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Schaal M, Baby A, Gruenewald M, Otto F, Forker R, Fratesi G, Fritz T. Triggered integer charge transfer: energy-level alignment at an organic-2D material interface. NANOSCALE ADVANCES 2024:d4na00462k. [PMID: 39144159 PMCID: PMC11320374 DOI: 10.1039/d4na00462k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 07/29/2024] [Indexed: 08/16/2024]
Abstract
Weakly interacting systems such as organic molecules on monolayers of hexagonal boron nitride (h-BN) offer the possibility of single integer charge transfer leading to the formation of organic ions. Such open-shell systems exhibit unique optical and electronic properties which differ from their neutral counterparts. In this study, we used a joint experimental and theoretical approach to investigate the charge transfer of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules on h-BN/Ni(111) by using differential reflectance spectroscopy (DRS), scanning tunneling spectroscopy (STS), and photoelectron orbital tomography (POT) measurements in combination with density functional theory (DFT) calculations. Our results show that the PTCDA monolayer consists of highly ordered organic radical anions and neutral molecules. In addition, the occurrence of the integer charge transfer is discussed based on the energy-level alignment. Since the integer charge transfer is not limited to PTCDA, we propose that the h-BN covered Ni(111) surface is a promising substrate for studying the optical and electronic properties of highly ordered organic anions.
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Affiliation(s)
- Maximilian Schaal
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Anu Baby
- Department of Materials Science, University of Milano-Bicocca Via R. Cozzi 55 20125 Milano Italy
- STMicroelectronics Via Tolomeo 1 20010 Cornaredo Italy
| | - Marco Gruenewald
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Felix Otto
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Roman Forker
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Guido Fratesi
- ETSF and Dipartimento di Fisica "Aldo Pontremoli", Università degli Studi di Milano Via Celoria, 16 20133 Milano Italy
| | - Torsten Fritz
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
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2
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Mo̷lnås H, Paul SJ, Scimeca MR, Mattu N, Zuo J, Parashar N, Li L, Riedo E, Sahu A. Dedoping of Intraband Silver Selenide Colloidal Quantum Dots through Strong Electronic Coupling at Organic/Inorganic Hybrid Interfaces. CRYSTAL GROWTH & DESIGN 2024; 24:2821-2832. [PMID: 38585377 PMCID: PMC10995946 DOI: 10.1021/acs.cgd.3c01474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 04/09/2024]
Abstract
Colloidal quantum dot (CQD) infrared (IR) photodetectors can be fabricated and operated with larger spectral tunability, fewer limitations in terms of cooling requirements and substrate lattice matching, and at a potentially lower cost than detectors based on traditional bulk materials. Silver selenide (Ag2Se) has emerged as a promising sustainable alternative to current state-of-the-art toxic semiconductors based on lead, cadmium, and mercury operating in the IR. However, an impeding gap in available absorption bandwidth for Ag2Se CQDs exists in the short-wave infrared (SWIR) region due to degenerate doping by the environment, switching the CQDs from intrinsic interband semiconductors in the near-infrared (NIR) to intraband absorbing CQDs in the mid-wave infrared (MWIR). Herein, we show that the small molecular p-type dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) can be used to extract electrons from the 1Se state of MWIR active Ag2Se CQDs to activate their intrinsic energy gap in the SWIR window. We demonstrate quenching of the MWIR Ag2Se absorbance peak, shifting of nitrile vibrational peaks characteristic of charge-neutral F4-TCNQ, as well as enhanced CQD absorption around ∼2500 nm after doping both in ambient and under air-free conditions. We elucidate the doping mechanism to be one that involves an integer charge transfer akin to doping in semiconducting polymers. These indications of charge transfer are promising milestones on the path to achieving sustainable SWIR Ag2Se CQD photodetectors.
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Affiliation(s)
- Håvard Mo̷lnås
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Shlok Joseph Paul
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Michael R. Scimeca
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Navkawal Mattu
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Jiaqi Zuo
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Nitika Parashar
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Letian Li
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Elisa Riedo
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
| | - Ayaskanta Sahu
- Department of Chemical and
Biomolecular Engineering, Tandon School of Engineering, New York University, Brooklyn, New York 11201, United States
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3
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Chattopadhyay S, Munya V, Kumar R, Pal D, Bandyopadhyay S, Ghosh A, Yogi P, Koch J, Pfnür H. F4-TCNQ on Epitaxial Bi-Layer Graphene: Concentration- and Orientation-Dependent Charge Transfer at the Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:16067-16072. [PMID: 36512752 DOI: 10.1021/acs.langmuir.2c02676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Bi-layer epitaxial graphene (BLG) on 6H-SiC(0001) (EG/SiC) was grown and modified by thermal deposition of the molecular electron acceptor tetrafluoro-tetra cyano quinodimethane (F4-TCNQ). The surface-modified system, F4-TCNQ/EG/SiC, was studied by X-ray photoelectron spectroscopy (XPS) and angle-resolved polarized Raman spectroscopy (ARPRS). XPS results indicate that bonding of deposited F4-TCNQ molecules depends on their concentration. Although bonding through the cyano groups is present at all concentrations, charge transfer from graphene to fluorine is evident only at sub-monolayer concentrations. The corresponding change in bond character is coupled with a change in molecular orientation. Raman spectroscopy not only provides results consistent with the findings from the XPS study but also reveals a significant degree of molecular stacking above the monolayer concentration. Thus, both the variation of the acceptor concentration and the number of graphene layers provide further handles to manipulate charge and doping that may be useful in device applications.
