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Di Trolio A, Testa AM, Amore Bonapasta A. Ferromagnetic Behavior and Magneto-Optical Properties of Semiconducting Co-Doped ZnO. NANOMATERIALS 2022; 12:nano12091525. [PMID: 35564236 PMCID: PMC9104787 DOI: 10.3390/nano12091525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/21/2022] [Accepted: 04/27/2022] [Indexed: 02/06/2023]
Abstract
ZnO is a well-known semiconducting material showing a wide bandgap and an n-type intrinsic behavior of high interest in applications such as transparent electronics, piezoelectricity, optoelectronics, and photovoltaics. This semiconductor becomes even more attractive when doped with a few atomic percent of a transition metal. Indeed, e.g., the introduction of substitutional Co atoms in ZnO (ZCO) induces the appearance of room temperature ferromagnetism (RT-FM) and magneto-optical effects, making this material one of the most important representatives of so-called dilute magnetic semiconductors (DMSs). In the present review, we discuss the magnetic and magneto-optical properties of Co-doped ZnO thin films by considering also the significant improvements in the properties induced by post-growth irradiation with atomic hydrogen. We also show how all of these properties can be accounted for by a theoretical model based on the formation of Co-VO (oxygen vacancy) complexes and the concurrent presence of shallow donor defects, thus giving a sound support to this model to explain the RT-FM in ZCO DMSs.
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Affiliation(s)
- Antonio Di Trolio
- CNR-Istituto di Struttura della Materia, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
- Correspondence:
| | - Alberto M. Testa
- CNR-Istituto di Struttura della Materia, Via Salaria Km. 29,300, 00015 Monterotondo, Italy; (A.M.T.); (A.A.B.)
| | - Aldo Amore Bonapasta
- CNR-Istituto di Struttura della Materia, Via Salaria Km. 29,300, 00015 Monterotondo, Italy; (A.M.T.); (A.A.B.)
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Zhang Z, Hao J, Lu Y, Xu Y, Li L, Shi W. Ink-Assisted Synthetic Strategy for Stable and Advanced Composite Electrocatalysts with Single Fe Sites. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2006113. [PMID: 33258294 DOI: 10.1002/smll.202006113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/10/2020] [Indexed: 06/12/2023]
Abstract
The oxygen evolution reaction is critical to the efficiency of many energy technologies that store renewable electricity in chemical form. However, the rational design of high-performance and stable catalysts to drive this reaction remains a formidable challenge. Here, a facile ink-assisted strategy to construct a series of stable and advanced composite electrocatalysts with single Fe sites for permitting seriously improved performance characteristics is reported. As revealed by a suit of characterization techniques and theoretical methods, the improved electrocatalytic performance and stability can be attributed to the unique coordination states of Fe in the form of distorted FeO4 C and the interfacial effect in the composite system that optimize and stabilize single Fe sites in changing to better configurations for intermediates adsorption. The findings provide a novel strategy to in-depth understanding of practical guidelines for the electrocatalyst design for energy conversion devices.
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Affiliation(s)
- Zhengyuan Zhang
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Jinhui Hao
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yahui Lu
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yuqi Xu
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Longhua Li
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Weidong Shi
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
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Wang C, Xie H, Chen S, Ge B, Liu D, Wu C, Xu W, Chu W, Babu G, Ajayan PM, Song L. Atomic Cobalt Covalently Engineered Interlayers for Superior Lithium-Ion Storage. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802525. [PMID: 29939441 DOI: 10.1002/adma.201802525] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/14/2018] [Indexed: 06/08/2023]
Abstract
With the unique-layered structure, MXenes show potential as electrodes in energy-storage devices including lithium-ion (Li+ ) capacitors and batteries. However, the low Li+ -storage capacity hinders the application of MXenes in place of commercial carbon materials. Here, the vanadium carbide (V2 C) MXene with engineered interlayer spacing for desirable storage capacity is demonstrated. The interlayer distance of pristine V2 C MXene is controllably tuned to 0.735 nm resulting in improved Li-ion capacity of 686.7 mA h g-1 at 0.1 A g-1 , the best MXene-based Li+ -storage capacity reported so far. Further, cobalt ions are stably intercalated into the interlayer of V2 C MXene to form a new interlayer-expanded structure via strong V-O-Co bonding. The intercalated V2 C MXene electrodes not only exhibit superior capacity up to 1117.3 mA h g-1 at 0.1 A g-1 , but also deliver a significantly ultralong cycling stability over 15 000 cycles. These results clearly suggest that MXene materials with an engineered interlayer distance will be a rational route for realizing them as superstable and high-performance Li+ capacitor electrodes.
