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Hwang J, Park J, Choi J, Lee T, Lee HC, Cho K. Self-Assembly of Organic Semiconductors on Strained Graphene under Strain-Induced Pseudo-Electric Fields. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400598. [PMID: 38477451 PMCID: PMC11109627 DOI: 10.1002/advs.202400598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Indexed: 03/14/2024]
Abstract
Graphene is used as a growth template for van der Waals epitaxy of organic semiconductor (OSC) thin films. During the synthesis and transfer of chemical-vapor-deposited graphene on a target substrate, local inhomogeneities in the graphene-in particular, a nonuniform strain field in the graphene template-can easily form, causing poor morphology and crystallinity of the OSC thin films. Moreover, a strain field in graphene introduces a pseudo-electric field in the graphene. Here, the study investigates how the strain and strain-induced pseudo-electric field of a graphene template affect the self-assembly of π-conjugated organic molecules on it. Periodically strained graphene templates are fabricated by transferring graphene onto an array of nanospheres and then analyzed the growth and nucleation behavior of C60 thin films on the strained graphene templates. Both experiments and a numerical simulation demonstrated that strained graphene reduced the desorption energy between the graphene and the C60 molecules and thereby suppressed both nucleation and growth of the C60. A mechanism is proposed in which the strain-induced pseudo-electric field in graphene modulates the binding energy of organic molecules on the graphene.
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Affiliation(s)
- Jinhyun Hwang
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Jisang Park
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Jinhyeok Choi
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
| | - Taeksang Lee
- Department of Mechanical EngineeringMyongji UniversityYongin17058Republic of Korea
| | - Hyo Chan Lee
- Department of Chemical EngineeringMyongji UniversityYongin17058Republic of Korea
| | - Kilwon Cho
- Department of Chemical EngineeringPohang University of Science and TechnologyPohang37673Republic of Korea
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2
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Li T, Bandari VK, Schmidt OG. Molecular Electronics: Creating and Bridging Molecular Junctions and Promoting Its Commercialization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209088. [PMID: 36512432 DOI: 10.1002/adma.202209088] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/28/2022] [Indexed: 06/02/2023]
Abstract
Molecular electronics is driven by the dream of expanding Moore's law to the molecular level for next-generation electronics through incorporating individual or ensemble molecules into electronic circuits. For nearly 50 years, numerous efforts have been made to explore the intrinsic properties of molecules and develop diverse fascinating molecular electronic devices with the desired functionalities. The flourishing of molecular electronics is inseparable from the development of various elegant methodologies for creating nanogap electrodes and bridging the nanogap with molecules. This review first focuses on the techniques for making lateral and vertical nanogap electrodes by breaking, narrowing, and fixed modes, and highlights their capabilities, applications, merits, and shortcomings. After summarizing the approaches of growing single molecules or molecular layers on the electrodes, the methods of constructing a complete molecular circuit are comprehensively grouped into three categories: 1) directly bridging one-molecule-electrode component with another electrode, 2) physically bridging two-molecule-electrode components, and 3) chemically bridging two-molecule-electrode components. Finally, the current state of molecular circuit integration and commercialization is discussed and perspectives are provided, hoping to encourage the community to accelerate the realization of fully scalable molecular electronics for a new era of integrated microsystems and applications.
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Affiliation(s)
- Tianming Li
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Vineeth Kumar Bandari
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Oliver G Schmidt
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
- Nanophysics, Dresden University of Technology, 01069, Dresden, Germany
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3
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Hazan Z, Averbukh M, Manassen Y. ESR-STM on diamagnetic molecule: C 60 on graphene. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 348:107377. [PMID: 36709618 DOI: 10.1016/j.jmr.2023.107377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
Electron Spin Resonance-Scanning Tunneling Microscopy (ESR-STM) of C60 radical ion on graphene is a first demonstration of ESR-STM on diamagnetic molecules. ESR-STM signal at gaverage=2.0±0.1 was measured in accordance with macroscopic ESR of C60 radical ion. The ESR-STM signal was bias voltage dependent, as it reflects the charge state of the molecule. The signal appears in the bias voltage which enables the ionization of the lowest unoccupied molecular orbital (LUMO) - creation of radical anion, and the highest occupied molecular orbital (HOMO) - creation of a radical cation of the C60 molecule when it deposited on graphene. In parallel, ESR-STM signal at gaverage=1.7±0.1 was ascribed to Tungsten oxide (WO3) at the tip apex. In several experiments, triplet spectrum was observed, and we ascribed their origin to zero-field splitting of doubly ionized C120O-2 dimer, as argued in previous ESR experiments of C60 samples. Second possibility is hyperfine coupling with two 13C nuclei. In addition, we further validate the interference mechanism previously suggested for ESR-STM noise spectroscopy. The ability of ESR-STM to observe ESR of diamagnetic molecules in parallel with observing their electronic structure, provides a general single molecule identification technique.
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Affiliation(s)
- Zion Hazan
- Department of Physics, Ben Gurion University, P.O. Box 653, Beer Sheva 84105, Israel
| | - Michael Averbukh
- Department of Physics, Ben Gurion University, P.O. Box 653, Beer Sheva 84105, Israel
| | - Yishay Manassen
- Department of Physics, Ben Gurion University, P.O. Box 653, Beer Sheva 84105, Israel.
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4
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Albani G, Capra M, Lodesani A, Calloni A, Bussetti G, Finazzi M, Ciccacci F, Brambilla A, Duò L, Picone A. Self-assembly of C 60 on a ZnTPP/Fe(001)- p(1 × 1)O substrate: observation of a quasi-freestanding C 60 monolayer. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:857-864. [PMID: 36105692 PMCID: PMC9443418 DOI: 10.3762/bjnano.13.76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Fullerene (C60) has been deposited in ultrahigh vacuum on top of a zinc tetraphenylporphyrin (ZnTPP) monolayer self-assembled on a Fe(001)-p(1 × 1)O substrate. The nanoscale morphology and the electronic properties of the C60/ZnTPP/Fe(001)-p(1 × 1)O heterostructure have been investigated by scanning tunneling microscopy/spectroscopy and ultraviolet photoemission spectroscopy. C60 nucleates compact and well-ordered hexagonal domains on top of the ZnTPP buffer layer, suggesting a high surface diffusivity of C60 and a weak coupling between the overlayer and the substrate. Accordingly, work function measurements reveal a negligible charge transfer at the C60/ZnTPP interface. Finally, the difference between the energy of the lowest unoccupied molecular orbital (LUMO) and that of the highest occupied molecular orbital (HOMO) measured on C60 is about 3.75 eV, a value remarkably higher than those found in fullerene films stabilized directly on metal surfaces. Our results unveil a model system that could be useful in applications in which a quasi-freestanding monolayer of C60 interfaced with a metallic electrode is required.
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Affiliation(s)
- Guglielmo Albani
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Michele Capra
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alessandro Lodesani
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alberto Calloni
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Gianlorenzo Bussetti
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marco Finazzi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Franco Ciccacci
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alberto Brambilla
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lamberto Duò
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Andrea Picone
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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5
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de la Rie J, Enache M, Wang Q, Lu W, Kivala M, Stöhr M. Self-Assembly of a Triphenylene-Based Electron Donor Molecule on Graphene: Structural and Electronic Properties. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:9855-9861. [PMID: 35747511 PMCID: PMC9207905 DOI: 10.1021/acs.jpcc.1c10266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 05/16/2022] [Indexed: 06/15/2023]
Abstract
In this study, we report on the self-assembly of the organic electron donor 2,3,6,7,10,11-hexamethoxytriphenylene (HAT) on graphene grown epitaxially on Ir(111). Using scanning tunneling microscopy and low-energy electron diffraction, we find that a monolayer of HAT assembles in a commensurate close-packed hexagonal network on graphene/Ir(111). X-ray and ultraviolet photoelectron spectroscopy measurements indicate that no charge transfer between the HAT molecules and the graphene/Ir(111) substrate takes place, while the work function decreases slightly. This demonstrates that the HAT/graphene interface is weakly interacting. The fact that the molecules nonetheless form a commensurate network deviates from what is established for adsorption of organic molecules on metallic substrates where commensurate overlayers are mainly observed for strongly interacting systems.
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Affiliation(s)
- Joris de la Rie
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Mihaela Enache
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Qiankun Wang
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Wenbo Lu
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Milan Kivala
- Institute
of Organic Chemistry, University of Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
- Centre
for Advanced Materials, University of Heidelberg, Im Neuenheimer Feld 225, Heidelberg 69120, Germany
| | - Meike Stöhr
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
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6
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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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7
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Bouatou M, Harsh R, Joucken F, Chacon C, Repain V, Bellec A, Girard Y, Rousset S, Sporken R, Gao F, Brandbyge M, Dappe YJ, Barreteau C, Smogunov A, Lagoute J. Intraconfigurational Transition due to Surface-Induced Symmetry Breaking in Noncovalently Bonded Molecules. J Phys Chem Lett 2020; 11:9329-9335. [PMID: 33089985 DOI: 10.1021/acs.jpclett.0c02407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The interaction of molecules with surfaces plays a crucial role in the electronic and chemical properties of supported molecules and needs a comprehensive description of interfacial effects. Here, we unveil the effect of the substrate on the electronic configuration of iron porphyrin molecules on Au(111) and graphene, and we provide a physical picture of the molecule-surface interaction. We show that the frontier orbitals derive from different electronic states depending on the substrate. The origin of this difference comes from molecule-substrate orbital selective coupling caused by reduced symmetry and interaction with the substrate. The weak interaction on graphene keeps a ground state configuration close to the gas phase, while the stronger interaction on gold stabilizes another electronic solution. Our findings reveal the origin of the energy redistribution of molecular states for noncovalently bonded molecules on surfaces.