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Affiliation(s)
| | - Vikas Munya
- Department of Physics, Indian Institute of Technology Indore, Indore453552, India
| | - Ravinder Kumar
- Department of Physics, Indian Institute of Technology Indore, Indore453552, India
| | - Dipayan Pal
- Department of Physics, Indian Institute of Technology Indore, Indore453552, India
| | - Sucheta Bandyopadhyay
- Indian Statistical Institute (Laboratory for Cognitive Systems and Cybernetics Research, Center for Soft Computing Research)Kolkata700108, India
| | - Arpan Ghosh
- Department of Physics, Indian Institute of Technology Indore, Indore453552, India
| | - Priyanka Yogi
- Department ATMOS, Institute for Solid State Physics, Leibniz Universität Hannover, D-30167Hannover, Germany
| | - Julian Koch
- Department ATMOS, Institute for Solid State Physics, Leibniz Universität Hannover, D-30167Hannover, Germany
| | - Herbert Pfnür
- Department ATMOS, Institute for Solid State Physics, Leibniz Universität Hannover, D-30167Hannover, Germany
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4
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Lv SY, Li G, Yang LM. Prognostication of two-dimensional transition-metal atoms embedded rectangular tetrafluorotetracyanoquinodimethane single-atom catalysts for high-efficiency electrochemical nitrogen reduction. J Colloid Interface Sci 2022; 621:24-32. [DOI: 10.1016/j.jcis.2022.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/25/2022] [Accepted: 04/01/2022] [Indexed: 10/18/2022]
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5
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Melani G, Guerrero-Felipe JP, Valencia AM, Krumland J, Cocchi C, Iannuzzi M. Donors, acceptors, and a bit of aromatics: electronic interactions of molecular adsorbates on hBN and MoS 2 monolayers. Phys Chem Chem Phys 2022; 24:16671-16679. [PMID: 35766517 DOI: 10.1039/d2cp01502a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design of low-dimensional organic-inorganic interfaces for the next generation of opto-electronic applications requires in-depth understanding of the microscopic mechanisms ruling electronic interactions in these systems. In this work, we present a first-principles study based on density-functional theory inspecting the structural, energetic, and electronic properties of five molecular donors and acceptors adsorbed on freestanding hexagonal boron nitride (hBN) and molybdenum disulfide (MoS2) monolayers. All considered interfaces are stable, due to the crucial contribution of dispersion interactions, which are maximized by the overall flat arrangement of the physisorbed molecules on both substrates. The level alignment of the hybrid systems depends on the characteristics of the constituents. On hBN, both type-I and type-II interfaces may form, depending on the relative energies of the frontier orbitals with respect to the vacuum level. On the other hand, all MoS2-based hybrid systems exhibit a type-II level alignment, with the molecular frontier orbitals positioned across the energy gap of the semiconductor. The electronic structure of the hybrid materials is further determined by the formation of interfacial dipole moments and by the wave-function hybridization between the organic and inorganic constituents. These results provide important indications for the design of novel low-dimensional hybrid materials with suitable characteristics for opto-electronics.
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Affiliation(s)
- Giacomo Melani
- Department of Chemistry, Universität Zürich, 8057 Zürich, Switzerland. .,Present Address: Pritzker School of Molecular Engineering, University of Chicago, 60637, Chicago, USA
| | - Juan Pablo Guerrero-Felipe
- Physics Department and IRIS Adlesrshof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany. .,Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Ana M Valencia
- Physics Department and IRIS Adlesrshof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany. .,Institute of Physics, Carl-von-Ossietzy Universität Oldenburg, 26129 Oldenburg, Germany
| | - Jannis Krumland
- Physics Department and IRIS Adlesrshof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany.
| | - Caterina Cocchi
- Physics Department and IRIS Adlesrshof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany. .,Institute of Physics, Carl-von-Ossietzy Universität Oldenburg, 26129 Oldenburg, Germany
| | - Marcella Iannuzzi
- Department of Chemistry, Universität Zürich, 8057 Zürich, Switzerland.
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6
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Lv SY, Li G, Yang LM. Transition Metals Embedded Two-Dimensional Square Tetrafluorotetracyanoquinodimethane Monolayers as a Class of Novel Electrocatalysts for Nitrogen Reduction Reaction. ACS APPLIED MATERIALS & INTERFACES 2022; 14:25317-25325. [PMID: 35608362 DOI: 10.1021/acsami.2c02677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The combination of transition metal (TM) atoms and high electron affinity organic framework tetrafluorotetracyanoquinodimethanes (F4TCNQs) makes the TM-embedded two-dimensional (2D) square F4TCNQ monolayers (TM-sF4TCNQ) possible to have excellent characteristics of single-atom catalysts and 2D materials. For the first time, the TM-sF4TCNQ monolayers have been considered for application in the electrocatalytic nitrogen reduction reaction (eNRR) field. Through high-throughput screening, the catalytic performance of 30 TM-sF4TCNQ (TM = 3d∼5d TMs) monolayers for eNRR was comprehensively evaluated. The Mo-, Nb-, and Tc-sF4TCNQ catalysts stand out with the onset potentials of -0.18, -0.44, and -0.54 V, respectively, through the optimal reaction paths. Our work will provide guidance for the green and sustainable development of electrocatalytic nitrogen fixation.
