2017] [Indexed: 06/07/2023]
Abstract
Thin-film transistors (TFTs) based on multilayer molybdenum diselenide (MoSe2 ) synthesized by modified atmospheric pressure chemical vapor deposition (APCVD) exhibit outstanding photoresponsivity (103.1 A W-1 ), while it is generally believed that optical response of multilayer transition metal dichalcogenides (TMDs) is significantly limited due to their indirect bandgap and inefficient photoexcitation process. Here, the fundamental origin of such a high photoresponsivity in the synthesized multilayer MoSe2 TFTs is sought. A unique structural characteristic of the APCVD-grown MoSe2 is observed, in which interstitial Mo atoms exist between basal planes, unlike usual 2H phase TMDs. Density functional theory calculations and photoinduced transfer characteristics reveal that such interstitial Mo atoms form photoreactive electronic states in the bandgap. Models indicate that huge photoamplification is attributed to trapped holes in subgap states, resulting in a significant photovoltaic effect. In this study, the fundamental origin of high responsivity with synthetic MoSe2 phototransistors is identified, suggesting a novel route to high-performance, multifunctional 2D material devices for future wearable sensor applications.
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Affiliation(s)
- Sunkook Kim
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Jesse Maassen
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Jiyoul Lee
- Department of Graphic Arts Information Engineering, Pukyong National University, Busan, 608-739, South Korea
| | - Seung Min Kim
- Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeonbuk, 565-905, South Korea
| | - Gyuchull Han
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology (WIN), University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Junyeon Kwon
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Seongin Hong
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Jozeph Park
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Na Liu
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Yun Chang Park
- Measurement & Analysis Team, National Nanofab Center, Daejeon, 34141, South Korea
| | - Inturu Omkaram
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Jong-Soo Rhyee
- Department of Applied Physics, Kyung Hee University, Gyeonggi, 17104, South Korea
| | - Young Ki Hong
- Multi-Functional Nano/Bio Electronics Laboratory, Sungkyunkwan University, Gyeonggi, 16419, South Korea
| | - Youngki Yoon
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology (WIN), University of Waterloo, Waterloo, ON, N2L 3G1, Canada
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180
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Wang Z, Shen Y, Ito Y, Zhang Y, Du J, Fujita T, Hirata A, Tang Z, Chen M. Synthesizing 1T-1H Two-Phase Mo 1-xW xS 2 Monolayers by Chemical Vapor Deposition. ACS NANO 2018; 12:1571-1579. [PMID: 29365263 DOI: 10.1021/acsnano.7b08149] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
1T-1H metal-semiconductor interfaces in two-dimensional (2D) transition-metal dichalcogenides (TMDs) play a crucial role in utilizing the band gaps of TMDs for applications in electronic devices. Although the 1T-1H two-phase structure has been observed in exfoliated 2D nanosheets and chemically or physically treated TMDs, it cannot in principle be achieved in large-scale TMD monolayers grown by chemical vapor deposition (CVD), which is a fabrication method for electronic device applications, because of the metastable nature of the 1T phase. In this study we report CVD growth of 1T-1H two phase TMD monolayers by controlling thermal strains and alloy compositions. It was found that in-plane thermal strains arising from the difference in thermal expansion coefficients between TMD monolayers and substrates can drive the 1H to 1T transition during cooling after CVD growth. Moreover, grain boundaries in the 2D crystals act as the nucleation sites of the 1T phase and the lattice strain perturbations from alloying noticeably promote the formation of the metastable 1T phase. This work has an important implication in tailoring structure and properties of CVD grown 2D TMDs by phase engineering.
