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Singla S, Joshi P, López-Morales GI, Sarkar S, Sarkar S, Flick J, Chakraborty B. Probing Correlation of Optical Emission and Defect Sites in Hexagonal Boron Nitride by High-Resolution STEM-EELS. NANO LETTERS 2024. [PMID: 38888554 DOI: 10.1021/acs.nanolett.4c01477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Optically bright emitters in hexagonal boron nitride (hBN) often acting as a source of a single-photon are mostly attributed to point-defect centers, featuring localized intra-bandgap electronic states. Although vacancies, anti-sites, and impurities have been proposed as candidates, the exact physical and chemical nature of most hBN single-photon emitters (SPEs) within the visible region are still up for debate. Combining site-specific high-angle annular dark-field imaging (HAADF) with electron energy loss spectroscopy (EELS), we resolve and identify a few carbon substitutions among neighboring hBN hexagons, all within the same sample region, from which typical defect emission is observed. Our experimental results are further supported by first-principles calculations, through which the stability and possible optical transitions of the proposed carbon-defect complex are assessed. The presented correlation between optical emission and defects provides valuable information toward the controlled creation of emitters in hBN, highlighting carbon complexes as another probable cause of its visible SPEs.
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Affiliation(s)
- Sakal Singla
- Department of Physics, Indian Institute of Technology Jammu, Jammu 181221, India
| | - Pragya Joshi
- Department of Physics, Indian Institute of Technology Jammu, Jammu 181221, India
| | | | - Suman Sarkar
- Central Instrumental Facility, Indian Institute of Technology Jammu, Jammu 181221, India
| | - Suman Sarkar
- Department of Materials Engineering, Indian Institute of Technology Jammu, Jammu 181221, India
| | - Johannes Flick
- Department of Physics, The Graduate Center, City University of New York, New York, New York 10016, United States
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
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2
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Tang R, Wang H, Dong X, Zhang L, Sun Y, Dong F. Selectivity regulation of CO 2 photoreduction via the electron configuration of active sites on single-atom photocatalysts. J Colloid Interface Sci 2024; 655:243-252. [PMID: 37944372 DOI: 10.1016/j.jcis.2023.10.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 10/23/2023] [Accepted: 10/29/2023] [Indexed: 11/12/2023]
Abstract
The major challenge in the photocatalytic reduction of CO2 is to achieve high conversion efficiency while maintaining selectivity for a single product. Photocatalysts containing single-metal Cu2+ with 3d9 and Zn2+ with 3d10 on g-C3N4 were prepared using a high-energy ball mill. Single-atom Zn inner electron configuration is stable (3d10) and the peripheral empty orbitals act as electron traps to trap photo-generated electrons and improve the efficiency of charge separation; Zn is an active site to enhance the adsorption and activation of CO2. The stable electron configuration can reduce the energy required for the overall reaction and increase the activity while changing the reaction pathway to form CO. As a result, the 0.5 mol% Zn/g-C3N4 (Zn-CN-0.5) photocatalyst achieves ∼100 % selectivity for the photocatalytic reduction of CO2 to CO at a rate of ∼21.1 μmol·g-1·h-1. In contrast, the 0.5 mol% Cu/g-C3N4 (Cu-CN-0.5) photocatalyst with an unstable electronic structure does not exhibit high selectivity.
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Affiliation(s)
- Ruofei Tang
- Yangtze Delta Region Institute (Huzhou) & Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Huzhou 313000, China; Sichuan Provincial Engineering Research Center of Functional Development and Application of High Performance Special Textile Materials, Chengdu Textile College, Chengdu, 611731, China
| | - Hong Wang
- Yangtze Delta Region Institute (Huzhou) & Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Huzhou 313000, China
| | - Xing'an Dong
- Yangtze Delta Region Institute (Huzhou) & Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Huzhou 313000, China
| | - Lili Zhang
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE(2)), Agency for Science, Technology and Research (A*STAR), 1 Pesek Road, Jurong Island 627833, Singapore
| | - Yanjuan Sun
- Yangtze Delta Region Institute (Huzhou) & Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Huzhou 313000, China
| | - Fan Dong
- Yangtze Delta Region Institute (Huzhou) & Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Huzhou 313000, China.
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3
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Olatomiwa A, Adam T, Edet C, Adewale A, Chik A, Mohammed M, Gopinath SC, Hashim U. Recent advances in density functional theory approach for optoelectronics properties of graphene. Heliyon 2023; 9:e14279. [PMID: 36950613 PMCID: PMC10025043 DOI: 10.1016/j.heliyon.2023.e14279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023] Open
Abstract
Graphene has received tremendous attention among diverse 2D materials because of its remarkable properties. Its emergence over the last two decades gave a new and distinct dynamic to the study of materials, with several research projects focusing on exploiting its intrinsic properties for optoelectronic devices. This review provides a comprehensive overview of several published articles based on density functional theory and recently introduced machine learning approaches applied to study the electronic and optical properties of graphene. A comprehensive catalogue of the bond lengths, band gaps, and formation energies of various doped graphene systems that determine thermodynamic stability was reported in the literature. In these studies, the peculiarity of the obtained results reported is consequent on the nature and type of the dopants, the choice of the XC functionals, the basis set, and the wrong input parameters. The different density functional theory models, as well as the strengths and uncertainties of the ML potentials employed in the machine learning approach to enhance the prediction models for graphene, were elucidated. Lastly, the thermal properties, modelling of graphene heterostructures, the superconducting behaviour of graphene, and optimization of the DFT models are grey areas that future studies should explore in enhancing its unique potential. Therefore, the identified future trends and knowledge gaps have a prospect in both academia and industry to design future and reliable optoelectronic devices.
