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Wang H, Hu J, Liang Z, Zhang H, Huang C, Xie L, Jiang Z, Huang H, Song F. Chirality variation from self-assembly on Ullmann coupling for the DBCh adsorbate on Au(111) and Ag(111). NANOSCALE ADVANCES 2023; 5:1368-1377. [PMID: 36866267 PMCID: PMC9972870 DOI: 10.1039/d2na00789d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/26/2023] [Indexed: 06/01/2023]
Abstract
On-surface Ullmann coupling has been considered an appealing approach for the precise fabrication of carbon-based covalent nanostructures under solution-free conditions. However, chirality has seldom been discussed in Ullmann reactions. In this report, self-assembled two-dimensional chiral networks are initially constructed in a large area on Au(111) and Ag(111) after adsorption of the prochiral precursor, 6,12-dibromochrysene (DBCh). Self-assembled phases are then transformed into organometallic (OM) oligomers after debromination, preserving the chirality; in particular, the formation of scarcely reported OM species on Au(111) is discovered herein. With the aryl-aryl bonding induced after intensive annealing, covalent chains are fabricated via the cyclodehydrogenation between chrysene blocks, resulting in the formation of 8-armchair graphene nanoribbons with staggered valleys on both sides. Before chiral polymer chains are constructed by chrysene blocks, the high structural flexibility of OM intermediates on Ag(111) is also revealed during reactions, which is derived from the twofold coordination of Ag atoms and conformationally flexible metal-carbon bonding. Our report not only provides solid evidence of atomically precise fabrication of covalent nanostructures with a feasible bottom-up approach but also sheds insights into the comprehensive investigation of chirality variation from monomers to artificial architectures via surface coupling reactions.
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Affiliation(s)
- Hongbing Wang
- Shanghai Institute of Applied Physics Zhangheng Road 239 Shanghai 201000 China
- University of Chinese Academy of Sciences Beijing 100000 China
| | - Jinping Hu
- Shanghai Institute of Applied Physics Zhangheng Road 239 Shanghai 201000 China
- University of Chinese Academy of Sciences Beijing 100000 China
| | - Zhaofeng Liang
- Shanghai Advanced Research Institute Zhangheng Road 239 Shanghai 201004 China
| | - Huan Zhang
- Shanghai Institute of Applied Physics Zhangheng Road 239 Shanghai 201000 China
- University of Chinese Academy of Sciences Beijing 100000 China
| | - Chaoqin Huang
- Shanghai Institute of Applied Physics Zhangheng Road 239 Shanghai 201000 China
- University of Chinese Academy of Sciences Beijing 100000 China
| | - Lei Xie
- Shanghai Advanced Research Institute Zhangheng Road 239 Shanghai 201004 China
| | - Zheng Jiang
- Shanghai Institute of Applied Physics Zhangheng Road 239 Shanghai 201000 China
- University of Chinese Academy of Sciences Beijing 100000 China
- Shanghai Advanced Research Institute Zhangheng Road 239 Shanghai 201004 China
| | - Han Huang
- School of Physics and Electronics, Central South University Changsha 410073 China
| | - Fei Song
- Shanghai Institute of Applied Physics Zhangheng Road 239 Shanghai 201000 China
- University of Chinese Academy of Sciences Beijing 100000 China
- Shanghai Advanced Research Institute Zhangheng Road 239 Shanghai 201004 China
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2
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Hu J, Wang H, Liang Z, Zhang H, Huang C, Xie L, Li Z, Jiang Z, Huang H, Song F. Tuning Dehalogenative Coupling of Br 2Py on Bimetallic Templates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13392-13400. [PMID: 36279423 DOI: 10.1021/acs.langmuir.2c01640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Considerable attention has been paid to on-surface Ullmann coupling during the past decade owing to the feasible synthesis of artificial nanostructures. While previous reports mainly concentrated on coupling reactions on single-metal-atom surfaces, herein we present the Ullmann coupling of 2,7-dibromopyrene (Br2Py) on bimetallic surfaces, Bi-Ag(111) and Bi-Au(111), respectively, with scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS). On the Bi-decorated Ag(111), self-assembly of intact Br2Py is realized due to the reduced activity at the interface. Subsequent annealing promotes the dehalogenation of Br2Py on Bi-Ag(111), while Bi adatoms do not bring any visible influence on coupling reactions. Furthermore, post-deposition of Bi onto preassembled nanostructures