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Affiliation(s)
- Mehdi Bouatou
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Rishav Harsh
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Frédéric Joucken
- Research Center in Physics of Matter and Radiation (PMR), Université de Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Cyril Chacon
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Vincent Repain
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Amandine Bellec
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Yann Girard
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Sylvie Rousset
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Robert Sporken
- Research Center in Physics of Matter and Radiation (PMR), Université de Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Fei Gao
- Center for Nanostructured Graphene, Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Mads Brandbyge
- Center for Nanostructured Graphene, Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Yannick J Dappe
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Cyrille Barreteau
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Alexander Smogunov
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Jérôme Lagoute
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
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Guo H, Martínez-Galera AJ, Gómez-Rodríguez JM. C 60 self-orientation on hexagonal boron nitride induced by intermolecular coupling. NANOTECHNOLOGY 2020; 32:025711. [PMID: 33073772 DOI: 10.1088/1361-6528/abbbb2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A deep grasp of the properties of the interface between organic molecules and hexagonal boron nitride (h-BN) is essential for the full implementation of these two building blocks in the next generation of electronic devices. Here, using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), we report on the geometric and electronic features of C60 evaporated on a single layer of h-BN grown on a Rh(110) surface under ultra-high vacuum. Two different molecular assemblies of C60 on the h-BN/Rh(110) surface were observed. The first STM study at room temperature (RT) and at low temperatures (40 K) looked at the molecular orientation of C60 on a two-dimensional layered material. Intramolecular-resolution images demonstrate the existence of a phase transition of C60 over the h-BN/Rh(110) surface similar to that found on bulk solid C60. At RT molecules exhibit random orientations, while at 40 K such rotational disorder vanishes and they adopt a common orientation over the h-BN/Rh(110) surface. The decrease in thermal energy allows recognition between C60 molecules, and they become equally oriented in the configuration at which the van der Waals intermolecular interactions are optimized. Bias-dependent submolecular features obtained by means of high-resolution STM images are interpreted as the highest occupied and lowest unoccupied molecular orbitals. STS data showed that fullerenes are electronically decoupled from the substrate, with a negligible charge transfer effect if any. Finally, the very early stages of multilayer growth were also investigated.
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Affiliation(s)
- Haojie Guo
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
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9
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Shang Y, Wang Z, Yang D, Wang Y, Ma C, Tao M, Sun K, Yang J, Wang J. Orientation Ordering and Chiral Superstructures in Fullerene Monolayer on Cd (0001). NANOMATERIALS 2020; 10:nano10071305. [PMID: 32635309 PMCID: PMC7407170 DOI: 10.3390/nano10071305] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/21/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022]
Abstract
The structure of C60 thin films grown on Cd (0001) surface has been investigated from submonolayer to second monolayer regimes with a low-temperature scanning tunneling microscopy (STM). There are different C60 domains with various misorientation angles relative to the lattice directions of Cd (0001). In the (2√3 × 2√3) R30° domain, orientational disorder of the individual C60 molecules with either pentagon, hexagon, or 6:6 bond facing up has been observed. However, orientation ordering appeared in the R26° domain such that all the C60 molecules adopt the same orientation with the 6:6 bond facing up. In particular, complex chiral motifs composed of seven C60 molecules with clockwise or anticlockwise handedness have been observed in the R4° and R8° domains, respectively. Scanning tunneling spectroscopy (STS) measurements reveal a reduced HOMO–LOMO gap of 2.1 eV for the C60 molecules adsorbed on Cd (0001) due to the substrate screening and charge transfer from Cd to C60 molecules.
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10
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John AS, Roth MW, Firlej L, Kuchta B, Charra F, Wexler C. Self-Assembled Two-Dimensional Nanoporous Crystals as Molecular Sieves: Molecular Dynamics Studies of 1,3,5-Tristyrilbenzene-C n Superstructures. J Chem Inf Model 2020; 60:2155-2168. [PMID: 32155335 DOI: 10.1021/acs.jcim.0c00015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Due to their unique geometry complex, self-assembled nanoporous 2D molecular crystals offer a broad landscape of potential applications, ranging from adsorption and catalysis to optoelectronics, substrate processes, and future nanomachine applications. Here we report and discuss the results of extensive all-atom Molecular Dynamics (MD) investigations of self-assembled organic monolayers (SAOM) of interdigitated 1,3,5-tristyrilbenzene (TSB) molecules terminated by alkoxy peripheral chains Cn containing n carbon atoms (TSB3,5-Cn) deposited onto highly ordered pyrolytic graphite (HOPG). In vacuo structural and electronic properties of the TSB3,5-Cn molecules were initially determined using ab initio second order Møller-Plesset (MP2) calculations. The MD simulations were then used to analyze the behavior of the self-assembled superlattices, including relaxed lattice geometry (in good agreement with experimental results) and stability at ambient temperatures. We show that the intermolecular disordering of the TSB3,5-Cn monolayers arises from competition between decreased rigidity of the alkoxy chains (loss of intramolecular order) and increased stabilization with increasing chain length (afforded by interdigitation). We show that the inclusion of guest organic molecules (e.g., benzene, pyrene, coronene, hexabenzocoronene) into the nanopores (voids formed by interdigitated alkoxy chains) of the TSB3,5-Cn superlattices stabilizes the superstructure, and we highlight the importance of alkoxy chain mobility and available pore space in the dynamics of the systems and their potential application in selective adsorption.
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Affiliation(s)
- Alexander St John
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Michael W Roth
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States.,Physics Department, Waldorf University, Forest City, Iowa 50436, United States
| | - Lucyna Firlej
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States.,Laboratoire Charles Coulomb, CNRS-Université de Montpellier, 34090 Montpellier, France
| | - Bogdan Kuchta
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States.,Faculty of Chemistry, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland.,Laboratoire MADRIEL, Aix-Marseille Université-CNRS, 13007 Marseille, France
| | - Fabrice Charra
- Service de Physique de l'État Condensé (SPEC), Université Paris Saclay, CEA CNRS UMR-3680 CEA Saclay F-91191 Gif-sur-Yvette, France
| | - Carlos Wexler
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
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11
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St John A, Roth MW, Firlej L, Kuchta B, Charra F, Wexler C. Computer modeling of 2D supramolecular nanoporous monolayers self-assembled on graphite. NANOSCALE 2019; 11:21284-21290. [PMID: 31667485 DOI: 10.1039/c9nr05710b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nano-porous two-dimensional molecular crystals, self-assembled on atomically flat host surfaces offer a broad range of possible applications, from molecular electronics to future nano-machines. Computer-assisted designing of such complex structures requires numerically intensive modeling methods. Here we present the results of extensive, fully atomistic simulations of self-assembled monolayers of interdigitated molecules of 1,3,5-tristyrilbenzene substituted by C6 alkoxy peripheral chains (TSB3,5-C6), deposited onto highly-ordered pyrolytic graphite. Structural and electronic properties of the TSB3,5-C6 molecules were determined from ab initio calculations, then used in Molecular Dynamics simulations to analyze the mechanism of formation, epitaxy, and stability of the TSB3,5-C6 nanoporous superlattice. We show that the monolayer disordering results from the competition between flexibility of the C6 chains and their stabilization by interdigitation. The inclusion of guest molecules (benzene and pyrene) into superlattice nanopores stabilizes the monolayer. The alkoxy chain mobility and available pore space defines the systems dynamics, essential for potential application.
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Affiliation(s)
- Alexander St John
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
| | - Michael W Roth
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA. and Physics Department, Waldorf University, Forest City, IA 50436, USA
| | - Lucyna Firlej
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA. and Laboratoire Charles Coulomb, CNRS-Université de Montpellier, Montpellier, France
| | - Bogdan Kuchta
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA. and Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, Poland and Laboratoire MADRIEL, Aix-Marseille Université-CNRS, Marseille, France
| | - Fabrice Charra
- Service de Physique de l'État Condensé (SPEC), CEA CNRS UMR-3680, Université Paris Saclay, CEA Saclay F-91191 Gif-sur-Yvette, France
| | - Carlos Wexler
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
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12
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Liu Z, Sun K, Li X, Li L, Zhang H, Chi L. Electronic Decoupling of Organic Layers by a Self-Assembled Supramolecular Network on Au(111). J Phys Chem Lett 2019; 10:4297-4302. [PMID: 31318568 DOI: 10.1021/acs.jpclett.9b01167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A cyanuric acid and melamine (CA·M) supramolecular network, prepared via the drop-casting method under ambient conditions, can be utilized as a spacer layer to decouple electronic interactions between upper organics and the metal substrate. Typical semiconducting organics 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) and C60 are deposited on the CA·M network under ultrahigh vacuum conditions, forming an organics/CA·M/metal heterosystem. Both geometric and electronic structures of the upper organics are characterized by using scanning tunneling microscopy/spectroscopy (STM/STS). On the CA·M network, PTCDA molecules form a well-ordered herringbone structure in submonolayer patterns, whereas C60 molecules aggregate into multilayered islands. STS spectra reveal that the energy gap between the highest occupied and the lowest unoccupied molecular orbitals (HOMO - LUMO) is 3.6 eV for PTCDA and 3.8 eV for the first layer of C60 on CA·M. The remarkable bandgap broadening compared with the metal-organic contact indicates successful electronic decoupling of the upper molecules from the metal surface due to the CA·M network.
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Affiliation(s)
- Zhonghua Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China
| | - Kewei Sun
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China
| | - Xuechao Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China
| | - Ling Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China
| | - Haiming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China
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13
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Sun J, Choi Y, Choi YJ, Kim S, Park JH, Lee S, Cho JH. 2D-Organic Hybrid Heterostructures for Optoelectronic Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1803831. [PMID: 30786064 DOI: 10.1002/adma.201803831] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 01/10/2019] [Indexed: 05/08/2023]
Abstract
The unique properties of hybrid heterostructures have motivated the integration of two or more different types of nanomaterials into a single optoelectronic device structure. Despite the promising features of organic semiconductors, such as their acceptable optoelectronic properties, availability of low-cost processes for their fabrication, and flexibility, further optimization of both material properties and device performances remains to be achieved. With the emergence of atomically thin 2D materials, they have been integrated with conventional organic semiconductors to form multidimensional heterostructures that overcome the present limitations and provide further opportunities in the field of optoelectronics. Herein, a comprehensive review of emerging 2D-organic heterostructures-from their synthesis and fabrication to their state-of-the-art optoelectronic applications-is presented. Future challenges and opportunities associated with these heterostructures are highlighted.
