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Fantasia A, Rovaris F, Abou El Kheir O, Marzegalli A, Lanzoni D, Pessina L, Xiao P, Zhou C, Li L, Henkelman G, Scalise E, Montalenti F. Development of a machine learning interatomic potential for exploring pressure-dependent kinetics of phase transitions in germanium. J Chem Phys 2024; 161:014110. [PMID: 38953439 DOI: 10.1063/5.0214588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 06/15/2024] [Indexed: 07/04/2024] Open
Abstract
We introduce a data-driven potential aimed at the investigation of pressure-dependent phase transitions in bulk germanium, including the estimate of kinetic barriers. This is achieved by suitably building a database including several configurations along minimum energy paths, as computed using the solid-state nudged elastic band method. After training the model based on density functional theory (DFT)-computed energies, forces, and stresses, we provide validation and rigorously test the potential on unexplored paths. The resulting agreement with the DFT calculations is remarkable in a wide range of pressures. The potential is exploited in large-scale isothermal-isobaric simulations, displaying local nucleation in the R8 to β-Sn pressure-induced phase transformation, taken here as an illustrative example.
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Affiliation(s)
- A Fantasia
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - F Rovaris
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - O Abou El Kheir
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - A Marzegalli
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - D Lanzoni
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - L Pessina
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - P Xiao
- Department of Physics and Atmospheric Science, Dalhousie University, 1453 Lord Dalhousie Drive, Halifax, Nova Scotia B3H 4R2, Canada
| | - C Zhou
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - L Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, 518055 Shenzhen, China
| | - G Henkelman
- Department of Chemistry, The University of Texas at Austin, 105 East 24th Street STOP A5300 Austin, Texas 78712, USA
| | - E Scalise
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - F Montalenti
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
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Zou Y, Wu N, Song T, Liu Z, Cui X. From Topological Nodal-Line Semimetal to Insulator in ABW-Ge 4: A New Member of the Germanium Allotrope. ACS OMEGA 2023; 8:27231-27237. [PMID: 37546633 PMCID: PMC10398855 DOI: 10.1021/acsomega.3c02542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/04/2023] [Indexed: 08/08/2023]
Abstract
Topological semimetals have attracted much attention because of their excellent properties, such as ultra-high speed, low energy consumption quantum transport, and negative reluctance. Searching materials with topological semimetallic properties has become a new research field for Group-IV materials. Herein, using first-principles calculations and tight-binding modeling, we proposed a topological nodal-line semimetal ABW-Ge4 when spin-orbit coupling (SOC) is ignored, which is composed of pure germanium atoms in a zeolite framework ABW. It holds excellent dynamic and thermal stability. In its electronic band structure, there exists a stable Dirac linear band crossing near the Fermi energy level, which forms a closed ring in the kx = 0 plane of the Brillouin zone (BZ). Our symmetry analysis reveals that the nodal ring is protected by Mx mirror symmetry. Furthermore, by examining the slope index in all possible k paths through the considered Dirac point, we find that the band dispersion near the Dirac point is greatly anisotropic. In some direction, the Fermi velocity is even larger than that of graphene, being promising for the future ultra-high speed device. When spin-orbit coupling is included, the nodal line is gapped and the system becomes a topological insulator with topological invariants Z2 = 1. Our findings not only identify a new Ge allotrope but also establish a promising topological material in Group-IV materials, which may have the desirable compatibility with the traditional semiconductor industry.
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Abstract
As the pioneer semiconductor in transistor, germanium (Ge) has been widely applied in information technology for over half a century. Although many phase transitions in Ge have been reported, the complicated phenomena of the phase structures in amorphous Ge under extreme conditions are still not fully investigated. Here, we report the different routes of phase transition in amorphous Ge under different compression conditions utilizing diamond anvil cell (DAC) combined with synchrotron-based X-ray diffraction (XRD) and Raman spectroscopy techniques. Upon non-hydrostatic compression of amorphous Ge, we observed that shear stress facilitates a reversible pressure-induced phase transformation, in contrast to the pressure-quenchable structure under a hydrostatic compression. These findings afford better understanding of the structural behaviors of Ge under extreme conditions, which contributes to more potential applications in the semiconductor field.