on Ag(111) immediately initiates the Ullmann coupling by inducing more Ag adatoms available on the surface, while stepwise annealing afterward leads to complete polymerization and formation of covalent chains with lateral displacement compared to that on the bare Ag(111), probably due to the space hindrance and confinement. For Bi-Au(111) with the modified reconstruction, higher-temperature annealing is required to trigger Ullmann coupling compared to that on Au(111). The exception is that the C-C coupling reaction remains impervious to Bi adatoms, and recovery of the Bi-Au reconstruction is realized after intensive annealing. In principle, bimetallic surfaces herein present intriguing behavior toward the controllable Ullmann coupling, and this report might provide different insights into the comprehensive atomistic elucidation of reaction mechanisms as well as the design of a new platform to effectively regulate Ullmann coupling.
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Affiliation(s)
- Jinping Hu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, China
- University of Chinese Academy Sciences, 101000, Beijing, China
| | - Hongbing Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, China
- University of Chinese Academy Sciences, 101000, Beijing, China
| | - Zhaofeng Liang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Huan Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, China
- University of Chinese Academy Sciences, 101000, Beijing, China
| | - Chaoqin Huang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, China
- University of Chinese Academy Sciences, 101000, Beijing, China
| | - Lei Xie
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Zheshen Li
- ISA, Department of Physics and Astronomy, University of Aarhus, Aarhus, 8000C, Denmark
| | - Zheng Jiang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, China
- University of Chinese Academy Sciences, 101000, Beijing, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Han Huang
- School of Physics and Electronics, Central South University, Changsha, 410012, China
| | - Fei Song
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, China
- University of Chinese Academy Sciences, 101000, Beijing, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
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3
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Mouli MSSV, Mishra AK. Formation of the silver-flavin coordination polymers and their morphological studies. CrystEngComm 2022. [DOI: 10.1039/d2ce00071g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This Communication describes the formation of 1D-coordination polymeric motifs involving modified flavin analog connected together through intervening silver ions. Rare bidentate coordination mode for model flavin was achieved with silver...
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4
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Nanofabrication Techniques in Large-Area Molecular Electronic Devices. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10176064] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The societal impact of the electronics industry is enormous—not to mention how this industry impinges on the global economy. The foreseen limits of the current technology—technical, economic, and sustainability issues—open the door to the search for successor technologies. In this context, molecular electronics has emerged as a promising candidate that, at least in the short-term, will not likely replace our silicon-based electronics, but improve its performance through a nascent hybrid technology. Such technology will take advantage of both the small dimensions of the molecules and new functionalities resulting from the quantum effects that govern the properties at the molecular scale. An optimization of interface engineering and integration of molecules to form densely integrated individually addressable arrays of molecules are two crucial aspects in the molecular electronics field. These challenges should be met to establish the bridge between organic functional materials and hard electronics required for the incorporation of such hybrid technology in the market. In this review, the most advanced methods for fabricating large-area molecular electronic devices are presented, highlighting their advantages and limitations. Special emphasis is focused on bottom-up methodologies for the fabrication of well-ordered and tightly-packed monolayers onto the bottom electrode, followed by a description of the top-contact deposition methods so far used.
