1
|
Zhao R, Kang S, Wu C, Cheng Z, Xie Z, Liu Y, Zhang D. Designable Electrical/Thermal Coordinated Dual-Regulation Based on Liquid Metal Shape Memory Polymer Foam for Smart Switch. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205428. [PMID: 36658714 PMCID: PMC10015848 DOI: 10.1002/advs.202205428] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/01/2022] [Indexed: 06/17/2023]
Abstract
Electronic components with tunable resistance, especially with synergistic regulation of thermal conductivity, play important roles in the fields of electronics, smart switch, soft robots, and so on. However, it is still a challenge to get the material with various resistance and thermal conductivity stably without lasting external force. Herein, a liquid metal shape memory polymer foam (LM-SMF) is developed by loading electrically and thermally conductive liquid metal (LM) on deformable foam skeleton. Based on thermal response shape memory effect, the foam skeleton can be reversibly pressed, the process of which enables LM to transfer between connected and disconnected states. As a result, obtained LM-SMF shows that the resistance stably changes from 0.8 Ω (conductor) to 200 MΩ (insulator), and the thermal conductivity difference is up to 4.71 times (0.108 to 0.509 W m-1 K-1 ), which indicates that LM-SMF can achieve the electrical and thermal dual-regulation. Moreover, LM-SMF can be used as a designable self-feedback/-warning integrated smart switch or tunable infrared stealth switch. This work proposes a novel strategy to get the material with electrical-thermal coordinated dual-regulation, which is possibly applied in intelligent heating system with real-time monitoring function, electrothermal sensor in the future.
Collapse
Affiliation(s)
- Ruoxi Zhao
- School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Sibo Kang
- State Key Laboratory of Marine CoatingMarine Chemical Research Institute Co., Ltd.Qingdao266071P. R. China
| | - Chao Wu
- School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Zhongjun Cheng
- School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Zhimin Xie
- National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsHarbin Institute of TechnologyHarbin150080P. R. China
| | - Yuyan Liu
- School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Dongjie Zhang
- School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| |
Collapse
|
2
|
Hydrothermal Synthesis of Vanadium Oxide Microstructures with Mixed Oxidation States. REACTIONS 2022. [DOI: 10.3390/reactions4010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
This review is based on hydrothermal synthetic procedures that generate different vanadium oxide microstructures with mixed oxidation states, where different vanadium (V5+) precursors (vanadate, vanadium oxide, vanadium alkoxide, etc.,) are used to obtain various types of morphologies and shapes, such as sea urchins, cogs, stars, squares, etc., depending on the amphiphilic molecules (usually surfactants) exhibiting a structural director role containing an organic functional group such as primary amines and thiols, respectively. The performance of sol–gel methodology, where intercalation processes sometimes take place, is crucial prior to the hydrothermal treatment stage to control the V4+/V5+. In every synthesis, many physical and chemical parameters, such as temperature, pH, reaction time., etc., are responsible for influencing the reactions in order to obtain different products; the final material usually corresponds to a mixed oxidation state structure with different content rates. This feature has been used in many technological applications, and some researchers have enhanced it by functionalizing the products to enhance their electrochemical and magnetic properties. Although some results have been auspicious, there are a number of projects underway to improve the synthesis in many ways, including yield, secondary products, size distribution, oxidation state ratio, etc., to achieve the best benefits from these microstructures in the large number of technological, catalytic, and magnetic devices, among other applications.
Collapse
|
3
|
Wang P, Niu Y, Cao W, Zhang Y, Zhang M. First-Principles Study of the Effect of Native Defects on Spin Polarization and Exchange Coupling Interaction in Semimetal V 3O 4. ACS OMEGA 2020; 5:9442-9447. [PMID: 32363296 PMCID: PMC7191853 DOI: 10.1021/acsomega.0c00607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
We use first-principles calculations to investigate the mechanism of the effect of native defects on the spin polarization and exchange coupling interaction in the V3O4 semimetal material. Our results reveal that, in contrast to other neutral defects, V vacancy defects in V3O4 at A/B sites are in favor of higher spin polarization degrees and lower defect formation energies. Compared to ideal V3O4, the V vacancy defects at A/B sites cause slightly lower spin polarization degrees but much higher exchange coupling interactions. Our results suggest an effective route to mediate the spin polarization and exchange coupling by defect engineering, which promotes the applications of the V3O4 semimetal material in spintronics.