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Affiliation(s)
- Ziqian Wang
- Department of Materials Science and Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
- Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Yuhao Shen
- Key Laboratory of Polar Materials and Devices, East China Normal University , Shanghai 200062, P. R. China
| | - Yoshikazu Ito
- Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba , Tsukuba 305-8573, Japan
| | - Yongzheng Zhang
- Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Jing Du
- Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Takeshi Fujita
- Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Akihiko Hirata
- Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Zheng Tang
- Key Laboratory of Polar Materials and Devices, East China Normal University , Shanghai 200062, P. R. China
| | - Mingwei Chen
- Department of Materials Science and Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
- Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
- CREST, JST , 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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181
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Lei B, Pan Y, Hu Z, Zhang J, Xiang D, Zheng Y, Guo R, Han C, Wang L, Lu J, Yang L, Chen W. Direct Observation of Semiconductor-Metal Phase Transition in Bilayer Tungsten Diselenide Induced by Potassium Surface Functionalization. ACS NANO 2018; 12:2070-2077. [PMID: 29369617 DOI: 10.1021/acsnano.8b00398] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Structures determine properties of materials, and controllable phase transitions are, therefore, highly desirable for exploring exotic physics and fabricating devices. We report a direct observation of a controllable semiconductor-metal phase transition in bilayer tungsten diselenide (WSe2) with potassium (K) surface functionalization. Through the integration of in situ field-effect transistors, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy measurements, and first-principles calculations, we identify that the electron doping from K adatoms drives bilayer WSe2 from a 2H phase semiconductor to a 1T' phase metal. The phase transition mechanism is satisfactorily explained by the electronic structures and energy alignment of the 2H and 1T' phases. This explanation can be generally applied to understand doping-induced phase transitions in two-dimensional (2D) structures. Finally, the associated dramatic changes of electronic structures and electrical conductance make this controllable semiconductor-metal phase transition of interest for 2D semiconductor-based electronic and optoelectronic devices.
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Affiliation(s)
- Bo Lei
- National University of Singapore (Suzhou) Research Institute , 377 Lin Quan Street, Suzhou, Jiang Su 215123, China
- Department of Physics, National University of Singapore , 117542 Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore 117546
| | - Yuanyuan Pan
- Department of Physics and Institute of Materials Science and Engineering, Washington University in St. Louis , St. Louis, Missouri 63130, United States
- State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, China
| | - Zehua Hu
- National University of Singapore (Suzhou) Research Institute , 377 Lin Quan Street, Suzhou, Jiang Su 215123, China
- Department of Physics, National University of Singapore , 117542 Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore 117546
| | - Jialin Zhang
- Department of Physics, National University of Singapore , 117542 Singapore
- Department of Chemistry, National University of Singapore , Singapore 117543
| | - Du Xiang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore 117546
- Department of Chemistry, National University of Singapore , Singapore 117543
| | - Yue Zheng
- Department of Physics, National University of Singapore , 117542 Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore 117546
| | - Rui Guo
- Department of Chemistry, National University of Singapore , Singapore 117543
| | - Cheng Han
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Shenzhen University , Shenzhen 518060, China
| | - Lianhui Wang
- Key Laboratory for Organic Electronics & Information Displays (KLOEID), Institute of Advanced Materials (IAM), Jiangsu National Syngerstic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts &Telecommunications , 9 Wenyuan Road, Nanjing 210023, China
| | - Jing Lu
- State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, China
| | - Li Yang
- Department of Physics and Institute of Materials Science and Engineering, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Wei Chen
- National University of Singapore (Suzhou) Research Institute , 377 Lin Quan Street, Suzhou, Jiang Su 215123, China
- Department of Physics, National University of Singapore , 117542 Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore 117546
- Department of Chemistry, National University of Singapore , Singapore 117543
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182
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Krishnamoorthy A, Bassman Oftelie L, Kalia RK, Nakano A, Shimojo F, Vashishta P. Semiconductor-metal structural phase transformation in MoTe 2 monolayers by electronic excitation. NANOSCALE 2018; 10:2742-2747. [PMID: 29334101 DOI: 10.1039/c7nr07890k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Optical modulation of the crystal structure and materials properties is an increasingly important technique for functionalization of two-dimensional and layered semiconductors, where traditional methods like chemical doping are ineffective. Controllable transformation between the semiconducting (H) and semimetallic (T') polytypes of transition metal chalcogenide monolayers is of central importance to two-dimensional electronics, and thermally-driven and strain-driven examples of this phase transformation have been previously reported. However, the possibility of a H-T' phase transformation driven by electronic or optical excitation is less explored and little is known about the potential energy surface and the magnitude of activation barriers or the mechanism of the phase transformation in the excited state. Here, we model the electronic and ionic structure of excited MoTe2 crystals and demonstrate how electronic excitation leads to a Fermi-surface-nesting driven softening of phonon modes at the Brillouin zone boundary and the subsequent stabilization of a low-energy intermediate crystal structure along the semiconductor-metal phase transition pathway. The significantly reduced barriers for this transformation upon electronic excitation suggest that optical excitation may enable rapid and controllable synthesis of lateral semiconductor-metal heterophase homojunctions in monolayer materials for use in next-generation two-dimensional nano-electronics applications.
