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Du Y, Chen W, Wang Y, Yu Y, Guo K, Qu G, Zhang J. Quantum Spin Exchange Interactions to Accelerate the Redox Kinetics in Li-S Batteries. NANO-MICRO LETTERS 2024; 16:100. [PMID: 38285199 PMCID: PMC10825106 DOI: 10.1007/s40820-023-01319-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 12/05/2023] [Indexed: 01/30/2024]
Abstract
Spin-engineering with electrocatalysts have been exploited to suppress the "shuttle effect" in Li-S batteries. Spin selection, spin-dependent electron mobility and spin potentials in activation barriers can be optimized as quantum spin exchange interactions leading to a significant reduction of the electronic repulsions in the orbitals of catalysts. Herein, we anchor the MgPc molecules on fluorinated carbon nanotubes (MgPc@FCNT), which exhibits the single active Mg sites with axial displacement. According to the density functional theory calculations, the electronic spin polarization in MgPc@FCNT not only increases the adsorption energy toward LiPSs intermediates but also facilitates the tunneling process of electron in Li-S batteries. As a result, the MgPc@FCNT provides an initial capacity of 6.1 mAh cm-2 even when the high sulfur loading is 4.5 mg cm-2, and still maintains 5.1 mAh cm-2 after 100 cycles. This work provides a new perspective to extend the main group single-atom catalysts enabling high-performance Li-S batteries.
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Affiliation(s)
- Yu Du
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Weijie Chen
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Yu Wang
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Yue Yu
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Kai Guo
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Gan Qu
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China.
| | - Jianan Zhang
- Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City, College of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China.
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2
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van Embden J, Gross S, Kittilstved KR, Della Gaspera E. Colloidal Approaches to Zinc Oxide Nanocrystals. Chem Rev 2023; 123:271-326. [PMID: 36563316 DOI: 10.1021/acs.chemrev.2c00456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Zinc oxide is an extensively studied semiconductor with a wide band gap in the near-UV. Its many interesting properties have found use in optics, electronics, catalysis, sensing, as well as biomedicine and microbiology. In the nanoscale regime the functional properties of ZnO can be precisely tuned by manipulating its size, shape, chemical composition (doping), and surface states. In this review, we focus on the colloidal synthesis of ZnO nanocrystals (NCs) and provide a critical analysis of the synthetic methods currently available for preparing ZnO colloids. First, we outline key thermodynamic considerations for the nucleation and growth of colloidal nanoparticles, including an analysis of different reaction methodologies and of the role of dopant ions on nanoparticle formation. We then comprehensively review and discuss the literature on ZnO NC systems, including reactions in polar solvents that traditionally occur at low temperatures upon addition of a base, and high temperature reactions in organic, nonpolar solvents. A specific section is dedicated to doped NCs, highlighting both synthetic aspects and structure-property relationships. The versatility of these methods to achieve morphological and compositional control in ZnO is explicated. We then showcase some of the key applications of ZnO NCs, both as suspended colloids and as deposited coatings on supporting substrates. Finally, a critical analysis of the current state of the art for ZnO colloidal NCs is presented along with existing challenges and future directions for the field.
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Affiliation(s)
- Joel van Embden
- School of Science, RMIT University, MelbourneVictoria, 3001, Australia
| | - Silvia Gross
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, 35131Padova, Italy.,Karlsruher Institut für Technologie (KIT), Institut für Technische Chemie und Polymerchemie (ITCP), Engesserstrasse 20, 76131Karlsruhe, Germany
| | - Kevin R Kittilstved
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts01003, United States
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3
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Qiao T, Liu X, Rossi D, Khurana M, Lin Y, Wen J, Cheon J, Akimov AV, Son DH. Magnetic Effect of Dopants on Bright and Dark Excitons in Strongly Confined Mn-Doped CsPbI 3 Quantum Dots. NANO LETTERS 2021; 21:9543-9550. [PMID: 34762431 DOI: 10.1021/acs.nanolett.1c03114] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We investigated the magnetic effect of Mn2+ ions on an exciton of Mn-doped CsPbI3 quantum dots (QDs), where we looked for the signatures of an exciton magnetic polaron known to produce a large effective magnetic field in Mn-doped CdSe QDs. In contrast to Mn-doped CdSe QDs that can produce ∼100 T of magnetic field upon photoexcitation, manifested as a large change in the energy and relaxation dynamics of a bright exciton, Mn-doped CsPbI3 QDs exhibited little influence of a magnetic dopant on the behavior of a bright exciton. However, a μs-lived dark exciton in CsPbI3 QDs showed 40% faster decay in the presence of Mn2+, equivalent to the effect of ∼3 T of an external magnetic field. While further study is necessary to fully understand the origin of the large difference in the magneto-optic property of an exciton in two systems, we consider that the difference in antiferromagnetic coupling of the dopants is an important contributing factor.
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Affiliation(s)
- Tian Qiao
- Department of Chemistry, Texas A&M University, College Station, Texas 777843, United States
| | - Xiaohan Liu
- Department of Physics, Texas A&M University, College Station, Texas 777843, United States
| | - Daniel Rossi
- Center for Nanomedicine, Institute for Basic Science and Graduate Program of Nano Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
| | - Mohit Khurana
- Department of Physics, Texas A&M University, College Station, Texas 777843, United States
| | - Yulin Lin
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jianguo Wen
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jinwoo Cheon
- Center for Nanomedicine, Institute for Basic Science and Graduate Program of Nano Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
| | - Alexey V Akimov
- Department of Physics, Texas A&M University, College Station, Texas 777843, United States
| | - Dong Hee Son
- Department of Chemistry, Texas A&M University, College Station, Texas 777843, United States
- Center for Nanomedicine, Institute for Basic Science and Graduate Program of Nano Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
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4
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Araujo JJ, Brozek CK, Liu H, Merkulova A, Li X, Gamelin DR. Tunable Band-Edge Potentials and Charge Storage in Colloidal Tin-Doped Indium Oxide (ITO) Nanocrystals. ACS NANO 2021; 15:14116-14124. [PMID: 34387483 DOI: 10.1021/acsnano.1c04660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Degenerately doped metal-oxide nanocrystals (NCs) show localized surface plasmon resonances (LSPRs) that are tunable via their tunable excess charge-carrier densities. Modulation of excess charge carriers has also been used to control magnetism in colloidal doped metal-oxide NCs. The addition of excess delocalized conduction-band (CB) electrons can be achieved through aliovalent doping or by postsynthetic techniques such as electrochemistry or photodoping. Here, we examine the influence of charge-compensating aliovalent dopants on the potentials of excess CB electrons in free-standing colloidal degenerately doped oxide NCs, both experimentally and through modeling. Taking Sn4+:In2O3 (ITO) NCs as a model system, we use spectroelectrochemical techniques to examine differences between aliovalent doping and photodoping. We demonstrate that whereas photodoping introduces excess CB electrons by raising the Fermi level relative to the CB edge, aliovalent impurity substitution introduces excess CB electrons by stabilizing the CB edge relative to an externally defined Fermi level. Significant differences are thus observed electrochemically between spectroscopically similar delocalized CB electrons compensated by aliovalent dopants and those compensated by surface cations (e.g., protons) during photodoping. Theoretical modeling illustrates the very different potentials that arise from charge compensation via aliovalent substitution and surface charge compensation. Spectroelectrochemical titrations allow the ITO NC band-edge stabilization as a function of Sn4+ doping to be quantified. Extremely large capacitances are observed in both In2O3 and ITO NCs, making these NCs attractive for reversible charge-storage applications.