Collapse
Affiliation(s)
- Pan Wang
- Research
Center for Semiconductor Materials and Devices, Shaanxi University of Science and Technology, Xiʼan 710021, China
| | - Yong Niu
- Research
Center for Semiconductor Materials and Devices, Shaanxi University of Science and Technology, Xiʼan 710021, China
| | - Wenbin Cao
- Research
Center for Semiconductor Materials and Devices, Shaanxi University of Science and Technology, Xiʼan 710021, China
| | - Yunxia Zhang
- Research
Center for Semiconductor Materials and Devices, Shaanxi University of Science and Technology, Xiʼan 710021, China
| | - Mingzhe Zhang
- State
Key Laboratory of Superhard Materials, Jilin
University, Changchun 130012, China
| |
Collapse
|
4
|
Kim MW, Jo YR, Lee C, Moon WJ, Shim JH, Kim BJ. Ultrafast Infrared Photoresponse from Heavily Hydrogen-Doped VO 2 Single Crystalline Nanoparticles. NANO LETTERS 2020; 20:2733-2740. [PMID: 32109067 DOI: 10.1021/acs.nanolett.0c00358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Infrared photodetectors are sought for diverse applications and their performance relies on photoactive materials and photocurrent generation mechanisms. Here, we fabricate IR photodetectors with heavily hydrogen-doped VO2 (i.e., HVO2) single-crystalline nanoparticles which show two orders greater resistivities than pure VO2. The I-V plots obtained under IR light irradiation are expressed by space charge limited current mechanism and the increase in photocurrent occurs due to the increase in the number of photoinduced trap sites. This phenomenon remarkably improves the key parameters at λ = 780 nm of high responsivity of 35280 A/W, high detectivity of 1.12 × 1013 Jones, and strikingly fast response times of 0.6-2.5 ns, that is, 3 orders of magnitude faster than the best records of two-dimensional structures and heterostructures. Density functional theory calculations illustrate that the generation of photoinduced trap sites is attributed to the movement of hydrogen atoms to less stable interstitial sites in VO2 under light exposure.
Collapse
Affiliation(s)
- Min-Woo Kim
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Yong-Ryun Jo
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Changhoon Lee
- Department of Chemistry, Pohang University of Science and Technology(POSTECH), Pohang 790-784, Republic of Korea
| | - Won-Jin Moon
- Korea Basic Science Institute (KBSI), Gwangju Center, Gwangju 61186, Republic of Korea
| | - Ji Hoon Shim
- Department of Chemistry, Pohang University of Science and Technology(POSTECH), Pohang 790-784, Republic of Korea
| | - Bong-Joong Kim
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| |
Collapse
|
5
|
Calais T, Valdivia y Alvarado P. Advanced functional materials for soft robotics: tuning physicochemical properties beyond rigidity control. ACTA ACUST UNITED AC 2019. [DOI: 10.1088/2399-7532/ab4f9d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
6
|
Petel BE, Meyer RL, Maiola ML, Brennessel WW, Müller AM, Matson EM. Site-Selective Halogenation of Polyoxovanadate Clusters: Atomically Precise Models for Electronic Effects of Anion Doping in VO2. J Am Chem Soc 2019; 142:1049-1056. [DOI: 10.1021/jacs.9b11874] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
7
|
Zhang J, Cui R, Gao C, Bian L, Pu Y, Zhu X, Li X, Huang W. Cation-Modulated HER and OER Activities of Hierarchical VOOH Hollow Architectures for High-Efficiency and Stable Overall Water Splitting. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1904688. [PMID: 31544337 DOI: 10.1002/smll.201904688] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/07/2019] [Indexed: 06/10/2023]
Abstract
Atom-scale modulation of electronic regulation in nonprecious-based electrocatalysts is promising for efficient catalytic activities. Here, hierarchically hollow VOOH nanostructures are rationally constructed by partial iron substitution and systematically investigated for electrocatalytic water splitting. Benefiting from the hierarchically stable scaffold configuration, highly electrochemically active surface area, the synergistic effect of the active metal atoms, and optimal adsorption energies, the 3% Fe (mole ratio) substituted electrocatalyst (VOOH-3Fe) exhibits a low overpotential of 90 and 195 mV at 10 mA cm-2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media, respectively, superior than the other samples with a different substituted ratio. To the best of current knowledge, 195 mV overpotential at 10 mA cm-2 is the best value reported for V or Fe (oxy)hydroxide-based OER catalysts. Moreover, the electrolytic cell employing the VOOH-3Fe electrode as both the cathode and anode exhibits a cell voltage of 0.30 V at 10 mA cm-2 with a remarkable stability over 60 h. This work heralds a new pathway to design efficient bifunctional catalysts toward overall water splitting.