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5
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Exploring the Adsorption Mechanism of Tetracene on Ag(110) by STM and Dispersion-Corrected DFT. CRYSTALS 2019. [DOI: 10.3390/cryst10010013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Self-assembled strategy has been proven to be a promising vista in constructing organized low-dimensional nanostructures with molecular precision and versatile functionalities on solid surfaces. Herein, we investigate by a combination of scanning tunneling microscopy (STM) and dispersion-corrected density functional theory (DFT), the adsorption of tetracene molecules on the silver substrate and the mechanism mediating the self-assembly on Ag(110). As expected, ordered domain is formed on Ag(110) after adsorption with adjacent molecules being imaged with alternating bright or dim pattern regularly. While such behavior has been assigned previously to the difference of molecular adsorption height, herein, it is possible to investigate essentially the mechanism leading to the periodic alternation of brightness and dimness for tetracene adsorbed on Ag(110) thanks to the consideration of Van der Waals (vdW) dispersion force. It is demonstrated that the adsorption height in fact is same for both bright and dim molecules, while the adsorption site and the corresponding interfacial charge transfer play an important role in the formation of such pattern. Our report reveals that vdW dispersion interaction is crucial to appropriately describe the adsorption of tetracene on the silver substrate, and the formation of delicate molecular architectures on metal surfaces might also offers a promising approach towards molecular electronics.
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6
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Ares P, Amo-Ochoa P, Soler JM, Palacios JJ, Gómez-Herrero J, Zamora F. High Electrical Conductivity of Single Metal-Organic Chains. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1705645. [PMID: 29659059 DOI: 10.1002/adma.201705645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Molecular wires are essential components for future nanoscale electronics. However, the preparation of individual long conductive molecules is still a challenge. MMX metal-organic polymers are quasi-1D sequences of single halide atoms (X) bridging subunits with two metal ions (MM) connected by organic ligands. They are excellent electrical conductors as bulk macroscopic crystals and as nanoribbons. However, according to theoretical calculations, the electrical conductance found in the experiments should be even higher. Here, a novel and simple drop-casting procedure to isolate bundles of few to single MMX chains is demonstrated. Furthermore, an exponential dependence of the electrical resistance of one or two MMX chains as a function of their length that does not agree with predictions based on their theoretical band structure is reported. This dependence is attributed to strong Anderson localization originated by structural defects. Theoretical modeling confirms that the current is limited by structural defects, mainly vacancies of iodine atoms, through which the current is constrained to flow. Nevertheless, measurable electrical transport along distances beyond 250 nm surpasses that of all other molecular wires reported so far. This work places in perspective the role of defects in 1D wires and their importance for molecular electronics.
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Affiliation(s)
- Pablo Ares
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, E-28049, Spain
| | - Pilar Amo-Ochoa
- Departamento de Química Inorgánica and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
| | - José M Soler
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, E-28049, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
| | - Juan José Palacios
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, E-28049, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
| | - Julio Gómez-Herrero
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, E-28049, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
| | - Félix Zamora
- Departamento de Química Inorgánica and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, Madrid, E-28049, Spain
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7
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Ohno S, Tanaka H, Tanaka K, Takahashi K, Tanaka M. Electronic structure of α-sexithiophene ultrathin films grown on. Phys Chem Chem Phys 2018; 20:1114-1126. [DOI: 10.1039/c7cp05222g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We investigated the electronic states of α-sexithiophene (α-6T) on by means of angle-resolved photoelectron spectroscopy using synchrotron radiation.