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Affiliation(s)
- Jia Sun
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Hunan Key Laboratory for Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan, 410083, P. R. China
| | - Yongsuk Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Young Jin Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Seongchan Kim
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Jin-Hong Park
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Sungjoo Lee
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Nano Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Jeong Ho Cho
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Nano Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
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14
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Cui X, Han D, Guo H, Zhou L, Qiao J, Liu Q, Cui Z, Li Y, Lin C, Cao L, Ji W, Petek H, Feng M. Realizing nearly-free-electron like conduction band in a molecular film through mediating intermolecular van der Waals interactions. Nat Commun 2019; 10:3374. [PMID: 31358744 PMCID: PMC6662711 DOI: 10.1038/s41467-019-11300-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 07/01/2019] [Indexed: 12/03/2022] Open
Abstract
Collective molecular physical properties can be enhanced from their intrinsic characteristics by templating at material interfaces. Here we report how a black phosphorous (BP) substrate concatenates a nearly-free-electron (NFE) like conduction band of a C60 monolayer. Scanning tunneling microscopy reveals the C60 lowest unoccupied molecular orbital (LUMO) band is strongly delocalized in two-dimensions, which is unprecedented for a molecular semiconductor. Experiment and theory show van der Waals forces between C60 and BP reduce the inter-C60 distance and cause mutual orientation, thereby optimizing the π-π wave function overlap and forming the NFE-like band. Electronic structure and carrier mobility calculations predict that the NFE band of C60 acquires an effective mass of 0.53-0.70 me (me is the mass of free electrons), and has carrier mobility of ~200 to 440 cm2V-1s-1. The substrate-mediated intermolecular van der Waals interactions provide a route to enhance charge delocalization in fullerenes and other organic semiconductors.
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Affiliation(s)
- Xingxia Cui
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Ding Han
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Hongli Guo
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Linwei Zhou
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Jingsi Qiao
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Qing Liu
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Zhihao Cui
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Yafei Li
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Chungwei Lin
- Mitsubishi Electric Research Laboratories, 201 Broadway, Cambridge, MA, 02139, USA
| | - Limin Cao
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China.
| | - Hrvoje Petek
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
| | - Min Feng
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China.
- Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China.
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15
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Jiang S, Qian J, Duan Y, Wang H, Guo J, Guo Y, Liu X, Wang Q, Shi Y, Li Y. Millimeter-Sized Two-Dimensional Molecular Crystalline Semiconductors with Precisely Defined Molecular Layers via Interfacial-Interaction-Modulated Self-Assembly. J Phys Chem Lett 2018; 9:6755-6760. [PMID: 30415550 DOI: 10.1021/acs.jpclett.8b03108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The newly emerging field in organic electronics is to control the molecule-substrate interface properties at a two-dimensional (2D) limit via interfacial interactions, which paves the way for driving the molecular assembly for highly ordered 2D molecular crystalline films with precise molecular layers and large-area uniformity. Here, by exploiting molecule-substrate van der Waals (vdW) interactions, we demonstrate thermally induced self-assembly of 2D organic crystalline films exhibiting well-defined molecular layer number over a millimeter-sized area. The organic field-effect transistors (OFETs) with bilayer films show excellent electrical performance with a maximum mobility of 12.8 cm2 V-1 s-1. Moreover, we find that the monolayer films can act as interfacial molecular templates to construct heterojunctions with well-balanced ambipolar transport behaviors. The capability of thermally induced self-assembly of 2D molecular crystalline films with controllable molecular layers and scale-up coverage opens up a way for realizing complicated electronic applications, such as lateral heterojunctions and superlattices.
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Affiliation(s)
- Sai Jiang
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Jun Qian
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Yiwei Duan
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Hengyuan Wang
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Jianhang Guo
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Yu Guo
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Xinyi Liu
- Nanjing Foreign Language School , Nanjing , Jiangsu 210008 , P. R. China
| | - Qijing Wang
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Yi Shi
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
| | - Yun Li
- National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing , Jiangsu 210093 , P. R. China
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16
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Schwarz M, Duncan DA, Garnica M, Ducke J, Deimel PS, Thakur PK, Lee TL, Allegretti F, Auwärter W. Quantitative determination of a model organic/insulator/metal interface structure. NANOSCALE 2018; 10:21971-21977. [PMID: 30444513 PMCID: PMC6289171 DOI: 10.1039/c8nr06387g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/28/2018] [Indexed: 05/22/2023]
Abstract
By combining X-ray photoelectron spectroscopy, X-ray standing waves and scanning tunneling microscopy, we investigate the geometric and electronic structure of a prototypical organic/insulator/metal interface, namely cobalt porphine on monolayer hexagonal boron nitride (h-BN) on Cu(111). Specifically, we determine the adsorption height of the organic molecule and show that the original planar molecular conformation is preserved in contrast to the adsorption on Cu(111). In addition, we highlight the electronic decoupling provided by the h-BN spacer layer and find that the h-BN-metal separation is not significantly modified by the molecular adsorption. Finally, we find indication of a temperature dependence of the adsorption height, which might be a signature of strongly-anisotropic thermal vibrations of the weakly bonded molecules.
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Affiliation(s)
- Martin Schwarz
- Physics Department
, Technical University of Munich
,
85748 Garching
, Germany
.
;
| | - David A. Duncan
- Diamond Light Source
, Harwell Science and Innovation Campus
,
Didcot OX11 0DE
, UK
| | - Manuela Garnica
- Physics Department
, Technical University of Munich
,
85748 Garching
, Germany
.
;
| | - Jacob Ducke
- Physics Department
, Technical University of Munich
,
85748 Garching
, Germany
.
;
| | - Peter S. Deimel
- Physics Department
, Technical University of Munich
,
85748 Garching
, Germany
.
;
| | - Pardeep K. Thakur
- Diamond Light Source
, Harwell Science and Innovation Campus
,
Didcot OX11 0DE
, UK
| | - Tien-Lin Lee
- Diamond Light Source
, Harwell Science and Innovation Campus
,
Didcot OX11 0DE
, UK
| | - Francesco Allegretti
- Physics Department
, Technical University of Munich
,
85748 Garching
, Germany
.
;
| | - Willi Auwärter
- Physics Department
, Technical University of Munich
,
85748 Garching
, Germany
.
;
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17
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Krane N, Lotze C, Reecht G, Zhang L, Briseno AL, Franke KJ. High-Resolution Vibronic Spectra of Molecules on Molybdenum Disulfide Allow for Rotamer Identification. ACS NANO 2018; 12:11698-11703. [PMID: 30380829 DOI: 10.1021/acsnano.8b07414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tunneling spectroscopy is an important tool for the chemical identification of single molecules on surfaces. Here, we show that oligothiophene-based large organic molecules which only differ by single bond orientations can be distinguished by their vibronic fingerprint. These molecules were deposited on a monolayer of the transition metal dichalcogenide molybdenum disulfide (MoS2) on top of a Au(111) substrate. MoS2 features an electronic band gap for efficient decoupling of the molecular states. Furthermore, it exhibits a small electron-phonon coupling strength. Both of these material properties allow for the resolution of vibronic states in the range of the limit set by temperature broadening in our scanning tunneling microscope at 4.6 K. Using DFT calculations of the molecule in gas phase provides all details for an accurate simulation of the vibronic spectra of both rotamers.
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Affiliation(s)
- Nils Krane
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Christian Lotze
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Gaël Reecht
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Lei Zhang
- Department of Polymer Science and Engineering , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Alejandro L Briseno
- Department of Polymer Science and Engineering , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Katharina J Franke
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
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18
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Qin S, Chen X, Du Q, Nie Z, Wang X, Lu H, Wang X, Liu K, Xu Y, Shi Y, Zhang R, Wang F. Sensitive and Robust Ultraviolet Photodetector Array Based on Self-Assembled Graphene/C 60 Hybrid Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:38326-38333. [PMID: 30207446 DOI: 10.1021/acsami.8b11596] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Graphene has been widely investigated for use in high-performance photodetectors due to its broad absorption band and high carrier mobility. While exhibiting remarkably strong absorption in the ultraviolet range, the fabrication of a large-scale integrable, graphene-based ultraviolet photodetector with long-term stability has proven to be a challenge. Here, using graphene as a template for C60 assembly, we synthesized a large-scale all-carbon hybrid film with inherently strong and tunable UV aborption. Efficient exciton dissociation at the heterointerface and enhanced optical absorption enables extremely high photoconductive gain, resulting in UV photoresponsivity of ∼107 A/W. Interestingly, due to the electron-hole recombination process at the heterointerface, the response time can be modulated by the gate voltage. More importantly, the use of all-carbon hybrid materials ensures robust operation and further allows the demonstration of an exemplary 5 × 5 (2-dimensional) photodetector array. The devices exhibit negligible degradation in figures of merit even after 2 month of operation, indicating excellent environmental robustness. The combination of high responsivity, reliability, and scalable processability makes this new all-carbon film a promising candidate for future integrable optoelectronics.