Collapse
Affiliation(s)
- Jian Zhang
- New Energy Technology Engineering Lab of Jiangsu Province, School of Science, Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
| | - Renjie Cui
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
| | - Chencheng Gao
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
| | - Linyi Bian
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
| | - Yong Pu
- New Energy Technology Engineering Lab of Jiangsu Province, School of Science, Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
| | - Xinbao Zhu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, P. R. China
| | - Xing'ao Li
- New Energy Technology Engineering Lab of Jiangsu Province, School of Science, Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
| | - Wei Huang
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing, 210023, P. R. China
- Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, Shaanxi, P. R. China
| |
Collapse
|
8
|
Wang H, Yao Y, He Z, Rao W, Hu L, Chen S, Lin J, Gao J, Zhang P, Sun X, Wang X, Cui Y, Wang Q, Dong S, Chen G, Liu J. A Highly Stretchable Liquid Metal Polymer as Reversible Transitional Insulator and Conductor. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901337. [PMID: 30972851 DOI: 10.1002/adma.201901337] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Indexed: 05/23/2023]
Abstract
Materials with a temperature-controlled reversible electrical transition between insulator and conductor are attracting huge attention due to their promising applications in many fields. However, most of them are intrinsically rigid and require complicated fabrication processes. Here, a highly stretchable (680% strain) liquid metal polymer composite as a reversible transitional insulator and conductor (TIC), which is accompanied with huge resistivity changes (more than 4 × 109 times) reversibly through a tuning temperature in a few seconds is introduced. When frozen, the insulated TIC becomes conductive and recovers after warming. Both the phase change of the liquid metal droplets and the rigidity change of the polymer contribute directly to transition between insulator and conductor. A simplified model is established to predict the expansion and connection of liquid metal droplets. Along with high stretchability, straightforward fabrication methods, rapid triggering time, large switching ratio, good repeatability, the TIC offers tremendous possibilities for numerous applications, like stretchable switches, semiconductors, temperature sensors, and resistive random-access memory. Accordingly, a system that can display numbers and letters via converting alternative TIC temperature to a binary signal on a computer is conceived and demonstrated. The present discovery suggests a general strategy for fabricating and stimulating a stretchable transitional insulator and conductor based on liquid metal and allied polymers.
Collapse
Affiliation(s)
- Hongzhang Wang
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Youyou Yao
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Zhizhu He
- Department of Vehicle Engineering, College of Engineering, China Agricultural University, Beijing, 100083, China
| | - Wei Rao
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liang Hu
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Sen Chen
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ju Lin
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Jianye Gao
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Pengju Zhang
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xuyang Sun
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiangjiang Wang
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Yuntao Cui
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Qian Wang
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shijin Dong
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guozhen Chen
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Jing Liu
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
- Beijing Key Lab of Cryobiomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| |
Collapse
|
9
|
Mukherjee D, Dey A, Mary Esther AC, Sridhara N, Kumar DR, Rajendra A, Sharma AK, Mukhopadhyay AK. Reversible and repeatable phase transition at a negative temperature regime for doped and co-doped spin coated mixed valence vanadium oxide thin films. RSC Adv 2018; 8:30966-30977. [PMID: 35559364 PMCID: PMC9088514 DOI: 10.1039/c8ra04957b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 08/20/2018] [Indexed: 11/23/2022] Open