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4
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Fan L, Yang D, Li D. A Review on Metastable Silicon Allotropes. MATERIALS 2021; 14:ma14143964. [PMID: 34300884 PMCID: PMC8303612 DOI: 10.3390/ma14143964] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 01/25/2023]
Abstract
Diamond cubic silicon is widely used for electronic applications, integrated circuits, and photovoltaics, due to its high abundance, nontoxicity, and outstanding physicochemical properties. However, it is a semiconductor with an indirect band gap, depriving its further development. Fortunately, other polymorphs of silicon have been discovered successfully, and new functional allotropes are continuing to emerge, some of which are even stable in ambient conditions and could form the basis for the next revolution in electronics, stored energy, and optoelectronics. Such structures can lead to some excellent features, including a wide range of direct or quasi-direct band gaps allowed efficient for photoelectric conversion (examples include Si-III and Si-IV), as well as a smaller volume expansion as lithium-battery anode material (such as Si24, Si46, and Si136). This review aims to give a detailed overview of these exciting new properties and routes for the synthesis of novel Si allotropes. Lastly, the key problems and the developmental trends are put forward at the end of this article.
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Affiliation(s)
- Linlin Fan
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; (L.F.); (D.Y.)
| | - Deren Yang
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; (L.F.); (D.Y.)
| | - Dongsheng Li
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; (L.F.); (D.Y.)
- Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027, China
- Correspondence: ; Tel.: +86-571-8795-3180
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5
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Kelsall LC, Peña-Alvarez M, Martinez-Canales M, Binns J, Pickard CJ, Dalladay-Simpson P, Howie RT, Gregoryanz E. High-temperature phase transitions in dense germanium. J Chem Phys 2021; 154:174702. [PMID: 34241079 DOI: 10.1063/5.0047359] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Through a series of high-pressure x-ray diffraction experiments combined with in situ laser heating, we explore the pressure-temperature phase diagram of germanium (Ge) at pressures up to 110 GPa and temperatures exceeding 3000 K. In the pressure range of 64-90 GPa, we observe orthorhombic Ge-IV transforming above 1500 K to a previously unobserved high-temperature phase, which we denote as Ge-VIII. This high-temperature phase is characterized by a tetragonal crystal structure, space group I4/mmm. Density functional theory simulations confirm that Ge-IV becomes unstable at high temperatures and that Ge-VIII is highly competitive and dynamically stable at these conditions. The existence of Ge-VIII has profound implications for the pressure-temperature phase diagram, with melting conditions increasing to much higher temperatures than previous extrapolations would imply.
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Affiliation(s)
- Liam C Kelsall
- SUPA, School of Physics and Astronomy and CSEC, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Miriam Peña-Alvarez
- SUPA, School of Physics and Astronomy and CSEC, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Miguel Martinez-Canales
- SUPA, School of Physics and Astronomy and CSEC, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Jack Binns
- Center for High-Pressure Science and Technology Advanced Research, Shanghai, People's Republic of China
| | - Chris J Pickard
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, United Kingdom
| | - Philip Dalladay-Simpson
- Center for High-Pressure Science and Technology Advanced Research, Shanghai, People's Republic of China
| | - Ross T Howie
- Center for High-Pressure Science and Technology Advanced Research, Shanghai, People's Republic of China
| | - Eugene Gregoryanz
- SUPA, School of Physics and Astronomy and CSEC, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
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6
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Branzi L, Back M, Cortelletti P, Pinna N, Benedetti A, Speghini A. Sodium niobate based hierarchical 3D perovskite nanoparticle clusters. Dalton Trans 2020; 49:15195-15203. [PMID: 33030177 DOI: 10.1039/d0dt02768e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report a microwave assisted synthesis of NaNbO3 perovskite mesocrystals with a hierarchical morphology formed by the self-assembly of nanoparticles in particle clusters. The synthesis method combines non-aqueous sol-gel synthesis and microwave heating in a single step process that allows us to isolate crystalline single phase NaNbO3 in few minutes. A detailed investigation of the effect of the reaction temperature on the crystallinity and morphology of the product was conducted. The synthesis stabilizes the unusual orthorhombic phase Pmma, a property that can be ascribed to the crystal size (24 nm). TEM and SAED analyses show that the hierarchical polycrystalline particles behave as single crystals, a feature related to a non-classical crystallization mechanism. Moreover, the optical bandgap of this NaNbO3 phase was estimated for the first time. The results suggest the potential of this synthetic procedure for the fast production of high quality tertiary oxide nanocrystals.