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Affiliation(s)
| | | | | | | | | | | | | | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, and School of Physics , Peking University , Beijing 100871 , China
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19
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He H, Kim KH, Danilov A, Montemurro D, Yu L, Park YW, Lombardi F, Bauch T, Moth-Poulsen K, Iakimov T, Yakimova R, Malmberg P, Müller C, Kubatkin S, Lara-Avila S. Uniform doping of graphene close to the Dirac point by polymer-assisted assembly of molecular dopants. Nat Commun 2018; 9:3956. [PMID: 30262825 PMCID: PMC6160407 DOI: 10.1038/s41467-018-06352-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 08/31/2018] [Indexed: 11/12/2022] Open
Abstract
Tuning the charge carrier density of two-dimensional (2D) materials by incorporating dopants into the crystal lattice is a challenging task. An attractive alternative is the surface transfer doping by adsorption of molecules on 2D crystals, which can lead to ordered molecular arrays. However, such systems, demonstrated in ultra-high vacuum conditions (UHV), are often unstable in ambient conditions. Here we show that air-stable doping of epitaxial graphene on SiC—achieved by spin-coating deposition of 2,3,5,6-tetrafluoro-tetracyano-quino-dimethane (F4TCNQ) incorporated in poly(methyl-methacrylate)—proceeds via the spontaneous accumulation of dopants at the graphene-polymer interface and by the formation of a charge-transfer complex that yields low-disorder, charge-neutral, large-area graphene with carrier mobilities ~70 000 cm2 V−1 s−1 at cryogenic temperatures. The assembly of dopants on 2D materials assisted by a polymer matrix, demonstrated by spin-coating wafer-scale substrates in ambient conditions, opens up a scalable technological route toward expanding the functionality of 2D materials. Incorporating dopants in the graphene lattice to tune its electronic properties is a challenging task. Here, the authors report a strategy to dope epitaxial large-area graphene on SiC by means of spin-coating deposition of F4TCNQ polymers in ambient conditions.
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Affiliation(s)
- Hans He
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Kyung Ho Kim
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.,Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Andrey Danilov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Domenico Montemurro
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Liyang Yu
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296, Göteborg, Sweden
| | - Yung Woo Park
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.,Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea.,Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Floriana Lombardi
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Thilo Bauch
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Kasper Moth-Poulsen
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296, Göteborg, Sweden
| | - Tihomir Iakimov
- Department of Physics, Chemistry and Biology, Linkoping University, 581 83, Linköping, Sweden
| | - Rositsa Yakimova
- Department of Physics, Chemistry and Biology, Linkoping University, 581 83, Linköping, Sweden
| | - Per Malmberg
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296, Göteborg, Sweden
| | - Christian Müller
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296, Göteborg, Sweden
| | - Sergey Kubatkin
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Samuel Lara-Avila
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden. .,National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK.
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20
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Chen C, Mills A, Zheng H, Li Y, Tao C. Preparation and Characterization of C60/Graphene Hybrid Nanostructures. J Vis Exp 2018. [PMID: 29863668 DOI: 10.3791/57257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We present methods for depositing and passively manipulating C60 molecules on rippled graphene that advance the pursuit of realizing applications involving 1D C60/graphene hybrid structures. The techniques applied in this exposition are geared towards high vacuum systems with preparation areas capable of supporting molecular deposition as well as thermal annealing of the samples. We focus on C60 deposition at low pressure using a homemade Knudsen cell connected to a scanning tunneling microscopy (STM) system. The number of molecules deposited is regulated by controlling the temperature of the Knudsen cell and the deposition time. One-dimensional (1D) C60 chain structures with widths of two to three molecules can be prepared via tuning of the experimental conditions. The surface mobility of the C60 molecules increases with annealing temperature allowing them to move within the periodic potential of the rippled graphene. Using this mechanism, it is possible to control the transition of 1D C60 chain structures to a hexagonal close packed quasi-1D stripe structure.
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Affiliation(s)
- Chuanhui Chen
- Department of Physics, Center for Soft Matter and Biological Physics, Virginia Tech
| | - Adam Mills
- Department of Physics, Center for Soft Matter and Biological Physics, Virginia Tech; Department of Physics, Princeton University
| | - Husong Zheng
- Department of Physics, Center for Soft Matter and Biological Physics, Virginia Tech
| | - Yanlong Li
- Department of Physics, Center for Soft Matter and Biological Physics, Virginia Tech
| | - Chenggang Tao
- Department of Physics, Center for Soft Matter and Biological Physics, Virginia Tech;
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21
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Anomalous Kondo resonance mediated by semiconducting graphene nanoribbons in a molecular heterostructure. Nat Commun 2017; 8:946. [PMID: 29038513 PMCID: PMC5643342 DOI: 10.1038/s41467-017-00881-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 07/31/2017] [Indexed: 11/18/2022] Open
Abstract
Kondo resonances in heterostructures formed by magnetic molecules on a metal require free host electrons to interact with the molecular spin and create delicate many-body states. Unlike graphene, semiconducting graphene nanoribbons do not have free electrons due to their large bandgaps, and thus they should electronically decouple molecules from the metal substrate. Here, we observe unusually well-defined Kondo resonances in magnetic molecules separated from a gold surface by graphene nanoribbons in vertically stacked heterostructures. Surprisingly, the strengths of Kondo resonances for the molecules on graphene nanoribbons appear nearly identical to those directly adsorbed on the top, bridge and threefold hollow sites of Au(111). This unexpectedly strong spin-coupling effect is further confirmed by density functional calculations that reveal no spin–electron interactions at this molecule-gold substrate separation if the graphene nanoribbons are absent. Our findings suggest graphene nanoribbons mediate effective spin coupling, opening a way for potential applications in spintronics. Semiconducting graphene nanoribbon provides a platform for band-gap engineering desired for electronic and optoelectronic applications. Here, Li et al. show that graphene nanoribbon can effectively mediate the interaction of molecular magnetic moment and electronic spin in underlying metallic substrates.
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22
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Tian T, Shih CJ. Molecular Epitaxy on Two-Dimensional Materials: The Interplay between Interactions. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.7b02669] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tian Tian
- Institute for Chemical and
Bioengineering, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
| | - Chih-Jen Shih
- Institute for Chemical and
Bioengineering, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
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23
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Santos EJG, Scullion D, Chu XS, Li DO, Guisinger NP, Wang QH. Rotational superstructure in van der Waals heterostructure of self-assembled C 60 monolayer on the WSe 2 surface. NANOSCALE 2017; 9:13245-13256. [PMID: 28853477 DOI: 10.1039/c7nr03951d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hybrid van der Waals (vdW) heterostructures composed of two-dimensional (2D) layered materials and self-assembled organic molecules are promising systems for electronic and optoelectronic applications with enhanced properties and performance. Control of molecular assembly is therefore paramount to fundamentally understand the nucleation, ordering, alignment, and electronic interaction of organic molecules with 2D materials. Here, we report the formation and detailed study of highly ordered, crystalline monolayers of C60 molecules self-assembled on the surface of WSe2 in well-ordered arrays with large grain sizes (∼5 μm). Using high-resolution scanning tunneling microscopy (STM), we observe a periodic 2 × 2 superstructure in the C60 monolayer and identify four distinct molecular appearances. Using vdW-corrected ab initio density functional theory (DFT) simulations, we determine that the interplay between vdW and Coulomb interactions as well as adsorbate-adsorbate and adsorbate-substrate interactions results in specific rotational arrangements of the molecules forming the superstructure. The orbital ordering through the relative positions of bonds in adjacent molecules creates a charge redistribution that links the molecule units in a long-range network. This rotational superstructure extends throughout the self-assembled monolayer and opens a pathway towards engineering aligned hybrid organic/inorganic vdW heterostructures with 2D layered materials in a precise and controlled way.
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Affiliation(s)
- Elton J G Santos
- School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, UK.
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24
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Matković A, Kratzer M, Kaufmann B, Vujin J, Gajić R, Teichert C. Probing charge transfer between molecular semiconductors and graphene. Sci Rep 2017; 7:9544. [PMID: 28842584 PMCID: PMC5572701 DOI: 10.1038/s41598-017-09419-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/24/2017] [Indexed: 11/09/2022] Open
Abstract
The unique density of states and exceptionally low electrical noise allow graphene-based field effect devices to be utilized as extremely sensitive potentiometers for probing charge transfer with adsorbed species. On the other hand, molecular level alignment at the interface with electrodes can strongly influence the performance of organic-based devices. For this reason, interfacial band engineering is crucial for potential applications of graphene/organic semiconductor heterostructures. Here, we demonstrate charge transfer between graphene and two molecular semiconductors, parahexaphenyl and buckminsterfullerene C60. Through in-situ measurements, we directly probe the charge transfer as the interfacial dipoles are formed. It is found that the adsorbed molecules do not affect electron scattering rates in graphene, indicating that charge transfer is the main mechanism governing the level alignment. From the amount of transferred charge and the molecular coverage of the grown films, the amount of charge transferred per adsorbed molecule is estimated, indicating very weak interaction.
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Affiliation(s)
- Aleksandar Matković
- Institute of Physics, Montanuniversität Leoben, Franz Josef Strasse 18, 8700, Leoben, Austria
| | - Markus Kratzer
- Institute of Physics, Montanuniversität Leoben, Franz Josef Strasse 18, 8700, Leoben, Austria
| | - Benjamin Kaufmann
- Institute of Physics, Montanuniversität Leoben, Franz Josef Strasse 18, 8700, Leoben, Austria
| | - Jasna Vujin
- Graphene Laboratory of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| | - Radoš Gajić
- Graphene Laboratory of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| | - Christian Teichert
- Institute of Physics, Montanuniversität Leoben, Franz Josef Strasse 18, 8700, Leoben, Austria.
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25
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Lee EK, Park CH, Lee J, Lee HR, Yang C, Oh JH. Chemically Robust Ambipolar Organic Transistor Array Directly Patterned by Photolithography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605282. [PMID: 28054398 DOI: 10.1002/adma.201605282] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/21/2016] [Indexed: 06/06/2023]
Abstract
Organic ambipolar transistor arrays for chemical sensors are prepared on a flexible plastic substrate with a bottom-gate bottom-contact configuration to minimize the damage to the organic semiconductors, for the first time, using a photolithographically patternable polymer semiconductor. Well-balanced ambipolar charge transport is achieved by introducing graphene electrodes because of the reduced contact resistance and energetic barrier for electron transport.