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Affiliation(s)
- Jose J Araujo
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Carl K Brozek
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Hongbin Liu
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Anna Merkulova
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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5
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Hu L, Cao L, Li L, Duan J, Liao X, Long F, Zhou J, Xiao Y, Zeng YJ, Zhou S. Two-dimensional magneto-photoconductivity in non-van der Waals manganese selenide. MATERIALS HORIZONS 2021; 8:1286-1296. [PMID: 34821921 DOI: 10.1039/d1mh00009h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Deficient intrinsic species and suppressed Curie temperatures (Tc) in two-dimensional (2D) magnets are major barriers for future spintronic applications. As an alternative, delaminating non-van der Waals (vdW) magnets can offset these shortcomings and involve robust bandgaps to explore 2D magneto-photoconductivity at ambient temperature. Herein, non-vdW α-MnSe2 is first delaminated as quasi-2D nanosheets for the study of emerging semiconductor, ferromagnetism and magneto-photoconductivity behaviors. Abundant nonstoichiometric surfaces induce the renormalization of the band structure and open a bandgap of 1.2 eV. The structural optimization strengthens ferromagnetic super-exchange interactions between the nearest-neighbor Mn2+, which enables us to achieve a high Tc of 320 K well above room temperature. The critical fitting of magnetization and transport measurements both verify that it is of quasi-2D nature. The above observations are evidenced by multiple microscopic and macroscopic characterization tools, in line with the prediction of first-principles calculations. Profiting from the negative magnetoresistance effect, the self-powered infrared magneto-photoconductivity performance including a responsivity of 330.4 mA W-1 and a millisecond-level response speed are further demonstrated. Such merits stem from the synergistic modulation of magnetic and light fields on photogenerated carriers. This provides a new strategy to manipulate both charge and spin in 2D non-vdW systems and displays their alluring prospects in magneto-photodetection.
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Affiliation(s)
- Liang Hu
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, Institute of Advanced Magnetic Materials, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
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6
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Volnianska O. Computational studies of the electronic structure of copper-doped ZnO quantum dots. J Chem Phys 2021; 154:124710. [PMID: 33810646 DOI: 10.1063/5.0039522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Copper-doped ZnO quantum dots (QDs) have attracted substantial interest. The electronic structure and optical and magnetic properties of Cu3+(d8)-, Cu2+(d9)-, and Cu+(d10)-doped ZnO QDs with sizes up to 1.5 nm are investigated using the GGA+U approximation, with the +U corrections applied to d (Zn), p(O), and d(Cu) orbitals. Taking +Us parameters, as optimized in previous bulk calculations, we obtain the correct band structure of ZnO QDs. Both the description of electronic structure and thermodynamic charge state transitions of Cu in ZnO QDs agree with the results of bulk calculations due to the strong localization of Cu defect energy levels. Atomic displacements around Cu are induced by strong Jahn-Teller distortion and affect Kohn-Sham energies and thermodynamic transition levels. The average bond length of Cu-O and the defect structure are crucial factors influencing the electronic properties of Cu in ZnO QDs. The analysis of the optical properties of Cu in ZnO QDs is reported. The GGA+U results, compared with the available experimental data, support Dingle's model [Phys. Rev. Lett. 23, 579 (1969)], in which the structured green luminescence observed in bulk and nanocrystals originates from the [(Cu+, hole) → Cu2+] transition. We also examine the magnetic interaction between the copper pair for two charge states: 0 and +2, and four positions relative to the center of QDs. Ferromagnetic interaction between ions is obtained for every investigated configuration. The magnitude of ferromagnetism increases for positive charge defects due to the strong hybridization of the d(Cu) and p(O) states.
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Affiliation(s)
- O Volnianska
- Institute of Physics PAS, al. Lotników 32/46, 02-668 Warsaw, Poland
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7
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Singh P, Singh RK, Kumar R. Journey of ZnO quantum dots from undoped to rare-earth and transition metal-doped and their applications. RSC Adv 2021; 11:2512-2545. [PMID: 35424186 PMCID: PMC8693809 DOI: 10.1039/d0ra08670c] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/05/2020] [Indexed: 12/20/2022] Open
Abstract
Currently, developments in the field of quantum dots (QDs) have attracted researchers worldwide. A large variety of QDs have been discovered in the few years, which have excellent optoelectronic, antibacterial, magnetic, and other properties. However, ZnO is the single known material that can exist in the quantum state and can hold all the above properties. There is a lot of work going on in this field and we will be shorthanded if we do not accommodate this treasure at one place. This manuscript will prove to be a milestone in this noble cause. Having a tremendous potential, there is a developing enthusiasm toward the application of ZnO QDs in diverse areas. Sol-gel method being the simplest is the widely-favored synthetic method. Synthesis via this method is largely affected by a number of factors such as the reaction temperature, duration of the reaction, type of solvent, pH of the solution, and the precipitating agent. Doping enhances the optical, magnetic, anti-bacterial, anti-microbial, and other properties of ZnO QDs. However, doping elements reside mostly on the surface of the QDs. The presence of doping elements inside the core is still a major challenge for doping techniques. In this review article, we have focused on pure, rare-earth, and transition metal-doped ZnO QD properties, and the various synthetic processes and applications. Quantum confinement effect is present in nearly every aspect of the QDs. The effect of quantum confinement has also been summarized in this manuscript. Furthermore, the doping of rare earth elements and transition metal, synthetic methods for different organic molecule-capped ZnO QDs, mechanisms for reactive oxygen species (ROS) generation, drug delivery system for cancer treatment, and many more application are discussed in this paper.
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Affiliation(s)
- Pushpendra Singh
- Department of Physics, Dr Harisingh Gour Central University Sagar 470003 M. P. India +91 9425635731
| | - Rajan Kumar Singh
- Department of Physics, Dr Harisingh Gour Central University Sagar 470003 M. P. India +91 9425635731
- Department of Chemical Engineering, National Taiwan University Taipei Taiwan ROC
| | - Ranveer Kumar
- Department of Physics, Dr Harisingh Gour Central University Sagar 470003 M. P. India +91 9425635731
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8
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Buz E, Zhou D, Kittilstved KR. Air-stable n-type Fe-doped ZnO colloidal nanocrystals. J Chem Phys 2019; 151:134702. [DOI: 10.1063/1.5124947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Enes Buz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - Dongming Zhou
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - Kevin R. Kittilstved
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
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9
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Yang X, Pu C, Qin H, Liu S, Xu Z, Peng X. Temperature- and Mn2+ Concentration-Dependent Emission Properties of Mn2+-Doped ZnSe Nanocrystals. J Am Chem Soc 2019; 141:2288-2298. [DOI: 10.1021/jacs.8b08480] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiaoli Yang
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Chaodan Pu
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Haiyan Qin
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Shaojie Liu
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Zhuan Xu
- Department of Physics, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Xiaogang Peng
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
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10
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Chang K, Gao D, Qi Q, Liu Y, Yuan Z. Engineering biocompatible benzodithiophene-based polymer dots with tunable absorptions as high-efficiency theranostic agents for multiscale photoacoustic imaging-guided photothermal therapy. Biomater Sci 2019; 7:1486-1492. [PMID: 30672925 DOI: 10.1039/c8bm01577e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Conjugated polymer dots with tunable absorptions by controlling the structure have been engineered for multiscale photoacoustic imaging-guided photothermal therapy.