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Affiliation(s)
- Sheng-Yao Lv
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica; Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Materials Chemistry and Service Failure; Hubei Engineering Research Center for Biomaterials and Medical Protective Materials; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education; Center for Computational Quantum Chemistry, School of Chemistry, South China Normal University, Guangzhou 510006, China
| | - Guoliang Li
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education; Center for Computational Quantum Chemistry, School of Chemistry, South China Normal University, Guangzhou 510006, China
| | - Li-Ming Yang
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica; Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Materials Chemistry and Service Failure; Hubei Engineering Research Center for Biomaterials and Medical Protective Materials; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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7
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Zhang H, Lu J, Zhang Y, Gao L, Zhao XJ, Tan YZ, Cai J. Magnetism engineering of nanographene: an enrichment strategy by co-depositing diverse precursors on Au(111). CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.04.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Nguyen NN, Lee H, Lee HC, Cho K. van der Waals Epitaxy of Organic Semiconductor Thin Films on Atomically Thin Graphene Templates for Optoelectronic Applications. Acc Chem Res 2022; 55:673-684. [PMID: 35142485 DOI: 10.1021/acs.accounts.1c00686] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ConspectusOrganic semiconductors (OSCs) offer unique advantages with respect to mechanical flexibility, low-cost processing, and tunable properties. The optical and electrical properties of devices based on OSCs can be greatly improved when an OSC is coupled with graphene in a certain manner. Our research group has focused on using graphene as a growth template for OSCs and incorporating such high-quality heterostructures into optoelectronic devices. The idea is that graphene's atomically flat surface with a uniform sp2 carbon network can serve as a perfect quasi-epitaxial template for the growth of OSCs. In addition, OSC-graphene heterostructures benefit from graphene's unique characteristics, such as its high charge-carrier mobility, excellent optical transparency, and fascinating mechanical durability and flexibility.However, we have often found that OSC molecules assemble on graphene in unpredictable manners that vary from batch to batch. From observations of numerous research systems, we elucidated the mechanism underlying such poor repeatability and set out a framework to actually control the template effect of graphene on OSCs. In this Account, we not only present our scientific findings in this spectrum of areas but also convey our research scheme to the readers so that similar heterostructure complexes can be systematically studied.We began with experiments showing that the growth of OSCs on a graphene surface was driven by van der Waals interactions and is therefore sensitive to the cleanliness of the graphene surface. Nonetheless, we noted that, even on similarly clean graphene surfaces, the OSC thin film still varied with the underlying substrate. Thanks to the graphene-transfer method and in situ gating methods that we developed, we discovered that the decisive parameter for molecule-graphene interaction (and, hence, for the growth of OSCs on graphene) is the charge density in the graphene. Thus, to prepare a graphene template for high-quality graphene-OSC heterostructures, we controlled the charge density in the graphene to minimize the molecule-graphene interaction. Moreover, the possible charge transfer between OSC molecules and graphene, which induces additional molecule-graphene interactions, should also be taken into account. Eventually, we demonstrated a wide range of optoelectronic applications that benefitted from high-quality OSC-graphene heterostructures fabricated using our proof-of-concept systems.
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Affiliation(s)
- Nguyen Ngan Nguyen
- Center for Advancing Electronics Dresden (cfaed) and Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
| | - Hansol Lee
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Department of Chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi 13120, Republic of Korea
| | - Hyo Chan Lee
- Department of Chemical Engineering, Myoungji University, Yongin 17058, Republic of Korea
| | - Kilwon Cho
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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9
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Jeong JH, Kang S, Kim N, Joshi RK, Lee GH. Recent trends in covalent functionalization of 2D materials. Phys Chem Chem Phys 2022; 24:10684-10711. [DOI: 10.1039/d1cp04831g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covalent functionalization of the surface is more crucial in 2D materials than in conventional bulk materials because of their atomic thinness, large surface-to-volume ratio, and uniform surface chemical potential. Because...
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10
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Kim JK, Cho K, Jang J, Baek KY, Kim J, Seo J, Song M, Shin J, Kim J, Parkin SSP, Lee JH, Kang K, Lee T. Molecular Dopant-Dependent Charge Transport in Surface-Charge-Transfer-Doped Tungsten Diselenide Field Effect Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101598. [PMID: 34533851 DOI: 10.1002/adma.202101598] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 08/15/2021] [Indexed: 06/13/2023]
Abstract
The controllability of carrier density and major carrier type of transition metal dichalcogenides(TMDCs) is critical for electronic and optoelectronic device applications. To utilize doping in TMDC devices, it is important to understand the role of dopants in charge transport properties of TMDCs. Here, the effects of molecular doping on the charge transport properties of tungsten diselenide (WSe2 ) are investigated using three p-type molecular dopants, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4 -TCNQ), tris(4-bromophenyl)ammoniumyl hexachloroantimonate (magic blue), and molybdenum tris(1,2-bis(trifluoromethyl)ethane-1,2-dithiolene) (Mo(tfd-COCF3 )3 ). The temperature-dependent transport measurements show that the dopant counterions on WSe2 surface can induce Coulomb scattering in WSe2 channel and the degree of scattering is significantly dependent on the dopant. Furthermore, the quantitative analysis revealed that the amount of charge transfer between WSe2 and dopants is related to not only doping density, but also the contribution of each dopant ion toward Coulomb scattering. The first-principles density functional theory calculations show that the amount of charge transfer is mainly determined by intrinsic properties of the dopant molecules such as relative frontier orbital positions and their spin configurations. The authors' systematic investigation of the charge transport of doped TMDCs will be directly relevant for pursuing molecular routes for efficient and controllable doping in TMDC nanoelectronic devices.
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Affiliation(s)
- Jae-Keun Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
- Max-Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Kyungjune Cho
- Max-Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
- Soft Hybrid Materials Research Center, Korea Institute of Science and Technology, Seoul, 02792, Korea
| | - Juntae Jang
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Kyeong-Yoon Baek
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Jehyun Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Junseok Seo
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Minwoo Song
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Jiwon Shin
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Jaeyoung Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Stuart S P Parkin
- Max-Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Jung-Hoon Lee
- Computational Science Research Center, Korea Institute of Science and Technology, Seoul, 02792, Korea
| | - Keehoon Kang
- Department of Materials Science & Engineering, Yonsei University, Seoul, 03722, Korea
| | - Takhee Lee
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
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11
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Liou F, Tsai HZ, Aikawa AS, Natividad KC, Tang E, Ha E, Riss A, Watanabe K, Taniguchi T, Lischner J, Zettl A, Crommie MF. Imaging Reconfigurable Molecular Concentration on a Graphene Field-Effect Transistor. NANO LETTERS 2021; 21:8770-8776. [PMID: 34653333 DOI: 10.1021/acs.nanolett.1c03039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The spatial arrangement of adsorbates deposited onto a clean surface under vacuum typically cannot be reversibly tuned. Here we use scanning tunneling microscopy to demonstrate that molecules deposited onto graphene field-effect transistors (FETs) exhibit reversible, electrically tunable surface concentration. Continuous gate-tunable control over the surface concentration of charged F4TCNQ molecules was achieved on a graphene FET at T = 4.5K. This capability enables the precisely controlled impurity doping of graphene devices and also provides a new method for determining molecular energy level alignment based on the gate-dependence of molecular concentration. Gate-tunable molecular concentration is explained by a dynamical molecular rearrangement process that reduces total electronic energy by maintaining Fermi level pinning in the device substrate. The molecular surface concentration is fully determined by the device back-gate voltage, its geometric capacitance, and the energy difference between the graphene Dirac point and the molecular LUMO level.