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Affiliation(s)
- A.L. Olatomiwa
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000, Kangar, Perlis, Malaysia
- Faculty of Electronic Engineering and Technology, Universiti Malaysia Perlis, 02600, Arau, Perlis, Malaysia
| | - Tijjani Adam
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000, Kangar, Perlis, Malaysia
- Faculty of Electronic Engineering and Technology, Universiti Malaysia Perlis, 02600, Arau, Perlis, Malaysia
- Micro System Technology, Centre of Excellence (CoE), Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600, Arau, Perlis, Malaysia
| | - C.O. Edet
- Faculty of Electronic Engineering and Technology, Universiti Malaysia Perlis, 02600, Arau, Perlis, Malaysia
- Institute of Engineering Mathematics, Universiti Malaysia Perlis, 02600, Arau, Perlis, Malaysia
- Department of Physics, Cross River University of Technology, Calabar, Nigeria
| | - A.A. Adewale
- Department of Pure and Applied Physics, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Abdullah Chik
- Centre for Frontier Materials Research, Universiti Malaysia Perlis, 01000, Kangar, Perlis, Malaysia
- Faculty of Chemical Engineering and Technology, Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, Jejawi, 02600, Arau, Perlis, Malaysia
| | - Mohammed Mohammed
- Faculty of Chemical Engineering and Technology, Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, Jejawi, 02600, Arau, Perlis, Malaysia
- Center of Excellence Geopolymer & Green Technology (CEGeoGTech), Universiti Malaysia Perlis, 02600, Arau, Perlis, Malaysia
| | - Subash C.B. Gopinath
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000, Kangar, Perlis, Malaysia
- Micro System Technology, Centre of Excellence (CoE), Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600, Arau, Perlis, Malaysia
- Faculty of Chemical Engineering and Technology, Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, Jejawi, 02600, Arau, Perlis, Malaysia
| | - U. Hashim
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000, Kangar, Perlis, Malaysia
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4
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Susi T. Identifying and manipulating single atoms with scanning transmission electron microscopy. Chem Commun (Camb) 2022; 58:12274-12285. [PMID: 36260089 PMCID: PMC9632407 DOI: 10.1039/d2cc04807h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/28/2022] [Indexed: 08/25/2023]
Abstract
The manipulation of individual atoms has developed from visionary speculation into an established experimental science. Using focused electron irradiation in a scanning transmission electron microscope instead of a physical tip in a scanning probe microscope confers several benefits, including thermal stability of the manipulated structures, the ability to reach into bulk crystals, and the chemical identification of single atoms. However, energetic electron irradiation also presents unique challenges, with an inevitable possibility of irradiation damage. Understanding the underlying mechanisms will undoubtedly continue to play an important role to guide experiments. Great progress has been made in several materials including graphene, carbon nanotubes, and crystalline silicon in the eight years since the discovery of electron-beam manipulation, but the important challenges that remain will determine how far we can expect to progress in the near future.
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Affiliation(s)
- Toma Susi
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
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5
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The effect of coordination environment on the activity and selectivity of single-atom catalysts. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214493] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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6
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Gou Z, Qu H, Liu H, Ma Y, Zong L, Li B, Xie C, Li Z, Li W, Wang L. Coupling of N-Doped Mesoporous Carbon and N-Ti 3 C 2 in 2D Sandwiched Heterostructure for Enhanced Oxygen Electroreduction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106581. [PMID: 35229469 DOI: 10.1002/smll.202106581] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/27/2022] [Indexed: 06/14/2023]
Abstract
2D heterostructures provide a competitive platform to tailor electrical property through control of layer structure and constituents. However, despite the diverse integration of 2D materials and their application flexibility, tailoring synergistic interlayer interactions between 2D materials that form electronically coupled heterostructures remains a grand challenge. Here, the rational design and optimized synthesis of electronically coupled N-doped mesoporous defective carbon and nitrogen modified titanium carbide (Ti3 C2 ) in a 2D sandwiched heterostructure, is reported. First, a F127-polydopamine single-micelle-directed interfacial assembly strategy guarantees the construction of two surrounding mesoporous N-doped carbon monolayers assembled on both sides of Ti3 C2 nanosheets. Second, the followed ammonia post-treatment successfully introduces N elements into Ti3 C2 structure and more defective sites in N-doped mesoporous carbon. Finally, the oxygen reduction reaction (ORR) and theoretical calculation prove the synergistic coupled electronic effect between N-Ti3 C2 and defective N-doped carbon active sites in the 2D sandwiched heterostructure. Compared with the control 2D samples (0.87-0.88 V, 4.90-5.15 mA cm-2 ), the coupled 2D heterostructure possesses the best onset potential of 0.90 V and limited density current of 5.50 mA cm-2 . Meanwhile, this catalyst exhibits superior methanol tolerance and cyclic durability. This design philosophy opens up a new thought for tailoring synergistic interlayer interactions between 2D materials.