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Affiliation(s)
- Eun Kwang Lee
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Cheol Hee Park
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
| | - Junghoon Lee
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
- Materials Research Laboratory, University of California, Santa Barbara, CA, 93106, USA
| | - Hae Rang Lee
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
| | - Changduk Yang
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Joon Hak Oh
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
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26
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Kumar A, Banerjee K, Liljeroth P. Molecular assembly on two-dimensional materials. NANOTECHNOLOGY 2017; 28:082001. [PMID: 28045007 DOI: 10.1088/1361-6528/aa564f] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Molecular self-assembly is a well-known technique to create highly functional nanostructures on surfaces. Self-assembly on two-dimensional (2D) materials is a developing field driven by the interest in functionalization of 2D materials in order to tune their electronic properties. This has resulted in the discovery of several rich and interesting phenomena. Here, we review this progress with an emphasis on the electronic properties of the adsorbates and the substrate in well-defined systems, as unveiled by scanning tunneling microscopy. The review covers three aspects of the self-assembly. The first one focuses on non-covalent self-assembly dealing with site-selectivity due to inherent moiré pattern present on 2D materials grown on substrates. We also see that modification of intermolecular interactions and molecule-substrate interactions influences the assembly drastically and that 2D materials can also be used as a platform to carry out covalent and metal-coordinated assembly. The second part deals with the electronic properties of molecules adsorbed on 2D materials. By virtue of being inert and possessing low density of states near the Fermi level, 2D materials decouple molecules electronically from the underlying metal substrate and allow high-resolution spectroscopy and imaging of molecular orbitals. The moiré pattern on the 2D materials causes site-selective gating and charging of molecules in some cases. The last section covers the effects of self-assembled, acceptor and donor type, organic molecules on the electronic properties of graphene as revealed by spectroscopy and electrical transport measurements. Non-covalent functionalization of 2D materials has already been applied for their application as catalysts and sensors. With the current surge of activity on building van der Waals heterostructures from atomically thin crystals, molecular self-assembly has the potential to add an extra level of flexibility and functionality for applications ranging from flexible electronics and OLEDs to novel electronic devices and spintronics.
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Affiliation(s)
- Avijit Kumar
- Department of Applied Physics Aalto, University School of Science, PO Box 15100, FI-00076 Aalto, Finland
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27
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Kłos J, Kim M, Alexander MH, Wang Y. Chemical Control and Spectral Fingerprints of Electronic Coupling in Carbon Nanostructures. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:29476-29483. [PMID: 28819465 PMCID: PMC5555747 DOI: 10.1021/acs.jpcc.6b09612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The optical and electronic properties of atomically thin materials such as single-walled carbon nanotubes and graphene are sensitively influenced by substrates, the degree of aggregation, and the chemical environment. However, it has been experimentally challenging to determine the origin and quantify these effects. Here we use time-dependent density-functional-theory calculations to simulate these properties for well-defined molecular systems. We investigate a series of core-shell structures containing C60 enclosed in progressively larger carbon shells and their perhydrogenated or perfluorinated derivatives. Our calculations reveal strong electronic coupling effects that depend sensitively on the interparticle distance and on the surface chemistry. In many of these systems we predict considerable orbital mixing and charge transfer between the C60 core and the enclosing shell. We predict that chemical functionalization of the shell can modulate the electronic coupling to the point where the core and shell are completely decoupled into two electronically independent chemical systems. Additionally, we predict that the C60 core will oscillate within the confining shell, at a frequency directly related to the strength of the electronic coupling. This low-frequency motion should be experimentally detectable in the IR region.
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Affiliation(s)
- Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Mijin Kim
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Millard H. Alexander
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
| | - YuHuang Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
- Maryland NanoCenter, University of Maryland, College Park, Maryland 20742, United States
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28
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Gonzalez Arellano DL, Lee H, Secor EB, Burnett EK, Hersam MC, Watkins JJ, Briseno AL. Graphene Ink as a Conductive Templating Interlayer for Enhanced Charge Transport of C 60-Based Devices. ACS APPLIED MATERIALS & INTERFACES 2016; 8:29594-29599. [PMID: 27723296 DOI: 10.1021/acsami.6b05536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We demonstrate conductive templating interlayers of graphene ink, integrating the electronic and chemical properties of graphene in a solution-based process relevant for scalable manufacturing. Thin films of graphene ink are coated onto ITO, following thermal annealing, to form a percolating network used as interlayer. We employ a benchmark n-type semiconductor, C60, to study the interface of the active layer/interlayer. On bare ITO, C60 molecules form films of homogeneously distributed grains; with a graphene interlayer, a preferential orientation of C60 molecules is observed in the individual graphene plates. This leads to crystal growth favoring enhanced charge transport. We fabricate devices to characterize the electron injection and the effect of graphene on the device performance. We observe a significant increase in the current density with the interlayer. Current densities as high as ∼1 mA/cm2 and ∼70 mA/cm2 are realized for C60 deposited with the substrate at 25 °C and 150 °C, respectively.
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Affiliation(s)
- D Leonardo Gonzalez Arellano
- Department of Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003, United States
| | - Hyunbok Lee
- Department of Physics, Kangwon National University , 1 Gangwondaehak-gil, 24341, Republic of Korea
| | - Ethan B Secor
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Edmund K Burnett
- Department of Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - James J Watkins
- Department of Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003, United States
| | - Alejandro L Briseno
- Department of Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003, United States
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29
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Direct observation of photocarrier electron dynamics in C 60 films on graphite by time-resolved two-photon photoemission. Sci Rep 2016; 6:35853. [PMID: 27775005 PMCID: PMC5075791 DOI: 10.1038/srep35853] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/06/2016] [Indexed: 12/27/2022] Open
Abstract
Time-resolved two-photon photoemission (TR-2PPE) spectroscopy is employed to probe the electronic states of a C60 fullerene film formed on highly oriented pyrolytic graphite (HOPG), acting as a model two-dimensional (2D) material for multi-layered graphene. Owing to the in-plane sp2-hybridized nature of the HOPG, the TR-2PPE spectra reveal the energetics and dynamics of photocarriers in the C60 film: after hot excitons are nascently formed in C60 via intramolecular excitation by a pump photon, they dissociate into photocarriers of free electrons and the corresponding holes, and the electrons are subsequently detected by a probe photon as photoelectrons. The decay rate of photocarriers from the C60 film into the HOPG is evaluated to be 1.31 × 1012 s−1, suggesting a weak van der Waals interaction at the interface, where the photocarriers tentatively occupy the lowest unoccupied molecular orbital (LUMO) of C60. The photocarrier electron dynamics following the hot exciton dissociation in the organic thin films has not been realized for any metallic substrates exhibiting strong interactions with the overlayer. Furthermore, the thickness dependence of the electron lifetime in the LUMO reveals that the electron hopping rate in C60 layers is 3.3 ± 1.2 × 1013 s−1.
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30
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Picone A, Giannotti D, Riva M, Calloni A, Bussetti G, Berti G, Duò L, Ciccacci F, Finazzi M, Brambilla A. Controlling the Electronic and Structural Coupling of C 60 Nano Films on Fe(001) through Oxygen Adsorption at the Interface. ACS APPLIED MATERIALS & INTERFACES 2016; 8:26418-26424. [PMID: 27603203 DOI: 10.1021/acsami.6b09641] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
C60 molecules coupled to metals form hybrid systems exploited in a broad range of emerging fields, such as nanoelectronics, spintronics, and photovoltaic solar cells. The electronic coupling at the C60/metal interface plays a crucial role in determining the charge and spin transport in C60-based devices; therefore, a detailed understanding of the interface electronic structure is a prerequisite to engineering the device functionalities. Here, we compare the electronic and structural properties of C60 monolayers interfaced with Fe(001) and oxygen-passivated Fe(001)-p(1 × 1)O substrates. By combining scanning tunneling microscopy and spectroscopy, Auger electron spectroscopy, photoemission and inverse photoemission spectroscopies, we are able to elucidate the striking effect of oxygen on the interaction between Fe(001) and C60. Upon C60 deposition on the oxygen-passivated surface, the oxygen layer remains buried at the C60/Fe(001)-p(1 × 1)O interface, efficiently decoupling the fullerene film from the metallic substrate. Tunneling and photoemission spectroscopies reveal the presence of well-defined molecular resonances for the C60/Fe(001)-p(1 × 1)O system, with a large HOMO-LUMO gap of about 3.4 eV. On the other hand, for the C60/Fe(001) interface, a strong hybridization between the substrate states and the C60 orbitals occurs, resulting in broader molecular resonances.
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Affiliation(s)
- Andrea Picone
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Dario Giannotti
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Michele Riva
- Institute of Applied Physics, TU-Wien , Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Alberto Calloni
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Gianlorenzo Bussetti
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Giulia Berti
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lamberto Duò
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Franco Ciccacci
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marco Finazzi
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alberto Brambilla
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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31
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Ciesielski A, Samorì P. Supramolecular Approaches to Graphene: From Self-Assembly to Molecule-Assisted Liquid-Phase Exfoliation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:6030-51. [PMID: 26928750 DOI: 10.1002/adma.201505371] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 11/29/2015] [Indexed: 05/19/2023]
Abstract
Graphene, a one-atom thick two-dimensional (2D) material, is at the core of an ever-growing research effort due to its combination of unique mechanical, thermal, optical and electrical properties. Two strategies are being pursued for the graphene production: the bottom-up and the top-down. The former relies on the use of covalent chemistry approaches on properly designed molecular building blocks undergoing chemical reaction to form 2D covalent networks. The latter occurs via exfoliation of bulk graphite into individual graphene sheets. Amongst the various types of exfoliations exploited so far, ultrasound-induced liquid-phase exfoliation (UILPE) is an attractive strategy, being extremely versatile, up-scalable and applicable to a variety of environments. In this review, we highlight the recent developments that have led to successful non-covalent functionalization of graphene and how the latter can be exploited to promote the process of molecule-assisted UILPE of graphite. The functionalization of graphene with non-covalently interacting molecules, both in dispersions as well as in dry films, represents a promising and modular approach to tune various physical and chemical properties of graphene, eventually conferring to such a 2D system a multifunctional nature.