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Affiliation(s)
- Changda Wang
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Hui Xie
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Shuangming Chen
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Binghui Ge
- Beijing National Laboratory for Condensed Mater Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Daobin Liu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Chuanqiang Wu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Wenjie Xu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Wangsheng Chu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Ganguli Babu
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Pulickel M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Li Song
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
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Formation of ferromagnetic Co-H-Co complex and spin-polarized conduction band in Co-doped ZnO. Sci Rep 2017; 7:11101. [PMID: 28894141 PMCID: PMC5593988 DOI: 10.1038/s41598-017-11078-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 08/15/2017] [Indexed: 12/02/2022] Open
Abstract
Magnetic oxide semiconductors with wide band gaps have promising spintronic applications, especially in the case of magneto-optic devices. Co-doped ZnO (ZnCoO) has been considered for these applications, but the origin of its ferromagnetism has been controversial for several decades and no substantial progress for a practical application has been made to date. In this paper, we present direct evidence of hydrogen-mediated ferromagnetism and spin polarization in the conduction band of ZnCoO. Electron density mapping reveals the formation of Co–H–Co, in agreement with theoretical predictions. Electron spin resonance measurement elucidates the ferromagnetic nature of ZnCoO by the formation of Co–H–Co. We provide evidence from magnetic circular dichroism measurements supporting the hypothesis that Co–H–Co contributes to the spin polarization of the conduction band of hydrogen-doped ZnCoO.
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Lu YH, Lin WH, Yang CY, Chiu YH, Pu YC, Lee MH, Tseng YC, Hsu YJ. A facile green antisolvent approach to Cu2+-doped ZnO nanocrystals with visible-light-responsive photoactivities. NANOSCALE 2014; 6:8796-803. [PMID: 24954742 DOI: 10.1039/c4nr01607f] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
An environmentally benign antisolvent method has been developed to prepare Cu(2+)-doped ZnO nanocrystals with controllable dopant concentrations. A room temperature ionic liquid, known as a deep eutectic solvent (DES), was used as the solvent to dissolve ZnO powders. Upon the introduction of the ZnO-containing DES into a bad solvent which shows no solvation to ZnO, ZnO was precipitated and grown due to the dramatic decrease of solubility. By adding Cu(2+) ions to the bad solvent, the growth of ZnO from the antisolvent process was accompanied by Cu(2+) introduction, resulting in the formation of Cu(2+)-doped ZnO nanocrystals. The as-prepared Cu(2+)-doped ZnO showed an additional absorption band in the visible range (400-800 nm), which conduced to an improvement in the overall photon harvesting efficiency. Time-resolved photoluminescence spectra, together with the photovoltage information, suggested that the doped Cu(2+) may otherwise trap photoexcited electrons during the charge transfer process, inevitably depressing the photoconversion efficiency. The photoactivity of Cu(2+)-doped ZnO nanocrystals for photoelectrochemical water oxidation was effectively enhanced in the visible region, which achieved the highest at 2.0 at% of Cu(2+). A further increase in the Cu(2+) concentration however led to a decrease in the photocatalytic performance, which was ascribed to the significant carrier trapping caused by the increased states given by excessive Cu(2+). The photocurrent action spectra illustrated that the enhanced photoactivity of the Cu(2+)-doped ZnO nanocrystals was mainly due to the improved visible photon harvesting achieved by Cu(2+) doping. These results may facilitate the use of transition metal ion-doped ZnO in other photoconversion applications, such as ZnO based dye-sensitized solar cells and magnetism-assisted photocatalytic systems.