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Affiliation(s)
- Zhaolin Gou
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Huiqi Qu
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
| | - Hanfang Liu
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Yiru Ma
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Lingbo Zong
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Bin Li
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
- College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Congxia Xie
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Zhenjiang Li
- College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Wei Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan University Shanghai, Shanghai, 200433, China
| | - Lei Wang
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology, Qingdao, 266042, China
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
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7
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Wang J, Liu Y, Sha Q, Cao D, Hu H, Shen T, He L, Song YF. Electronic Structure Reconfiguration of Self-Supported Polyoxometalate-Based Lithium-Ion Battery Anodes for Efficient Lithium Storage. ACS APPLIED MATERIALS & INTERFACES 2022; 14:1169-1176. [PMID: 34935340 DOI: 10.1021/acsami.1c21461] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Polyoxometalate (POM)-based materials are considered as promising candidates for lithium-ion batteries (LIBs) due to their stable and well-defined molecular structure and reversible multielectron redox properties. Currently, POM-based electrode materials suffer from high interfacial resistance and low uniformity. Herein, we reported a self-supported POM-based anode material for LIBs by electrodepositing H3PMo12O40 (PMo12) and aniline on carbon cloth (CC) for the first time. The as-prepared polyaniline (PANi)-PMo12/CC composite exhibited an excellent reversible capacity of 1092 mA h g-1 for 200 cycles at 1 A g-1. Such an outstanding performance was attributed to the rapid electron transfer and Li+ diffusion stemming from the exposure of more active sites by the self-supported structure, the strong electrostatic interaction, and electronic structure reconfiguration between the active PMo12 cluster and conductive PANi polymer. This work provides insight into the electronic structure engineering of highly efficient LIB anode materials.
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Affiliation(s)
- Jiaxin Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Yubing Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Quan Sha
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Dongwei Cao
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Hanbin Hu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Tianyang Shen
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Lei He
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Yu-Fei Song
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
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8
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Fonseca J, Lu J. Single-Atom Catalysts Designed and Prepared by the Atomic Layer Deposition Technique. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01200] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Javier Fonseca
- Nanomaterial Laboratory for Catalysis and Advanced Separations, Department of Chemical Engineering, Northeastern University, 313 Snell Engineering Center, 360 Huntington Avenue, Boston, Massachusetts 02115-5000, United States
| | - Junling Lu
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China
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9
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Chen Z, Jaworski A, Chen J, Budnyak TM, Szewczyk I, Rokicińska A, Dronskowski R, Hedin N, Kuśtrowski P, Slabon A. Graphitic nitrogen in carbon catalysts is important for the reduction of nitrite as revealed by naturally abundant 15N NMR spectroscopy. Dalton Trans 2021; 50:6857-6866. [PMID: 33912887 DOI: 10.1039/d1dt00658d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal-free nitrogen-doped carbon is considered as a green functional material, but the structural determination of the atomic positions of nitrogen remains challenging. We recently demonstrated that directly-excited solid state 15N NMR (ssNMR) spectroscopy is a powerful tool for the determination of such positions in N-doped carbon at natural 15N isotope abundance. Here we report a green chemistry approach for the synthesis of N-doped carbon using cellulose as a precursor, and a study of the catalytic properties and atomic structures of the related catalyst. N-doped carbon (NH3) was obtained by the oxidation of cellulose with HNO3 followed by ammonolysis at 800 °C. It had a N content of 6.5 wt% and a surface area of 557 m2 g-1, and 15N ssNMR spectroscopy provided evidence for graphitic nitrogen besides regular pyrrolic and pyridinic nitrogen. This structural determination allowed probing the role of graphitic nitrogen in electrocatalytic reactions, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and nitrite reduction reaction. The N-doped carbon catalyst (NH3) showed higher electrocatalytic activities in the OER and HER under alkaline conditions and higher activity for nitrite reduction, as compared with a catalyst prepared by the carbonization of HNO3-treated cellulose in N2. The electrocatalytic selectivity for nitrite reduction of the N-doped carbon catalyst (NH3) was directly related to the graphitic nitrogen functions. Complementary structural analyses by means of 13C and 1H ssNMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature N2 adsorption were performed and provided support to the findings. The results show that directly-excited 15N ssNMR spectroscopy at natural 15N abundance is generally capable of providing information on N-doped carbon materials if relaxation properties are favorable. It is expected that this approach can be applied to a wide range of solids with an intermediate concentration of N atoms.