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Affiliation(s)
- Artur Ciesielski
- Nanochemistry Laboratory, ISIS & icFRC, Université de Strasbourg & CNRS, 8 allée Gaspard Monge, 67000, Strasbourg, France
| | - Paolo Samorì
- Nanochemistry Laboratory, ISIS & icFRC, Université de Strasbourg & CNRS, 8 allée Gaspard Monge, 67000, Strasbourg, France
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32
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Gao L, Pal PP, Seideman T, Guisinger NP, Guest JR. Current-Driven Hydrogen Desorption from Graphene: Experiment and Theory. J Phys Chem Lett 2016; 7:486-494. [PMID: 26787160 DOI: 10.1021/acs.jpclett.5b02471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electron-stimulated desorption of hydrogen from the graphene/SiC(0001) surface at room temperature was investigated with ultrahigh vacuum scanning tunneling microscopy and ab initio calculations in order to elucidate the desorption mechanisms and pathways. Two different desorption processes were observed. In the high electron energy regime (4-8 eV), the desorption yield is independent of both voltage and current, which is attributed to the direct electronic excitation of the C-H bond. In the low electron energy regime (2-4 eV), however, the desorption yield exhibits a threshold dependence on voltage, which is explained by the vibrational excitation of the C-H bond via transient ionization induced by inelastic tunneling electrons. The observed current independence of the desorption yield suggests that the vibrational excitation is a single-electron process. We also observed that the curvature of graphene dramatically affects hydrogen desorption. Desorption from concave regions was measured to be much more probable than desorption from convex regions in the low electron energy regime (∼2 eV), as would be expected from the identified desorption mechanism.
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Affiliation(s)
- Li Gao
- Department of Physics and Astronomy, California State University , Northridge, California 91330, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Partha Pratim Pal
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Tamar Seideman
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Nathan P Guisinger
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Jeffrey R Guest
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
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33
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Valeš V, Verhagen T, Vejpravová J, Frank O, Kalbáč M. Addressing asymmetry of the charge and strain in a two-dimensional fullerene peapod. NANOSCALE 2016; 8:735-740. [PMID: 26661834 DOI: 10.1039/c5nr06271c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We prepared a two-dimensional C70 fullerene peapod by the sequential assembly of (12)C graphene, C70 fullerenes and (13)C graphene. The local changes in the strain and doping were correlated with local roughness revealing asymmetry in the strain and doping with respect to the top and bottom graphene layers of the peapod.
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Affiliation(s)
- V Valeš
- J. Heyrovský Institute of Physical Chemistry, CAS, v.v.i., Dolejškova 3, 182 23 Praha, Czech Republic.
| | - T Verhagen
- Institute of Physics, CAS, v.v.i., Na Slovance 2, 182 21 Praha, Czech Republic
| | - J Vejpravová
- Institute of Physics, CAS, v.v.i., Na Slovance 2, 182 21 Praha, Czech Republic
| | - O Frank
- J. Heyrovský Institute of Physical Chemistry, CAS, v.v.i., Dolejškova 3, 182 23 Praha, Czech Republic.
| | - M Kalbáč
- J. Heyrovský Institute of Physical Chemistry, CAS, v.v.i., Dolejškova 3, 182 23 Praha, Czech Republic.
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34
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Avramopoulos A, Otero N, Karamanis P, Pouchan C, Papadopoulos MG. A Computational Study of the Interaction and Polarization Effects of Complexes Involving Molecular Graphene and C60 or a Nucleobases. J Phys Chem A 2016; 120:284-98. [PMID: 26690053 DOI: 10.1021/acs.jpca.5b09813] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A systematic analysis of the molecular structure, energetics, electronic (hyper)polarizabilities and their interaction-induced counterparts of C60 with a series of molecular graphene (MG) models, CmHn, where m = 24, 84, 114, 222, 366, 546 and n = 12, 24, 30, 42, 54, 66, was performed. All the reported data were computed by employing density functional theory and a series of basis sets. The main goal of the study is to investigate how alteration of the size of the MG model affects the strength of the interaction, charge rearrangement, and polarization and interaction-induced polarization of the complex, C60-MG. A Hirshfeld-based scheme has been employed in order to provide information on the intrinsic polarizability density representations of the reported complexes. It was found that the interaction energy increases approaching a limit of -26.98 kcal/mol for m = 366 and 546; the polarizability and second hyperpolarizability increase with increasing the size of MG. An opposite trend was observed for the dipole moment. Interestingly, the variation of the first hyperpolarizability is relatively small with m. Since polarizability is a key factor for the stability of molecular graphene with nucleobases (NB), a study of the magnitude of the interaction-induced polarizability of C84H24-NB complexes is also reported, aiming to reveal changes of its magnitude with the type of NB. The binding strength of C84H24-NB complexes is also computed and found to be in agreement with available theoretical and experimental data. The interaction involved in C60 B12N12H24-NB complexes has also been considered, featuring the effect of contamination on the binding strength between MG and NBs.
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Affiliation(s)
- Aggelos Avramopoulos
- Institute of Biology, Pharmaceutical Chemistry and Biotechnology, National Hellenic Research Foundation , 48 Vas. Constantinou Avenue, Athens 11635, Greece
| | - Nicolás Otero
- Equipe de Chimie Théorique, ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254 , Hélioparc Pau Pyrénées 2 avenue du Président Angot, 64053 Pau Cedex 09, Pau, France
| | - Panaghiotis Karamanis
- Equipe de Chimie Théorique, ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254 , Hélioparc Pau Pyrénées 2 avenue du Président Angot, 64053 Pau Cedex 09, Pau, France
| | - Claude Pouchan
- Equipe de Chimie Théorique, ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254 , Hélioparc Pau Pyrénées 2 avenue du Président Angot, 64053 Pau Cedex 09, Pau, France
| | - Manthos G Papadopoulos
- Institute of Biology, Pharmaceutical Chemistry and Biotechnology, National Hellenic Research Foundation , 48 Vas. Constantinou Avenue, Athens 11635, Greece
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35
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Jiang Y, Yang L, Guo Z, Lei S. The Assembling of Poly (3-Octyl-Thiophene) on CVD Grown Single Layer Graphene. Sci Rep 2015; 5:17720. [PMID: 26634648 PMCID: PMC4669485 DOI: 10.1038/srep17720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 11/03/2015] [Indexed: 01/06/2023] Open
Abstract
The interface between organic semiconductor and graphene electrode, especially the structure of the first few molecular layers at the interface, is crucial for the device properties such as the charge transport in organic field effect transistors. In this work, we have used scanning tunneling microscopy to investigate the poly (3-octyl-thiophene) (P3OT)-graphene interface. Our results reveal the dynamic assembling of P3OT on single layer graphene. As on other substrates the epitaxial effect plays a role in determining the orientation of the P3OT assembling, however, the inter-thiophene distance along the backbone is consistent with that optimized in vaccum, no compression was observed. Adsorption of P3OT on ripples is weaker due to local curvature, which has been verified both by scanning tunneling microscopy and density functional theory simulation. Scanning tunneling microscopy also reveals that P3OT tends to form hairpin folds when meets a ripple.
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Affiliation(s)
- Yanqiu Jiang
- Key Laboratory of Microsystems and Microstructures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin, 150080, People's Republic of China
| | - Ling Yang
- Key Laboratory of Microsystems and Microstructures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin, 150080, People's Republic of China
| | - Zongxia Guo
- School of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, People's Republic of China
| | - Shengbin Lei
- Key Laboratory of Microsystems and Microstructures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin, 150080, People's Republic of China
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36
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Zhao Y, Wu Q, Chen Q, Wang J. Molecular self-assembly on two-dimensional atomic crystals: insights from molecular dynamics simulations. J Phys Chem Lett 2015; 6:4518-4524. [PMID: 26523464 DOI: 10.1021/acs.jpclett.5b02147] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
van der Waals (vdW) epitaxy of ultrathin organic films on two-dimensional (2D) atomic crystals has become a sovereign area because of their unique advantages in organic electronic devices. However, the dynamic mechanism of the self-assembly remains elusive. Here, we visualize the nanoscale self-assembly of organic molecules on graphene and boron nitride monolayer from a disordered state to a 2D lattice via molecular dynamics simulation for the first time. It is revealed that the assembly toward 2D ordered structures is essentially the minimization of the molecule-molecule interaction, that is, the vdW interaction in nonpolar systems and the vdW and Coulomb interactions in polar systems that are the decisive factors for the formation of the 2D ordering. The role of the substrate is mainly governing the array orientation of the adsorbates. The mechanisms unveiled here are generally applicable to a broad class of organic thin films via vdW epitaxy.
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Affiliation(s)
- Yinghe Zhao
- Department of Physics, Southeast University , Nanjing 211189, China
| | - Qisheng Wu
- Department of Physics, Southeast University , Nanjing 211189, China
| | - Qian Chen
- Department of Physics, Southeast University , Nanjing 211189, China
| | - Jinlan Wang
- Department of Physics, Southeast University , Nanjing 211189, China
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37
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Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene. Sci Rep 2015; 5:14336. [PMID: 26391054 PMCID: PMC4585716 DOI: 10.1038/srep14336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/25/2015] [Indexed: 11/08/2022] Open
Abstract
We report the preparation of novel quasi-one-dimensional (quasi-1D) C60 nanostructures on rippled graphene. Through careful control of the subtle balance between the linear periodic potential of rippled graphene and the C60 surface mobility, we demonstrate that C60 molecules can be arranged into a quasi-1D C60 chain structure with widths of two to three molecules. At a higher annealing temperature, the quasi-1D chain structure transitions to a more compact hexagonal close packed quasi-1D stripe structure. This first experimental realization of quasi-1D C60 structures on graphene may pave a way for fabricating new C60/graphene hybrid structures for future applications in electronics, spintronics and quantum information.
