1
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Li D, Gui Z, Ling M, Guo L, Wang Z, Yuan Q, Cheng L. Modulating the bandgap of Cr-intercalated bilayer graphene via combining the 18-electron rule and the 2D superatomic-molecule theory. NANOSCALE 2024. [PMID: 39219367 DOI: 10.1039/d4nr02440k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Bandgap engineering of graphene is of great significance for its potential applications in electronic devices. Herein, we used a sandwich compound Cr(C6H6)2 as the building block to construct Cr-intercalated bilayer graphene (BLG), namely a C12Cr monolayer. Chemical bonding analysis reveals that strong d-π interaction ensures π electrons of the graphene layers and d orbitals of the Cr atoms localized in C6CrC6 units to achieve the favored 18-electron rule, thus leading to a bandgap of 0.24 eV. Subsequently, a C48Cr monolayer with lower proportion of Cr is further designed using Cr(C54H18)2 as building units, where a newly developed two-dimensional (2D) superatomic-molecule theory is introduced to rationalize its electronic structure. The C48Cr monolayer not only satisfies the 18-electron rule, but also localizes extra π electrons to form two layers of 2D superatomic crystals composed of 2D superatoms (◊O and ◊N), resulting in a wider bandgap of 0.74 eV. This work opens an effective avenue to modulate the bandgap of BLG via combining the 18-electron rule and the 2D superatomic-molecule theory.
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Affiliation(s)
- Dan Li
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Zaijun Gui
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Mengxuan Ling
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Lijiao Guo
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Zhifang Wang
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Qinqin Yuan
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Longjiu Cheng
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Hefei, 230601, P. R. China
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2
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Ekka J, Upadhyay SN, Keil FJ, Pakhira S. Unveiling the role of 2D monolayer Mn-doped MoS 2 material: toward an efficient electrocatalyst for H 2 evolution reaction. Phys Chem Chem Phys 2021; 24:265-280. [PMID: 34881758 DOI: 10.1039/d1cp04344g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two-dimensional (2D) monolayer pristine MoS2 transition metal dichalcogenide (TMD) is the most studied material because of its potential applications as nonprecious electrocatalyst for the hydrogen evolution reaction (HER). Previous studies have shown that the basal planes of 2D MoS2 are catalytically inert, and hence it cannot be used directly in desired applications such as electrochemical HER in industry. Here, we thoroughly studied a defect-engineered Mn-doped 2D monolayer MoS2 (Mn-MoS2) material, where Mn was doped in pristine MoS2 to activate its inert basal planes. Using the density functional theory (DFT) method, we performed rigorous inspection of the electronic structures and properties of the 2D monolayer Mn-MoS2 as a promising alternative to noble metal-free catalyst for effective HER. A periodic 2D slab of monolayer Mn-MoS2 was created to study the electronic properties (such as band gap, band structures and total density of states (DOS)) and the reaction pathways occurring on the surface of this material. The detailed HER mechanism was explored by creating an Mn1Mo9S21 non-periodic finite molecular cluster model system using the M06-L DFT method including solvation effects to determine the reaction barriers and kinetics. Our study revealed that the 2D Mn-MoS2 follows the most favorable Volmer-Heyrovsky reaction mechanism with a very low energy barrier during H2 evolution. It was found that the change in the free energy barrier (ΔG) during the H˙-migration (i.e., Volmer) and Heyrovsky reactions is about 10.34-10.79 kcal mol-1 (computed in the solvent phase), indicating that this material is an exceptional electrocatalyst for the HER. The Tafel slope (y) was lower in the case of the 2D monolayer Mn-MoS2 material due to the overlap of the s-orbital of hydrogen and d-orbitals of the Mn atoms in the HOMO and LUMO transition states (TS1 and TS2) of both the Volmer and Heyrovsky reaction steps, respectively. The better stabilization of the atomic orbitals in the HER rate-limiting step Heyrovsky TS2 is the key for reducing the reaction barrier, and thus the overall catalysis, indicating a better electrocatalytic performance for H2 evolution. This study focused on designing low-cost and efficient electrocatalysts for the HER using earth abundant transition metal dichalcogenides (TMDs) and decreasing the activation energy barriers by scrutinizing the kinetics of the reaction to achieve high reactivity.
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Affiliation(s)
- Joy Ekka
- Department of Physics, Indian Institute of Technology Indore (IIT Indore), Simrol, Khandwa Road, Indore 453552, MP, India.