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Affiliation(s)
- Kaiwen Chang
- Bioimaging Core
- Faculty of Health Sciences
- University of Macau
- Macau SAR 999078
- China
| | - Duyang Gao
- Bioimaging Core
- Faculty of Health Sciences
- University of Macau
- Macau SAR 999078
- China
| | - Qiaofang Qi
- Key Laboratory of Medical Molecular Probes
- Department of Chemistry
- School of Basic Medical Sciences
- Xinxiang Medical University
- Xinxiang 453003
| | - Yubin Liu
- Bioimaging Core
- Faculty of Health Sciences
- University of Macau
- Macau SAR 999078
- China
| | - Zhen Yuan
- Bioimaging Core
- Faculty of Health Sciences
- University of Macau
- Macau SAR 999078
- China
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11
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Tan H, Wang C, Hu W, Duan H, Guo P, Li N, Li G, Cai L, Sun Z, Hu F, Yan W. Reversible Tuning of the Ferromagnetic Behavior in Mn-Doped MoS 2 Nanosheets via Interface Charge Transfer. ACS APPLIED MATERIALS & INTERFACES 2018; 10:31648-31654. [PMID: 30156104 DOI: 10.1021/acsami.8b11623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Reversible manipulation of the magnetic behavior of two-dimensional van der Waals crystals is crucial for expanding their applications in spin-based information-processing technologies. However, to date, most experimental approaches to tune the magnetic properties are single way and have very limited practical applications. Here, we report an interface charge-transfer method for obtaining a reversible and air-stable magnetic response at room temperature in Mn-doped MoS2 nanosheets. By adsorption of benzyl viologen (BV) molecules as the charge donor, the saturation magnetization of Mn-doped MoS2 nanosheets is enhanced by a magnitude of 60%, and the magnetization can be restored to the original value when the adsorbed BV molecules are removed. This cycle can be repeated many times on the same sample without detectable degradation. Experimental characterizations and first-principles calculations suggest that the enhanced magnetization can be attributed to the increase of Mn magnetic moment because of the enriched electrons transferred from BV molecules. This work shows that interface charge transfer may open up a new pathway for reversibly tuning the exchange interactions in two-dimensional nanostructures.
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Affiliation(s)
- Hao Tan
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Chao Wang
- Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology , Chinese Academy of Sciences , Hefei 230031 , Anhui , P. R. China
| | - Wei Hu
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Hengli Duan
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Peng Guo
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Na Li
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Guinan Li
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Liang Cai
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Zhihu Sun
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Fengchun Hu
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
| | - Wensheng Yan
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230029 , P. R. China
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12
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Brozek CK, Zhou D, Liu H, Li X, Kittilstved KR, Gamelin DR. Soluble Supercapacitors: Large and Reversible Charge Storage in Colloidal Iron-Doped ZnO Nanocrystals. NANO LETTERS 2018; 18:3297-3302. [PMID: 29693400 DOI: 10.1021/acs.nanolett.8b01264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Colloidal ZnO semiconductor nanocrystals have previously been shown to accumulate multiple delocalized conduction-band electrons under chemical, electrochemical, or photochemical reducing conditions, leading to emergent semimetallic characteristics such as quantum plasmon resonances and raising prospects for application in multielectron redox transformations. Here, we demonstrate a dramatic enhancement in the capacitance of colloidal ZnO nanocrystals through aliovalent Fe3+-doping. Very high areal and volumetric capacitances (33 μF cm-2, 233 F cm-3) are achieved in Zn0.99Fe0.01O nanocrystals that rival those of the best supercapacitors used in commercial energy-storage devices. The redox properties of these nanocrystals are probed by potentiometric titration and optical spectroscopy. These data indicate an equilibrium between electron localization by Fe3+ dopants and electron delocalization within the ZnO conduction band, allowing facile reversible charge storage and removal. As "soluble supercapacitors", colloidal iron-doped ZnO nanocrystals constitute a promising class of solution-processable electronic materials with large charge-storage capacity attractive for future energy-storage applications.
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Affiliation(s)
- Carl K Brozek
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Dongming Zhou
- Department of Chemistry , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Hongbin Liu
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Xiaosong Li
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Kevin R Kittilstved
- Department of Chemistry , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Daniel R Gamelin
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
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13
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Pinchetti V, Di Q, Lorenzon M, Camellini A, Fasoli M, Zavelani-Rossi M, Meinardi F, Zhang J, Crooker SA, Brovelli S. Excitonic pathway to photoinduced magnetism in colloidal nanocrystals with nonmagnetic dopants. NATURE NANOTECHNOLOGY 2018; 13:145-151. [PMID: 29255289 DOI: 10.1038/s41565-017-0024-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/03/2017] [Indexed: 06/07/2023]
Abstract
Electronic doping of colloidal semiconductor nanostructures holds promise for future device concepts in optoelectronic and spin-based technologies. Ag+ is an emerging electronic dopant in III-V and II-VI nanostructures, introducing intragap electronic states optically coupled to the host conduction band. With its full 4d shell Ag+ is nonmagnetic, and the dopant-related luminescence is ascribed to decay of the conduction-band electron following transfer of the photoexcited hole to Ag+. This optical activation process and the associated modification of the electronic configuration of Ag+ remain unclear. Here, we trace a comprehensive picture of the excitonic process in Ag-doped CdSe nanocrystals and demonstrate that, in contrast to expectations, capture of the photohole leads to conversion of Ag+ to paramagnetic Ag2+. The process of exciton recombination is thus inextricably tied to photoinduced magnetism. Accordingly, we observe strong optically activated magnetism and diluted magnetic semiconductor behaviour, demonstrating that optically switchable magnetic nanomaterials can be obtained by exploiting excitonic processes involving nonmagnetic impurities.
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Affiliation(s)
- Valerio Pinchetti
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Milano, Italy
| | - Qiumei Di
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, China
| | - Monica Lorenzon
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Milano, Italy
| | | | - Mauro Fasoli
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Milano, Italy
| | | | - Francesco Meinardi
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Milano, Italy
| | - Jiatao Zhang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, China.
| | - Scott A Crooker
- National High Magnetic Field Laboratory, Los Alamos, NM, USA
| | - Sergio Brovelli
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Milano, Italy.
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14
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Hartstein KH, Erickson CS, Tsui EY, Marchioro A, Gamelin DR. Electron Stability and Negative-Tetron Luminescence in Free-Standing Colloidal n-Type CdSe/CdS Quantum Dots. ACS NANO 2017; 11:10430-10438. [PMID: 28915009 DOI: 10.1021/acsnano.7b05551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We examine the effects of CdS shell growth on photochemical reduction of colloidal CdSe quantum dots (QDs) and describe the spectroscopic properties of the resulting n-type CdSe/CdS QDs. CdS shell growth greatly slows electron trapping. Because of this improvement, complete two-electron occupancy of the 1Se conduction-band orbital is achieved in CdSe/CdS QDs and found to be much more stable than in past experiments. Simultaneous photoluminescence at two different energies is now observed from QDs possessing two excess conduction-band electrons, reflecting competing recombination of discretized 1Se and 1Pe conduction-band electrons within photogenerated four-carrier negative tetrons (three electrons and one hole). Stable occupancy of the 1Pe level is not achievable under these conditions, and possible reasons are discussed. The stability and accessibility of these multielectron configurations, and the facile spectroscopic detection of negative tetrons, both make photodoped core/shell QDs attractive for exploring the physical properties of free-standing heavily n-doped colloidal CdSe-based QDs.
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Affiliation(s)
- Kimberly H Hartstein
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Christian S Erickson
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Emily Y Tsui
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Arianna Marchioro
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
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15
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Tan H, Hu W, Wang C, Ma C, Duan H, Yan W, Cai L, Guo P, Sun Z, Liu Q, Zheng X, Hu F, Wei S. Intrinsic Ferromagnetism in Mn-Substituted MoS 2 Nanosheets Achieved by Supercritical Hydrothermal Reaction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1701389. [PMID: 28834215 DOI: 10.1002/smll.201701389] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/06/2017] [Indexed: 06/07/2023]
Abstract
Doping atomically thick nanosheets is a great challenge due to the self-purification effect that drives the precipitation of dopants. Here, a breakthrough is made to dope Mn atoms substitutionally into MoS2 nanosheets in a sulfur-rich supercritical hydrothermal reaction environment, where the formation energy of Mn substituting for Mo sites in MoS2 is significantly reduced to overcome the self-purification effect. The substitutional Mn doping is convincingly evidenced by high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine spectroscopy characterizations. The Mn-doped MoS2 nanosheets show robust intrinsic ferromagnetic response with a saturation magnetic moment of 0.05 µB Mn-1 at room temperature. The intrinsic ferromagnetism is further confirmed by the reversibility of the magnetic behavior during the cycle of incorporating/removing Li codopants, showing the critical role of Mn 3d electronic states in mediating the magnetic interactions in MoS2 nanosheets.