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Telychko M, Mutombo P, Merino P, Hapala P, Ondráček M, Bocquet FC, Sforzini J, Stetsovych O, Vondráček M, Jelínek P, Švec M. Electronic and Chemical Properties of Donor, Acceptor Centers in Graphene. ACS NANO 2015; 9:9180-9187. [PMID: 26256407 DOI: 10.1021/acsnano.5b03690] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chemical doping is one of the most suitable ways of tuning the electronic properties of graphene and a promising candidate for a band gap opening. In this work we report a reliable and tunable method for preparation of high-quality boron and nitrogen co-doped graphene on silicon carbide substrate. We combine experimental (dAFM, STM, XPS, NEXAFS) and theoretical (total energy DFT and simulated STM) studies to analyze the structural, chemical, and electronic properties of the single-atom substitutional dopants in graphene. We show that chemical identification of boron and nitrogen substitutional defects can be achieved in the STM channel due to the quantum interference effect, arising due to the specific electronic structure of nitrogen dopant sites. Chemical reactivity of single boron and nitrogen dopants is analyzed using force-distance spectroscopy by means of dAFM.
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Affiliation(s)
- Mykola Telychko
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
- Faculty of Mathematics and Physics, Charles University , V Holešovičkách 2, Praha 8, Czech Republic
| | - Pingo Mutombo
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
| | - Pablo Merino
- Max Planck Institute for Solid State Research , Heisenberg Strasse 1, 70569 Stuttgart, Germany
| | - Prokop Hapala
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
| | - Martin Ondráček
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
| | - François C Bocquet
- Peter Grünberg Institut (PGI-3) , Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich-Aachen Research Alliance (JARA) ; Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Jessica Sforzini
- Peter Grünberg Institut (PGI-3) , Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich-Aachen Research Alliance (JARA) ; Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Oleksandr Stetsovych
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
| | - Martin Vondráček
- Institute of Physics, Academy of Sciences of the Czech Republic , Na Slovance 2, 10, CZ 18228, Prague, Czech Republic
| | - Pavel Jelínek
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
| | - Martin Švec
- Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnická 10, CZ 16200, Prague, Czech Republic
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Jnawali G, Rao Y, Beck JH, Petrone N, Kymissis I, Hone J, Heinz TF. Observation of Ground- and Excited-State Charge Transfer at the C60/Graphene Interface. ACS NANO 2015; 9:7175-7185. [PMID: 26072947 DOI: 10.1021/acsnano.5b01896] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We examine charge transfer interactions in the hybrid system of a film of C60 molecules deposited on single-layer graphene using Raman spectroscopy and Terahertz (THz) time-domain spectroscopy. In the absence of photoexcitation, we find that the C60 molecules in the deposited film act as electron acceptors for graphene, yielding increased hole doping in the graphene layer. Hole doping of the graphene film by a uniform C60 film at a level of 5.6 × 10(12)/cm(2) or 0.04 holes per interfacial C60 molecule was determined by the use of both Raman and THz spectroscopy. We also investigate transient charge transfer occurring upon photoexcitation by femtosecond laser pulses with a photon energy of 3.1 eV. The C60/graphene hybrid exhibits a short-lived (ps) decrease in THz conductivity, followed by a long-lived increase in conductivity. The initial negative photoconductivity transient, which decays within 2 ps, reflects the intrinsic photoresponse of graphene. The longer-lived positive conductivity transient, with a lifetime on the order of 100 ps, is attributed to photoinduced hole doping of graphene by interfacial charge transfer. We discuss possible microscopic pathways for hot carrier processes in the hybrid system.
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Affiliation(s)
- Giriraj Jnawali
- †Department of Physics, Columbia University, New York, New York 10027, United States
| | - Yi Rao
- †Department of Physics, Columbia University, New York, New York 10027, United States
| | - Jonathan H Beck
- §Department of Electrical Engineering, Columbia University, New York, New York 10027, United States
| | - Nicholas Petrone
- ∥Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Ioannis Kymissis
- §Department of Electrical Engineering, Columbia University, New York, New York 10027, United States
| | - James Hone
- ∥Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Tony F Heinz
- †Department of Physics, Columbia University, New York, New York 10027, United States
- §Department of Electrical Engineering, Columbia University, New York, New York 10027, United States
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40
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Reddy CD, Gen Yu Z, Zhang YW. Two-dimensional van der Waals C60 molecular crystal. Sci Rep 2015; 5:12221. [PMID: 26183501 PMCID: PMC4505331 DOI: 10.1038/srep12221] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/22/2015] [Indexed: 11/09/2022] Open
Abstract
Two-dimensional (2D) atomic crystals, such as graphene and transition metal dichalcogenides et al. have drawn extraordinary attention recently. For these 2D materials, atoms within their monolayer are covalently bonded. An interesting question arises: Can molecules form a 2D monolayer crystal via van der Waals interactions? Here, we first study the structural stability of a free-standing infinite C60 molecular monolayer using molecular dynamic simulations, and find that the monolayer is stable up to 600 K. We further study the mechanical properties of the monolayer, and find that the elastic modulus, ultimate tensile stress and failure strain are 55-100 GPa, 90-155 MPa, and 1.5-2.3%, respectively, depending on the stretching orientation. The monolayer fails due to shearing and cavitation under uniaxial tensile loading. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the monolayer are found to be delocalized and as a result, the band gap is reduced to only 60% of the isolated C60 molecule. Interestingly, this band gap can be tuned up to ±30% using strain engineering. Owing to its thermal stability, low density, strain-tunable semi-conducting characteristics and large bending flexibility, this van der Waals molecular monolayer crystal presents aplenty opportunities for developing novel applications in nanoelectronics.
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Affiliation(s)
- C D Reddy
- Institute of High Performance Computing, A*STAR, Singapore 138632
| | - Zhi Gen Yu
- Institute of High Performance Computing, A*STAR, Singapore 138632
| | - Yong-Wei Zhang
- Institute of High Performance Computing, A*STAR, Singapore 138632
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41
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Kim K, Lee TH, Santos EJG, Jo PS, Salleo A, Nishi Y, Bao Z. Structural and Electrical Investigation of C60-Graphene Vertical Heterostructures. ACS NANO 2015; 9:5922-5928. [PMID: 26027690 DOI: 10.1021/acsnano.5b00581] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Graphene, with its unique electronic and structural qualities, has become an important playground for studying adsorption and assembly of various materials including organic molecules. Moreover, organic/graphene vertical structures assembled by van der Waals interaction have potential for multifunctional device applications. Here, we investigate structural and electrical properties of vertical heterostructures composed of C60 thin film on graphene. The assembled film structure of C60 on graphene is investigated using transmission electron microscopy, which reveals a uniform morphology of C60 film on graphene with a grain size as large as 500 nm. The strong epitaxial relations between C60 crystal and graphene lattice directions are found, and van der Waals ab initio calculations support the observed phenomena. Moreover, using C60-graphene heterostructures, we fabricate vertical graphene transistors incorporating n-type organic semiconducting materials with an on/off ratio above 3 × 10(3). Our work demonstrates that graphene can serve as an excellent substrate for assembly of molecules, and attained organic/graphene heterostructures have great potential for electronics applications.
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Affiliation(s)
- Kwanpyo Kim
- ‡Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | | | - Elton J G Santos
- #School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom
- ∧School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast BT9 5AL, United Kingdom
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42
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Urgel JI, Schwarz M, Garnica M, Stassen D, Bonifazi D, Ecija D, Barth JV, Auwärter W. Controlling Coordination Reactions and Assembly on a Cu(111) Supported Boron Nitride Monolayer. J Am Chem Soc 2015; 137:2420-3. [DOI: 10.1021/ja511611r] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- José I. Urgel
- Physik
Department E20, Technische Universität München, James
Franck Str. 1, D-85748 Garching, Germany
| | - Martin Schwarz
- Physik
Department E20, Technische Universität München, James
Franck Str. 1, D-85748 Garching, Germany
| | - Manuela Garnica
- Physik
Department E20, Technische Universität München, James
Franck Str. 1, D-85748 Garching, Germany
| | - Daphné Stassen
- Department
of Chemistry and Namur Research College (NARC), University of Namur (UNamur), Namur, Belgium
| | - Davide Bonifazi
- Department
of Chemistry and Namur Research College (NARC), University of Namur (UNamur), Namur, Belgium
| | - David Ecija
- Physik
Department E20, Technische Universität München, James
Franck Str. 1, D-85748 Garching, Germany
- IMDEA Nanoscience, 28049 Madrid, Spain
| | - Johannes V. Barth
- Physik
Department E20, Technische Universität München, James
Franck Str. 1, D-85748 Garching, Germany
| | - Willi Auwärter
- Physik
Department E20, Technische Universität München, James
Franck Str. 1, D-85748 Garching, Germany
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43
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Jeong YJ, Yun DJ, Jang J, Park S, An TK, Kim LH, Kim SH, Park CE. Solution-processed n-type fullerene field-effect transistors prepared using CVD-grown graphene electrodes: improving performance with thermal annealing. Phys Chem Chem Phys 2015; 17:6635-43. [DOI: 10.1039/c4cp05787b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Solution-processed organic field effect transistors (OFETs) have generated significant interest as key elements for use in all-organic electronic applications aimed at realizing low-cost, lightweight, and flexible devices.