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Affiliation(s)
- Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089, USA.
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183
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Milekhin AG, Rahaman M, Rodyakina EE, Latyshev AV, Dzhagan VM, Zahn DRT. Giant gap-plasmon tip-enhanced Raman scattering of MoS 2 monolayers on Au nanocluster arrays. NANOSCALE 2018; 10:2755-2763. [PMID: 29308796 DOI: 10.1039/c7nr06640f] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this article, we present the results of a gap-plasmon tip-enhanced Raman scattering study of MoS2 monolayers deposited on a periodic array of Au nanostructures on a silicon substrate forming a two dimensional (2D) crystal/plasmonic heterostructure. We observe a giant Raman enhancement of the phonon modes in the MoS2 monolayer located in the plasmonic gap between the Au tip apex and Au nanoclusters. Tip-enhanced Raman mapping allows us to determine the gap-plasmon field distribution responsible for the formation of hot spots. These hot spots provide an unprecedented giant Raman enhancement of 5.6 × 108 and a spatial resolution as small as 2.3 nm under ambient conditions. Moreover, due to strong hot electron doping in the order of 1.8 × 1013 cm-2, we observe a structural change of MoS2 from the 2H to the 1T phase. Owing to the very good spatial resolution, we are able to spatially resolve those doping sites. To the best of our knowledge, this is the first time reporting of such a phenomenon with nm spatial resolution. Our results will open the perspectives of optical diagnostics with nanometer resolution for many other 2D materials.
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Affiliation(s)
- Alexander G Milekhin
- Rzhanov Institute of Semiconductor Physics RAS, Lavrentiev Ave. 13, 630090, Novosibirsk, Russia.
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184
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Xu W, Li S, Zhou S, Lee JK, Wang S, Sarwat SG, Wang X, Bhaskaran H, Pasta M, Warner JH. Large Dendritic Monolayer MoS 2 Grown by Atmospheric Pressure Chemical Vapor Deposition for Electrocatalysis. ACS APPLIED MATERIALS & INTERFACES 2018; 10:4630-4639. [PMID: 29360347 DOI: 10.1021/acsami.7b14861] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The edge sites of MoS2 are catalytically active for the hydrogen evolution reaction (HER), and growing monolayer structures that are edge-rich is desirable. Here, we show the production of large-area highly branched MoS2 dendrites on amorphous SiO2/Si substrates using an atmospheric pressure chemical vapor deposition and explore their use in electrocatalysis. By tailoring the substrate construction, the monolayer MoS2 evolves from triangular to dendritic morphology because of the change of growth conditions. The rough edges endow dendritic MoS2 with a fractal dimension down to 1.54. The highly crystalline basal plane and the edge of the dendrites are visualized at atomic resolution using an annular dark field scanning transmission electron microscope. The monolayer dendrites exhibit strong photoluminescence, which is indicative of the direct band gap emission, which is preserved after being transferred. Post-transfer sulfur annealing restores the structural defects and decreases the n-type doping in MoS2 monolayers. The annealed MoS2 dendrites show good and highly durable HER performance on the glassy carbon with a large exchange current density of 32 μA cmgeo-2, demonstrating its viability as an efficient HER catalyst.
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Affiliation(s)
- Wenshuo Xu
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Sha Li
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Si Zhou
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Ja Kyung Lee
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Shanshan Wang
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Syed Ghazi Sarwat
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Xiaochen Wang
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Harish Bhaskaran
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Mauro Pasta
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, U.K
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185
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Voiry D, Shin HS, Loh KP, Chhowalla M. Low-dimensional catalysts for hydrogen evolution and CO2 reduction. Nat Rev Chem 2018. [DOI: 10.1038/s41570-017-0105] [Citation(s) in RCA: 485] [Impact Index Per Article: 80.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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186
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Wang YY, Deng JJ, Wang X, Che JT, Ding XL. Small stoichiometric (MoS2)n clusters with the 1T phase. Phys Chem Chem Phys 2018; 20:6365-6373. [DOI: 10.1039/c7cp07914a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stoichiometric (MoS2)n clusters (n = 1–6) were systematically studied by density functional theory calculations with hybrid B3LYP and pure GGA PW91 functionals.