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Affiliation(s)
- Lorenzo Branzi
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy.
| | - Michele Back
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy.
| | - Paolo Cortelletti
- Nanomaterials Research Group, Department of Biotechnology and INSTM, RU Verona, University of Verona, Strada le Grazie 15, Verona, Italy.
| | - Nicola Pinna
- Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - Alvise Benedetti
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy.
| | - Adolfo Speghini
- Nanomaterials Research Group, Department of Biotechnology and INSTM, RU Verona, University of Verona, Strada le Grazie 15, Verona, Italy.
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7
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Djomani D, Capitani F, Brubach JB, Calandrini E, Renard C, Bouchier D, Itié JP, Roy P, Vincent L. Atypical reversed pressure-induced phase transformation in Ge nanowires. NANOTECHNOLOGY 2020; 31:235711. [PMID: 32109895 DOI: 10.1088/1361-6528/ab7b06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phase transformations of Ge under compression/decompression cycle at room temperature were studied in a diamond anvil cell (DAC) using in situ synchrotron x-ray diffraction, Raman spectroscopy and near infrared absorption techniques. Upon compression similar behavior is observed in nanowires and in bulk although a higher stability is observed in nanowires. The cubic-diamond phase (Ge-3C), the most energetically favorable phase, transforms into the β-tin metallic phase at high pressure and the reverse Ge-β-tin to Ge-3C transformation is generally inhibited by kinetics when pressure is released. While the transformation in Ge bulk leads mostly to Ge-ST12 phase, the loading/unloading cycle of Ge nanowires in DAC leads back to Ge-3C, exhibiting unprecedented size effects. A comprehensive characterization of the final states is described.
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Affiliation(s)
- Doriane Djomani
- Centre de Nanosciences et Nanotechnologies (C2N), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 10 Boulevard Thomas Gobert, F-91120 Palaiseau, France
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8
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Morozova NV, Korobeinikov IV, Abrosimov NV, Ovsyannikov SV. Controlling the thermoelectric power of silicon–germanium alloys in different crystalline phases by applying high pressure. CrystEngComm 2020. [DOI: 10.1039/d0ce00672f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Si–Ge crystals are promising materials for use in various stress-controlled electronic junctions for next-generation nanoelectronic devices.
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Affiliation(s)
- Natalia V. Morozova
- M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences
- Yekaterinburg 620137
- Russia
| | - Igor V. Korobeinikov
- M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences
- Yekaterinburg 620137
- Russia
| | | | - Sergey V. Ovsyannikov
- Bayerisches Geoinstitut
- Universität Bayreuth
- Bayreuth
- Germany
- Institute for Solid State Chemistry of Ural Branch of Russian Academy of Sciences
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9
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Song Y, Chai C, Fan Q, Zhang W, Yang Y. Physical properties of Si-Ge alloys in C2/m phase: a comprehensive investigation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:255703. [PMID: 30893672 DOI: 10.1088/1361-648x/ab11a2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A new phase of C2/m Ge16 is first proposed in this paper. The structures and mechanical, anisotropic, electronic, transport and optical properties of Si-Ge alloys in the C2/m phase are studied using first principles calculations. All Ge16 and Si16-x Ge x alloys in the C2/m phase are proven to have mechanical and dynamic stability. By analyzing the three-dimensional (3D) perspective of the effective mass and Young's modulus, obvious anisotropies of transport and mechanical properties are found. Higher-resolution full band structures are obtained to determine the positions of the valence band maximum (VBM) and conduction band minimum (CBM). All materials have a higher photoelectron absorption than that of diamond Si. A high electronic mobility (16 527 cm2 V-1 s-1) and hole mobility (3033 cm2 V-1 s-1) are found in C2/m Si8Ge8 and Si4Ge12, respectively. Based on the large mobility and photoelectron absorption, the Si-Ge alloys in the C2/m phase are promising materials for electronics and optoelectronics applications.