Abstract
Smooth, uniform mixed valance vanadium oxide (VO) thin films are grown on flexible, transparent Kapton and opaque Al6061 substrates by the spin coating technique at a constant rpm of 3000. Various elements e.g., F, Ti, Mo and W are utilized for doping and co-doping of VO. All the spin coated films are heat treated in a vacuum. Other than the doping elements the existence of only V4+ and V5+ species is noticed in the present films. Transmittance as a function of wavelength and the optical band gap are also investigated for doped and co-doped VO thin films grown on a Kapton substrate. The highest transparency (∼75%) is observed for the Ti, Mo and F (i.e., Ti–Mo–FVO) co-doped VO system while the lowest transparency (∼35%) is observed for the F (i.e., FVO) doped VO system. Thus, the highest optical band gap is estimated as 2.73 eV for Ti–Mo–FVO and the lowest optical band gap (i.e., 2.59 eV) is found for the FVO system. The temperature dependent phase transition characteristics of doped and co-doped VO films on both Kapton and Al6061 are studied by the differential scanning calorimetry (DSC) technique. Reversible and repeatable phase transition is noticed in the range of −24 to −26.3 °C. Smooth, uniform mixed valance vanadium oxide (VO) thin films are grown on flexible, transparent Kapton and opaque Al6061 substrates by the spin coating technique at a constant rpm of 3000.![]()
Collapse
Affiliation(s)
- Dipta Mukherjee
- Advanced Mechanical and Materials Characterization Division, CSIR-Central Glass and Ceramic Research Institute Kolkata-700 032 India +91 33 2473 3469/76/77/96
| | - Arjun Dey
- Thermal Systems Group, U. R. Rao Satellite Centre (Formarly Known as ISRO Satellite Centre) Bangalore-560 017 India +91 80 2508 3203 +91 80 2508 3214
| | - A Carmel Mary Esther
- Thermal Systems Group, U. R. Rao Satellite Centre (Formarly Known as ISRO Satellite Centre) Bangalore-560 017 India +91 80 2508 3203 +91 80 2508 3214
| | - N Sridhara
- Thermal Systems Group, U. R. Rao Satellite Centre (Formarly Known as ISRO Satellite Centre) Bangalore-560 017 India +91 80 2508 3203 +91 80 2508 3214
| | - D Raghavendra Kumar
- Thermal Systems Group, U. R. Rao Satellite Centre (Formarly Known as ISRO Satellite Centre) Bangalore-560 017 India +91 80 2508 3203 +91 80 2508 3214
| | - A Rajendra
- Thermal Systems Group, U. R. Rao Satellite Centre (Formarly Known as ISRO Satellite Centre) Bangalore-560 017 India +91 80 2508 3203 +91 80 2508 3214
| | - Anand Kumar Sharma
- Thermal Systems Group, U. R. Rao Satellite Centre (Formarly Known as ISRO Satellite Centre) Bangalore-560 017 India +91 80 2508 3203 +91 80 2508 3214
| | - Anoop Kumar Mukhopadhyay
- Advanced Mechanical and Materials Characterization Division, CSIR-Central Glass and Ceramic Research Institute Kolkata-700 032 India +91 33 2473 3469/76/77/96
| |
Collapse
|
10
|
Ojelere O, Graf D, Ludwig T, Vogt N, Klein A, Mathur S. Reductive transformation of V(iii) precursors into vanadium(ii) oxide nanowires. Dalton Trans 2018; 47:6842-6849. [PMID: 29725681 DOI: 10.1039/c8dt00848e] [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
Vanadium(ii) oxide nanostructures are promising materials for supercapacitors and electrocatalysis because of their excellent electrochemical properties and high surface area. In this study, new homoleptic vanadium(iii) complexes with bi-dentate O,N-chelating heteroarylalkenol ligands (DmoxCH[double bond, length as m-dash]COCF3, PyCH[double bond, length as m-dash]COCF3 and PyN[double bond, length as m-dash]COCF3) were synthesized and successfully transformed by reductive conversion into VO nanowires. The chemical identity of V(iii) complexes and their redox behaviour were unambiguously established by single crystal X-ray diffraction studies, cyclic voltammetry, spectrometric studies and DFT calculations. Transformation into the metastable VO phase was verified by powder X-ray diffraction and thermo-gravimetry. Transmission electron microscopy and X-ray photoelectron spectroscopy data confirmed the morphology and chemical composition of VO nanostructures, respectively.
Collapse
Affiliation(s)
- Olusola Ojelere
- Institute of Inorganic Chemistry, University of Cologne, Greinstraße 6, D-50939 Cologne, Germany.