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Affiliation(s)
- Ya-Ya Wang
- Department of Mathematics and Physics
- North China Electric Power University
- Beijing
- P. R. China
| | - Jia-Jun Deng
- Department of Mathematics and Physics
- North China Electric Power University
- Beijing
- P. R. China
| | - Xin Wang
- Department of Mathematics and Physics
- North China Electric Power University
- Beijing
- P. R. China
| | - Jian-Tao Che
- Department of Mathematics and Physics
- North China Electric Power University
- Beijing
- P. R. China
| | - Xun-Lei Ding
- Department of Mathematics and Physics
- North China Electric Power University
- Beijing
- P. R. China
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187
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Wang Z, Jingjing Q, Wang X, Zhang Z, Chen Y, Huang X, Huang W. Two-dimensional light-emitting materials: preparation, properties and applications. Chem Soc Rev 2018; 47:6128-6174. [DOI: 10.1039/c8cs00332g] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We review the recent development in two-dimensional (2D) light-emitting materials and describe their preparation methods, optical/optoelectronic properties and applications.
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Affiliation(s)
- Zhiwei Wang
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
| | - Qiu Jingjing
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
| | - Xiaoshan Wang
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
| | - Zhipeng Zhang
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
| | - Yonghua Chen
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
| | - Xiao Huang
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
| | - Wei Huang
- Institute of Advanced Materials (IAM)
- Nanjing Tech University (NanjingTech)
- Nanjing 211816
- P. R. China
- Shaanxi Institute of Flexible Electronics (SIFE)
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188
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Huang HH, Fan X, Singh DJ, Zheng WT. First principles study on 2H–1T′ transition in MoS2 with copper. Phys Chem Chem Phys 2018; 20:26986-26994. [DOI: 10.1039/c8cp05445b] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adsorption of Cu can induce phase transition of MoS2 from 2H to metallic 1T′.
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Affiliation(s)
- H. H. Huang
- Key Laboratory of Automobile Materials (Jilin University)
- Ministry of Education
- College of Materials Science and Engineering
- Jilin University
- Changchun 130012
| | - Xiaofeng Fan
- Key Laboratory of Automobile Materials (Jilin University)
- Ministry of Education
- College of Materials Science and Engineering
- Jilin University
- Changchun 130012
| | - David J. Singh
- Department of Physics and Astronomy
- University of Missouri
- Columbia
- USA
| | - W. T. Zheng
- Key Laboratory of Automobile Materials (Jilin University)
- Ministry of Education
- College of Materials Science and Engineering
- Jilin University
- Changchun 130012
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189
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Xu W, Yan S, Qiao W. Magnetism in monolayer 1T-MoS2 and 1T-MoS2H tuned by strain. RSC Adv 2018; 8:8435-8441. [PMID: 35542012 PMCID: PMC9078537 DOI: 10.1039/c7ra10304b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 02/17/2018] [Indexed: 12/13/2022] Open
Abstract
The magnetic properties of 1T-MoS2 and 1T-MoS2H subjected to equiaxial tensile strain are calculated using density functional theory. It is shown that in a strain-free state, 1T-MoS2 and 1T-MoS2H both exhibit magnetic behavior; as the strain increases, their magnetic properties show an increasing trend. This shows a significant difference from those of 2H-MoS2 and 2H-MoS2H. Based on Crystal Field Theory, the magnetic generation and variation of 1T-MoS2 and 1T-MoS2H are explained in this paper. The good tunable magnetic properties of 1T-MoS2 and 1T-MoS2H suggest that they could be applied as a spin injection source for spin electronics. The magnetic properties of 1T-MoS2 and 1T-MoS2H subjected to equiaxial tensile strain are calculated using density functional theory.![]()
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Affiliation(s)
- Wei Xu
- College of Science
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Shiming Yan
- College of Science
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
| | - Wen Qiao
- College of Science
- Henan University of Technology
- Zhengzhou 450001
- P. R. China
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190
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Xu X, Shi Y, Liu X, Sun M. Femtosecond dynamics of monolayer MoS2-Ag nanoparticles hybrid probed at 532 nm. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.12.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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191
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192
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Li B, Zu S, Zhou J, Jiang Q, Du B, Shan H, Luo Y, Liu Z, Zhu X, Fang Z. Single-Nanoparticle Plasmonic Electro-optic Modulator Based on MoS 2 Monolayers. ACS NANO 2017; 11:9720-9727. [PMID: 28863263 DOI: 10.1021/acsnano.7b05479] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The manipulation of light in an integrated circuit is crucial for the development of high-speed electro-optic devices. Recently, molybdenum disulfide (MoS2) monolayers generated broad interest for the optoelectronics because of their huge exciton binding energy, tunable optical emission, direct electronic band-gap structure, etc. Miniaturization and multifunctionality of electro-optic devices further require the manipulation of light-matter interaction at the single-nanoparticle level. The strong exciton-plasmon interaction that is generated between the MoS2 monolayers and metallic nanostructures may be a possible solution for compact electro-optic devices at the nanoscale. Here, we demonstrate a nanoplasmonic modulator in the visible spectral region by combining the MoS2 monolayers with a single Au nanodisk. The narrow MoS2 excitons coupled with broad Au plasmons result in a deep Fano resonance, which can be switched on and off by applying different gate voltages on the MoS2 monolayers. A reversible display device that is based on this single-nanoparticle modulator is demonstrated with a heptamer pattern that is actively controlled by the external gates. Our work provides a potential application for electro-optic modulation on the nanoscale and promotes the development of gate-tunable nanoplasmonic devices in the future.