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Affiliation(s)
- Hao Tan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Wei Hu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Chao Wang
- Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Chao Ma
- College of Materials Science and Engineering, Hunan University, Changsha, Hunan, 410082, P. R. China
| | - Hengli Duan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Wensheng Yan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Liang Cai
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Peng Guo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Zhihu Sun
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Qinghua Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Xusheng Zheng
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Fengchun Hu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Shiqiang Wei
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, P. R. China
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16
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Muckel F, Barrows CJ, Graf A, Schmitz A, Erickson CS, Gamelin DR, Bacher G. Current-Induced Magnetic Polarons in a Colloidal Quantum-Dot Device. NANO LETTERS 2017; 17:4768-4773. [PMID: 28653543 DOI: 10.1021/acs.nanolett.7b01496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electrical spin manipulation remains a central challenge for the realization of diverse spin-based information processing technologies. Motivated by the demonstration of confinement-enhanced sp-d exchange interactions in colloidal diluted magnetic semiconductor (DMS) quantum dots (QDs), such materials are considered promising candidates for future spintronic or spin-photonic applications. Despite intense research into DMS QDs, electrical control of their magnetic and magneto-optical properties remains a daunting goal. Here, we report the first demonstration of electrically induced magnetic polaron formation in any DMS, achieved by embedding Mn2+-doped CdSe/CdS core/shell QDs as the active layer in an electrical light-emitting device. Tracing the electroluminescence from cryogenic to room temperatures reveals an anomalous energy shift that reflects current-induced magnetization of the Mn2+ spin sublattice, that is, excitonic magnetic polaron formation. These electrically induced magnetic polarons exhibit an energy gain comparable to their optically excited counterparts, demonstrating that magnetic polaron formation is achievable by current injection in a solid-state device.
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Affiliation(s)
- Franziska Muckel
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| | - Charles J Barrows
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Arthur Graf
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| | - Alexander Schmitz
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| | - Christian S Erickson
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
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17
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Gopalakrishnan S, Kolandaivel P. Electronic, optical and magnetic properties of Co, Fe and Ni doped (ZnX) 6 ; (X = O, S & Se) quantum dots – A DFT study. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Pradhan N, Das Adhikari S, Nag A, Sarma DD. Luminescence, Plasmonic, and Magnetic Properties of Doped Semiconductor Nanocrystals. Angew Chem Int Ed Engl 2017; 56:7038-7054. [DOI: 10.1002/anie.201611526] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/18/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Narayan Pradhan
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 India
| | - Samrat Das Adhikari
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 India
| | - Angshuman Nag
- Department of Chemistry and Centre for Energy Science; Indian Institute of Science Education and Research, IISER; Pune 411008 India
| | - D. D. Sarma
- Solid State and Structural Chemistry Unit; Indian Institute of Science; Bengaluru 560012 India
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19
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Xu K, Lin CC, Xie X, Meijerink A. Efficient and Stable Luminescence from Mn 2+ in Core and Core-Isocrystalline Shell CsPbCl 3 Perovskite Nanocrystals. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2017; 29:4265-4272. [PMID: 28572703 PMCID: PMC5445715 DOI: 10.1021/acs.chemmater.7b00345] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/23/2017] [Indexed: 05/21/2023]
Abstract
There has been a growing interest in applying CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) for optoelectronic application. However, research on doping of this new class of promising NCs with optically active and/or magnetic transition metal ions is still limited. Here we report a facile room temperature method for Mn2+ doping into CsPbCl3 NCs. By addition of a small amount of concentrated HCl acid to a clear solution containing Mn2+, Cs+, and Pb2+ precursors, Mn2+-doped CsPbCl3 NCs with strong orange luminescence of Mn2+ at ∼600 nm are obtained. Mn2+-doped CsPbCl3 NCs show the characteristic cubic phase structure very similar to the undoped counterpart, indicating that the nucleation and growth mechanism are not significantly modified for the doping concentrations realized (0.1 at. % - 2.1 at. %). To enhance the Mn2+ emission intensity and to improve the stability of the doped NCs, isocrystalline shell growth was applied. Growth of an undoped CsPbCl3 shell greatly enhanced the emission intensity of Mn2+ and resulted in lengthening the radiative lifetime of the Mn2+ emission to 1.4 ms. The core-shell NCs also show superior thermal stability and no thermal degradation up to at least 110 °C, which is important in applications.
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Affiliation(s)
- Kunyuan Xu
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
| | - Chun Che Lin
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
- Institute
of Organic and Polymeric Materials, National
Taipei University of Technology, Taipei 106, Taiwan
| | - Xiaobin Xie
- Soft
Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Andries Meijerink
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
- E-mail:
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20
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Pradhan N, Das Adhikari S, Nag A, Sarma DD. Dotierte Halbleiter-Nanokristalle: Lumineszenz, plasmonische und magnetische Eigenschaften. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611526] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Narayan Pradhan
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 Indien
| | - Samrat Das Adhikari
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 Indien
| | - Angshuman Nag
- Department of Chemistry and Centre for Energy Science; Indian Institute of Science Education and Research, IISER; Pune 411008 Indien
| | - D. D. Sarma
- Solid State and Structural Chemistry Unit; Indian Institute of Science; Bengaluru 560012 Indien
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21
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Kortshagen UR, Sankaran RM, Pereira RN, Girshick SL, Wu JJ, Aydil ES. Nonthermal Plasma Synthesis of Nanocrystals: Fundamental Principles, Materials, and Applications. Chem Rev 2016; 116:11061-127. [DOI: 10.1021/acs.chemrev.6b00039] [Citation(s) in RCA: 248] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Uwe R. Kortshagen
- Department
of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - R. Mohan Sankaran
- Department
of Chemical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Rui N. Pereira
- Department
of Physics and I3N, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
- Walter
Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Steven L. Girshick
- Department
of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jeslin J. Wu
- Department
of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Eray S. Aydil
- Department
of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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22
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Proshchenko V, Dahnovsky Y. Optical spectra of CdMnSe of nano-ferro- and antiferro-magnets. Phys Chem Chem Phys 2016; 17:26828-32. [PMID: 26400615 DOI: 10.1039/c5cp02457a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study optical transitions in CdSe quantum dots doped by Mn atoms. At low concentrations the transitions are spin-forbidden. Nevertheless, strong light absorption was experimentally found. To explain this effect we propose a new mechanism that includes two or more Mn atoms closely placed to each other containing the electrons with opposite spin projections. In this case the spin-flip is unnecessary. In addition we study absorption from quantum dots containing two Mn atoms with different multiplicities. We find that the strongest absorption from the gap is for an antiferromagnetic arrangement. The obtained results confirm the experimental concentration dependencies.
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Affiliation(s)
- Vitaly Proshchenko
- Department of Physics and Astronomy/3905 1000 E, University Avenue, University of Wyoming, Laramie, WY 82071, USA.
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23
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Xu B, Luo Z, Wilson AJ, Chen K, Gao W, Yuan G, Chopra HD, Chen X, Willets KA, Dauter Z, Ren S. Multifunctional Charge-Transfer Single Crystals through Supramolecular Assembly. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:5322-9. [PMID: 27146726 PMCID: PMC7798091 DOI: 10.1002/adma.201600383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/08/2016] [Indexed: 05/07/2023]
Abstract
Centimeter-sized segregated stacking TTF-C60 single crystals are crystallized by a mass-transport approach combined with solvent-vapor evaporation for the first time. The intermolecular charge-transfer interaction in the long-range ordered superstructure enables the crystals to demonstrate external stimuli-controlled multifunctionalities and angle/electrical-potential-dependent luminescence.