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Affiliation(s)
- Yong Jin Jeong
- Polymer Research Institute
- Department of Chemical Engineering
- Pohang University of Science and Technology
- Pohang
- Korea
| | - Dong-Jin Yun
- Analytical Science Laboratory of Samsung Advanced Institute of Technology
- Yongin 446-712
- Republic of Korea
| | - Jaeyoung Jang
- Polymer Research Institute
- Department of Chemical Engineering
- Pohang University of Science and Technology
- Pohang
- Korea
| | - Seonuk Park
- Polymer Research Institute
- Department of Chemical Engineering
- Pohang University of Science and Technology
- Pohang
- Korea
| | - Tae Kyu An
- Polymer Research Institute
- Department of Chemical Engineering
- Pohang University of Science and Technology
- Pohang
- Korea
| | - Lae Ho Kim
- Polymer Research Institute
- Department of Chemical Engineering
- Pohang University of Science and Technology
- Pohang
- Korea
| | - Se Hyun Kim
- Department of Nano, Medical and Polymer Materials
- Yeungnam University
- North Gyeongsang 712-749
- South Korea
| | - Chan Eon Park
- Polymer Research Institute
- Department of Chemical Engineering
- Pohang University of Science and Technology
- Pohang
- Korea
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44
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Endlich M, Gozdzik S, Néel N, da Rosa AL, Frauenheim T, Wehling TO, Kröger J. Phthalocyanine adsorption to graphene on Ir(111): Evidence for decoupling from vibrational spectroscopy. J Chem Phys 2014; 141:184308. [PMID: 25399148 DOI: 10.1063/1.4901283] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Endlich
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - S. Gozdzik
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - N. Néel
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - A. L. da Rosa
- Bremen Center for Computational Materials Science, University Bremen, D-28359 Bremen, Germany
- Department of Physics, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
| | - T. Frauenheim
- Bremen Center for Computational Materials Science, University Bremen, D-28359 Bremen, Germany
| | - T. O. Wehling
- Bremen Center for Computational Materials Science, University Bremen, D-28359 Bremen, Germany
- Institute for Theoretical Physics, University Bremen, D-28359 Bremen, Germany
| | - J. Kröger
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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45
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Jung M, Shin D, Sohn SD, Kwon SY, Park N, Shin HJ. Atomically resolved orientational ordering of C60 molecules on epitaxial graphene on Cu(111). NANOSCALE 2014; 6:11835-11840. [PMID: 25169153 DOI: 10.1039/c4nr03249g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A detailed understanding of interactions between molecules and graphene is one of the key issues for tailoring the properties of graphene-based molecular devices, because the electronic and structural properties of molecular layers on surfaces are determined by intermolecular and molecule-substrate interactions. Here, we present the atomically resolved experimental measurements of the self-assembled fullerene molecules on single-layer graphene on Cu(111). Fullerene molecules form a (4 × 4) superstructure on graphene/Cu(111), revealing only single molecular orientation. We can resolve the exact adsorption site and the configuration of fullerene by means of low-temperature scanning tunnelling microscopy (LT-STM) and density functional theory (DFT) calculations. The adsorption orientation can be explained in terms of the competition between intermolecular interactions and molecule-substrate interactions, where strong Coulomb interactions among the fullerenes determine the in-plane orientation of the fullerene. Our results provide important implications for developing carbon-based organic devices using a graphene template in the future.
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Affiliation(s)
- Minbok Jung
- School of Materials Science and Engineering, Center for Multidimensional Carbon Materials and Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan 689-798, Republic of Korea.
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46
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Nirmalraj P, Thompson D, Molina-Ontoria A, Sousa M, Martín N, Gotsmann B, Riel H. Nanoelectrical analysis of single molecules and atomic-scale materials at the solid/liquid interface. NATURE MATERIALS 2014; 13:947-953. [PMID: 25129620 DOI: 10.1038/nmat4060] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 07/15/2014] [Indexed: 06/03/2023]
Abstract
Evaluating the built-in functionality of nanomaterials under practical conditions is central for their proposed integration as active components in next-generation electronics. Low-dimensional materials from single atoms to molecules have been consistently resolved and manipulated under ultrahigh vacuum at low temperatures. At room temperature, atomic-scale imaging has also been performed by probing materials at the solid/liquid interface. We exploit this electrical interface to develop a robust electronic decoupling platform that provides precise information on molecular energy levels recorded using in situ scanning tunnelling microscopy/spectroscopy with high spatial and energy resolution in a high-density liquid environment. Our experimental findings, supported by ab initio electronic structure calculations and atomic-scale molecular dynamics simulations, reveal direct mapping of single-molecule structure and resonance states at the solid/liquid interface. We further extend this approach to resolve the electronic structure of graphene monolayers at atomic length scales under standard room-temperature operating conditions.
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Affiliation(s)
- Peter Nirmalraj
- IBM Research-Zurich, Säumerstrasse 4 8803 Rüschlikon, Switzerland
| | - Damien Thompson
- 1] Department of Physics and Energy, University of Limerick, Ireland [2] Materials and Surface Science Institute, University of Limerick, Ireland
| | - Agustín Molina-Ontoria
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain
| | - Marilyne Sousa
- IBM Research-Zurich, Säumerstrasse 4 8803 Rüschlikon, Switzerland
| | - Nazario Martín
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain
| | - Bernd Gotsmann
- IBM Research-Zurich, Säumerstrasse 4 8803 Rüschlikon, Switzerland
| | - Heike Riel
- IBM Research-Zurich, Säumerstrasse 4 8803 Rüschlikon, Switzerland
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47
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Pham VD, Lagoute J, Mouhoub O, Joucken F, Repain V, Chacon C, Bellec A, Girard Y, Rousset S. Electronic interaction between nitrogen-doped graphene and porphyrin molecules. ACS NANO 2014; 8:9403-9409. [PMID: 25187965 DOI: 10.1021/nn503753e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The chemical doping of graphene is a promising route to improve the performances of graphene-based devices through enhanced chemical reactivity, catalytic activity, or transport characteristics. Understanding the interaction of molecules with doped graphene at the atomic scale is therefore a leading challenge to be overcome for the development of graphene-based electronics and sensors. Here, we use scanning tunneling microscopy and spectroscopy to study the electronic interaction of pristine and nitrogen-doped graphene with self-assembled tetraphenylporphyrin molecules. We provide an extensive measurement of the electronic structure of single porphyrins on Au(111), thus revealing an electronic decoupling effect of the porphyrins adsorbed on graphene. A tip-induced switching of the inner hydrogen atoms of porphyrins, first identified on Au(111), is observed on graphene, allowing the identification of the molecular conformation of porphyrins in the self-assembled molecular layer. On nitrogen-doped graphene, a local modification of the charge transfer around the nitrogen sites is evidenced via a downshift of the energies of the molecular elecronic states. These data show how the presence of nitrogen atoms in the graphene network modifies the electronic interaction of organic molecules with graphene. These results provide a basic understanding for the exploitation of doped graphene in molecular sensors or nanoelectronics.
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Affiliation(s)
- Van Dong Pham
- Laboratoire Matériaux et Phénomènes Quantiques, CNRS-Université Paris 7 , 10 Rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
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48
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Riss A, Wickenburg S, Tan LZ, Tsai HZ, Kim Y, Lu J, Bradley AJ, Ugeda MM, Meaker KL, Watanabe K, Taniguchi T, Zettl A, Fischer FR, Louie SG, Crommie MF. Imaging and tuning molecular levels at the surface of a gated graphene device. ACS NANO 2014; 8:5395-401. [PMID: 24746016 PMCID: PMC4070845 DOI: 10.1021/nn501459v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 04/18/2014] [Indexed: 05/20/2023]
Abstract
Gate-controlled tuning of the charge carrier density in graphene devices provides new opportunities to control the behavior of molecular adsorbates. We have used scanning tunneling microscopy (STM) and spectroscopy (STS) to show how the vibronic electronic levels of 1,3,5-tris(2,2-dicyanovinyl)benzene molecules adsorbed onto a graphene/BN/SiO2 device can be tuned via application of a backgate voltage. The molecules are observed to electronically decouple from the graphene layer, giving rise to well-resolved vibronic states in dI/dV spectroscopy at the single-molecule level. Density functional theory (DFT) and many-body spectral function calculations show that these states arise from molecular orbitals coupled strongly to carbon-hydrogen rocking modes. Application of a back-gate voltage allows switching between different electronic states of the molecules for fixed sample bias.
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Affiliation(s)
- Alexander Riss
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Address correspondence to , ,
| | - Sebastian Wickenburg
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Liang Z. Tan
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hsin-Zon Tsai
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Youngkyou Kim
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jiong Lu
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Aaron J. Bradley
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Miguel M. Ugeda
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Kacey L. Meaker
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Alex Zettl
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Felix R. Fischer
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute, University of California and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Address correspondence to , ,
| | - Steven G. Louie
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Michael F. Crommie
- Department of Physics, Department of Chemical and Biomolecular Engineering, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute, University of California and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Address correspondence to , ,
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49
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Sun X, Mu Y, Zhang J, Wang X, Hu P, Wan X, Guo Z, Lei S. Tuning the Self-Assembly of Oligothiophenes on Chemical Vapor Deposition Graphene: Effect of Functional Group, Solvent, and Substrate. Chem Asian J 2014; 9:1888-94. [DOI: 10.1002/asia.201402075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Indexed: 11/08/2022]
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50
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MacLeod JM, Rosei F. Molecular self-assembly on graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:1038-1049. [PMID: 24155272 DOI: 10.1002/smll.201301982] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Indexed: 06/02/2023]
Abstract
The formation of ordered arrays of molecules via self-assembly is a rapid, scalable route towards the realization of nanoscale architectures with tailored properties. In recent years, graphene has emerged as an appealing substrate for molecular self-assembly in two dimensions. Here, the first five years of progress in supramolecular organization on graphene are reviewed. The self-assembly process can vary depending on the type of graphene employed: epitaxial graphene, grown in situ on a metal surface, and non-epitaxial graphene, transferred onto an arbitrary substrate, can have different effects on the final structure. On epitaxial graphene, the process is sensitive to the interaction between the graphene and the substrate on which it is grown. In the case of graphene that strongly interacts with its substrate, such as graphene/Ru(0001), the inhomogeneous adsorption landscape of the graphene moiré superlattice provides a unique opportunity for guiding molecular organization, since molecules experience spatially constrained diffusion and adsorption. On weaker-interacting epitaxial graphene films, and on non-epitaxial graphene transferred onto a host substrate, self-assembly leads to films similar to those obtained on graphite surfaces. The efficacy of a graphene layer for facilitating planar adsorption of aromatic molecules has been repeatedly demonstrated, indicating that it can be used to direct molecular adsorption, and therefore carrier transport, in a certain orientation, and suggesting that the use of transferred graphene may allow for predictible molecular self-assembly on a wide range of surfaces.
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Affiliation(s)
- J M MacLeod
- Centre Énergie Matériaux Télécommunications, Institut national de la recherche scientifique, 1650 Boul. Lionel-Boulet, Varennes, QC, J3X 1S2, Canada
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