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Affiliation(s)
- Yi-Hsuan Lu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan 30010, Republic of China.
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Huang W, Zhou J, Li B, Ma J, Tao S, Xia D, Chu W, Wu Z. Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries. Sci Rep 2014; 4:4188. [PMID: 24595232 PMCID: PMC3942702 DOI: 10.1038/srep04188] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/17/2014] [Indexed: 01/08/2023] Open
Abstract
Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V.
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Affiliation(s)
- Weifeng Huang
- 1] National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China [2] Key lab of theory and technology for advanced batteries materials, College of Engineering, Peking University, Beijing 100871, P. R. China [3] Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jing Zhou
- Chinese Academy of Sciences, Shanghai Institute Applied Physics, Shanghai 201204, P. R. China
| | - Biao Li
- Key lab of theory and technology for advanced batteries materials, College of Engineering, Peking University, Beijing 100871, P. R. China
| | - Jin Ma
- Key lab of theory and technology for advanced batteries materials, College of Engineering, Peking University, Beijing 100871, P. R. China
| | - Shi Tao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Dingguo Xia
- Key lab of theory and technology for advanced batteries materials, College of Engineering, Peking University, Beijing 100871, P. R. China
| | - Wangsheng Chu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Ziyu Wu
- 1] National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China [2] Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
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Yan W, Liu Q, Wang C, Yang X, Yao T, He J, Sun Z, Pan Z, Hu F, Wu Z, Xie Z, Wei S. Realizing Ferromagnetic Coupling in Diluted Magnetic Semiconductor Quantum Dots. J Am Chem Soc 2014; 136:1150-5. [DOI: 10.1021/ja411900w] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wensheng Yan
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Qinghua Liu
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Chao Wang
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Xiaoyu Yang
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Tao Yao
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Jingfu He
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Zhihu Sun
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Zhiyun Pan
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Fengchun Hu
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Ziyu Wu
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Zhi Xie
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Shiqiang Wei
- National Synchrotron Radiation
Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
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Pham A, Zhang YB, Assadi MHN, Yu AB, Li S. Ferromagnetism in ZnO:Co originating from a hydrogenated Co-O-Co complex. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:116002. [PMID: 23406681 DOI: 10.1088/0953-8984/25/11/116002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The effects of hydrogen interstitials and oxygen vacancies on the overall ferromagnetic behaviour of Co doped ZnO (ZnO:Co) have been closely examined using different density functional calculations. The results demonstrate the importance of correcting the bandgap problem of the ZnO host as well as the lack of correlation in Co's 3d states which can severely affect the coupling of H and Co's impurity bands. Our results show that in hydrogenated ZnO:Co, hydrogen interstitial can also stabilize the ferromagnetic interaction at low Co concentrations, but this requires the formation of the in-plane O-H-Co-O-Co complex. In this structure, the hydrogen interstitial forms an anionic complex with the neighbouring oxygen, which polarizes the surrounding oxygen to mediate the ferromagnetism through the superexchange mechanism. An oxygen vacancy by itself would not cause ferromagnetism in ZnO:Co. On the other hand, in the presence of hydrogen interstitials, oxygen vacancies can significantly enhance the magnetic coupling between H and Co-O-Co as a shallow donor if it is far away from the in-plane O-H-Co-O-Co complex. However, the total energy results show that this is much more favoured when the oxygen vacancy is near the in-plane O-H-Co-O-Co complex, which can inhibit the ferromagnetic interaction between Co ions.
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Affiliation(s)
- Anh Pham
- School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Ning J, Xiao G, Wang C, Liu B, Zou G, Zou B. Synthesis of doped zinc blende-phase InSe:M (M = Fe and Co) nanocrystals for diluted magnetic semiconductor nanomaterials. CrystEngComm 2013. [DOI: 10.1039/c3ce26872a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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