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Affiliation(s)
- Franklin Liou
- Department of Physics, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, California 94720, United States
| | - Hsin-Zon Tsai
- Department of Physics, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew S Aikawa
- Department of Physics, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kyler C Natividad
- Department of Physics, University of California, Berkeley, California 94720, United States
| | - Eric Tang
- Department of Physics, University of California, Berkeley, California 94720, United States
| | - Ethan Ha
- Department of Physics, University of California, Berkeley, California 94720, United States
| | - Alexander Riss
- Physics Department E20, Technical University of Munich, James-Franck-Straße 1, D-85748 Garching, Germany
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Johannes Lischner
- Department of Materials, Imperial College London, Prince Consort Road, London SW7 2BB, United Kingdom
| | - Alex Zettl
- Department of Physics, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, California 94720, United States
| | - Michael F Crommie
- Department of Physics, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, California 94720, United States
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12
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Zhou C, Wang C, Fan G, Deng L. DFT Study on Capacitive Property of Composites Built by Phosphomolybdic Acid with Nitrogen-Doped Graphene. J Inorg Organomet Polym Mater 2021. [DOI: 10.1007/s10904-021-02081-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Kumar A, Banerjee K, Ervasti MM, Kezilebieke S, Dvorak M, Rinke P, Harju A, Liljeroth P. Electronic Characterization of a Charge-Transfer Complex Monolayer on Graphene. ACS NANO 2021; 15:9945-9954. [PMID: 34028269 PMCID: PMC8223480 DOI: 10.1021/acsnano.1c01430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
Organic charge-transfer complexes (CTCs) formed by strong electron acceptor and strong electron donor molecules are known to exhibit exotic effects such as superconductivity and charge density waves. We present a low-temperature scanning tunneling microscopy and spectroscopy (LT-STM/STS) study of a two-dimensional (2D) monolayer CTC of tetrathiafulvalene (TTF) and fluorinated tetracyanoquinodimethane (F4TCNQ), self-assembled on the surface of oxygen-intercalated epitaxial graphene on Ir(111) (G/O/Ir(111)). We confirm the formation of the charge-transfer complex by dI/dV spectroscopy and direct imaging of the singly occupied molecular orbitals. High-resolution spectroscopy reveals a gap at zero bias, suggesting the formation of a correlated ground state at low temperatures. These results point to the possibility to realize and study correlated ground states in charge-transfer complex monolayers on weakly interacting surfaces.
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Affiliation(s)
- Avijit Kumar
- School
of Basic Sciences, Indian Institute of Technology
Bhubaneswar, Jatni, 752050 Khurda, India
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - Kaustuv Banerjee
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - Mikko M. Ervasti
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | | | - Marc Dvorak
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - Patrick Rinke
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - Ari Harju
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
- Varian
Medical Systems Finland, FI-00270 Helsinki, Finland
| | - Peter Liljeroth
- Department
of Applied Physics, Aalto University, FI-00076 Aalto, Finland
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14
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Meng C, Gao K, Tang S, Zhou L, Lai W, Luo L, Wang X, Liu Y, Wang K, Chen Y, Liu X. The adsorption of aromatic macromolecules on graphene with entropy-tailored behavior and its utilization in exfoliating graphite. J Colloid Interface Sci 2021; 599:12-22. [PMID: 33933787 DOI: 10.1016/j.jcis.2021.04.103] [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: 02/18/2021] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 11/29/2022]
Abstract
Aromatic macromolecules tend to form a compact conformation after physically adsorbed on graphene and it brings about great entropy loss for physisorption, due to the strong interaction between aromatic macromolecules and graphene. However, previous researches have validated the availability of aromatic macromolecules to stabilize graphene based on physisorption. In order to clarify the underlying mechanism of this physisorption process on graphene, a series of aromatic polyamide copolymers are used as models in this research. Apart from their adsorbed conformations on graphene, the conformations of these copolymers as the free states in diluted solutions are taken into consideration. Although these copolymers present the fully extended conformation on graphene, their conformations in diluted solutions vary largely with the copolymer composition. It is verified that the copolymer with smaller conformational change could have the better stabilization effectiveness for graphene, rather than the one having stronger interaction with graphene. Therefore, the entropy-tailored behavior for the adsorption of aromatic macromolecules on graphene is put forward. Based on this mechanism, the chemical structure of aromatic polyamide is optimized and furthermore it is utilized to directly exfoliate natural graphite flakes. Eventually, high-quality graphene nanosheets with a large dimension and low defects are obtained. Moreover, its exfoliating effectiveness is superior to those of the commonly used exfoliating agents nowadays.
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Affiliation(s)
- Chenbo Meng
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Kexiong Gao
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Siyi Tang
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Linsen Zhou
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, Sichuan 621908, PR China
| | - Wenchuan Lai
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Longbo Luo
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Xu Wang
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Yang Liu
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China.
| | - Ke Wang
- College of Physics, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China
| | - Yue Chen
- State Key Lab of Fluorinated Functional Membrane Materials, Dongyue Polymer Material Company of Dongyue Federation, Zibo, Shandong 256401, PR China
| | - Xiangyang Liu
- State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, Sichuan 610065, PR China.
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15
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Song S, Su J, Telychko M, Li J, Li G, Li Y, Su C, Wu J, Lu J. On-surface synthesis of graphene nanostructures with π-magnetism. Chem Soc Rev 2021; 50:3238-3262. [PMID: 33481981 DOI: 10.1039/d0cs01060j] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Graphene nanostructures (GNs) including graphene nanoribbons and nanoflakes have attracted tremendous interest in the field of chemistry and materials science due to their fascinating electronic, optical and magnetic properties. Among them, zigzag-edged GNs (ZGNs) with precisely-tunable π-magnetism hold great potential for applications in spintronics and quantum devices. To improve the stability and processability of ZGNs, substitutional groups are often introduced to protect the reactive edges in organic synthesis, which renders the study of their intrinsic properties difficult. In contrast to the conventional wet-chemistry method, on-surface bottom-up synthesis presents a promising approach for the fabrication of both unsubstituted ZGNs and functionalized ZGNs with atomic precision via surface-catalyzed transformation of rationally-designed precursors. The structural and spin-polarized electronic properties of these ZGNs can then be characterized with sub-molecular resolution by means of scanning probe microscopy techniques. This review aims to highlight recent advances in the on-surface synthesis and characterization of a diversity of ZGNs with π-magnetism. We also discuss the important role of precursor design and reaction stimuli in the on-surface synthesis of ZGNs and their π-magnetism origin. Finally, we will highlight the existing challenges and future perspective surrounding the synthesis of novel open-shell ZGNs towards next-generation quantum technology.