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Affiliation(s)
- Beibei Xu
- Department of Mechanical Engineering, Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA
| | - Zhipu Luo
- Synchrotron Radiation Research Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Andrew J Wilson
- Department of Chemistry, Temple University, Philadelphia, PA, 19122, USA
| | - Ke Chen
- Department of Physics, Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA
| | - Wenxiu Gao
- School of Materials Science and Engineering, Nanjing University of Science Technology, Nanjing, 210094, P. R. China
| | - Guoliang Yuan
- School of Materials Science and Engineering, Nanjing University of Science Technology, Nanjing, 210094, P. R. China
| | - Harsh Deep Chopra
- Department of Mechanical Engineering, Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA
| | - Xing Chen
- Energy Systems Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | | | - Zbigniew Dauter
- Synchrotron Radiation Research Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Shenqiang Ren
- Department of Mechanical Engineering, Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA
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24
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Jagadeeswararao M, Pal S, Nag A, Sarma DD. Electrical and Plasmonic Properties of Ligand-Free Sn4+-Doped In2O3(ITO) Nanocrystals. Chemphyschem 2016; 17:710-6. [DOI: 10.1002/cphc.201500973] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Metikoti Jagadeeswararao
- Department of Chemistry; Indian Institute of Science Education and Research (IISER); Pune 411008 India
| | - Somnath Pal
- Solid State and Structural Chemistry Unit; Indian Institute of Science; Bangalore 560012 India
| | - Angshuman Nag
- Department of Chemistry; Indian Institute of Science Education and Research (IISER); Pune 411008 India
| | - D. D. Sarma
- Solid State and Structural Chemistry Unit; Indian Institute of Science; Bangalore 560012 India
- Department of Physics and Astronomy; Uppsala University; Box 516 75120 Uppsala Sweden
- Council of Scientific and Industrial Research-Network of Institutes for Solar Energy (CSIR-NISE); New Delhi 110001 India
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25
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Zhou D, Kittilstved KR. Electron trapping on Fe3+ sites in photodoped ZnO colloidal nanocrystals. Chem Commun (Camb) 2016; 52:9101-4. [DOI: 10.1039/c6cc00514d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Experimental study of photodoped colloidal Fe-doped ZnO quantum dots suggest electrons trap on Fe3+ sites before accumulating in the ZnO conduction band.
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Affiliation(s)
- Dongming Zhou
- Department of Chemistry
- University of Massachusetts
- Amherst
- USA
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26
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Zhang L, Zhu L, Hu L, Li Y, Song H, Ye Z. Interfacial effect on Mn-doped TiO2 nanoparticles: from paramagnetism to ferromagnetism. RSC Adv 2016. [DOI: 10.1039/c6ra06606b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Interfacial defects created during phase-transformation leads to room temperature ferromagnetism of manganese-doped TiO2 nanoparticles.
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Affiliation(s)
- Le Zhang
- State Key Laboratory of Silicon Materials
- Department of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- People's Republic of China
| | - Liping Zhu
- State Key Laboratory of Silicon Materials
- Department of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- People's Republic of China
| | - Liang Hu
- State Key Laboratory of Silicon Materials
- Department of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- People's Republic of China
| | - Yaguang Li
- State Key Laboratory of Silicon Materials
- Department of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- People's Republic of China
| | - Hui Song
- State Key Laboratory of Silicon Materials
- Department of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- People's Republic of China
| | - Zhizhen Ye
- State Key Laboratory of Silicon Materials
- Department of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- People's Republic of China
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27
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Nelson HD, Bradshaw LR, Barrows CJ, Vlaskin VA, Gamelin DR. Picosecond Dynamics of Excitonic Magnetic Polarons in Colloidal Diffusion-Doped Cd(1-x)Mn(x)Se Quantum Dots. ACS NANO 2015; 9:11177-11191. [PMID: 26417918 DOI: 10.1021/acsnano.5b04719] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Spontaneous magnetization is observed at zero magnetic field in photoexcited colloidal Cd(1-x)Mn(x)Se (x = 0.13) quantum dots (QDs) prepared by diffusion doping, reflecting strong Mn(2+)-exciton exchange coupling. The picosecond dynamics of this phenomenon, known as an excitonic magnetic polaron (EMP), are examined using a combination of time-resolved photoluminescence, magneto-photoluminescence, and Faraday rotation (TRFR) spectroscopies, in conjunction with continuous-wave absorption, magnetic circular dichroism (MCD), and magnetic circularly polarized photoluminescence (MCPL) spectroscopies. The data indicate that EMPs form with random magnetization orientations at zero external field, but their formation can be directed by an external magnetic field. After formation, however, external magnetic fields are unable to reorient the EMPs within the luminescence lifetime, implicating anisotropy in the EMP potential-energy surfaces. TRFR measurements in a transverse magnetic field reveal rapid (<5 ps) spin transfer from excitons to Mn(2+) followed by coherent EMP precession at the Mn(2+) Larmor frequency for over a nanosecond. A dynamical TRFR phase inversion is observed during EMP formation attributed to the large shifts in excitonic absorption energies during spontaneous magnetization. Partial optical orientation of the EMPs by resonant circularly polarized photoexcitation is also demonstrated. Collectively, these results highlight the extraordinary physical properties of colloidal diffusion-doped Cd(1-x)Mn(x)Se QDs that result from their unique combination of strong quantum confinement, large Mn(2+) concentrations, and relatively narrow size distributions. The insights gained from these measurements advance our understanding of spin dynamics and magnetic exchange in colloidal doped semiconductor nanostructures, with potential ramifications for future spin-based information technologies.
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Affiliation(s)
- Heidi D Nelson
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Liam R Bradshaw
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Charles J Barrows
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Vladimir A Vlaskin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
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28
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Yang J, Fainblat R, Kwon SG, Muckel F, Yu JH, Terlinden H, Kim BH, Iavarone D, Choi MK, Kim IY, Park I, Hong HK, Lee J, Son JS, Lee Z, Kang K, Hwang SJ, Bacher G, Hyeon T. Route to the Smallest Doped Semiconductor: Mn2+-Doped (CdSe)13 Clusters. J Am Chem Soc 2015; 137:12776-9. [DOI: 10.1021/jacs.5b07888] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jiwoong Yang
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Rachel Fainblat
- Werkstoffe
der Elektrotechnik und CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany
| | - Soon Gu Kwon
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Franziska Muckel
- Werkstoffe
der Elektrotechnik und CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany
| | - Jung Ho Yu
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Hendrik Terlinden
- Werkstoffe
der Elektrotechnik und CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany
| | - Byung Hyo Kim
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Dino Iavarone
- Werkstoffe
der Elektrotechnik und CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany
| | - Moon Kee Choi
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - In Young Kim
- Materials
Research Institute for Clean Energy, Department of Chemistry and Nano
Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
| | - Inchul Park
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Hyo-Ki Hong
- School of
Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea
| | - Jihwa Lee
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Jae Sung Son
- School of
Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea
| | - Zonghoon Lee
- School of
Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea
| | - Kisuk Kang
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
| | - Seong-Ju Hwang
- Materials
Research Institute for Clean Energy, Department of Chemistry and Nano
Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
| | - Gerd Bacher
- Werkstoffe
der Elektrotechnik und CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany
| | - Taeghwan Hyeon
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
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29
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Hu L, Chen J, Fan L, Ren Y, Huang Q, Sanson A, Jiang Z, Zhou M, Rong Y, Wang Y, Deng J, Xing X. High-Curie-Temperature Ferromagnetism in (Sc,Fe)F3 Fluorides and its Dependence on Chemical Valence. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:4592-4596. [PMID: 26149472 DOI: 10.1002/adma.201500868] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/07/2015] [Indexed: 06/04/2023]
Abstract
A magnetic metal-fluoride system is shown for the first time to have a high Curie temperature (≈545 K). The magnetism correlates intimately with the Fe(2+)/Fe(3+) ratio. As the ratio increases, the weak magnetism displayed by unordered magnetic moments intensifies, and these magnetic moments align in parallel. Simultaneously, a magneto-volume effect is also shown to increase the lattice volume.
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Affiliation(s)
- Lei Hu
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jun Chen
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China
- Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials, University of Science and Technology Beijing, Beijing, 100083, China
| | - Longlong Fan
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yang Ren
- Argonne National Laboratory, X-Ray Science Division, Argonne, IL, 60439, USA
| | - Qingzhen Huang
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899-6102, USA
| | - Andrea Sanson
- Department of Physics and Astronomy, University of Padova, Padova, I-35131, Italy
| | - Zheng Jiang
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Mei Zhou
- Physics Department, Tsinghua University, Beijing, 100084, China
| | - Yangchun Rong
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yong Wang
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Jinxia Deng
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xianran Xing
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China
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30
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Kilina S, Kilin D, Tretiak S. Light-Driven and Phonon-Assisted Dynamics in Organic and Semiconductor Nanostructures. Chem Rev 2015; 115:5929-78. [DOI: 10.1021/acs.chemrev.5b00012] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Svetlana Kilina
- Chemistry
and Biochemistry Department, North Dakota State University, Fargo, North Dakota 5810, United States
| | - Dmitri Kilin
- Department
of Chemistry, University of South Dakota, Vermillion, South Dakota 57069, United States
| | - Sergei Tretiak
- Theoretical
Division, Center for Nonlinear Studies (CNLS) and Center for Integrated
Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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31
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Fischer SA, Lingerfelt DB, May JW, Li X. Non-adiabatic molecular dynamics investigation of photoionization state formation and lifetime in Mn²⁺-doped ZnO quantum dots. Phys Chem Chem Phys 2015; 16:17507-14. [PMID: 25019366 DOI: 10.1039/c4cp01683a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The unique electronic structure of Mn(2+)-doped ZnO quantum dots gives rise to photoionization states that can be used to manipulate the magnetic state of the material and to generate zero-reabsorption luminescence. Fast formation and long non-radiative decay of this photoionization state is a necessary requirement for these important applications. In this work, surface hopping based non-adiabatic molecular dynamics are used to demonstrate the fast formation of a metal-to-ligand charge transfer state in a Mn(2+)-doped ZnO quantum dot. The formation occurs on an ultrafast timescale and is aided by the large density of states and significant mixing of the dopant Mn(2+) 3dt2 levels with the valence-band levels of the ZnO lattice. The non-radiative lifetime of the photoionization states is also investigated.
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Affiliation(s)
- Sean A Fischer
- Department of Chemistry, University of Washington, Seattle, Washington, USA.
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32
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Schimpf AM, Rinehart JD, Ochsenbein ST, Gamelin DR. Charge-State Control of Mn(2+) Spin Relaxation Dynamics in Colloidal n-Type Zn1-xMnxO Nanocrystals. J Phys Chem Lett 2015; 6:1748-1753. [PMID: 26263344 DOI: 10.1021/acs.jpclett.5b00621] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Colloidal diluted magnetic semiconductor (DMS) nanocrystals are model systems for studying spin effects in semiconductor nanostructures with relevance to future spin-based information processing technologies. The introduction of excess delocalized charge carriers into such nanocrystals turns on strong dopant-carrier magnetic exchange interactions, with important consequences for the physical properties of these materials. Here, we use pulsed electron paramagnetic resonance (pEPR) spectroscopy to probe the effects of excess conduction band electrons on the spin dynamics of colloidal Mn(2+)-doped ZnO nanocrystals. Mn(2+) spin-lattice relaxation is strongly accelerated by the addition of even one conduction band electron per Zn1-xMnxO nanocrystal, attributable to the introduction of a new exchange-based Mn(2+) spin relaxation pathway. A kinetic model is used to describe the enhanced relaxation rates, yielding new insights into the spin dynamics and electronic structures of these materials with potential ramifications for future applications of DMS nanostructures in spin-based technologies.
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Affiliation(s)
- Alina M Schimpf
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Jeffrey D Rinehart
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Stefan T Ochsenbein
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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33
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Boncher W, Dalafu H, Rosa N, Stoll S. Europium chalcogenide magnetic semiconductor nanostructures. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.12.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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34
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Cai L, He J, Liu Q, Yao T, Chen L, Yan W, Hu F, Jiang Y, Zhao Y, Hu T, Sun Z, Wei S. Vacancy-Induced Ferromagnetism of MoS2 Nanosheets. J Am Chem Soc 2015; 137:2622-7. [DOI: 10.1021/ja5120908] [Citation(s) in RCA: 542] [Impact Index Per Article: 60.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Liang Cai
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Jingfu He
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Qinghua Liu
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Tao Yao
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Lin Chen
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Wensheng Yan
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Fengchun Hu
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Yong Jiang
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Yidong Zhao
- Beijing
Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Tiandou Hu
- Beijing
Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zhihu Sun
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Shiqiang Wei
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
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35
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Zou SJ, Wang ST, Wu MF, Jian WB, Cheng SJ. Exposure of the hidden anti-ferromagnetism in paramagnetic CdSe:Mn nanocrystals. ACS NANO 2015; 9:503-511. [PMID: 25551417 DOI: 10.1021/nn5056892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present theoretical and experimental investigations of the magnetism of paramagnetic semiconductor CdSe:Mn nanocrystals and propose an efficient approach to the exposure and analysis of the underlying anti-ferromagnetic interactions between magnetic ions therein. A key advance made here is the development of an analysis method with the exploitation of group theory technique that allows us to distinguish the anti-ferromagnetic interactions between aggregative Mn(2+) ions from the overall pronounced paramagnetism of magnetic-ion-doped semiconductor nanocrystals. By using the method, we clearly reveal and identify the signatures of anti-ferromagnetism from the measured temperature-dependent magnetisms and furthermore determine the average number of Mn(2+) ions and the fraction of aggregative ones in the measured CdSe:Mn nanocrystals.
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Affiliation(s)
- Shou-Jyun Zou
- Department of Electrophysics, National Chiao Tung University , Hsinchu 300, Taiwan
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36
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Sun Z, Yang X, Wang C, Yao T, Cai L, Yan W, Jiang Y, Hu F, He J, Pan Z, Liu Q, Wei S. Graphene activating room-temperature ferromagnetic exchange in cobalt-doped ZnO dilute magnetic semiconductor quantum dots. ACS NANO 2014; 8:10589-10596. [PMID: 25222885 DOI: 10.1021/nn5040845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Control over the magnetic interactions in dilute magnetic semiconductor quantum dots (DMSQDs) is a key issue to future development of nanometer-sized integrated "spintronic" devices. However, manipulating the magnetic coupling between impurity ions in DMSQDs remains a great challenge because of the intrinsic quantum confinement effects and self-purification of the quantum dots. Here, we propose a hybrid structure to achieve room-temperature ferromagnetic interactions in DMSQDs, via engineering the density and nature of the energy states at the Fermi level. This idea has been applied to Co-doped ZnO DMSQDs where the growth of a reduced graphene oxide shell around the Zn(0.98)Co(0.02)O core turns the magnetic interactions from paramagnetic to ferromagnetic at room temperature, due to the hybridization of 2p(z) orbitals of graphene and 3d obitals of Co(2+)-oxygen-vacancy complexes. This design may open up a kind of possibility for manipulating the magnetism of doped oxide nanostructures.