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Affiliation(s)
- Yanxing Song
- State Key Discipline Laboratory of Wide BandGap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an, People's Republic of China
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10
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Beekman M, Kauzlarich SM, Doherty L, Nolas GS. Zintl Phases as Reactive Precursors for Synthesis of Novel Silicon and Germanium-Based Materials. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E1139. [PMID: 30965603 PMCID: PMC6479709 DOI: 10.3390/ma12071139] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/24/2019] [Accepted: 03/27/2019] [Indexed: 01/15/2023]
Abstract
Recent experimental and theoretical work has demonstrated significant potential to tune the properties of silicon and germanium by adjusting the mesostructure, nanostructure, and/or crystalline structure of these group 14 elements. Despite the promise to achieve enhanced functionality with these already technologically important elements, a significant challenge lies in the identification of effective synthetic approaches that can access metastable silicon and germanium-based extended solids with a particular crystal structure or specific nano/meso-structured features. In this context, the class of intermetallic compounds known as Zintl phases has provided a platform for discovery of novel silicon and germanium-based materials. This review highlights some of the ways in which silicon and germanium-based Zintl phases have been utilized as precursors in innovative approaches to synthesize new crystalline modifications, nanoparticles, nanosheets, and mesostructured and nanoporous extended solids with properties that can be very different from the ground states of the elements.
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Affiliation(s)
- Matt Beekman
- Department of Physics, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
| | - Susan M Kauzlarich
- Department of Chemistry, University of California, Davis, CA 95616, USA.
| | - Luke Doherty
- Department of Physics, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
- Department of Materials Engineering, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
| | - George S Nolas
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
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11
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Litvinchuk AP, Gavrilenko VI, Tang Z, Guloy AM. Optical properties and lattice dynamics of a novel allotrope of orthorhombic elemental germanium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:135401. [PMID: 30658348 DOI: 10.1088/1361-648x/aaffe9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Optical and vibrational properties of a novel allotrope of elemental germanium Ge(oP32), which crystallizes in the structure corresponding to the orthorhombic space group Pbcm, are studied experimentally by means of absorption and polarized Raman scattering measurements and theoretically using the first principles density functional theory. Material is found to be a direct band gap semiconductor with E g = 0.33 eV. Out of theoretically predicted 48 Raman-active modes, 27 are observed in the spectra and assigned to the specific lattice eigenmodes of the crystal based on their symmetry and a comparison with the results of first principles lattice dynamics calculations. Remarkably, the highest frequency vibration is observed at 316 cm-1, that is higher than the cubic crystalline [Formula: see text]-Ge mode at 300 cm-1. Exceptional sharpness of observed phonon lines (between 0.8 and 2.5 cm-1 at T = 10 K) implies excellent crystallinity of Ge(oP32) crystals.
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Affiliation(s)
- Alexander P Litvinchuk
- Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204-5002, United States of America
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12
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He C, Shi X, Clark SJ, Li J, Pickard CJ, Ouyang T, Zhang C, Tang C, Zhong J. Complex Low Energy Tetrahedral Polymorphs of Group IV Elements from First Principles. PHYSICAL REVIEW LETTERS 2018; 121:175701. [PMID: 30411915 DOI: 10.1103/physrevlett.121.175701] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Indexed: 06/08/2023]
Abstract
The energy landscape of carbon is exceedingly complex, hosting diverse and important metastable phases, including diamond, fullerenes, nanotubes, and graphene. Searching for structures, especially those with large unit cells, in this landscape is challenging. Here we use a combined stochastic search strategy employing two algorithms (ab initio random structure search and random sampling strategy combined with space group and graph theory) to apply connectivity constraints to unit cells containing up to 100 carbon atoms. We uncover three low energy carbon polymorphs (Pbam-32, P6/mmm, and I4[over ¯]3d) with new topologies, containing 32, 36, and 94 atoms in their primitive cells, respectively. Their energies relative to diamond are 96, 131, and 112 meV/atom, respectively, which suggests potential metastability. These three carbon allotropes are mechanically and dynamically stable, insulating carbon crystals with superhard mechanical properties. The I4[over ¯]3d structure possesses a direct band gap of 7.25 eV, which is the widest gap in the carbon allotrope family. Silicon, germanium, and tin versions of Pbam-32, P6/mmm, and I4[over ¯]3d also show energetic, dynamical, and mechanical stability. The computed electronic properties show that they are potential materials for semiconductor and photovoltaic applications.