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Affiliation(s)
- Shaotang Song
- SZU-NUS Collaborative Center, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology of Ministry of Education, Engineering Technology Research Center for 2D Materials Information Functional Devices and Systems of Guangdong Province, Institute of Microscale Optoelectronics, Shenzhen University, Shen Zhen, 518060, China.
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16
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Iida K. Electric Field Effect on Graphene/Organic Interface under Bias Voltage. CHEM LETT 2020. [DOI: 10.1246/cl.200349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kenji Iida
- Institute for Catalysis, Hokkaido University, N21 W10 Kita-ku, Sapporo, Hokkaido 001-0021, Japan
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17
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Sun Q, Mateo LM, Robles R, Ruffieux P, Lorente N, Bottari G, Torres T, Fasel R. Inducing Open-Shell Character in Porphyrins through Surface-Assisted Phenalenyl π-Extension. J Am Chem Soc 2020; 142:18109-18117. [DOI: 10.1021/jacs.0c07781] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Qiang Sun
- nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Luis M. Mateo
- Departamento de Quı́mica Orgánica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- IMDEA-Nanociencia, Campus
de Cantoblanco, 28049 Madrid, Spain
| | - Roberto Robles
- Centro de Fı́sica de Materiales, CFM/MPC (CSIC-UPV/EHU), Paseo de Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
| | - Pascal Ruffieux
- nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Nicolas Lorente
- Centro de Fı́sica de Materiales, CFM/MPC (CSIC-UPV/EHU), Paseo de Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| | - Giovanni Bottari
- Departamento de Quı́mica Orgánica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- IMDEA-Nanociencia, Campus
de Cantoblanco, 28049 Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Tomás Torres
- Departamento de Quı́mica Orgánica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- IMDEA-Nanociencia, Campus
de Cantoblanco, 28049 Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Roman Fasel
- nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
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18
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Ajayakumar MR, Moreno C, Alcón I, Illas F, Rovira C, Veciana J, Bromley ST, Mugarza A, Mas-Torrent M. Neutral Organic Radical Formation by Chemisorption on Metal Surfaces. J Phys Chem Lett 2020; 11:3897-3904. [PMID: 32343903 DOI: 10.1021/acs.jpclett.0c00269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organic radical monolayers (r-MLs) bonded to metal surfaces are potential materials for the development of molecular (spin)electronics. Typically, stable radicals bearing surface anchoring groups are used to generate r-MLs. Following a recent theoretical proposal based on a model system, we report the first experimental realization of a metal surface-induced r-ML, where a rationally chosen closed-shell precursor 3,5-dichloro-4-[bis(2,4,6-trichlorophenyl)methylen]cyclohexa-2,5-dien-1-one (1) transforms into a stable neutral open-shell species (1•) via chemisorption on the Ag(111) surface. X-ray photoelectron spectroscopy reveals that the >C═O group of 1 reacts with the surface, forming a C-O-Ag linkage that induces an electronic rearrangement that transforms 1 to 1•. We further show that surface reactivity is an important factor in this process whereby Au(111) is inert towards 1, whereas the Cu(111) surface leads to dehalogenation reactions. The radical nature of the Ag(111)-bound monolayer was further confirmed by angle-resolved photoelectron spectroscopy and electronic structure calculations, which provide evidence of the emergence of the singly occupied molecular orbital (SOMO) of 1•.
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Affiliation(s)
- M R Ajayakumar
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
| | - César Moreno
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Isaac Alcón
- Departament de Ciència de Materials i Quı́mica Fı́sica & Institut de Quı́mica Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain
| | - Francesc Illas
- Departament de Ciència de Materials i Quı́mica Fı́sica & Institut de Quı́mica Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain
| | - Concepció Rovira
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
| | - Jaume Veciana
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
| | - Stefan T Bromley
- Departament de Ciència de Materials i Quı́mica Fı́sica & Institut de Quı́mica Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), E-08010 Barcelona, Spain
| | - Aitor Mugarza
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), E-08010 Barcelona, Spain
| | - Marta Mas-Torrent
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
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19
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Nguyen NN, Lee HC, Yoo MS, Lee E, Lee H, Lee SB, Cho K. Charge-Transfer-Controlled Growth of Organic Semiconductor Crystals on Graphene. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1902315. [PMID: 32195079 PMCID: PMC7080519 DOI: 10.1002/advs.201902315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/09/2019] [Indexed: 06/10/2023]
Abstract
Controlling the growth behavior of organic semiconductors (OSCs) is essential because it determines their optoelectronic properties. In order to accomplish this, graphene templates with electronic-state tunability are used to affect the growth of OSCs by controlling the van der Waals interaction between OSC ad-molecules and graphene. However, in many graphene-molecule systems, the charge transfer between an ad-molecule and a graphene template causes another important interaction. This charge-transfer-induced interaction is never considered in the growth scheme of OSCs. Here, the effects of charge transfer on the formation of graphene-OSC heterostructures are investigated, using fullerene (C60) as a model compound. By in situ electrical doping of a graphene template to suppress the charge transfer between C60 ad-molecules and graphene, the layer-by-layer growth of a C60 film on graphene can be achieved. Under this condition, the graphene-C60 interface is free of Fermi-level pinning; thus, barristors fabricated on the graphene-C60 interface show a nearly ideal Schottky-Mott limit with efficient modulation of the charge-injection barrier. Moreover, the optimized C60 film exhibits a high field-effect electron mobility of 2.5 cm2 V-1 s-1. These results provide an efficient route to engineering highly efficient optoelectronic graphene-OSC hybrid material applications.