| | | | | | | | | | | |
Collapse
|
11
|
Émond N, Torriss B, Chaker M. Natural and induced growth of VO 2 (M) on VO 2 (B) ultrathin films. Sci Rep 2018; 8:7153. [PMID: 29740103 PMCID: PMC5940801 DOI: 10.1038/s41598-018-25656-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/24/2018] [Indexed: 11/16/2022] Open
Abstract
This work examines the synthesis of single phase VO2 (B) thin films on LaAlO3 (100) substrates, and the naturally-occurring and induced subsequent growth of VO2 (M) phase on VO2 (B) films. First, the thickness (t) dependence of structural, morphological and electrical properties of VO2 films is investigated, evidencing that the growth of VO2 (B) phase is progressively replaced by that of VO2 (M) when t > ~11 nm. This change originates from the relaxation of the substrate-induced strain in the VO2 (B) films, as corroborated by the simultaneous increase of surface roughness and decrease of the c-axis lattice parameter towards that of bulk VO2 (B) for such films, yielding a complex mixed-phase structure composed of VO2 (B)/VO2 (M) phases, accompanied by the emergence of the VO2 (M) insulator-to-metal phase transition. Second, the possibility of inducing this phase conversion, through a proper surface modification of the VO2 (B) films via plasma treatment, is demonstrated. These natural and induced VO2 (M) growths not only provide substantial insights into the competing nature of phases in the complex VO2 polymorphs system, but can also be further exploited to synthesize VO2 (M)/VO2 (B) heterostructures at the micro/nanoscale for advanced electronics and energy applications.
Collapse
Affiliation(s)
- Nicolas Émond
- INRS-Énergie, Matériaux et Télécommunications, 1650, Boulevard Lionel Boulet, Varennes, Québec, J3X 1S2, Canada
| | - Badr Torriss
- INRS-Énergie, Matériaux et Télécommunications, 1650, Boulevard Lionel Boulet, Varennes, Québec, J3X 1S2, Canada
| | - Mohamed Chaker
- INRS-Énergie, Matériaux et Télécommunications, 1650, Boulevard Lionel Boulet, Varennes, Québec, J3X 1S2, Canada.
| |
Collapse
|
12
|
Li M, Magdassi S, Gao Y, Long Y. Hydrothermal Synthesis of VO 2 Polymorphs: Advantages, Challenges and Prospects for the Application of Energy Efficient Smart Windows. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1701147. [PMID: 28722273 DOI: 10.1002/smll.201701147] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 06/03/2017] [Indexed: 06/07/2023]
Abstract
Vanadium dioxide (VO2 ) is a widely studied inorganic phase change material, which has a reversible phase transition from semiconducting monoclinic to metallic rutile phase at a critical temperature of τc ≈ 68 °C. The abrupt decrease of infrared transmittance in the metallic phase makes VO2 a potential candidate for thermochromic energy efficient windows to cut down building energy consumption. However, there are three long-standing issues that hindered its application in energy efficient windows: high τc , low luminous transmittance (Tlum ), and undesirable solar modulation ability (ΔTsol ). Many approaches, including nano-thermochromism, porous films, biomimetic surface reconstruction, gridded structures, antireflective overcoatings, etc, have been proposed to tackle these issues. The first approach-nano-thermochromism-which is to integrate VO2 nanoparticles in a transparent matrix, outperforms the rest; while the thermochromic performance is determined by particle size, stoichiometry, and crystallinity. A hydrothermal method is the most common method to fabricate high-quality VO2 nanoparticles, and has its own advantages of large-scale synthesis and precise phase control of VO2 . This Review focuses on hydrothermal synthesis, physical properties of VO2 polymorphs, and their transformation to thermochromic VO2 (M), and discusses the advantages, challenges, and prospects of VO2 (M) in energy-efficient smart windows application.
Collapse
Affiliation(s)
- Ming Li
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Shlomo Magdassi
- Institute of Chemistry, The Hebrew University, Edmond Safra Campus, Jerusalem, 91904, Israel
| | - Yanfeng Gao
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China
| | - Yi Long
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| |
Collapse
|
13
|
Wang C, Zhao Y, Ximei Z, Su D, Ding C, Li J, Jin H. The effect of the phase structure on physicochemical properties of TMO materials: a case of spinel to bunsenite. CrystEngComm 2017. [DOI: 10.1039/c7ce01491k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is worthwhile to comprehensively investigate the relationship between different phase structures and physicochemical properties of TMO materials.
Collapse
Affiliation(s)
- Chengzhi Wang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| | - Yongjie Zhao
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| | - Zhai Ximei
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| | - Dezhi Su
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| | - Caihua Ding
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| | - Jingbo Li
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| | - Haibo Jin
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications
- School of Materials Science and Engineering
- Beijing Institute of Technology
- Beijing 100081
- PR China
| |
Collapse
|
14
|
Liang HP, Du J, Jones TGJ, Lawrence NS, Meredith AW. Large-Scale Production of V 6O 13 Cathode Materials Assisted by Thermal Gravimetric Analysis-Infrared Spectroscopy Technology. ACS APPLIED MATERIALS & INTERFACES 2016; 8:25674-25679. [PMID: 27661096 DOI: 10.1021/acsami.6b10832] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The kilogram-scale fabrication of V6O13 cathode materials has been notably assisted by in situ thermal gravimetric analysis (TGA)-infrared spectroscopy (IR) technology. This technology successfully identified a residue of ammonium metavanadate in commercial V6O13, which is consistent with the X-ray photoelectron spectroscopy result. Samples of V6O13 materials have been fabricated and characterized by TGA-IR, scanning electron microscopy, and X-ray diffraction. The initial testing results at 125 °C have shown that test cells containing the sample prepared at 500 °C show up to a 10% increase in the initial specific capacity in comparison with commercial V6O13.