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Affiliation(s)
- Zheng Chen
- Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany and Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
| | - Aleksander Jaworski
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
| | - Jianhong Chen
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
| | - Tetyana M Budnyak
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
| | - Ireneusz Szewczyk
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
| | - Anna Rokicińska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
| | - Richard Dronskowski
- Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany and Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Blvd, Shenzhen, China
| | - Niklas Hedin
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
| | - Piotr Kuśtrowski
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
| | - Adam Slabon
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
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10
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Stasyuk AJ, Stasyuk OA, Solà M, Voityuk AA. Triquinoline‐ versus Fullerene‐Based Cycloparaphenylene Ionic Complexes: Comparison of Photoinduced Charge‐Shift Reactions. Chemistry 2020; 26:10896-10902. [DOI: 10.1002/chem.202002179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Anton J. Stasyuk
- Institut de Química Computacional and Departament de Química Universitat de Girona C/ Maria Aurèlia Capmany 69 17003 Girona Spain
| | - Olga A. Stasyuk
- Institut de Química Computacional and Departament de Química Universitat de Girona C/ Maria Aurèlia Capmany 69 17003 Girona Spain
| | - Miquel Solà
- Institut de Química Computacional and Departament de Química Universitat de Girona C/ Maria Aurèlia Capmany 69 17003 Girona Spain
| | - Alexander A. Voityuk
- Institut de Química Computacional and Departament de Química Universitat de Girona C/ Maria Aurèlia Capmany 69 17003 Girona Spain
- Institució Catalana de Recerca i Estudis Avancats (ICREA) 08010 Barcelona Spain
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11
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Direct imaging of light-element impurities in graphene reveals triple-coordinated oxygen. Nat Commun 2019; 10:4570. [PMID: 31594951 PMCID: PMC6783479 DOI: 10.1038/s41467-019-12537-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/17/2019] [Indexed: 12/03/2022] Open
Abstract
Along with hydrogen, carbon, nitrogen and oxygen are the arguably most
important elements for organic chemistry. Due to their rich variety of possible
bonding configurations, they can form a staggering number of compounds. Here, we
present a detailed analysis of nitrogen and oxygen bonding configurations in a
defective carbon (graphene) lattice. Using aberration-corrected scanning
transmission electron microscopy and single-atom electron energy loss spectroscopy,
we directly imaged oxygen atoms in graphene oxide, as well as nitrogen atoms
implanted into graphene. The collected data allows us to compare nitrogen and oxygen
bonding configurations, showing clear differences between the two elements. As
expected, nitrogen forms either two or three bonds with neighboring carbon atoms,
with three bonds being the preferred configuration. Oxygen, by contrast, tends to
bind with only two carbon atoms. Remarkably, however, triple-coordinated oxygen with
three carbon neighbors is also observed, a configuration that is exceedingly rare in
organic compounds. Annular dark field scanning transmission electron microscopy is able to
distinguish the contrasts between light elements. Here, the authors directly image
the bonding configurations of oxygen and nitrogen atoms in defective graphene, and
surprisingly identify instances of unusual triple-coordinated oxygen with three
carbon neighbors.
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12
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Abstract
The bottom-up synthesis of structurally well-defined motifs of graphitic materials is crucial to understanding their physicochemical properties and to elicit new functions. Herein, we report the design and synthesis of TriQuinoline (TQ) as a molecular model for pyridinic-nitrogen defects in graphene sheets. TQ is a trimer of quinoline units concatenated at the 2- and 8-positions in a head-to-tail fashion, whose structure leads to unusual aromatisation behaviour at the final stage of the synthesis. The central atomic-sized void endows TQ with high proton affinity, which was confirmed empirically and computationally. TQ•H+ is a two-dimensional cationic molecule that displays both π-π and CH-π contact modes, culminating in the formation of the ternary complex ([12]cycloparaphenylene(CPP) ⊃ (TQ•H+/coronene)) that consists of TQ•H+, coronene (flat), and [12]cycloparaphenylene ([12]CPP) (ring). The water-miscibility of TQ•H+ allows it to serve as an efficient DNA intercalator for e.g. the inhibition of topoisomerase I activity.
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Affiliation(s)
- Shinya Adachi
- Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan
| | - Masakatsu Shibasaki
- Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan
| | - Naoya Kumagai
- Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan.