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Affiliation(s)
- Chaoyu He
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - Xizhi Shi
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - S J Clark
- Durham University, Centre for Material Physics, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
| | - Jin Li
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - Chris J Pickard
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB30FS, United Kingdom
- Advanced Institute for Materials Research, Tohoku University 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
| | - Tao Ouyang
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - Chunxiao Zhang
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - Chao Tang
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - Jianxin Zhong
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105, People's Republic of China
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
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13
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You D, Xu C, Wang J, Su W, Zhang W, Zhao J, Qin F, Liu Y. Three-Dimensional Core-Shell Nanorod Arrays for Efficient Visible-Light Photocatalytic H 2 Production. ACS APPLIED MATERIALS & INTERFACES 2018; 10:35184-35193. [PMID: 30256090 DOI: 10.1021/acsami.8b11988] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Constructing heterostructured nanomaterials with integrating different functional materials into well-oriented nanoarchitectures is an efficacious tactic to obtain high-performance photocatalysts. In this paper, we fabricated three-dimensional ZnO-WS2@CdS core-shell nanorod arrays as visible-light-driven photocatalysts for efficient photocatalytic H2 production. This unique core-shell heterostructure extends visible-light absorption and provides more active sites. More importantly, the ZnO-WS2@CdS nanorod arrays build a beneficial energy level configuration and spatial structure to accelerate the generation, separation, and transfer of the photogenerated electron-hole. On the basis of the synergistic effects, the photocatalytic H2 rate of optimized ZnO-WS2@CdS nanorod arrays achieves 15.12 mmol h-1 g-1 in visible light irradiation, which is 39, 9, and 8 times higher than pure CdS, ZnO-CdS, and CdS-WS2 photocatalysts. The apparent quantum yield is up to 14.92% at 420 nm. Moreover, the core-shell heterostructure photocatalyst can recycle and maintain stability.
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Affiliation(s)
- Daotong You
- State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering , Southeast University , Nanjing 210096 , P. R. China
| | - Chunxiang Xu
- State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering , Southeast University , Nanjing 210096 , P. R. China
| | - Jing Wang
- State Key Laboratory of Photocatalysis on Energy and Environment , Fuzhou University , Fuzhou 350002 , P. R. China
| | - Wenyue Su
- State Key Laboratory of Photocatalysis on Energy and Environment , Fuzhou University , Fuzhou 350002 , P. R. China
| | - Wei Zhang
- State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering , Southeast University , Nanjing 210096 , P. R. China
| | - Jie Zhao
- State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering , Southeast University , Nanjing 210096 , P. R. China
| | - Feifei Qin
- State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering , Southeast University , Nanjing 210096 , P. R. China
| | - Yanjun Liu
- State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering , Southeast University , Nanjing 210096 , P. R. China
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14
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Tang Z, Litvinchuk AP, Gooch M, Guloy AM. Narrow Gap Semiconducting Germanium Allotrope from the Oxidation of a Layered Zintl Phase in Ionic Liquids. J Am Chem Soc 2018; 140:6785-6788. [PMID: 29782155 DOI: 10.1021/jacs.8b03503] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A metastable germanium allotrope, Ge(oP32), was synthesized as polycrystalline powders and single crystals from the mild-oxidation/delithiation of Li7Ge12 in ionic liquids. Its crystal structure, from single crystal X-ray diffraction ( Pbcm, a = 8.1527(4) Å, b = 11.7572(5) Å, c = 7.7617(4) Å), features a complex covalent network of 4-bonded Ge, resulting from a well-ordered topotactic oxidative condensation of [Ge12]7- layers. It is a diamagnetic semiconductor ( Eg = 0.33 eV), and transforms exothermically and irreversibly to α-Ge at 363 °C. This demonstrates the potential of ionic liquids as reactive media in the mild oxidation of Zintl phases to new highly crystallized modifications of elements and simple compounds.
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Affiliation(s)
- Zhongjia Tang
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States
| | - Alexander P Litvinchuk
- Department of Physics , University of Houston , Houston , Texas 77204-5005 , United States.,Texas Center for Superconductivity , University of Houston , Houston , Texas 77204-5002 , United States
| | - Melissa Gooch
- Department of Physics , University of Houston , Houston , Texas 77204-5005 , United States.,Texas Center for Superconductivity , University of Houston , Houston , Texas 77204-5002 , United States
| | - Arnold M Guloy
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States.,Texas Center for Superconductivity , University of Houston , Houston , Texas 77204-5002 , United States
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