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Affiliation(s)
- Shinya Ohno
- Faculty of Engineering
- Yokohama National University
- Yokohama 240-8501
- Japan
| | - Hiroya Tanaka
- Faculty of Engineering
- Yokohama National University
- Yokohama 240-8501
- Japan
| | - Kazuma Tanaka
- Faculty of Engineering
- Yokohama National University
- Yokohama 240-8501
- Japan
| | | | - Masatoshi Tanaka
- Faculty of Engineering
- Yokohama National University
- Yokohama 240-8501
- Japan
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8
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Kolmer M, Olszowski P, Zuzak R, Godlewski S, Joachim C, Szymonski M. Two-probe STM experiments at the atomic level. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:444004. [PMID: 28869213 DOI: 10.1088/1361-648x/aa8a05] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Direct characterization of planar atomic or molecular scale devices and circuits on a supporting surface by multi-probe measurements requires unprecedented stability of single atom contacts and manipulation of scanning probes over large, nanometer scale area with atomic precision. In this work, we describe the full methodology behind atomically defined two-probe scanning tunneling microscopy (STM) experiments performed on a model system: dangling bond dimer wire supported on a hydrogenated germanium (0 0 1) surface. We show that 70 nm long atomic wire can be simultaneously approached by two independent STM scanners with exact probe to probe distance reaching down to 30 nm. This allows direct wire characterization by two-probe I-V characteristics at distances below 50 nm. Our technical results presented in this work open a new area for multi-probe research, which can be now performed with precision so far accessible only by single-probe scanning probe microscopy (SPM) experiments.
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Affiliation(s)
- Marek Kolmer
- Faculty of Physics, Astronomy and Applied Computer Science, Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
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9
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Lord AM, Evans JE, Barnett CJ, Allen MW, Barron AR, Wilks SP. Surface sensitivity of four-probe STM resistivity measurements of bulk ZnO correlated to XPS. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:384001. [PMID: 28678024 DOI: 10.1088/1361-648x/aa7dc8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Multi-probe instruments based on scanning tunnelling microscopy (STM) are becoming increasingly common for their ability to perform nano- to atomic-scale investigations of nanostructures, surfaces and in situ reactions. A common configuration is the four-probe STM often coupled with in situ scanning electron microscopy (SEM) that allows precise positioning of the probes onto surfaces and nanostructures enabling electrical and scanning experiments to be performed on highly localised regions of the sample. In this paper, we assess the sensitivity of four-probe STM for in-line resistivity measurements of the bulk ZnO surface. The measurements allow comparisons to established models that are used to relate light plasma treatments (O and H) of the surfaces to the resistivity measurements. The results are correlated to x-ray photoelectron spectroscopy (XPS) and show that four-probe STM can detect changes in surface and bulk conduction mechanisms that are beyond conventional monochromatic XPS.
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Affiliation(s)
- Alex M Lord
- Centre for NanoHealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP, United Kingdom
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10
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Liang Z, Sun H, Shen K, Hu J, Song B, Lu Y, Jiang Z, Song F. Unveiling orbital coupling at the CoPc/Bi(111) surface by ab initio calculations and photoemission spectroscopy. RSC Adv 2017. [DOI: 10.1039/c7ra09495g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Orbital coupling is revealed at the CoPc/Bi(111) interface with the local magnetic moment retained in CoPc.
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Affiliation(s)
- Zhaofeng Liang
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
- University of Chinese Academy of Sciences
| | - Haoliang Sun
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
- University of Chinese Academy of Sciences
| | - Kongchao Shen
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| | - Jinbang Hu
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| | - Bo Song
- University of Shanghai for Science and Technology
- Shanghai
- China
| | - Yunhao Lu
- College of Materials Science and Engineering
- Zhejiang University
- Hangzhou
- China
| | - Zheng Jiang
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| | - Fei Song
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
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11
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Shen K, Narsu B, Ji G, Sun H, Hu J, Liang Z, Gao X, Li H, Li Z, Song B, Jiang Z, Huang H, Wells J, Song F. On-surface manipulation of atom substitution between cobalt phthalocyanine and the Cu(111) substrate. RSC Adv 2017. [DOI: 10.1039/c7ra00636e] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An on-surface atom substation has been manipulated by thermal annealing which transmetalizes CoPc to CuPc for various applications.
