51
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Kamenetska M, Widawsky JR, Dell’Angela M, Frei M, Venkataraman L. Temperature dependent tunneling conductance of single molecule junctions. J Chem Phys 2017. [DOI: 10.1063/1.4973318] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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52
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Pirrotta A, De Vico L, Solomon GC, Franco I. Single-molecule force-conductance spectroscopy of hydrogen-bonded complexes. J Chem Phys 2017. [DOI: 10.1063/1.4976626] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alessandro Pirrotta
- Nano-Science Center and Department of Chemistry, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Luca De Vico
- Department of Chemistry, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Gemma C. Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Ignacio Franco
- Departments of Chemistry and Physics, University of Rochester, Rochester, New York 14627-0216, USA
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53
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Kiran V, Cohen SR, Naaman R. Structure dependent spin selectivity in electron transport through oligopeptides. J Chem Phys 2017. [DOI: 10.1063/1.4966237] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Vankayala Kiran
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot NA 76100, Israel
| | - Sidney R. Cohen
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ron Naaman
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot NA 76100, Israel
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54
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Vilan A, Aswal D, Cahen D. Large-Area, Ensemble Molecular Electronics: Motivation and Challenges. Chem Rev 2017; 117:4248-4286. [DOI: 10.1021/acs.chemrev.6b00595] [Citation(s) in RCA: 243] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ayelet Vilan
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
| | | | - David Cahen
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
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55
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Zhai X, Alexander D, Derosa P, Garno JC. Distance-Dependent Measurements of the Conductance of Porphyrin Nanorods Studied with Conductive Probe Atomic Force Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1132-1138. [PMID: 28081363 PMCID: PMC5497462 DOI: 10.1021/acs.langmuir.6b03525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Protocols for nanopatterning porphyrins on Au(111) were developed based on immersion particle lithography. Porphyrins with and without a central metal ion, 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin cobalt(II) (CoTPP), were selected for study, which spontaneously formed nanorod geometries depending on concentration parameters. The elongated shapes of the nanorods offers an opportunity for successive distance-dependent conductive probe atomic force microscopy (CP-AFM) measurements along the length of the nanorods. To prepare patterns of TPP and CoTPP nanorods, a mask of silica mesospheres was placed on gold substrates to generate nanoholes within an alkanethiol matrix film. The nanoholes prepared by particle lithography with an immersion step were backfilled with porphyrins by a second immersion step. By controlling the concentration and immersion interval, nanorods of porphyrins were generated with one end of the nanostructure attached to gold within a nanohole. The porphyrin nanorods exhibited slight differences in dimensions at the nanoscale to enable size-dependent measurements of conductive properties. The conductivity along the horizontal direction of the nanorods was evaluated with CP-AFM studies. Changes in conductivity were measured along the long axis of TPP and CoTPP nanorods. The TPP nanorods exhibited conductive profiles of an insulating material, and the CoTPP nanorods exhibited profiles of a semiconductor. The experiments demonstrate the applicability of particle lithography for preparing unique and functional surface platforms of porphyrins to measure distance-dependent conductive properties on gold.
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Affiliation(s)
- Xianglin Zhai
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Denzel Alexander
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Pedro Derosa
- Institute for Micromanufacturing, Chemistry Department, and Physics Department, Louisiana Tech University, Ruston, Louisiana 71272, United States
| | - Jayne C. Garno
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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56
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Trace Detection of Metalloporphyrin-Based Coordination Polymer Particles via Modified Surface-Enhanced Raman Scattering Assisted by Surface Metallization. Int J Anal Chem 2017; 2016:6394858. [PMID: 28115934 PMCID: PMC5220509 DOI: 10.1155/2016/6394858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/21/2016] [Accepted: 12/05/2016] [Indexed: 11/17/2022] Open
Abstract
This study proposed a facile method to detect metalloporphyrin-based coordination polymer particles (Z-CPPs) in aqueous solution by modified surface-enhanced Raman scattering (SERS). The SERS-active particles are photodeposited on the surface of Z-CPPs, offering an enhanced Raman signal for the trace detection of Z-CPPs.
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57
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Zhai X, Arachchige NMKK, Derosa P, Garno JC. Conductive-probe measurements with nanodots of free-base and metallated porphyrins. J Colloid Interface Sci 2017; 486:38-45. [PMID: 27693519 DOI: 10.1016/j.jcis.2016.09.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/12/2016] [Accepted: 09/16/2016] [Indexed: 12/28/2022]
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58
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Vilan A. Revealing tunnelling details by normalized differential conductance analysis of transport across molecular junctions. Phys Chem Chem Phys 2017; 19:27166-27172. [DOI: 10.1039/c7cp05536f] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new analysis tool reveals hidden fingerprints of tunnelling mechanisms and quantifies the bias response via a scaling bias parameter.
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Affiliation(s)
- A. Vilan
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot
- Israel
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59
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Ekiz MS, Cinar G, Khalily MA, Guler MO. Self-assembled peptide nanostructures for functional materials. NANOTECHNOLOGY 2016; 27:402002. [PMID: 27578525 DOI: 10.1088/0957-4484/27/40/402002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.
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Affiliation(s)
- Melis Sardan Ekiz
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, 06800 Turkey
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60
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Baldacchini C, Bizzarri AR, Cannistraro S. Electron transfer, conduction and biorecognition properties of the redox metalloprotein Azurin assembled onto inorganic substrates. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.04.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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61
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Xie Z, Shi S, Liu F, Smith DL, Ruden PP, Frisbie CD. Large Magnetoresistance at Room Temperature in Organic Molecular Tunnel Junctions with Nonmagnetic Electrodes. ACS NANO 2016; 10:8571-7. [PMID: 27598057 DOI: 10.1021/acsnano.6b03853] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We report room-temperature resistance changes of up to 30% under weak magnetic fields (0.1 T) for molecular tunnel junctions composed of oligophenylene thiol molecules, 1-2 nm in length, sandwiched between gold contacts. The magnetoresistance (MR) is independent of field orientation and the length of the molecule; it appears to be an interface effect. Theoretical analysis suggests that the source of the MR is a two-carrier (two-hole) interaction at the interface, resulting in spin coupling between the tunneling hole and a localized hole at the Au/molecule contact. Such coupling leads to significantly different singlet and triplet transmission barriers at the interface. Even weak magnetic fields impede spin relaxation processes and thus modify the ratio of holes tunneling via the singlet state versus the triplet state, which leads to the large MR. Overall, the experiments and analysis suggest significant opportunities to explore large MR effects in molecular tunnel junctions based on widely available molecules.
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Affiliation(s)
- Zuoti Xie
- Department of Chemical Engineering and Materials Science and ‡Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Sha Shi
- Department of Chemical Engineering and Materials Science and ‡Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Feilong Liu
- Department of Chemical Engineering and Materials Science and ‡Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Darryl L Smith
- Department of Chemical Engineering and Materials Science and ‡Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - P Paul Ruden
- Department of Chemical Engineering and Materials Science and ‡Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science and ‡Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
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62
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Sangeeth CSS, Demissie AT, Yuan L, Wang T, Frisbie CD, Nijhuis CA. Comparison of DC and AC Transport in 1.5-7.5 nm Oligophenylene Imine Molecular Wires across Two Junction Platforms: Eutectic Ga-In versus Conducting Probe Atomic Force Microscope Junctions. J Am Chem Soc 2016; 138:7305-14. [PMID: 27172452 DOI: 10.1021/jacs.6b02039] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have utilized DC and AC transport measurements to measure the resistance and capacitance of thin films of conjugated oligophenyleneimine (OPI) molecules ranging from 1.5 to 7.5 nm in length. These films were synthesized on Au surfaces utilizing the imine condensation chemistry between terephthalaldehyde and 1,4-benzenediamine. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy yielded molecular tilt angles of 33-43°. To probe DC and AC transport, we employed Au-S-OPI//GaOx/EGaIn junctions having contact areas of 9.6 × 10(2) μm(2) (10(9) nm(2)) and compared to previously reported DC results on the same OPI system obtained using Au-S-OPI//Au conducting probe atomic force microscopy (CP-AFM) junctions with 50 nm(2) areas. We found that intensive observables agreed very well across the two junction platforms. Specifically, the EGaIn-based junctions showed: (i) a crossover from tunneling to hopping transport at molecular lengths near 4 nm; (ii) activated transport for wires >4 nm in length with an activation energy of 0.245 ± 0.008 eV for OPI-7; (iii) exponential dependence of conductance with molecular length with a decay constant β = 2.84 ± 0.18 nm(-1) (DC) and 2.92 ± 0.13 nm(-1) (AC) in the tunneling regime, and an apparent β = 1.01 ± 0.08 nm(-1) (DC) and 0.99 ± 0.11 nm(-1) (AC) in the hopping regime; (iv) previously unreported dielectric constant of 4.3 ± 0.2 along the OPI wires. However, the absolute resistances of Au-S-OPI//GaOx/EGaIn junctions were approximately 100 times higher than the corresponding CP-AFM junctions due to differences in metal-molecule contact resistances between the two platforms.
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Affiliation(s)
- C S Suchand Sangeeth
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543
| | - Abel T Demissie
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Li Yuan
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543
| | - Tao Wang
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543.,Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore 117546
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63
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Yang G, Hu L, Keiper TD, Xiong P, Hallinan DT. Gold Nanoparticle Monolayers with Tunable Optical and Electrical Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4022-4033. [PMID: 27018432 DOI: 10.1021/acs.langmuir.6b00347] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Centimeter-scale gold nanoparticle (Au NP) monolayer films have been fabricated using a water/organic solvent self-assembly strategy. A recently developed approach, drain to deposit, is demonstrated to be most effective in transferring the Au NP films from the water/organic solvent interface to various solid substrates while maintaining their integrity. The interparticle spacing was tuned from 1.4 to 3.1 nm using alkylamine ligands of different lengths. The ordering of the films increased with increasing ligand length. The surface plasmon resonance and the in-plane electrical conductivity of the Au NP films both exhibit an exponential dependence on the interparticle spacing. These findings show great potential in scaling up the manufacturing of high-performance optical and electronic devices based on two-dimensional metallic nanoparticle superlattices.
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Affiliation(s)
- Guang Yang
- Aero-Propulsion, Mechatronics, and Energy Center, Florida State University , 2003 Levy Avenue, Tallahassee, Florida 32310, United States
- Department of Chemical & Biomedical Engineering, College of Engineering, Florida A&M University-Florida State University , 2525 Pottsdamer Street, Tallahassee, Florida 32310, United States
| | - Longqian Hu
- Department of Physics, Florida State University , Tallahassee, Florida 32306, United States
| | - Timothy D Keiper
- Department of Physics, Florida State University , Tallahassee, Florida 32306, United States
| | - Peng Xiong
- Department of Physics, Florida State University , Tallahassee, Florida 32306, United States
| | - Daniel T Hallinan
- Aero-Propulsion, Mechatronics, and Energy Center, Florida State University , 2003 Levy Avenue, Tallahassee, Florida 32310, United States
- Department of Chemical & Biomedical Engineering, College of Engineering, Florida A&M University-Florida State University , 2525 Pottsdamer Street, Tallahassee, Florida 32310, United States
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64
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Szwajca A, Koroniak H. Fluorinated SAMs on Si(001) surface: Surface electronic properties and structural aspects. PHOSPHORUS SULFUR 2016. [DOI: 10.1080/10426507.2015.1100190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Anna Szwajca
- Faculty of Chemistry, A. Mickiewicz University in Poznan, Poznan, Poland
| | - Henryk Koroniak
- Faculty of Chemistry, A. Mickiewicz University in Poznan, Poznan, Poland
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65
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Xiang D, Wang X, Jia C, Lee T, Guo X. Molecular-Scale Electronics: From Concept to Function. Chem Rev 2016; 116:4318-440. [DOI: 10.1021/acs.chemrev.5b00680] [Citation(s) in RCA: 816] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Dong Xiang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
- Key
Laboratory of Optical Information Science and Technology, Institute
of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071, China
| | - Xiaolong Wang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Chuancheng Jia
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Takhee Lee
- Department
of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Xuefeng Guo
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
- Department
of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
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66
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Jeong H, Kim D, Kwon H, Hwang WT, Jang Y, Min M, Char K, Xiang D, Jeong H, Lee T. Statistical investigation of the length-dependent deviations in the electrical characteristics of molecular electronic junctions fabricated using the direct metal transfer method. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:094003. [PMID: 26871992 DOI: 10.1088/0953-8984/28/9/094003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We fabricated and analyzed the electrical transport characteristics of vertical type alkanethiolate molecular junctions using the high-yield fabrication method that we previously reported. The electrical characteristics of the molecular electronic junctions were statistically collected and investigated in terms of current density and transport parameters based on the Simmons tunneling model, and we determined representative current-voltage characteristics of the molecular junctions. In particular, we examined the statistical variations in the length-dependent electrical characteristics, especially the Gaussian standard deviation σ of the current density histogram. From the results, we found that the magnitude of the σ value can be dependent on the individual molecular length due to specific microscopic structures in the molecular junctions. The probable origin of the molecular length-dependent deviation of the electrical characteristics is discussed.
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Affiliation(s)
- Hyunhak Jeong
- Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
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67
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Zhang G, Güell AG, Kirkman PM, Lazenby RA, Miller TS, Unwin PR. Versatile Polymer-Free Graphene Transfer Method and Applications. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8008-16. [PMID: 26953499 DOI: 10.1021/acsami.6b00681] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A new method for transferring chemical vapor deposition (CVD)-grown monolayer graphene to a variety of substrates is described. The method makes use of an organic/aqueous biphasic configuration, avoiding the use of any polymeric materials that can cause severe contamination problems. The graphene-coated copper foil sample (on which graphene was grown) sits at the interface between hexane and an aqueous etching solution of ammonium persulfate to remove the copper. With the aid of an Si/SiO2 substrate, the graphene layer is then transferred to a second hexane/water interface to remove etching products. From this new location, CVD graphene is readily transferred to arbitrary substrates, including three-dimensional architectures as represented by atomic force microscopy (AFM) tips and transmission electron microscopy (TEM) grids. Graphene produces a conformal layer on AFM tips, to the very end, allowing easy production of tips for conductive AFM imaging. Graphene transferred to copper TEM grids provides large-area, highly electron-transparent substrates for TEM imaging. These substrates can also be used as working electrodes for electrochemistry and high-resolution wetting studies. By using scanning electrochemical cell microscopy, it is possible to make electrochemical and wetting measurements at either a freestanding graphene film or a copper-supported graphene area and readily determine any differences in behavior.
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Affiliation(s)
- Guohui Zhang
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Aleix G Güell
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Paul M Kirkman
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Robert A Lazenby
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Thomas S Miller
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Patrick R Unwin
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
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68
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Dou W, Nitzan A, Subotnik JE. Molecular electronic states near metal surfaces at equilibrium using potential of mean force and numerical renormalization group methods: Hysteresis revisited. J Chem Phys 2016; 144:074109. [DOI: 10.1063/1.4941848] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Wenjie Dou
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Abraham Nitzan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- School of Chemistry, The Sackler Faculty of Science, Tel Aviv University, Tel Aviv 69978, Israel
| | - Joseph E. Subotnik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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69
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Rincón-García L, Evangeli C, Rubio-Bollinger G, Agraït N. Thermopower measurements in molecular junctions. Chem Soc Rev 2016; 45:4285-306. [DOI: 10.1039/c6cs00141f] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The measurement of thermopower in molecular junctions offers complementary information to conductance measurements and is becoming essential for the understanding of transport processes at the nanoscale.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Universitario de Ciencia de Materiales “Nicolás Cabrera”
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
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70
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Smith CE, Odoh SO, Ghosh S, Gagliardi L, Cramer CJ, Frisbie CD. Length-Dependent Nanotransport and Charge Hopping Bottlenecks in Long Thiophene-Containing π-Conjugated Molecular Wires. J Am Chem Soc 2015; 137:15732-41. [DOI: 10.1021/jacs.5b07400] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Christopher E. Smith
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, §Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Samuel O. