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Zhang S, Chen S, Ma T, Zou H, Li B, Miao X, Cheng X, Deng W. Terminal Group Effect on Two-Dimensional Self-Assembly of Fluorenone-Based Liquid Crystals at the Solid/Liquid Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1902-1908. [PMID: 38194665 DOI: 10.1021/acs.langmuir.3c03318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Self-assemblies of two fluorenone-based derivatives (FE and FEC) consisting of a central 2,7-diphenyl-9-fluorenone polar moiety but differing in the flexible terminal groups were investigated by scanning tunneling microscopy (STM) at the 1-octanoic acid/HOPG interface under different concentrations and density functional theory calculation (DFT). STM results reveal a concentration-dependent polymorphic self-assembly behavior for FE, but without the presence of co-adsorbed solvents. As the concentration decreases, the dimer, bracket-like, and ribbon-like self-assembled structures were observed. On the contrary, FEC molecules assemble into only a type of oval-shaped morphology by the intermolecular N···H-O hydrogen bonds with the solvent molecules. Combined with DFT calculations, it can be deduced that the intermolecular van der Waals forces, dipole-dipole interactions, and hydrogen bonding are the main driving forces to stabilize the molecular packing of fluorenone-based polycatenars with strong polarity. Our work is of significance at the molecular level to further clarify the intermolecular interactions and conformational effects on the formation of molecular packing structures with liquid crystal property.
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Affiliation(s)
- Songyao Zhang
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China
| | - Shibo Chen
- Key Laboratory of Medicinal Chemistry for Natural Resources, Chemistry School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Tao Ma
- Key Laboratory of Medicinal Chemistry for Natural Resources, Chemistry School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Hengqi Zou
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China
| | - Bang Li
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China
| | - Xinrui Miao
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China
| | - Xiaohong Cheng
- Key Laboratory of Medicinal Chemistry for Natural Resources, Chemistry School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Wenli Deng
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China
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Yu LH, Cai ZF, Verstraete L, Xia Y, Fang Y, Cuccia L, Ivasenko O, De Feyter S. Defect-engineered surfaces to investigate the formation of self-assembled molecular networks. Chem Sci 2022; 13:13212-13219. [PMID: 36425498 PMCID: PMC9667956 DOI: 10.1039/d2sc04599k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/24/2022] [Indexed: 08/28/2024] Open
Abstract
Herein we report the impact of covalent modification (grafting), inducing lateral nanoconfinement conditions, on the self-assembly of a quinonoid zwitterion derivative into self-assembled molecular networks at the liquid/solid interface. At low concentrations where the compound does not show self-assembly behaviour on bare highly oriented pyrolytic graphite (HOPG), close-packed self-assembled structures are visualized by scanning tunneling microscopy on covalently modified HOPG. The size of the self-assembled domains decreases with increasing the density of grafted molecules, i.e. the molecules covalently bound to the surface. The dynamics of domains are captured with molecular resolution, revealing not only time-dependent growth and shrinkage processes but also the orientation conversion of assembled domains. Grafted pins play a key role in initiating the formation of on-surface molecular self-assembly and their stabilization, providing an elegant route to study various aspects of nucleation and growth processes of self-assembled molecular networks.
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Affiliation(s)
- Li-Hua Yu
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven Celestijnenlaan 200F B-3001 Leuven Belgium
| | - Zhen-Feng Cai
- Department of Chemistry and Applied Biosciences, ETH Zurich Zurich CH-8093 Switzerland
| | - Lander Verstraete
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven Celestijnenlaan 200F B-3001 Leuven Belgium
- imec Kapeldreef 75 3001 Leuven Belgium
| | - Yuanzhi Xia
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven Celestijnenlaan 200F B-3001 Leuven Belgium
| | - Yuan Fang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University Suzhou 215123 PR China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University Suzhou 215123 Jiangsu PR China
| | - Louis Cuccia
- Department of Chemistry and Biochemistry, Concordia University 7141 Sherbrooke St. W. Montreal Québec Canada
| | - Oleksandr Ivasenko
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven Celestijnenlaan 200F B-3001 Leuven Belgium
- Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University Suzhou 215123 Jiangsu PR China
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University Suzhou 215123 PR China
| | - Steven De Feyter
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven Celestijnenlaan 200F B-3001 Leuven Belgium
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Boosting the electronic and catalytic properties of 2D semiconductors with supramolecular 2D hydrogen-bonded superlattices. Nat Commun 2022; 13:510. [PMID: 35082288 PMCID: PMC8791956 DOI: 10.1038/s41467-022-28116-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 12/06/2021] [Indexed: 12/13/2022] Open
Abstract
The electronic properties of two-dimensional semiconductors can be strongly modulated by interfacing them with atomically precise self-assembled molecular lattices, yielding hybrid van der Waals heterostructures (vdWHs). While proof-of-concepts exploited molecular assemblies held together by lateral unspecific van der Waals interactions, the use of 2D supramolecular networks relying on specific non-covalent forces is still unexplored. Herein, prototypical hydrogen-bonded 2D networks of cyanuric acid (CA) and melamine (M) are self-assembled onto MoS2 and WSe2 forming hybrid organic/inorganic vdWHs. The charge carrier density of monolayer MoS2 exhibits an exponential increase with the decreasing area occupied by the CA·M unit cell, in a cooperatively amplified process, reaching 2.7 × 1013 cm−2 and thereby demonstrating strong n-doping. When the 2D CA·M network is used as buffer layer, a stark enhancement in the catalytic activity of monolayer MoS2 for hydrogen evolution reactions is observed, outperforming the platinum (Pt) catalyst via gate modulation. Here, the authors report the functionalization of monolayer transition metal dichalcogenides with hydrogen-bonded 2D supramolecular networks of cyanuric acid and melamine, leading to a pronounced n-doping effect and enhancement of MoS2 catalytic activity for hydrogen evolution reactions.
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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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Li SY, Yang XQ, Chen T, Wang D, Wang SF, Wan LJ. Tri-Stable Structural Switching in 2D Molecular Assembly at the Liquid/Solid Interface Triggered by External Electric Field. ACS NANO 2019; 13:6751-6759. [PMID: 31188581 DOI: 10.1021/acsnano.9b01337] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A tri-stable structural switching between different polymorphisms is presented in the 2D molecular assembly of a 5-(benzyloxy)isophthalic acid derivative (BIC-C12) at the liquid/solid interface. The assembled structure of BIC-C12 is sensitive to the applied voltage between the STM tip and the sample surface. A compact lamellar structure is exclusively observed at positive sample bias, while a porous honeycomb structure or a quadrangular structure is preferred at negative sample bias. Selective switching between the lamellar structure and the honeycomb structure or the quadrangular structure is realized by controlling the polarity and magnitude of the sample bias. The transition between the honeycomb structure and the quadrangular structure is, however, absent in the assembly. This tri-stable structural switching is closely related to the molecular concentration in the liquid phase. This result provides insights into the effect of external electric field on molecular assembly and benefits the design and construction of switchable molecular architectures on surfaces.
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Affiliation(s)
- Shu-Ying Li
- Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences (CAS) , Beijing 100190 , People's Republic of China
- Faculty of Chemistry , Northeast Normal University , Changchun 130024 , People's Republic of China
| | - Xue-Qing Yang
- Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences (CAS) , Beijing 100190 , People's Republic of China
- Hubei University , Wuhan 400062 , People's Republic of China
| | - Ting Chen
- Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences (CAS) , Beijing 100190 , People's Republic of China
| | - Dong Wang
- Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences (CAS) , Beijing 100190 , People's Republic of China
- University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| | - Sheng-Fu Wang
- Hubei University , Wuhan 400062 , People's Republic of China
| | - Li-Jun Wan
- Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences (CAS) , Beijing 100190 , People's Republic of China
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