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12
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Chen Y, Cao W, Wang C, Qi D, Wang K, Jiang J. Four Dibutylamino Substituents Are Better Than Eight in Modulating the Electronic Structure and Third-Order Nonlinear-Optical Properties of Phthalocyanines. Inorg Chem 2016; 55:3151-60. [PMID: 26931202 DOI: 10.1021/acs.inorgchem.6b00100] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
2(3),9(10),16(17),23(24)-Tetrakis(dibutylamino)phthalocyanine compounds M{Pc[N(C4H9)2]4} (1-5; M = 2H, Mg, Ni, Cu, Zn) were prepared and characterized by a range of spectroscopic methods in addition to elemental analysis. Electrochemical and electronic absorption spectroscopic studies revealed the more effective conjugation of the nitrogen lone pair of electrons in the dibutylamino side chains with the central phthalocyanine π system in M{Pc[N(C4H9)2]4} than in M{Pc[N(C4H9)2]8}, which, in turn, results in superior third-order nonlinear-optical (NLO) properties of H2{Pc[N(C4H9)2]4} (1) over H2{Pc[N(C4H9)2]8}, as revealed by the obviously larger effective imaginary third-order molecular hyperpolarizability (Im{χ((3))}) of 6.5 × 10(-11) esu for the former species than for the latter one with a value of 3.4 × 10(-11) esu. This is well rationalized on the basis of both structural and theoretical calculation results. The present result seems to represent the first effort toward directly connecting the peripheral functional substituents, electronic structures, and NLO functionality together for phthalocyanine molecular materials, which will be helpful for the development of functional phthalocyanine materials via molecular design and synthesis even through only tuning of the peripheral functional groups.
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Affiliation(s)
- Yuxiang Chen
- Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry, University of Science and Technology Beijing , Beijing 100083, China
| | - Wei Cao
- Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry, University of Science and Technology Beijing , Beijing 100083, China
| | - Chiming Wang
- Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry, University of Science and Technology Beijing , Beijing 100083, China
| | - Dongdong Qi
- Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry, University of Science and Technology Beijing , Beijing 100083, China
| | - Kang Wang
- Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry, University of Science and Technology Beijing , Beijing 100083, China
| | - Jianzhuang Jiang
- Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry, University of Science and Technology Beijing , Beijing 100083, China
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13
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Adsorption of tetrathiafulvalene (TTF) on Cu(1 0 0): can π-stacked 1-D aggregates be formed at low temperature? Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.07.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Polley CM, Clarke WR, Miwa JA, Scappucci G, Wells JW, Jaeger DL, Bischof MR, Reidy RF, Gorman BP, Simmons M. Exploring the limits of N-type ultra-shallow junction formation. ACS NANO 2013; 7:5499-5505. [PMID: 23721101 DOI: 10.1021/nn4016407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Low resistivity, near-surface doping in silicon represents a formidable challenge for both the microelectronics industry and future quantum electronic devices. Here we employ an ultra-high vacuum strategy to create highly abrupt doping profiles in silicon, which we characterize in situ using a four point probe scanning tunnelling microscope. Using a small molecule gaseous dopant source (PH3) which densely packs on a reconstructed silicon surface, followed by encapsulation in epitaxial silicon, we form highly conductive dopant sheets with subnanometer control of the depth profiles. This approach allows us to test the limits of ultra-shallow junction formation, with room temperature resistivities of 780 Ω/□ at an encapsulation depth of 4.3 nm, increasing to 23 kΩ/□ at an encapsulation depth of only 0.5 nm. We show that this depth-dependent resistivity can be accounted for by a combination of dopant segregation and surface scattering.