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Affiliation(s)
- Zhihu Sun
- National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei, Anhui 230029, People's Republic of China
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37
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Teunis MB, Dolai S, Sardar R. Effects of surface-passivating ligands and ultrasmall CdSe nanocrystal size on the delocalization of exciton confinement. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:7851-7858. [PMID: 24926916 DOI: 10.1021/la501533t] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Here we report an unprecedentedly large and controllable decrease in the optical band gap (up to 107 nm, 610 meV) of molecule-like ultrasmall CdSe nanocrystals (diameters ranging from 1.6 to 2.0 nm) by passivating their surfaces with conjugated ligands (phenyldithiocarbamates, PDTCs) containing a series of electron-donating and -withdrawing functional groups through a ligand-exchange reaction on dodecylamine (DDA)-coated nanocrystals. This band-edge absorption shift is due to the delocalization of the strongly confined excitonic hole from nanocrystals to the ligand molecular orbitals and not from nanocrystal growth or dielectric constant effects. (1)H NMR analysis confirmed that the nanocrystal surface contained a mixed ligation of DDA and PDTC. The effects of the nanocrystal size on the extent of exciton delocalization were also studied and found to be smaller for larger nanocrystals. Modulating the energy level of ligand-passivated ultrasmall nanocrystals and controlling the electronic interaction at the nanocrystal-passivating ligand interface are very important to the fabrication of solid-state devices.
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Affiliation(s)
- Meghan B Teunis
- Department of Chemistry and Chemical Biology and ‡Integrated Nanosystems Development Institute, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana 46202, United States
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38
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Farvid SS, Sabergharesou T, Hutfluss LN, Hegde M, Prouzet E, Radovanovic PV. Evidence of Charge-Transfer Ferromagnetism in Transparent Diluted Magnetic Oxide Nanocrystals: Switching the Mechanism of Magnetic Interactions. J Am Chem Soc 2014; 136:7669-79. [PMID: 24835755 DOI: 10.1021/ja501888a] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Shokouh S. Farvid
- Department of Chemistry, University of Waterloo, 200 University
Avenue West, Waterloo, Ontario N2L
3G1, Canada
| | - Tahereh Sabergharesou
- Department of Chemistry, University of Waterloo, 200 University
Avenue West, Waterloo, Ontario N2L
3G1, Canada
| | - Lisa N. Hutfluss
- Department of Chemistry, University of Waterloo, 200 University
Avenue West, Waterloo, Ontario N2L
3G1, Canada
| | - Manu Hegde
- Department of Chemistry, University of Waterloo, 200 University
Avenue West, Waterloo, Ontario N2L
3G1, Canada
| | - Eric Prouzet
- Department of Chemistry, University of Waterloo, 200 University
Avenue West, Waterloo, Ontario N2L
3G1, Canada
| | - Pavle V. Radovanovic
- Department of Chemistry, University of Waterloo, 200 University
Avenue West, Waterloo, Ontario N2L
3G1, Canada
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39
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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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40
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Yang Y, Li Y, Zhu L, He H, Hu L, Huang J, Hu F, He B, Ye Z. Shape control of colloidal Mn doped ZnO nanocrystals and their visible light photocatalytic properties. NANOSCALE 2013; 5:10461-10471. [PMID: 24056701 DOI: 10.1039/c3nr03160h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
For colloidal semiconductor nanocrystals (NCs), shape control and doping as two widely applied strategies are crucial for enhancing and manipulating their functional properties. Here we report a facile and green synthetic approach for high-quality colloidal Mn doped ZnO NCs with simultaneous control over composition, shape and optical properties. Specifically, the shape of doped ZnO NCs can be finely modulated from three dimensional (3D) tetrapods to 0D spherical nanoparticles in a single reaction scheme. The growth mechanism of doped ZnO NCs with interesting shape transition is explored. Furthermore, we demonstrate the tunable optical absorption features of Mn doped ZnO NCs by varying the Mn doping levels, and the enhanced photocatalytic performance of Mn doped ZnO NCs under visible light, which can be further optimized by delicately controlling their shapes and Mn doping concentrations. Our results provide an improved understanding of the growth mechanism of doped NCs during the growth process and can be potentially extended to ZnO NCs doped with other metal ions for various applications.
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Affiliation(s)
- Yefeng Yang
- State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. China.
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41
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Schimpf AM, Gunthardt CE, Rinehart JD, Mayer JM, Gamelin DR. Controlling Carrier Densities in Photochemically Reduced Colloidal ZnO Nanocrystals: Size Dependence and Role of the Hole Quencher. J Am Chem Soc 2013; 135:16569-77. [DOI: 10.1021/ja408030u] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Alina M. Schimpf
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Carolyn E. Gunthardt
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Jeffrey D. Rinehart
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - James M. Mayer
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R. Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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42
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Ruddy DA, Erslev PT, Habas SE, Seabold JA, Neale NR. Surface Chemistry Exchange of Alloyed Germanium Nanocrystals: A Pathway Toward Conductive Group IV Nanocrystal Films. J Phys Chem Lett 2013; 4:416-421. [PMID: 26281733 DOI: 10.1021/jz3020875] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present an expansion of the mixed-valence iodide reduction method for the synthesis of Ge nanocrystals (NCs) to incorporate low levels (∼1 mol %) of groups III, IV, and V elements to yield main-group element-alloyed Ge NCs (Ge1-xEx NCs). Nearly every main-group element (E) that surrounds Ge on the periodic table (Al, P, Ga, As, In, Sn, and Sb) may be incorporated into Ge1-xEx NCs with remarkably high E incorporation into the product (>45% of E added to the reaction). Importantly, surface chemistry modification via ligand exchange allowed conductive films of Ge1-xEx NCs to be prepared, which exhibit conductivities over large distances (25 μm) relevant to optoelectronic device development of group IV NC thin films.
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Affiliation(s)
- Daniel A Ruddy
- †Chemical and Materials Science Center and ‡National Center for Photovoltaics, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Peter T Erslev
- †Chemical and Materials Science Center and ‡National Center for Photovoltaics, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Susan E Habas
- †Chemical and Materials Science Center and ‡National Center for Photovoltaics, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Jason A Seabold
- †Chemical and Materials Science Center and ‡National Center for Photovoltaics, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Nathan R Neale
- †Chemical and Materials Science Center and ‡National Center for Photovoltaics, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
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43
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Nag A, Chung DS, Dolzhnikov DS, Dimitrijevic NM, Chattopadhyay S, Shibata T, Talapin DV. Effect of metal ions on photoluminescence, charge transport, magnetic and catalytic properties of all-inorganic colloidal nanocrystals and nanocrystal solids. J Am Chem Soc 2012; 134:13604-15. [PMID: 22812398 DOI: 10.1021/ja301285x] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Colloidal semiconductor nanocrystals (NCs) provide convenient "building blocks" for solution-processed solar cells, light-emitting devices, photocatalytic systems, etc. The use of inorganic ligands for colloidal NCs dramatically improved inter-NC charge transport, enabling fast progress in NC-based devices. Typical inorganic ligands (e.g., Sn(2)S(6)(4-), S(2-)) are represented by negatively charged ions that bind covalently to electrophilic metal surface sites. The binding of inorganic charged species to the NC surface provides electrostatic stabilization of NC colloids in polar solvents without introducing insulating barriers between NCs. In this work we show that cationic species needed for electrostatic balance of NC surface charges can also be employed for engineering almost every property of all-inorganic NCs and NC solids, including photoluminescence efficiency, electron mobility, doping, magnetic susceptibility, and electrocatalytic performance. We used a suite of experimental techniques to elucidate the impact of various metal ions on the characteristics of all-inorganic NCs and developed strategies for engineering and optimizing NC-based materials.