Collapse
Affiliation(s)
- Han-Pu Liang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, China
| | - Jian Du
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao 266101, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Timothy G J Jones
- Schlumberger Cambridge Research , High Cross, Madingley Road, Cambridge CB3 0EL, U.K
| | - Nathan S Lawrence
- Schlumberger Cambridge Research , High Cross, Madingley Road, Cambridge CB3 0EL, U.K
| | - Andrew W Meredith
- Schlumberger Cambridge Research , High Cross, Madingley Road, Cambridge CB3 0EL, U.K
| |
Collapse
|
15
|
Thickness-Induced Metal-Insulator Transition in Sb-doped SnO2 Ultrathin Films: The Role of Quantum Confinement. Sci Rep 2015; 5:17424. [PMID: 26616286 PMCID: PMC4663506 DOI: 10.1038/srep17424] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 10/29/2015] [Indexed: 11/21/2022] Open
Abstract
A thickness induced metal-insulator transition (MIT) was firstly observed in Sb-doped SnO2 (SnO2:Sb) epitaxial ultrathin films deposited on sapphire substrates by pulsed laser deposition. Both electrical and spectroscopic studies provide clear evidence of a critical thickness for the metallic conductivity in SnO2:Sb thin films and the oxidation state transition of the impurity element Sb. With the shrinkage of film thickness, the broadening of the energy band gap as well as the enhancement of the impurity activation energy was studied and attributed to the quantum confinement effect. Based on the scenario of impurity level pinning and band gap broadening in quantum confined nanostructures, we proposed a generalized energy diagram to understand the thickness induced MIT in the SnO2:Sb system.
Collapse
|
16
|
Lourembam J, Srivastava A, La-o-vorakiat C, Rotella H, Venkatesan T, Chia EEM. New insights into the diverse electronic phases of a novel vanadium dioxide polymorph: a terahertz spectroscopy study. Sci Rep 2015; 5:9182. [PMID: 25777320 PMCID: PMC4361872 DOI: 10.1038/srep09182] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/23/2015] [Indexed: 11/08/2022] Open
Abstract
A remarkable feature of vanadium dioxide is that it can be synthesized in a number of polymorphs. The conductivity mechanism in the metastable layered polymorph VO2(B) thin films has been investigated by terahertz time-domain spectroscopy (THz-TDS). In VO2(B), a critical temperature of 240 K marks the appearance of a non-zero Drude term in the observed complex conductivity, indicating the evolution from a pure insulating state towards a metallic state. In contrast, the THz conductivity of the well-known VO2(M1) is well fitted only by a modification of the Drude model to include backscattering. We also identified two different THz conductivity regimes separated by temperature in these two polymorphs. The electronic phase diagram is constructed, revealing that the width and onset of the metal-insulator transition in the B phase develop differently from the M1 phase.
Collapse
Affiliation(s)
- James Lourembam
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Amar Srivastava
- NUSNNI-Nanocore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Chan La-o-vorakiat
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - H. Rotella
- NUSNNI-Nanocore, National University of Singapore, Singapore 117411, Singapore
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603
| | - T. Venkatesan
- NUSNNI-Nanocore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Elbert E. M. Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| |
Collapse
|
17
|
Qian X, Wang N, Li Y, Zhang J, Xu Z, Long Y. Bioinspired multifunctional vanadium dioxide: improved thermochromism and hydrophobicity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10766-71. [PMID: 25164486 DOI: 10.1021/la502787q] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Vanadium dioxide (VO2) films with moth-eye nanostructures have been fabricated to enhance the thermochromic properties with different periodicity (d) to achieve antireflection (AR). It is revealed that the films with smaller d (210 and 440 nm) could increase both the luminous transmission (Tlum) and infrared transmission (TIR) at 25 and 90 °C, as the d is smaller than the given wavelength and the gradient refractive index produces antireflection. The average Tlum and TIR of VO2 increase with decreasing d. Compared with the planar film, the AR sample with periodicity of 210 nm and thickness of 140 nm can offer approximately 10% enhancement of Tlum and 24.5% increase in solar modulation (ΔTsol). With the addition of hydrophobic overcoat on the patterned VO2, ∼120° contact angle could be achieved. The present approach can tailor the optical transmittance in different wavelengths at high and low temperature together with self-cleaning, opening new avenues for producing hydrophobic VO2 with enhanced thermochromic properties for smart window applications.