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Affiliation(s)
- Nguyen Ngan Nguyen
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Hyo Chan Lee
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Min Seok Yoo
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Eunho Lee
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Hansol Lee
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Seon Baek Lee
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Kilwon Cho
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
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20
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Islam A, Hwa Teo S, Awual MR, Taufiq-Yap YH. Ultrathin Assembles of Porous Array for Enhanced H 2 Evolution. Sci Rep 2020; 10:2324. [PMID: 32047187 PMCID: PMC7012925 DOI: 10.1038/s41598-020-59325-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 01/27/2020] [Indexed: 11/20/2022] Open
Abstract
Since the complexity of photocatalyst synthesis process and high cost of noble cocatalyst leftovers a major hurdle to producing hydrogen (H2) from water, a noble metal-free Ni-Si/MgO photocatalyst was realized for the first time to generate H2 effectively under illumination with visible light. The catalyst was produced by means of simple one-pot solid reaction using self-designed metal reactor. The physiochemical properties of photocatalyst were identified by XRD, FESEM, HRTEM, EDX, UV-visible, XPS, GC and PL. The photocatalytic activities of Ni-Si/MgO photocatalyst at different nickel concentrations were evaluated without adjusting pH, applied voltage, sacrificial agent or electron donor. The ultrathin-nanosheet with hierarchically porous structure of catalyst was found to exhibit higher photocatalytic H2 production than hexagonal nanorods structured catalyst, which suggests that the randomly branched nanosheets are more active surface to increase the light-harvesting efficiency due to its short electron diffusion path. The catalyst exhibited remarkable performance reaching up to 714 µmolh−1 which is higher among the predominant semiconductor catalyst. The results demonstrated that the photocatalytic reaction irradiated under visible light illumination through the production of hydrogen and hydroxyl radicals on metals. The outcome indicates an important step forward one-pot facile approach to prepare noble ultrathin photocatalyst for hydrogen production from water.
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Affiliation(s)
- Aminul Islam
- Department of Petroleum and Mining Engineering, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
| | - Siow Hwa Teo
- Chancellery Office, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia.,Catalysis Science and Technology Research Centre, Faculty of Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Md Rabiul Awual
- Materials Science and Research Center, Japan Atomic Energy Agency (JAEA), Hyogo, 679-5148, Japan
| | - Yun Hin Taufiq-Yap
- Chancellery Office, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia. .,Catalysis Science and Technology Research Centre, Faculty of Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
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21
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Sun M, Tang W, Li S, Chou JP, Hu A, Schwingenschlögl U. Molecular doping of blue phosphorene: a first-principles investigation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:055501. [PMID: 31665125 DOI: 10.1088/1361-648x/ab4628] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Using first-principles calculations, we show that p-doped blue phosphorene can be obtained by molecular doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and 1,3,4,5,7,8-hexafluorotetracyanonaphthoquinodimethane (F6-TNAP), whereas n-doped blue phosphorene can be realized by doping with tetrathiafulvalene (TTF) and cyclooctadecanonaene (CCO). Moreover, the doping gap can be effectively modulated in each case by applying an external perpendicular electric field. The optical absorption of blue phosphorene can be considerably enhanced in a broad spectral range through the adsorption of CCO, F4-TCNQ, and F6-TNAP molecules, suggesting potential of the doped materials in the field of renewable energy.
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Affiliation(s)
- Minglei Sun
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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22
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Järvi J, Rinke P, Todorović M. Detecting stable adsorbates of (1 S)-camphor on Cu(111) with Bayesian optimization. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1577-1589. [PMID: 33134002 PMCID: PMC7590619 DOI: 10.3762/bjnano.11.140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/16/2020] [Indexed: 05/08/2023]
Abstract
Identifying the atomic structure of organic-inorganic interfaces is challenging with current research tools. Interpreting the structure of complex molecular adsorbates from microscopy images can be difficult, and using atomistic simulations to find the most stable structures is limited to partial exploration of the potential energy surface due to the high-dimensional phase space. In this study, we present the recently developed Bayesian Optimization Structure Search (BOSS) method as an efficient solution for identifying the structure of non-planar adsorbates. We apply BOSS with density-functional theory simulations to detect the stable adsorbate structures of (1S)-camphor on the Cu(111) surface. We identify the optimal structure among eight unique types of stable adsorbates, in which camphor chemisorbs via oxygen (global minimum) or physisorbs via hydrocarbons to the Cu(111) surface. This study demonstrates that new cross-disciplinary tools, such as BOSS, facilitate the description of complex surface structures and their properties, and ultimately allow us to tune the functionality of advanced materials.
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Affiliation(s)
- Jari Järvi
- Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Espoo, Finland
| | - Patrick Rinke
- Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Espoo, Finland
| | - Milica Todorović
- Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Espoo, Finland
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23
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Tan A, Zhang P. Tailoring the growth and electronic structures of organic molecular thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:503001. [PMID: 31422957 DOI: 10.1088/1361-648x/ab3c22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In the rapidly developing electronics industry, it has become increasingly necessary to explore materials that are cheap, flexible and versatile which have led to significant research efforts towards organic molecular thin films. Organic molecules are unique compared to their inorganic atomic counterparts as their properties can be tuned drastically through chemical functionalization, offering versatility, though their extended shape and weak intermolecular interactions bring significant challenges to the control of both the growth and the electronic structures of molecular thin films. In this paper, we will review the self-assembly process and how to establish long-range ordered organic molecular thin films. We will also discuss how the electronic structures of thin films are impacted by the molecule's local electrostatic environment and its interaction with the substrate, within the context of controlling interfacial energy level alignment between organic semiconductors and electrodes in electronic devices.