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Affiliation(s)
- Angshuman Nag
- Department of Chemistry and James Frank Institute, University of Chicago, Illinois 60637, USA
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44
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Abolfath RM, Korkusinski M, Brabec T, Hawrylak P. Spin textures in strongly coupled electron spin and magnetic or nuclear spin systems in quantum dots. PHYSICAL REVIEW LETTERS 2012; 108:247203. [PMID: 23004315 DOI: 10.1103/physrevlett.108.247203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 02/20/2012] [Indexed: 06/01/2023]
Abstract
Controlling electron spins strongly coupled to magnetic and nuclear spins in solid state systems is an important challenge in the field of spintronics and quantum computation. We show here that electron droplets with no net spin in semiconductor quantum dots strongly coupled with magnetic ion or nuclear spin systems break down at low temperature and form a nontrivial antiferromagnetic spatially ordered spin texture of magnetopolarons. The spatially ordered combined electron-magnetic ion spin texture, associated with spontaneous symmetry breaking in the parity of electronic charge and spin densities and magnetization of magnetic ions, emerges from an ab initio density functional approach to the electronic system coupled with mean-field approximation for the magnetic or nuclear spin system. The predicted phase diagram determines the critical temperature as a function of coupling strength and identifies possible phases of the strongly coupled spin system. The prediction may arrest fluctuations in the spin system and open the way to control, manipulate, and prepare magnetic and nuclear spin ensembles in semiconductor nanostructures.
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Affiliation(s)
- Ramin M Abolfath
- School of Natural Sciences and Mathematics, University of Texas at Dallas, Richardson, Texas 75080, USA
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45
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May JW, McMorris RJ, Li X. Ferromagnetism in p-Type Manganese-Doped Zinc Oxide Quantum Dots. J Phys Chem Lett 2012; 3:1374-1380. [PMID: 26286785 DOI: 10.1021/jz300273k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The magnetic exchange interactions between paramagnetic Mn(2+) dopants in the presence of a N(2-) p-type defect in zinc oxide quantum dots are studied using density functional theory. Spin-dependent delocalization of the N(2-) 2p acceptor level among the nearest-neighbor Mn(2+) dopants is observed. The calculations show that parallel Mn(2+) spin alignment is favored upon the formation of a nitrogen-bridged Mn-Mn dimer. Although the effect is short-ranged, the observed magnitude of stabilization of the ferromagnetic alignment of nearest-neighbor Mn(2+) spins arises from p-d exchange and suggests p-type Mn(2+)-doped ZnO quantum dots as excellent candidates for exhibiting room-temperature ferromagnetism. Analytical expressions are derived and supported by density functional theory calculations that show that the N(2-) concentration has a stronger influence on the magnetic splitting compared with that of the Mn(2+) concentration.
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Affiliation(s)
- Joseph W May
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Ryan J McMorris
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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46
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Cohn AW, Kittilstved KR, Gamelin DR. Tuning the Potentials of “Extra” Electrons in Colloidal n-Type ZnO Nanocrystals via Mg2+ Substitution. J Am Chem Soc 2012; 134:7937-43. [DOI: 10.1021/ja3019934] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alicia W. Cohn
- Department
of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Kevin R. Kittilstved
- Department
of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R. Gamelin
- Department
of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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47
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Trojnar AH, Korkusiński M, Kadantsev ES, Hawrylak P, Goryca M, Kazimierczuk T, Kossacki P, Wojnar P, Potemski M. Quantum interference in exciton-Mn spin interactions in a CdTe semiconductor quantum dot. PHYSICAL REVIEW LETTERS 2011; 107:207403. [PMID: 22181774 DOI: 10.1103/physrevlett.107.207403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Indexed: 05/31/2023]
Abstract
We show theoretically and experimentally the existence of a new quantum-interference effect between the electron-hole interactions and the scattering by a single Mn impurity. The theoretical model, including electron-valence-hole correlations, the short- and long-range exchange interaction of a Mn ion with the heavy hole and with electron and anisotropy of the quantum dot, is compared with photoluminescence spectroscopy of CdTe dots with single magnetic ions. We show how the design of the electronic levels of a quantum dot enables the design of an exciton, control of the quantum interference, and hence engineering of light-Mn interaction.
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Affiliation(s)
- A H Trojnar
- Institute for Microstructural Sciences, National Research Council, Ottawa, Canada
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48
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Viswanatha R, Brovelli S, Pandey A, Crooker SA, Klimov VI. Copper-doped inverted core/shell nanocrystals with "permanent" optically active holes. NANO LETTERS 2011; 11:4753-8. [PMID: 21942276 DOI: 10.1021/nl202572c] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We have developed a new class of colloidal nanocrystals composed of Cu-doped ZnSe cores overcoated with CdSe shells. Via spectroscopic and magneto-optical studies, we conclusively demonstrate that Cu impurities represent paramagnetic +2 species and serve as a source of permanent optically active holes. This implies that the Fermi level is located below the Cu(2+)/Cu(1+) state, that is, in the lower half of the forbidden gap, which is a signature of a p-doped material. It further suggests that the activation of optical emission due to the Cu level requires injection of only an electron without a need for a valence-band hole. This peculiar electron-only emission mechanism is confirmed by experiments in which the titration of the nanocrystals with hole-withdrawing molecules leads to enhancement of Cu-related photoluminescence while simultaneously suppressing the intrinsic, band-edge exciton emission. In addition to containing permanent optically active holes, these newly developed materials show unprecedented emission tunability from near-infrared (1.2 eV) to the blue (3.1 eV) and reduced losses from reabsorption due to a large Stokes shift (up to 0.7 eV). These properties make them very attractive for applications in light-emission and lasing technologies and especially for the realization of novel device concepts such as "zero-threshold" optical gain.
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Affiliation(s)
- Ranjani Viswanatha
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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White MA, Weaver AL, Beaulac R, Gamelin DR. Electrochemically controlled auger quenching of Mn²+ photoluminescence in doped semiconductor nanocrystals. ACS NANO 2011; 5:4158-4168. [PMID: 21452880 DOI: 10.1021/nn200889q] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Auger processes in colloidal semiconductor nanocrystals have been scrutinized extensively in recent years. Whether involving electron-exciton, hole-exciton, or exciton-exciton interactions, such Auger processes are generally fast and hence have been considered prominent candidates for interpreting fast processes relevant to photoluminescence blinking and multiexciton decay. With recent advances in the chemistries of nanocrystal doping, increasing attention is now being paid to analogous photophysical properties of colloidal-doped semiconductor nanocrystals. Here, we report the first investigation of the effects of electron-dopant exchange interactions on dopant luminescence in doped semiconductor nanocrystals. Using electrochemical techniques, electrical control of charge-carrier densities in films of colloidal Mn(2+)-doped CdS quantum dots has been achieved and used to demonstrate remarkably effective Auger de-excitation of photoexcited Mn(2+). The doped nanocrystals are found to be substantially more sensitive to Auger de-excitation than their undoped analogues, a result shown to arise primarily from the long Mn(2+) excited-state lifetime. This observation of exceptionally effective Auger quenching has broader implications in areas of high-power, single-particle, or electrically driven luminescence of doped semiconductor nanocrystals, and also suggests interesting opportunities for modulating Mn(2+) photoluminescence intensities on sublifetime time scales, or for imaging charge carriers in nanocrystal-based devices.
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Affiliation(s)
- Michael A White
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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Oszwałdowski R, Zutić I, Petukhov AG. Magnetism in closed-shell quantum dots: emergence of magnetic bipolarons. PHYSICAL REVIEW LETTERS 2011; 106:177201. [PMID: 21635058 DOI: 10.1103/physrevlett.106.177201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Indexed: 05/30/2023]
Abstract
Similar to atoms and nuclei, semiconductor quantum dots exhibit the formation of shells. Predictions of magnetic behavior of the dots are often based on the shell occupancies. Thus, closed-shell quantum dots are assumed to be inherently nonmagnetic. Here, we propose a possibility of magnetism in such dots doped with magnetic impurities. On the example of the system of two interacting fermions, the simplest embodiment of the closed-shell structure, we demonstrate the emergence of a novel broken-symmetry ground state that is neither spin singlet nor spin triplet. We propose experimental tests of our predictions and the magnetic-dot structures to perform them.
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Affiliation(s)
- Rafał Oszwałdowski
- Department of Physics, University at Buffalo, Buffalo, New York 14260-1500, USA
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