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13
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Sinha S, Sheng Y, Griffiths I, Young NP, Zhou S, Kirkland AI, Porfyrakis K, Warner JH. In Situ Atomic-Level Studies of Gd Atom Release and Migration on Graphene from a Metallofullerene Precursor. ACS NANO 2018; 12:10439-10451. [PMID: 30256088 DOI: 10.1021/acsnano.8b06057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We show how gadolinium (Gd)-based metallofullerene (Gd3N@C80) molecules can be used to create single adatoms and nanoclusters on a graphene surface. An in situ heating holder within an aberration-corrected scanning transmission electron microscope is used to track the adhesion of endohedral metallofullerenes (MFs) to the surface of graphene, followed by Gd metal ejection and diffusion across the surface. Heating to 900 °C is used to promote adatom migration and metal nanocluster formation, enabling direct imaging of the assembly of nanoclusters of Gd. We show that hydrogen can be used to reduce the temperature of MF fragmentation and metal ejection, enabling Gd nanocluster formation on graphene surfaces at temperatures as low as 300 °C. The process of MF fragmentation and metal ejection is captured in situ and reveals that after metal release, the C80 cage opens further and fuses with the surface monolayer carbon glass on graphene, creating a highly stable carbon layer for further Gd adatom adhesion. Small voids and defects (∼1 nm) in the surface carbon glass act as trapping sites for Gd atoms, leading to atomic self-assembly of 2D monolayer Gd clusters. These results show that MFs can adhere to graphene surfaces at temperatures well above their bulk sublimation point, indicating that the surface bound MFs have strong adhesion to dangling bonds on graphene surfaces. The ability to create dispersed single Gd adatoms and Gd nanoclusters on graphene may have impact in spintronics and magnetism.
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Affiliation(s)
- Sapna Sinha
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Yuewen Sheng
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Ian Griffiths
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Neil P Young
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Si Zhou
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Angus I Kirkland
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
- Electron Physical Sciences Imaging Center , Diamond Light Source Ltd , Didcot OX11 0DE , United Kingdom
| | - Kyriakos Porfyrakis
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Jamie H Warner
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
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14
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Wang S, Sawada H, Chen Q, Han GGD, Allen C, Kirkland AI, Warner JH. In Situ Atomic-Scale Studies of the Formation of Epitaxial Pt Nanocrystals on Monolayer Molybdenum Disulfide. ACS NANO 2017; 11:9057-9067. [PMID: 28806068 DOI: 10.1021/acsnano.7b03648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pt-nanocrystal:MoS2 hybrid materials have promising catalytic properties for hydrogen evolution, and understanding their detailed structures at the atomic scale is crucial to further development. Here, we use an in situ heating holder in an aberration-corrected transmission electron microscope to study the formation of Pt nanocrystals directly on the surface of monolayer MoS2 from a precursor on heating to 800 °C. Isolated single Pt atoms and small nanoclusters are observed after in situ heating, with two types of preferential alignment between the Pt nanocrystals and the underlying monolayer MoS2. Strain effects and thickness variations of the ultrasmall Pt nanocrystal supported on MoS2 are studied, revealing that single atomic planes are formed from a nonlayered face-centered cubic bulk Pt configuration with a lattice expansion of 7-10% compared to that of bulk Pt. The Pt nanocrystals are surrounded by an amorphous carbon layer and in some cases have etched the local surrounding MoS2 material after heating. Electron beam irradiation also initiates Pt nanocrystal etching of the local MoS2, and we study this process in real time at atomic resolution. These results show that the presence of carbon around the Pt nanocrystals does not affect their epitaxial relationship with the MoS2 lattice. Single Pt atoms within the carbon layer are also immobilized at high temperature. These results provide important insights into the formation of Pt:MoS2 hybrid materials.
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Affiliation(s)
- Shanshan Wang
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Hidetaka Sawada
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Centre, Diamond Lightsource Ltd, Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE, United Kingdom
- JEOL UK Ltd. , Silver Court Watchmead, Welwyn Garden City, Hertfordshire AL7 1LT, United Kingdom
| | - Qu Chen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Grace G D Han
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Christopher Allen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Centre, Diamond Lightsource Ltd, Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Centre, Diamond Lightsource Ltd, Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
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15
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Liu J. Aberration-corrected scanning transmission electron microscopy in single-atom catalysis: Probing the catalytically active centers. CHINESE JOURNAL OF CATALYSIS 2017. [DOI: 10.1016/s1872-2067(17)62900-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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16
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Hardcastle TP, Seabourne CR, Kepaptsoglou DM, Susi T, Nicholls RJ, Brydson RMD, Scott AJ, Ramasse QM. Robust theoretical modelling of core ionisation edges for quantitative electron energy loss spectroscopy of B- and N-doped graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:225303. [PMID: 28394256 DOI: 10.1088/1361-648x/aa6c4f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electron energy loss spectroscopy (EELS) is a powerful tool for understanding the chemical structure of materials down to the atomic level, but challenges remain in accurately and quantitatively modelling the response. We compare comprehensive theoretical density functional theory (DFT) calculations of 1s core-level EEL K-edge spectra of pure, B-doped and N-doped graphene with and without a core-hole to previously published atomic-resolution experimental electron microscopy data. The ground state approximation is found in this specific system to perform consistently better than the frozen core-hole approximation. The impact of including or excluding a core-hole on the resultant theoretical band structures, densities of states, electron densities and EEL spectra were all thoroughly examined and compared. It is concluded that the frozen core-hole approximation exaggerates the effects of the core-hole in graphene and should be discarded in favour of the ground state approximation. These results are interpreted as an indicator of the overriding need for theorists to embrace many-body effects in the pursuit of accuracy in theoretical spectroscopy instead of a system-tailored approach whose approximations are selected empirically.