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Affiliation(s)
- Andrew Tan
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, United States of America
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24
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Ye JP, Liu G, Han Y, Luo WW, Sun BZ, Lei XL, Xu B, Ouyang CY, Zhang HL. Electric-field-tunable molecular adsorption on germanane. Phys Chem Chem Phys 2019; 21:20287-20295. [PMID: 31490507 DOI: 10.1039/c9cp04122b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fully-hydrogenated germanene, named germanane, represents a new nanostructured material for a variety of potential applications, such as electronics and optoelectronics. However, a critical requirement for developing practical and reliable electronic devices based on germanane consists of achieving a flexibly controllable charge carrier and doping level. Different to the conventional doping methods such as ion implantation and diffusion, by first-principles calculations we demonstrate that tetracyanobenzene (TCNB) molecular adsorption could introduce effective p-type doping in germanane due to the combination of germanane with electroactive acceptor molecule TCNB. The corresponding energy difference between the empty band minimum of the dopant and the valence band maximum for electron excitation is 0.173 eV. More importantly, this nondestructive p-type doping could be linearly tuned under an external E-field. Analysis of charge transfer by means of the equivalent capacitor model and the shift of energy levels in the superstructure of germanane/TCNB further reveals that the superposition of the external E-field and molecular adsorption-induced internal E-field plays a key role in the charge transfer between TCNB and germanane, especially in achieving a controllable p-type molecular doping level in germanane. Such convenient and flexible E-field-engineering of p-type molecular doping in germanane would be very helpful for potential applications of germanane-based electronic and optoelectronic devices in the future.
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Affiliation(s)
- J P Ye
- College of Physics and Communication Electronics, Laboratory of Computational Material Physics, Jiangxi Normal University, Nanchang 330022, China.
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25
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Scheuerer P, Patera LL, Simbürger F, Queck F, Swart I, Schuler B, Gross L, Moll N, Repp J. Charge-Induced Structural Changes in a Single Molecule Investigated by Atomic Force Microscopy. PHYSICAL REVIEW LETTERS 2019; 123:066001. [PMID: 31491133 DOI: 10.1103/physrevlett.123.066001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/12/2019] [Indexed: 06/10/2023]
Abstract
Intramolecular structural relaxations occurring upon electron transfer are crucial in determining the rate of redox reactions. Here, we demonstrate that subangstrom structural changes occurring upon single-electron charging can be quantified by means of atomically resolved atomic force microscopy (AFM) for the case of single copper(II)phthalocyanine (CuPc) molecules deposited on an ultrathin NaCl film. Imaging the molecule in distinct charge states (neutral and anionic) reveals characteristic differences in the AFM contrast. In comparison to density functional theory simulations these changes in contrast can be directly related to relaxations of the molecule's geometric structure upon charging. The dominant contribution arises from a nonhomogeneous vertical relaxation of the molecule, caused by a change in the electrostatic interaction with the surface.
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Affiliation(s)
- Philipp Scheuerer
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Laerte L Patera
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Felix Simbürger
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Fabian Queck
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Ingmar Swart
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
- Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80 000, 3508 TA Utrecht, Netherlands
| | - Bruno Schuler
- IBM Research-Zurich, 8803 Rüschlikon, Switzerland
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Leo Gross
- IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - Nikolaj Moll
- IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - Jascha Repp
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
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26
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Patera LL, Sokolov S, Low JZ, Campos LM, Venkataraman L, Repp J. Resolving the Unpaired‐Electron Orbital Distribution in a Stable Organic Radical by Kondo Resonance Mapping. Angew Chem Int Ed Engl 2019; 58:11063-11067. [DOI: 10.1002/anie.201904851] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Laerte L. Patera
- Institute of Experimental and Applied PhysicsUniversity of Regensburg 93053 Regensburg Germany
| | - Sophia Sokolov
- Institute of Experimental and Applied PhysicsUniversity of Regensburg 93053 Regensburg Germany
| | - Jonathan Z. Low
- Department of ChemistryColumbia University New York NY 10027 USA
| | - Luis M. Campos
- Department of ChemistryColumbia University New York NY 10027 USA
| | - Latha Venkataraman
- Department of ChemistryColumbia University New York NY 10027 USA
- Department of Applied Physics and Applied MathematicsColumbia University New York NY 10027 USA
| | - Jascha Repp
- Institute of Experimental and Applied PhysicsUniversity of Regensburg 93053 Regensburg Germany
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27
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Patera LL, Sokolov S, Low JZ, Campos LM, Venkataraman L, Repp J. Abbildung des Orbitals des ungepaarten Elektrons in einem stabilen, organischen Radikal anhand seiner Kondo‐Resonanz. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laerte L. Patera
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg 93053 Regensburg Deutschland
| | - Sophia Sokolov
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg 93053 Regensburg Deutschland
| | - Jonathan Z. Low
- Department of ChemistryColumbia University New York NY 10027 USA
| | - Luis M. Campos
- Department of ChemistryColumbia University New York NY 10027 USA
| | - Latha Venkataraman
- Department of ChemistryColumbia University New York NY 10027 USA
- Department of Applied Physics and Applied MathematicsColumbia University New York NY 10027 USA
| | - Jascha Repp
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg 93053 Regensburg Deutschland
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Kumar A, Banerjee K, Foster AS, Liljeroth P. Two-Dimensional Band Structure in Honeycomb Metal-Organic Frameworks. NANO LETTERS 2018; 18:5596-5602. [PMID: 30134111 PMCID: PMC6179349 DOI: 10.1021/acs.nanolett.8b02062] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/08/2018] [Indexed: 05/31/2023]
Abstract
Two-dimensional (2D) metal-organic frameworks (MOFs) have been recently proposed as a flexible material platform for realizing exotic quantum phases including topological and anomalous quantum Hall insulators. Experimentally, direct synthesis of 2D MOFs has been essentially confined to metal substrates, where the strong interaction with the substrate masks the intrinsic electronic properties of the MOF. In addition to electronic decoupling from the underlying metal support, synthesis on weakly interacting substrates (e.g., graphene) would enable direct realization of heterostructures of 2D MOFs with inorganic 2D materials. Here, we demonstrate synthesis of 2D honeycomb MOFs on epitaxial graphene substrate. Using low-temperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM) complemented by density-functional theory (DFT) calculations, we show the formation of a 2D band structure in the MOF decoupled from the substrate. These results open the experimental path toward MOF-based designer electronic materials with complex, engineered electronic structures.