Collapse
Affiliation(s)
- Xukun Qian
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
| | | | | | | | | | | |
Collapse
|
18
|
Li XZ, Wu KL, Ye Y, Wei XW. Controllable synthesis of Ni nanotube arrays and their structure-dependent catalytic activity toward dye degradation. CrystEngComm 2014. [DOI: 10.1039/c4ce00225c] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ni nanotube (nanorod) arrays are controllably fabricated by a one-step approach, the GDDATG and DDCG growth mechanisms are introduced. The Ni nanostructures present higher catalytic activities for dye degradation, the relationship between structures and catalytic properties is also studied.
Collapse
Affiliation(s)
- Xiang-Zi Li
- Department of Chemistry
- Wannan Medical College
- 241002 Wuhu, China
- College of Chemistry and Materials Science
- Key Laboratory of Functional Molecular Solids
| | - Kong-Lin Wu
- College of Chemistry and Materials Science
- Key Laboratory of Functional Molecular Solids
- The Ministry of Education
- Anhui Laboratory of Molecule-Based Materials
- Anhui Normal University
| | - Yin Ye
- College of Chemistry and Materials Science
- Key Laboratory of Functional Molecular Solids
- The Ministry of Education
- Anhui Laboratory of Molecule-Based Materials
- Anhui Normal University
| | - Xian-Wen Wei
- College of Chemistry and Materials Science
- Key Laboratory of Functional Molecular Solids
- The Ministry of Education
- Anhui Laboratory of Molecule-Based Materials
- Anhui Normal University
| |
Collapse
|
19
|
Sun PC, Wu YL, Gao JW, Cheng GA, Chen G, Zheng RT. Room temperature electrical and thermal switching CNT/hexadecane composites. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:4938-4943. [PMID: 23857730 DOI: 10.1002/adma.201302165] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Indexed: 06/02/2023]
Abstract
A large contrast in the electrical and thermal conductivities via a first order phase transition in surface-functionalized carbon nanotube(CNT)/hexadecane composites is reported. Surface modification of the CNTs improves the electrical conductivity contrast and the stability of the composites. We demonstrate that, with these composites, the electrical conductivity changes above 10(5) times and the thermal conductivity varies up to 3 times at 18 °C.
Collapse
Affiliation(s)
- P C Sun
- Key Laboratory of Radiation Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, P. R. China
| | | | | | | | | | | |
Collapse
|
20
|
Kim H, Kim Y, Kim KS, Jeong HY, Jang AR, Han SH, Yoon DH, Suh KS, Shin HS, Kim T, Yang WS. Flexible thermochromic window based on hybridized VO2/graphene. ACS NANO 2013; 7:5769-5776. [PMID: 23758656 DOI: 10.1021/nn400358x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Large-scale integration of vanadium dioxide (VO2) on mechanically flexible substrates is critical to the realization of flexible smart window films that can respond to environmental temperatures to modulate light transmittance. Until now, the formation of highly crystalline and stoichiometric VO2 on flexible substrate has not been demonstrated due to the high-temperature condition for VO2 growth. Here, we demonstrate a VO2-based thermochromic film with unprecedented mechanical flexibility by employing graphene as a versatile platform for VO2. The graphene effectively functions as an atomically thin, flexible, yet robust support which enables the formation of stoichiometric VO2 crystals with temperature-driven phase transition characteristics. The graphene-supported VO2 was capable of being transferred to a plastic substrate, forming a new type of flexible thermochromic film. The flexible VO2 films were then integrated into the mock-up house, exhibiting its efficient operation to reduce the in-house temperature under infrared irradiation. These results provide important progress for the fabrication of flexible thermochromic films for energy-saving windows.