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Affiliation(s)
- T P Hardcastle
- SuperSTEM Laboratory, STFC Daresbury Campus, Daresbury, WA4 4AD, United Kingdom. School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
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17
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Li H, Wang S, Sawada H, Han GGD, Samuels T, Allen CS, Kirkland AI, Grossman JC, Warner JH. Atomic Structure and Dynamics of Single Platinum Atom Interactions with Monolayer MoS 2. ACS NANO 2017; 11:3392-3403. [PMID: 28256826 DOI: 10.1021/acsnano.7b00796] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We have studied atomic level interactions between single Pt atoms and the surface of monolayer MoS2 using aberration-corrected annular dark field scanning transmission electron microscopy at an accelerating voltage of 60 kV. Strong contrast from single Pt atoms on the atomically resolved monolayer MoS2 lattice enables their exact position to be determined with respect to the MoS2 lattice, revealing stable binding sites. In regions of MoS2 free from surface contamination, the Pt atoms are localized in S vacancy sites and exhibit dynamic hopping to nearby vacancy sites driven by the energy supplied by the electron beam. However, in areas of MoS2 contaminated with carbon surface layers, the Pt atoms appear at various positions with respect to the underlying MoS2 lattice, including on top of Mo and in off-axis positions. These variations are due to the Pt bonding with the surrounding amorphous carbon layer, which disrupts the intrinsic Pt-MoS2 interactions, leading to more varied positions. Density functional theory (DFT) calculations reveal that Pt atoms on the surface of MoS2 have a small barrier for migration and are stabilized when bound to either a single or double sulfur vacancies. DFT calculations have been used to understand how the catalytic activity of the MoS2 basal plane for hydrogen evolution reaction is influenced by Pt dopants by variation of the hydrogen adsorption free energy. This strong dependence of catalytic effect on interfacial configurations is shown to be common for a series of dopants, which may provide a means to create and optimize reaction centers.
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Affiliation(s)
- Huashan Li
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Shanshan Wang
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
| | - Hidetake Sawada
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
- JEOL Ltd. , 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
- Electron Physical Sciences Imaging Center, Diamond Light Source Ltd , Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - Grace G D Han
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Thomas Samuels
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
| | - Christopher S Allen
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Center, Diamond Light Source Ltd , Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Center, Diamond Light Source Ltd , Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
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18
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Hydrogen adsorption on Be, Mg, Ca and Sr doped graphenes: The role of the dopant in the IIA main group. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2016.12.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Affiliation(s)
- Jingyue Liu
- Department of Physics, Arizona State University, Tempe, Arizona 85287, United States
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20
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Robertson AW, Lin YC, Wang S, Sawada H, Allen CS, Chen Q, Lee S, Lee GD, Lee J, Han S, Yoon E, Kirkland AI, Kim H, Suenaga K, Warner JH. Atomic Structure and Spectroscopy of Single Metal (Cr, V) Substitutional Dopants in Monolayer MoS 2. ACS NANO 2016; 10:10227-10236. [PMID: 27934090 DOI: 10.1021/acsnano.6b05674] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dopants in two-dimensional dichalcogenides have a significant role in affecting electronic, mechanical, and interfacial properties. Controllable doping is desired for the intentional modification of such properties to enhance performance; however, unwanted defects and impurity dopants also have a detrimental impact, as often found for chemical vapor deposition (CVD) grown films. The reliable identification, and subsequent characterization, of dopants is therefore of significant importance. Here, we show that Cr and V impurity atoms are found in CVD grown MoS2 monolayer 2D crystals as single atom substitutional dopants in place of Mo. We attribute these impurities to trace elements present in the MoO3 CVD precursor. Simultaneous annular dark field scanning transmission electron microscopy (ADF-STEM) and electron energy loss spectroscopy (EELS) is used to map the location of metal atom substitutions of Cr and V in MoS2 monolayers with single atom precision. The Cr and V are stable under electron irradiation at 60 to 80 kV, when incorporated into line defects, and when heated to elevated temperatures. The combined ADF-STEM and EELS differentiates these Cr and V dopants from other similar contrast defect structures, such as 2S self-interstitials at the Mo site, preventing misidentification. Density functional theory calculations reveal that the presence of Cr or V causes changes to the density of states, indicating doping of the MoS2 material. These transferred impurities could help explain the presence of trapped charges in CVD prepared MoS2.