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Affiliation(s)
- Craig M Polley
- School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
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15
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Peng W, Aksamija Z, Scott SA, Endres JJ, Savage DE, Knezevic I, Eriksson MA, Lagally MG. Probing the electronic structure at semiconductor surfaces using charge transport in nanomembranes. Nat Commun 2013; 4:1339. [DOI: 10.1038/ncomms2350] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 11/30/2012] [Indexed: 11/09/2022] Open
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16
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Toader M, Shukrynau P, Knupfer M, Zahn DRT, Hietschold M. Site-dependent donation/backdonation charge transfer at the CoPc/Ag(111) interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13325-30. [PMID: 22931485 DOI: 10.1021/la302792z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The organic/metal interface formed upon adsorption of cobalt(II) phthalocyanine (CoPc) molecules on a flat Ag(111) single crystal was investigated using a combination of scanning tunneling microscopy (STM) and photoemission spectroscopy (PES). A flat-lying molecular adsorption with the π conjugated phthalocyanine ligand parallel to the substrate was found to lead to an effective molecule-substrate coupling which governs a template-guided molecular growth. A voltage polarity dependence at the cobalt ion site was emphasized and correlated with the Co 2p core level spectra evolution which sustains an interface-confined reduction effect of the cobalt oxidation state. The formation of interface dipoles was observed via monitoring the changes in the work function (WF) upon deposition. The observations are discussed on the basis of a site-dependent donation/backdonation charge transfer at the molecule-substrate interface.
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Affiliation(s)
- Marius Toader
- Chemnitz University of Technology, Institute of Physics, Solid Surfaces Analysis Group, D-09107 Chemnitz, Germany.
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17
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Wang W, Ji Y, Zhang H, Zhao A, Wang B, Yang J, Hou JG. Negative differential resistance in a hybrid silicon-molecular system: resonance between the intrinsic surface-states and the molecular orbital. ACS NANO 2012; 6:7066-7076. [PMID: 22793258 DOI: 10.1021/nn302107k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
It has been a long-term desire to fabricate hybrid silicon-molecular devices by taking advantages of organic molecules and the existing silicon-based technology. However, one of the challenging tasks is to design applicable functions on the basis of the intrinsic properties of the molecules, as well as the silicon substrates. Here we demonstrate a silicon-molecular system that produces negative differential resistance (NDR) by making use of the well-defined intrinsic surface-states of the Si (111)-√3 × √3-Ag (R3-Ag/Si) surface and the molecular orbital of cobalt(II)-phthalocyanine (CoPc) molecules. From our experimental results obtained using scanning tunneling microscopy/spectroscopy, we find that NDR robustly appears at the Co(2+) ion centers of the CoPc molecules, independent of the adsorption configuration of the CoPc molecules and irrespective of doping type and doping concentration of the silicon substrates. Joint with first principle calculations, we conclude that NDR is originated from the resonance between the intrinsic surface-state band S(1) of the R3-Ag/Si surface and the localized unoccupied Co(2+)d(z(2)) orbital of the adsorbed CoPc molecules. We expect that such a mechanism can be generally used in other silicon-molecular systems.
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Affiliation(s)
- Weihua Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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18
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Welte L, Calzolari A, Di Felice R, Zamora F, Gómez-Herrero J. Highly conductive self-assembled nanoribbons of coordination polymers. NATURE NANOTECHNOLOGY 2010; 5:110-115. [PMID: 19966794 DOI: 10.1038/nnano.2009.354] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 10/27/2009] [Indexed: 05/28/2023]
Abstract
Organic molecules can self-assemble into well-ordered structures, but the conductance of these structures is limited, which is a disadvantage for applications in molecular electronics. Conductivity can be improved by using coordination polymers-in which metal centres are incorporated into a molecular backbone-and such structures have been used as molecular wires by self-assembling them into ordered films on metal surfaces. Here, we report electrically conductive nanoribbons of the coordination polymer [Pt(2)I(S(2)CCH(3))(4)](n) self-assembled on an insulating substrate by direct sublimation of polymer crystals. Conductance atomic force microscopy is used to probe the electrical characteristics of a few polymer chains ( approximately 10) within the nanoribbons. The observed currents exceed those previously sustained in organic and metal-organic molecules assembled on surfaces by several orders of magnitude and over much longer distances. These results, and the results of theoretical calculations based on density functional theory, confirm coordination polymers as candidate materials for applications in molecular electronics.
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Affiliation(s)
- Lorena Welte
- Departamento de Química Inorgánica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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