Collapse
Affiliation(s)
- Hyeongkeun Kim
- Electronic Materials and Device Research Center, Korea Electronics Technology Institute, Gyeonggi-do 463-816, Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Zhou M, Bao J, Tao M, Zhu R, Lin Y, Zhang X, Xie Y. Periodic porous thermochromic VO2(M) films with enhanced visible transmittance. Chem Commun (Camb) 2013; 49:6021-3. [DOI: 10.1039/c3cc42112k] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
22
|
Wu C, Feng F, Xie Y. Design of vanadium oxide structures with controllable electrical properties for energy applications. Chem Soc Rev 2013; 42:5157-83. [DOI: 10.1039/c3cs35508j] [Citation(s) in RCA: 347] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
23
|
Xiao C, Qin X, Zhang J, An R, Xu J, Li K, Cao B, Yang J, Ye B, Xie Y. High thermoelectric and reversible p-n-p conduction type switching integrated in dimetal chalcogenide. J Am Chem Soc 2012; 134:18460-6. [PMID: 23066707 DOI: 10.1021/ja308936b] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The subject of the involved phase transition in solid materials has formed not only the basis of materials technology but also the central issue of solid-state chemistry for centuries. The ability to design and control the required changes in physical properties within phase transition becomes key prerequisite for the modern functionalized materials. Herein, we have experimentally achieved the high thermoelectric performance (ZT value reaches 1.5 at 700 K) and reversible p-n-p semiconducting switching integrated in a dimetal chalcogenide, AgBiSe(2) during the continuous hexagonal-rhombohedral-cubic phase transition. The clear-cut evidences in temperature-dependent positron annihilation and Raman spectra confirmed that the p-n-p switching is derived from the bimetal atoms exchange within phase transition, whereas the full disordering of bimetal atoms after the bimetal exchange results in the high thermoelectric performance. The combination of p-n-p switching and high thermoelectric performance enables the dimetal chalcogenides perfect candidates for novel multifunctional electronic devices. The discovery of bimetal atoms exchange during the phase transition brings novel phenomena with unusual properties which definitely enrich solid-state chemistry and materials science.
Collapse
Affiliation(s)
- Chong Xiao
- Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei, Anhui, 230026, P. R. China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Quantum tunneling of magnetization in ultrasmall half-metallic V3O4 quantum dots: displaying quantum superparamagnetic state. Sci Rep 2012; 2:755. [PMID: 23091695 PMCID: PMC3477649 DOI: 10.1038/srep00755] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/06/2012] [Indexed: 11/08/2022] Open
Abstract
Quantum tunneling of magnetization (QTMs), stemming from their importance for understanding materials with unconventional properties, has continued to attract widespread theoretical and experimental attention. However, the observation of QTMs in the most promising candidates of molecular magnets and few iron-based compounds is limited to very low temperature. Herein, we first highlight a simple system, ultrasmall half-metallic V(3)O(4) quantum dots, as a promising candidate for the investigation of QTMs at high temperature. The quantum superparamagnetic state (QSP) as a high temperature signature of QTMs is observed at 16 K, which is beyond absolute zero temperature and much higher than that of conventional iron-based compounds due to the stronger spin-orbital coupling of V(3+) ions bringing high anisotropy energy. It is undoubtedly that this ultrasmall quantum dots, V(3)O(4), offers not only a promising candidate for theoretical understanding of QTMs but also a very exciting possibility for computers using mesoscopic magnets.
Collapse
|
25
|
Yao T, Zhang X, Sun Z, Liu S, Huang Y, Xie Y, Wu C, Yuan X, Zhang W, Wu Z, Pan G, Hu F, Wu L, Liu Q, Wei S. Understanding the nature of the kinetic process in a VO2 metal-insulator transition. PHYSICAL REVIEW LETTERS 2010; 105:226405. [PMID: 21231405 DOI: 10.1103/physrevlett.105.226405] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Indexed: 05/30/2023]
Abstract
Understanding the kinetics during the metal-insulator transition process is crucial to sort out the underlying physical nature of electron-lattice interactions in correlated materials. Here, based on the temperature-dependent in situ x-ray absorption fine structure measurement and density-functional theory calculations, we have revealed that the monoclinic-to-tetragonal phase transition of VO2 near the critical temperature is characterized by a sharp decrease of the twisting angle δ of the nearest V-V coordination. The VO2 metallization occurs in the intermediate monoclinic like structure with a large twist of V-V pairs when the δ angle is smaller than 1.4°. The correlation between structural kinetics and electronic structure points out that the structural rearrangement is a key factor to narrow the insulating band gap.
Collapse
Affiliation(s)
- Tao Yao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|