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Affiliation(s)
- Alex W Robertson
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Yung-Chang Lin
- Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST) , AIST Central 5, Tsukuba 305-8564, Japan
| | - Shanshan Wang
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Hidetaka Sawada
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- JEOL Limited, 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
- Electron Physical Sciences Imaging Center, Diamond Light Source Limited, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Christopher S Allen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Center, Diamond Light Source Limited, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Qu Chen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Sungwoo Lee
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Gun-Do Lee
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Joohee Lee
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Seungwu Han
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Euijoon Yoon
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Center, Diamond Light Source Limited, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Heeyeon Kim
- Convergence Materials Laboratory, Korea Institute of Energy Research , 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Korea
| | - Kazu Suenaga
- Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST) , AIST Central 5, Tsukuba 305-8564, Japan
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
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21
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Koshino M. OM-III-4Low-voltage STEM-EELS for Single Atom- and Single Molecule- Analysis and Its Interpretations. Microscopy (Oxf) 2016. [DOI: 10.1093/jmicro/dfw089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Gong C, He K, Lee GD, Chen Q, Robertson AW, Yoon E, Hong S, Warner JH. In Situ Atomic Level Dynamics of Heterogeneous Nucleation and Growth of Graphene from Inorganic Nanoparticle Seeds. ACS NANO 2016; 10:9397-9410. [PMID: 27643716 DOI: 10.1021/acsnano.6b04356] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An in situ heating holder inside an aberration-corrected transmission electron microscope (AC-TEM) is used to investigate the real-time atomic level dynamics associated with heterogeneous nucleation and growth of graphene from Au nanoparticle seeds. Heating monolayer graphene to an elevated temperature of 800 °C removes the majority of amorphous carbon adsorbates and leaves a clean surface. The aggregation of Au impurity atoms into nanoparticle clusters that are bound to the surface of monolayer graphene causes nucleation of secondary graphene layers from carbon feedstock present within the microscope chamber. This enables the in situ study of heterogeneous nucleation and growth of graphene at the atomic level. We show that the growth mechanism consists of alternating C cluster attachment and indentation filling to maintain a uniform growth front of lowest energy. Back-folding of the graphene growth front is observed, followed by a process that involves flipping back and attaching to the surrounding region. We show how the highly polycrystalline graphene seed evolves with time into a higher order crystalline structure using a combination of AC-TEM and tight-binding molecular dynamics (TBMD) simulations. This helps understand the detailed lowest-energy step-by-step pathways associated with grain boundaries (GB) migration and crystallization processes. We find the motion of the GB is discontinuous and mediated by both bond rotation and atom evaporation, supported by density functional theory calculations and TBMD. These results provide insights into the formation of crystalline seed domains that are generated during bottom-up graphene synthesis.
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Affiliation(s)
- Chuncheng Gong
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Kuang He
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Gun-Do Lee
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Qu Chen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Alex W Robertson
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Euijoon Yoon
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Suklyun Hong
- Department of Physics and Graphene Research Institute, Sejong University , Seoul 143-747, Korea
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
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23
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Jiang J, Pachter R, Islam AE, Maruyama B, Boeckl JJ. Defect-induced Raman spectroscopy in single-layer graphene with boron and nitrogen substitutional defects by theoretical investigation. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.09.067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Schiros T, Nordlund D, Palova L, Zhao L, Levendorf M, Jaye C, Reichman D, Park J, Hybertsen M, Pasupathy A. Atomistic Interrogation of B-N Co-dopant Structures and Their Electronic Effects in Graphene. ACS NANO 2016; 10:6574-6584. [PMID: 27327863 DOI: 10.1021/acsnano.6b01318] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chemical doping has been demonstrated to be an effective method for producing high-quality, large-area graphene with controlled carrier concentrations and an atomically tailored work function. The emergent optoelectronic properties and surface reactivity of carbon nanostructures are dictated by the microstructure of atomic dopants. Co-doping of graphene with boron and nitrogen offers the possibility to further tune the electronic properties of graphene at the atomic level, potentially creating p- and n-type domains in a single carbon sheet, opening a gap between valence and conduction bands in the 2-D semimetal. Using a suite of high-resolution synchrotron-based X-ray techniques, scanning tunneling microscopy, and density functional theory based computation we visualize and characterize B-N dopant bond structures and their electronic effects at the atomic level in single-layer graphene grown on a copper substrate. We find there is a thermodynamic driving force for B and N atoms to cluster into BNC structures in graphene, rather than randomly distribute into isolated B and N graphitic dopants, although under the present growth conditions, kinetics limit segregation of large B-N domains. We observe that the doping effect of these BNC structures, which open a small band gap in graphene, follows the B:N ratio (B > N, p-type; B < N, n-type; B═N, neutral). We attribute this to the comparable electron-withdrawing and -donating effects, respectively, of individual graphitic B and N dopants, although local electrostatics also play a role in the work function change.