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Affiliation(s)
- Bowen Li
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Shuai Zu
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Jiadong Zhou
- Center for Programmable Materials, School of Electrical and Electronic Engineering, Nanyang Technology University , Singapore 639798
| | - Qiao Jiang
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Bowen Du
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Hangyong Shan
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Yang Luo
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Zheng Liu
- Center for Programmable Materials, School of Electrical and Electronic Engineering, Nanyang Technology University , Singapore 639798
| | - Xing Zhu
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
| | - Zheyu Fang
- School of Physics, State Key Lab for Mesoscopic Physics; Academy for Advanced Interdisciplinary Studies; Collaborative Innovation Center of Quantum Matter, Peking University , Beijing 100871, China
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193
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Sun Y, Zhong W, Wang Y, Xu X, Wang T, Wu L, Du Y. MoS 2-Based Mixed-Dimensional van der Waals Heterostructures: A New Platform for Excellent and Controllable Microwave-Absorption Performance. ACS APPLIED MATERIALS & INTERFACES 2017; 9:34243-34255. [PMID: 28901126 DOI: 10.1021/acsami.7b10114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
It is widely recognized that constructing multiple interface structures for enhanced interface polarization is beneficial to microwave absorption. Here, we report our work of achieving excellent microwave-absorption performance and controlling better-defined interfaces in vertically stacked two-dimensional (2D) MoS2 with other dimensional building blocks. The optimal reflection loss and effective absorbing bandwidth (reflection loss <-10 dB) of several mixed-dimensional van der Waals heterostructures are as follows: (i) for 2-0 type (2D MoS2/zero-dimensional Ni nanoparticles), -19.7 dB and 2.92 GHz; (ii) for 2-1 type (2D MoS2/one-dimensional carbon nanotubes), -47.9 dB and 5.60 GHz; and (iii) for 2-3 type (2D MoS2/three-dimensional carbon layers), -69.2 dB and 4.88 GHz. As a result, by selected synthesis of different types of microstructures, we can regulate and control microwave-absorption properties in MoS2 mixed-dimensional van der Waals heterostructures. In addition, attributing to the better-defined interfaces generated in mixed-dimensional van der Waals heterostructures, we found an alternative strategy to improve microwave attenuation properties of 2-0, 2-1, and 2-3 samples by controlling interfacial contacts. The results indicate that mixed-dimensional van der Waals heterostructures provide a new stage for the next generation of microwave-absorbing materials.
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Affiliation(s)
- Yuan Sun
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
| | - Wei Zhong
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
| | - Yuanqi Wang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
| | - Xiaobing Xu
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
| | - Tingting Wang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
| | - Liqian Wu
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
| | - Youwei Du
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, and Jiangsu Provincial Laboratory for NanoTechnology, Nanjing University , Nanjing 210093, China
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194
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Interplay of hot electrons from localized and propagating plasmons. Nat Commun 2017; 8:771. [PMID: 28974685 PMCID: PMC5626744 DOI: 10.1038/s41467-017-00815-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 07/30/2017] [Indexed: 11/08/2022] Open
Abstract
Plasmon-induced hot-electron generation has recently received considerable interest and has been studied to develop novel applications in optoelectronics, photovoltaics and green chemistry. Such hot electrons are typically generated from either localized plasmons in metal nanoparticles or propagating plasmons in patterned metal nanostructures. Here we simultaneously generate these heterogeneous plasmon-induced hot electrons and exploit their cooperative interplay in a single metal-semiconductor device to demonstrate, as an example, wavelength-controlled polarity-switchable photoconductivity. Specifically, the dual-plasmon device produces a net photocurrent whose polarity is determined by the balance in population and directionality between the hot electrons from localized and propagating plasmons. The current responsivity and polarity-switching wavelength of the device can be varied over the entire visible spectrum by tailoring the hot-electron interplay in various ways. This phenomenon may provide flexibility to manipulate the electrical output from light-matter interaction and offer opportunities for biosensors, long-distance communications, and photoconversion applications. Plasmon-induced hot electrons have potential applications spanning photodetection and photocatalysis. Here, Hoang et al. study the interplay between hot electrons generated by localized and propagating plasmons, and demonstrate wavelength-controlled polarity-switchable photoconductivity
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195
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Wang M, Li W, Scarabelli L, Rajeeva BB, Terrones M, Liz-Marzán LM, Akinwande D, Zheng Y. Plasmon-trion and plasmon-exciton resonance energy transfer from a single plasmonic nanoparticle to monolayer MoS 2. NANOSCALE 2017; 9:13947-13955. [PMID: 28782790 DOI: 10.1039/c7nr03909c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Resonance energy transfer (RET) from plasmonic metal nanoparticles (NPs) to two-dimensional (2D) materials enhances the performance of 2D optoelectronic devices and sensors. Herein, single-NP scattering spectroscopy is employed to investigate plasmon-trion and plasmon-exciton RET from single Au nanotriangles (AuNTs) to monolayer MoS2, at room temperature. The large quantum confinement and reduced dielectric screening in monolayer MoS2 facilitates efficient RET between single plasmonic metal NPs and the monolayer. Because of the large exciton binding energy of monolayer MoS2, charged excitons (i.e., trions) are observed at room temperature, which enable us to study the plasmon-trion interactions under ambient conditions. Tuning of plasmon-trion and plasmon-exciton RET is further achieved by controlling the dielectric constant of the medium surrounding the AuNT-MoS2 hybrids. Our observation of switchable plasmon-trion and plasmon-exciton RET inspires new applications of the hybrids of 2D materials and metal nanoparticles.
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Affiliation(s)
- Mingsong Wang
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
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196
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Yoshida M, Ye J, Zhang Y, Imai Y, Kimura S, Fujiwara A, Nishizaki T, Kobayashi N, Nakano M, Iwasa Y. Extended Polymorphism of Two-Dimensional Material. NANO LETTERS 2017; 17:5567-5571. [PMID: 28777578 DOI: 10.1021/acs.nanolett.7b02374] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
When controlling electronic properties of bulk materials, we usually assume that the basic crystal structure is fixed. However, in two-dimensional (2D) materials, atomic structure or polymorph is attracting growing interest as a controlling parameter to functionalize their properties. Various polymorphs can exist in transition metal dichalcogenides (TMDCs) from which 2D materials are generated, and polymorphism has drastic impacts on the electronic states. Here we report the discovery of an unprecedented polymorph of a TMDC 2D material. By mechanical exfoliation, we made thin flakes from a single crystal of 2Ha-type tantalum disulfide (TaS2), a metallic TMDC with a charge-density-wave (CDW) phase. Microbeam X-ray diffraction measurements and electrical transport measurements indicate that thin flakes possess a polymorph different from any one known in TaS2 bulk crystals. Moreover, the flakes with the unique polymorph displayed the dramatically enhanced CDW ordering temperature. The present results suggest the potential existence of diverse structural and electronic phases accessible only in 2D materials.
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Affiliation(s)
- Masaro Yoshida
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo , Tokyo 113-8656, Japan
| | - Jianting Ye
- Zernike Institute for Advanced Materials, University of Groningen , 9747 AG Groningen, The Netherlands
| | - Yijin Zhang
- The Institute of Scientific and Industrial Research, Osaka University , Osaka 067-0047, Japan
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Yasuhiko Imai
- Japan Synchrotron Radiation Research Institute (JASRI), Hyogo 679-5198, Japan
| | - Shigeru Kimura
- Japan Synchrotron Radiation Research Institute (JASRI), Hyogo 679-5198, Japan
| | - Akihiko Fujiwara
- School of Science and Technology, Kwansei Gakuin University , Hyogo 669-1337, Japan
| | - Terukazu Nishizaki
- Department of Electrical Engineering, Kyushu Sangyo University , Fukuoka 813-8503, Japan
| | - Norio Kobayashi
- Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Masaki Nakano
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo , Tokyo 113-8656, Japan
| | - Yoshihiro Iwasa
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo , Tokyo 113-8656, Japan
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197
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Yin X, Wang Q, Cao L, Tang CS, Luo X, Zheng Y, Wong LM, Wang SJ, Quek SY, Zhang W, Rusydi A, Wee ATS. Tunable inverted gap in monolayer quasi-metallic MoS 2 induced by strong charge-lattice coupling. Nat Commun 2017; 8:486. [PMID: 28883392 PMCID: PMC5589873 DOI: 10.1038/s41467-017-00640-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/17/2017] [Indexed: 11/09/2022] Open
Abstract
Polymorphism of two-dimensional transition metal dichalcogenides such as molybdenum disulfide (MoS2) exhibit fascinating optical and transport properties. Here, we observe a tunable inverted gap (~0.50 eV) and a fundamental gap (~0.10 eV) in quasimetallic monolayer MoS2. Using spectral-weight transfer analysis, we find that the inverted gap is attributed to the strong charge–lattice coupling in two-dimensional transition metal dichalcogenides (2D-TMDs). A comprehensive experimental study, supported by theoretical calculations, is conducted to understand the transition of monolayer MoS2 on gold film from trigonal semiconducting 1H phase to the distorted octahedral quasimetallic 1T’ phase. We clarify that electron doping from gold, facilitated by interfacial tensile strain, is the key mechanism leading to its 1H–1T’ phase transition, thus resulting in the formation of the inverted gap. Our result shows the importance of charge–lattice coupling to the intrinsic properties of the inverted gap and polymorphism of MoS2, thereby unlocking new possibilities for 2D-TMD-based device fabrication. MoS2 exhibits multiple electronic properties associated with different crystal structures. Here, the authors observe inverted and fundamental gaps through a designed annealing-based strategy, to induce a semiconductor-to-metal phase transition in monolayer-MoS2 on Au, facilitated by interfacial strain and electron transfer from Au to MoS2.
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Affiliation(s)
- Xinmao Yin
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.,Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore.,Singapore Synchrotron Light Source (SSLS), National University of Singapore, 117603, Singapore, Singapore
| | - Qixing Wang
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore
| | - Liang Cao
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore.,Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei, 230031, China
| | - Chi Sin Tang
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore, Singapore
| | - Xin Luo
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore.,Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 117551, Singapore, Singapore.,Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Yujie Zheng
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore
| | - Lai Mun Wong
- Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, 138634, Singapore
| | - Shi Jie Wang
- Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, 138634, Singapore
| | - Su Ying Quek
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore.,Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 117551, Singapore, Singapore
| | - Wenjing Zhang
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Andrivo Rusydi
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore. .,Singapore Synchrotron Light Source (SSLS), National University of Singapore, 117603, Singapore, Singapore. .,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore, Singapore. .,NUSNNI-NanoCore, National University of Singapore, Singapore, 117576, Singapore.
| | - Andrew T S Wee
- Department of Physics, Faculty of Science, National University of Singapore, 117542, Singapore, Singapore. .,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore, Singapore. .,Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 117551, Singapore, Singapore.
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198
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Yan W, Yang L, Chen J, Wu Y, Wang P, Li Z. In Situ Two-Step Photoreduced SERS Materials for On-Chip Single-Molecule Spectroscopy with High Reproducibility. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1702893. [PMID: 28718979 DOI: 10.1002/adma.201702893] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Indexed: 05/26/2023]
Abstract
A method is developed to synthesize surface-enhanced Raman scattering (SERS) materials capable of single-molecule detection, integrated with a microfluidic system. Using a focused laser, silver nanoparticle aggregates as SERS monitors are fabricated in a microfluidic channel through photochemical reduction. After washing out the monitor, the aggregates are irradiated again by the same laser. This key step leads to full reduction of the residual reactants, which generates numerous small silver nanoparticles on the former nanoaggregates. Consequently, the enhancement ability of the SERS monitor is greatly boosted due to the emergence of new "hot spots." At the same time, the influence of the notorious "memory effect" in microfluidics is substantially suppressed due to the depletion of surface residues. Taking these advantages, two-step photoreduced SERS materials are able to detect different types of molecules with the concentration down to 10-13 m. Based on a well-accepted bianalyte approach, it is proved that the detection limit reaches the single-molecule level. From a practical point of view, the detection reproducibility at different probing concentrations is also investigated. It is found that the effective single-molecule SERS measurements can be raised up to ≈50%. This microfluidic SERS with high reproducibility and ultrasensitivity will find promising applications in on-chip single-molecule spectroscopy.
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Affiliation(s)
- Wenjie Yan
- The Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Center for Condensed Matter Physics, Department of Physics, Capital Normal University, Beijing, 100048, P. R. China
| | - Longkun Yang
- The Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Center for Condensed Matter Physics, Department of Physics, Capital Normal University, Beijing, 100048, P. R. China
| | - Jianing Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences, University of Physics Chinese Academy of Sciences, Collaborative Innovation Center of Quantum Matter, Beijing, 100190, P. R. China
| | - Yaqi Wu
- The Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Center for Condensed Matter Physics, Department of Physics, Capital Normal University, Beijing, 100048, P. R. China
| | - Peijie Wang
- The Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Center for Condensed Matter Physics, Department of Physics, Capital Normal University, Beijing, 100048, P. R. China
| | - Zhipeng Li
- The Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Center for Condensed Matter Physics, Department of Physics, Capital Normal University, Beijing, 100048, P. R. China
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199
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Designing artificial 2D crystals with site and size controlled quantum dots. Sci Rep 2017; 7:9965. [PMID: 28855567 PMCID: PMC5577271 DOI: 10.1038/s41598-017-08776-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/18/2017] [Indexed: 11/10/2022] Open
Abstract
Ordered arrays of quantum dots in two-dimensional (2D) materials would make promising optical materials, but their assembly could prove challenging. Here we demonstrate a scalable, site and size controlled fabrication of quantum dots in monolayer molybdenum disulfide (MoS2), and quantum dot arrays with nanometer-scale spatial density by focused electron beam irradiation induced local 2H to 1T phase change in MoS2. By designing the quantum dots in a 2D superlattice, we show that new energy bands form where the new band gap can be controlled by the size and pitch of the quantum dots in the superlattice. The band gap can be tuned from 1.81 eV to 1.42 eV without loss of its photoluminescence performance, which provides new directions for fabricating lasers with designed wavelengths. Our work constitutes a photoresist-free, top-down method to create large-area quantum dot arrays with nanometer-scale spatial density that allow the quantum dots to interfere with each other and create artificial crystals. This technique opens up new pathways for fabricating light emitting devices with 2D materials at desired wavelengths. This demonstration can also enable the assembly of large scale quantum information systems and open up new avenues for the design of artificial 2D materials.
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200
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Ai Y, Nguyen VQ, Ghilane J, Lacaze PC, Lacroix JC. Plasmon-Induced Conductance Switching of an Electroactive Conjugated Polymer Nanojunction. ACS APPLIED MATERIALS & INTERFACES 2017; 9:27817-27824. [PMID: 28767223 DOI: 10.1021/acsami.7b04695] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A plasmonic molecular electronic device, consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires bridging an ultramicroelectrode and an indium tin oxide (ITO) substrate covered by gold nanoparticles (Au NPs), has been developed. Light irradiation of this device has a dramatic impact on its conductance. Polymer strands, maintained electrochemically in their oxidized, conducting state, reversibly switch to their insulating state upon irradiation by visible-wavelength light, resulting in a sharp decrease in the conductance. The high-conductance state is restored when the light is turned off. Switching depends on the wavelength and the intensity of the incident light. It is due to reversible reduction of the nanosized region of PEDOT nanowires in contact with a gold NP and is attributed to plasmon-induced hot-electron injection into the PEDOT. The high/low conductance ratio can be as great as 1000, and switching requires low light intensity (220 W/m2). These results could open the way to the design of a new family of optoelectronic switches.
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Affiliation(s)
- Yong Ai
- Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Université Paris Diderot , 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Van Quynh Nguyen
- Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Université Paris Diderot , 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
- Department of Advanced Material Science and Nanotechnology, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology , 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Jalal Ghilane
- Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Université Paris Diderot , 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Pierre-Camille Lacaze
- Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Université Paris Diderot , 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Jean-Christophe Lacroix
- Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Université Paris Diderot , 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
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