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Affiliation(s)
- Avijit Kumar
- Department
of Applied Physics, Aalto University School
of Science, PO Box 15100, 00076 Aalto, Finland
| | - Kaustuv Banerjee
- Department
of Applied Physics, Aalto University School
of Science, PO Box 15100, 00076 Aalto, Finland
| | - Adam S. Foster
- Department
of Applied Physics, Aalto University School
of Science, P.O. Box 11100, 00076 Aalto, Finland
- WPI
Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
- Graduate
School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Peter Liljeroth
- Department
of Applied Physics, Aalto University School
of Science, PO Box 15100, 00076 Aalto, Finland
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Liu C, Huang Z, Hu X, Meng X, Huang L, Xiong J, Tan L, Chen Y. Grain Boundary Modification via F4TCNQ To Reduce Defects of Perovskite Solar Cells with Excellent Device Performance. ACS APPLIED MATERIALS & INTERFACES 2018; 10:1909-1916. [PMID: 29271205 DOI: 10.1021/acsami.7b15031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Solar cells based on hybrid organic-inorganic metal halide perovskites are being developed to achieve high efficiency and stability. However, inevitably, there are defects in perovskite films, leading to poor device performance. Here, we employ an additive-engineering strategy to modify the grain boundary (GB) defects and crystal lattice defects by introducing a strong electron acceptor of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) into perovskite functional layer. Importantly, it has been found that F4TCNQ is filled in GBs and there is a significant reduction of metallic lead defects and iodide vacancies in the perovskite crystal lattice. The bulk heterojunction perovskite-F4TCNQ film exhibits superior electronic quality with improved charge separation and transfer, enhanced and balanced charge mobility, as well as suppressed recombination. As a result, the F4TCNQ doped perovskite device shows excellent device performance, especially the reproducible high fill factor (up to 80%) and negligible hysteresis effect.
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Affiliation(s)
- Cong Liu
- College of Chemistry and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Institute of Polymers, Nanchang University , 999 Xuefu Avenue, Nanchang 330031, China
| | - Zengqi Huang
- College of Chemistry and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Institute of Polymers, Nanchang University , 999 Xuefu Avenue, Nanchang 330031, China
| | - Xiaotian Hu
- Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences (ICCAS) , 2 Zhongguancun Beiyi Street, Beijing 100190, China
| | - Xiangchuan Meng
- College of Chemistry and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Institute of Polymers, Nanchang University , 999 Xuefu Avenue, Nanchang 330031, China
| | - Liqiang Huang
- College of Chemistry and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Institute of Polymers, Nanchang University , 999 Xuefu Avenue, Nanchang 330031, China
| | - Jian Xiong
- Guangxi Key Laboratory of Information Materials, School of Materials Science and Engineering, Guilin University of Electronic Technology , 1 Jinji Road, Guilin 541004, China
| | - Licheng Tan
- College of Chemistry and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Institute of Polymers, Nanchang University , 999 Xuefu Avenue, Nanchang 330031, China
| | - Yiwang Chen
- College of Chemistry and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Institute of Polymers, Nanchang University , 999 Xuefu Avenue, Nanchang 330031, China
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30
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Du L, Zheng K, Cui H, Wang Y, Tao L, Chen X. Novel electronic structures and enhanced optical properties of boron phosphide/blue phosphorene and F4TCNQ/blue phosphorene heterostructures: a DFT + NEGF study. Phys Chem Chem Phys 2018; 20:28777-28785. [DOI: 10.1039/c8cp05119d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Blue phosphorene (Blue-p), an allotrope of black phosphorene, has attracted extensive interest due to its hexagonal crystal with a flat arranged layer of phosphorus atoms.
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Affiliation(s)
- Leqian Du
- Key Laboratory of Optoelectronic Technology & Systems
- Education Ministry of China
- Chongqing University and College of Optoelectronic Engineering
- Chongqing University
- 400044 Chongqing
| | - Kai Zheng
- Key Laboratory of Optoelectronic Technology & Systems
- Education Ministry of China
- Chongqing University and College of Optoelectronic Engineering
- Chongqing University
- 400044 Chongqing
| | - Heping Cui
- Key Laboratory of Optoelectronic Technology & Systems
- Education Ministry of China
- Chongqing University and College of Optoelectronic Engineering
- Chongqing University
- 400044 Chongqing
| | - Yunhao Wang
- School of Economics
- Northeast Normal University
- Changchun 130117
- China
| | - Luqi Tao
- Key Laboratory of Optoelectronic Technology & Systems
- Education Ministry of China
- Chongqing University and College of Optoelectronic Engineering
- Chongqing University
- 400044 Chongqing
| | - Xianping Chen
- Key Laboratory of Optoelectronic Technology & Systems
- Education Ministry of China
- Chongqing University and College of Optoelectronic Engineering
- Chongqing University
- 400044 Chongqing
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31
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Yamane H, Kosugi N. High Hole-Mobility Molecular Layer Made from Strong Electron Acceptor Molecules with Metal Adatoms. J Phys Chem Lett 2017; 8:5366-5371. [PMID: 29043806 DOI: 10.1021/acs.jpclett.7b02390] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The electronic structure of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-TCNQ (F4TCNQ) monolayers on Au(111) has been investigated by means of angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. In contrast to the physisorbed TCNQ/Au(111) interface, the high-resolution core-level photoemission spectra and the low-energy electron diffraction at the F4TCNQ/Au(111) interface show evidence for the strong charge transfer (CT) from Au to F4TCNQ and for the Au atom segregation from the underlying Au(111) surface, suggesting a possible origin of the spontaneous formation of the two-dimensional F4TCNQ-Au network. The ARPES experiment reveals a low hole-injection barrier and large band dispersion in the CT-induced topmost valence level of the F4TCNQ-Au network with 260 meV bandwidth due to the adatom-mediated intermolecular interaction. These results indicate that strong electron acceptor molecules with metal adatoms can form high hole-mobility molecular layers by controlling the molecule-metal ordered structure and their CT interaction.
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Affiliation(s)
- Hiroyuki Yamane
- Institute for Molecular Science, National Institutes of Natural Sciences , Myodaiji, Okazaki 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies) , Myodaiji, Okazaki 444-8585, Japan
| | - Nobuhiro Kosugi
- Institute for Molecular Science, National Institutes of Natural Sciences , Myodaiji, Okazaki 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies) , Myodaiji, Okazaki 444-8585, Japan
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