| | - Shrish Nath Upadhyay
- Department of Metallurgy Engineering and Materials Science (MEMS), Indian Institute of Technology Indore (IIT Indore), Khandwa Road, Simrol, Indore 453552, MP, India
| | - Frerich J Keil
- Department of Chemical Reaction Engineering, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Srimanta Pakhira
- Department of Physics, Indian Institute of Technology Indore (IIT Indore), Simrol, Khandwa Road, Indore 453552, MP, India. .,Department of Metallurgy Engineering and Materials Science (MEMS), Indian Institute of Technology Indore (IIT Indore), Khandwa Road, Simrol, Indore 453552, MP, India.,Centre for Advanced Electronics (CAE), Indian Institute of Technology Indore (IIT Indore), Khandwa Road, Simrol, Indore 453552, MP, India
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3
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Wang C, Wang H, Chen W, Xie X, Zong J, Liu L, Jin S, Zhang Y, Yu F, Meng Q, Tian Q, Wang L, Ren W, Li F, Zhang H, Zhang Y. Direct Observation of Global Elastic Intervalley Scattering Induced by Impurities on Graphene. NANO LETTERS 2021; 21:8258-8265. [PMID: 34570496 DOI: 10.1021/acs.nanolett.1c02714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The scattering process induced by impurities in graphene plays a key role in transport properties. Especially, the disorder impurities can drive the ordered state with a hexagonal superlattice on graphene by electron-mediated interaction at a transition temperature. Using angle-resolved photoemission spectroscopy (ARPES), we reveal that the epitaxial monolayer and bilayer graphene with various impurities display global elastic intervalley scattering and quantum interference below the critical temperature (34 K), which leads to a set of new folded Dirac cones at the Brillouin-zone center by mixing two inequivalent Dirac cones. The Dirac electrons generated from intervalley scattering without chirality can be due to the breaking of the sublattice symmetry. In addition, the temperature-dependent ARPES measurements indicate the thermal damping of quantum interference patterns from Dirac electron scattering on impurities. Our results demonstrate that the electron scattering and interference induced by impurities can completely modulate the Dirac bands of graphene.
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Affiliation(s)
- Can Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Huaiqiang Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wang Chen
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Xuedong Xie
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Junyu Zong
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Lulu Liu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Shaoen Jin
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Yongheng Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Fan Yu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Qinghao Meng
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Qichao Tian
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Li Wang
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Wei Ren
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Fangsen Li
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Haijun Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yi Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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4
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Guo H, Zhang R, Li H, Wang X, Lu H, Qian K, Li G, Huang L, Lin X, Zhang YY, Ding H, Du S, Pantelides ST, Gao HJ. Sizable Band Gap in Epitaxial Bilayer Graphene Induced by Silicene Intercalation. NANO LETTERS 2020; 20:2674-2680. [PMID: 32125162 DOI: 10.1021/acs.nanolett.0c00306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Opening a band gap in bilayer graphene (BLG) is of significance for potential applications in graphene-based electronic and photonic devices. Here, we report the generation of a sizable band gap in BLG by intercalating silicene between BLG and Ru substrate. We first grow high-quality Bernal-stacked BLG on Ru(0001) and then intercalate silicene to the interface between the BLG and Ru, which is confirmed by low-energy electron diffraction and scanning tunneling microscopy. Raman spectroscopy shows that the G and 2D peaks of the intercalated BLG are restored to the freestanding-BLG features. Angle-resolved photoelectron spectroscopy measurements show that a band gap of about 0.2 eV opens in the BLG. Density functional theory calculations indicate that the large-gap opening results from a cooperative contribution of the doping and rippling/strain in the BLG. This work provides insightful understanding on the mechanism of band gap opening in BLG and enhances the potential of graphene-based device development.
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Affiliation(s)
- Hui Guo
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Ruizi Zhang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Hang Li
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Xueyan Wang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Hongliang Lu
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Kai Qian
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Geng Li
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Li Huang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Xiao Lin
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Yu-Yang Zhang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Hong Ding
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, P.R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, P.R. China
| | - Shixuan Du
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, P.R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, P.R. China
| | - Sokrates T Pantelides
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Hong-Jun Gao
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, P.R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, P.R. China
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5
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Pradhan NR, Garcia C, Lucking MC, Pakhira S, Martinez J, Rosenmann D, Divan R, Sumant AV, Terrones H, Mendoza-Cortes JL, McGill SA, Zhigadlo ND, Balicas L. Raman and electrical transport properties of few-layered arsenic-doped black phosphorus. NANOSCALE 2019; 11:18449-18463. [PMID: 31576874 DOI: 10.1039/c9nr04598h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Black phosphorus (b-P) is an allotrope of phosphorus whose properties have attracted great attention. In contrast to other 2D compounds, or pristine b-P, the properties of b-P alloys have yet to be explored. In this report, we present a detailed study on the Raman spectra and on the temperature dependence of the electrical transport properties of As-doped black phosphorus (b-AsP) for an As fraction x = 0.25. The observed complex Raman spectra were interpreted with the support of Density Functional Theory (DFT) calculations since each original mode splits in three due to P-P, P-As, and As-As bonds. Field-effect transistors (FET) fabricated from few-layered b-AsP exfoliated onto Si/SiO2 substrates exhibit hole-doped like conduction with a room temperature ON/OFF current ratio of ∼103 and an intrinsic field-effect mobility approaching ∼300 cm2 V-1 s-1 at 300 K which increases up to 600 cm2 V-1 s-1 at 100 K when measured via a 4-terminal method. Remarkably, these values are comparable to, or higher, than those initially reported for pristine b-P, indicating that this level of As doping is not detrimental to its transport properties. The ON to OFF current ratio is observed to increase up to 105 at 4 K. At high gate voltages b-AsP displays metallic behavior with the resistivity decreasing with decreasing temperature and saturating below T ∼100 K, indicating a gate-induced insulator to metal transition. Similarly to pristine b-P, its transport properties reveal a high anisotropy between armchair (AC) and zig-zag (ZZ) directions. Electronic band structure computed through periodic dispersion-corrected hybrid Density Functional Theory (DFT) indicate close proximity between the Fermi level and the top of the valence band(s) thus explaining its hole doped character. Our study shows that b-AsP has potential for optoelectronics applications that benefit from its anisotropic character and the ability to tune its band gap as a function of the number of layers and As content.
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Affiliation(s)
- Nihar R Pradhan
- Department of Chemistry, Physics and Atmospheric Sciences, Jackson State University, Jackson, MS 39217, USA.
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6
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Sinha N, Deshpande I, Pakhira S. Substituents Effects of Organic Linkers on Rotational Energy Barriers in Metal‐Organic Frameworks. ChemistrySelect 2019. [DOI: 10.1002/slct.201901278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Nilima Sinha
- Discipline of Metallurgy Engineering and Materials Science (MEMS)Indian Institute of Technology Indore (IIT Indore), Simrol, Khandwa Road Indore- 453552, Madhya Pradesh (M.P.) India
| | - Indraneel Deshpande
- Discipline of Metallurgy Engineering and Materials Science (MEMS)Indian Institute of Technology Indore (IIT Indore), Simrol, Khandwa Road Indore- 453552, Madhya Pradesh (M.P.) India
| | - Srimanta Pakhira
- Discipline of Metallurgy Engineering and Materials Science (MEMS)Indian Institute of Technology Indore (IIT Indore), Simrol, Khandwa Road Indore- 453552, Madhya Pradesh (M.P.) India
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7
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Davydov VN. Some peculiarities of thermopower at the Lifshitz topological transitions due to stacking change in bilayer and multilayer graphene. Proc Math Phys Eng Sci 2019. [DOI: 10.1098/rspa.2019.0028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Singularities of thermopower (the Seebeck coefficient) are considered at the Lifshitz topological transitions (LTT) in bilayer graphene (BLG) and multilayer graphene (MLG) due to stacking change from
AB
to
AA
. The dependence of singularities on
μ
,
γ
1
and
Δ
is investigated (
μ
is the chemical potential,
γ
1
is the interlayer hopping parameter and
Δ
is the gap value) for the gapped graphene, as well as for the gapless one. The present paper results indicate that effects of the thermopower singularities are appreciable and can be used to observe the LTT, and to explore the degree of stacking change from
AB
to
AA
in graphene. Therefore, the thermopower singularities at LTT due to stacking change from
AB
to
AA
can be used as a powerful tool to control electronic properties of BLG- and MLG-based structures.
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Affiliation(s)
- V. N. Davydov
- M. V. Lomonosov Moscow State University, Leninsky pr. 71, app. 121, 117296 Moscow, Russia
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8
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Pandey D, Kamal C, Chakrabarti A. Intercalation of transition metals in aluminene bi-layers: An ab initio study. J Chem Phys 2019; 150:194702. [PMID: 31117777 DOI: 10.1063/1.5093945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using first principles calculations based on density functional theory (DFT), we probe various possible stacking arrangements of bilayer aluminene and intercalate six transition metal (TM) atoms (Ti, Cr, Mn, Fe, Co, and Ni) in unique bilayer aluminene systems. Further, we calculate valence charge density and electron localization function to ascertain the nature of bonding present in both the pristine and TM-intercalated composite systems. Intercalation of Cr, Mn, and Fe is found to result in the magnetic ground state. For Ti, Co, and Ni-intercalated systems, the starting trigonal symmetry has changed to a tetragonal symmetry. Co and Ni intercalated systems exhibit much higher (negative) formation energies compared to the other composite systems. In addition, nesting of the Fermi surface has been probed for the Co and Ni intercalated systems and observations indicate the possibility of the presence of charge density wave in the systems. A dispersion-corrected DFT study suggests that the van der Waals interaction is not likely to play a crucial role in determining the properties of both the pristine and TM-intercalated systems.
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Affiliation(s)
- Dhanshree Pandey
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - C Kamal
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Aparna Chakrabarti
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
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Pakhira S, Mendoza-Cortes JL. Intercalation of first row transition metals inside covalent-organic frameworks (COFs): a strategy to fine tune the electronic properties of porous crystalline materials. Phys Chem Chem Phys 2019; 21:8785-8796. [DOI: 10.1039/c8cp07396a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covalent-organic frameworks (COFs) have emerged as an important class of nano-porous crystalline materials with many potential applications. Here we present an strategy to control their electronic properties.
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Affiliation(s)
- Srimanta Pakhira
- Discipline of Metallurgy Engineering and Materials Science
- Indian Institute of Technology Indore (IIT Indore)
- Indore-453552
- India
- Condensed Matter Science
| | - Jose L. Mendoza-Cortes
- Condensed Matter Science
- National High Magnetic Field Laboratory (NHMFL)
- Florida State University (FSU)
- Tallahassee
- USA
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