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Affiliation(s)
- Theanne Schiros
- Department of Science and Mathematics, Fashion Institute of Technology/State University of New York , New York, New York 10001, United States
| | - Dennis Nordlund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | | | | | - Mark Levendorf
- Chemistry Department, Cornell University , Ithaca, New York 10065, United States
| | - Cherno Jaye
- Materials Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | | | - Jiwoong Park
- Chemistry Department, Cornell University , Ithaca, New York 10065, United States
| | - Mark Hybertsen
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
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25
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Liu Z, Tizei LHG, Sato Y, Lin YC, Yeh CH, Chiu PW, Terauchi M, Iijima S, Suenaga K. Postsynthesis of h-BN/Graphene Heterostructures Inside a STEM. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:252-9. [PMID: 26618896 PMCID: PMC4738398 DOI: 10.1002/smll.201502408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/01/2015] [Indexed: 05/25/2023]
Abstract
Combinations of 2D materials with different physical properties can form heterostructures with modified electrical, mechanical, magnetic, and optical properties. The direct observation of a lateral heterostructure synthesis is reported by epitaxial in-plane graphene growth from the step-edge of hexagonal BN (h-BN) within a scanning transmission electron microscope chamber. Residual hydrocarbon in the chamber is the carbon source. The growth interface between h-BN and graphene is atomically identified as largely N-C bonds. This postgrowth method can form graphene nanoribbons connecting two h-BN domains with different twisting angles, as well as isolated carbon islands with arbitrary shapes embedded in the h-BN layer. The electronic properties of the vertically stacked h-BN/graphene heterostructures are investigated by electron energy-loss spectroscopy (EELS). Low-loss EELS analysis of the dielectric response suggests a robust coupling effect between the graphene and h-BN layers.
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Affiliation(s)
- Zheng Liu
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Luiz H G Tizei
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, Orsay, 91405, France
| | - Yohei Sato
- Division of Electron Crystallography and Spectroscopy, Tohoku University, Sendai, 980-8577, Japan
| | - Yung-Chang Lin
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Chao-Hui Yeh
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Masami Terauchi
- Division of Electron Crystallography and Spectroscopy, Tohoku University, Sendai, 980-8577, Japan
| | - Sumio Iijima
- Meijo University, Department of Materials Science and Engeering, Nagoya, 468-8502, Japan
| | - Kazu Suenaga
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
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26
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Kepaptsoglou D, Hardcastle TP, Seabourne CR, Bangert U, Zan R, Amani JA, Hofsäss H, Nicholls RJ, Brydson RMD, Scott AJ, Ramasse QM. Electronic Structure Modification of Ion Implanted Graphene: The Spectroscopic Signatures of p- and n-Type Doping. ACS NANO 2015; 9:11398-11407. [PMID: 26446310 DOI: 10.1021/acsnano.5b05305] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A combination of scanning transmission electron microscopy, electron energy loss spectroscopy, and ab initio calculations is used to describe the electronic structure modifications incurred by free-standing graphene through two types of single-atom doping. The N K and C K electron energy loss transitions show the presence of π* bonding states, which are highly localized around the N dopant. In contrast, the B K transition of a single B dopant atom shows an unusual broad asymmetric peak which is the result of delocalized π* states away from the B dopant. The asymmetry of the B K toward higher energies is attributed to highly localized σ* antibonding states. These experimental observations are then interpreted as direct fingerprints of the expected p- and n-type behavior of graphene doped in this fashion, through careful comparison with density functional theory calculations.
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Affiliation(s)
- Demie Kepaptsoglou
- SuperSTEM Laboratory , SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
| | - Trevor P Hardcastle
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Che R Seabourne
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Ursel Bangert
- School of Materials, University of Manchester , Manchester M13 9PL, United Kingdom
| | - Recep Zan
- School of Materials, University of Manchester , Manchester M13 9PL, United Kingdom
| | - Julian Alexander Amani
- II. Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hans Hofsäss
- II. Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Rebecca J Nicholls
- Deparment of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Rik M D Brydson
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Andrew J Scott
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Quentin M Ramasse
- SuperSTEM Laboratory , SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
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27
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Lin YC, Teng PY, Yeh CH, Koshino M, Chiu PW, Suenaga K. Structural and Chemical Dynamics of Pyridinic-Nitrogen Defects in Graphene. NANO LETTERS 2015; 15:7408-13. [PMID: 26488153 DOI: 10.1021/acs.nanolett.5b02831] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
High density and controllable nitrogen doping in graphene is a critical issue to realize high performance graphene-based devices. In this paper, we demonstrate an efficient method to selectively produce graphitic-N and pyridinic-N defects in graphene by using the mixture plasma of ozone and nitrogen. The atomic structure, electronic structure, and dynamic behavior of these nitrogen defects are systematically studied at the atomic level by using a scanning transmission electron microscopy. The pyridinic-N exhibits higher chemical activity and tends to trap a series of transition metal atoms (Mg, Al, Ca, Ti, Cr, Mn, and Fe) as individual atoms.
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Affiliation(s)
- Yung-Chang Lin
- National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8565, Japan
| | - Po-Yuan Teng
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Chao-Hui Yeh
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Masanori Koshino
- National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8565, Japan
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Kazu Suenaga
- National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8565, Japan
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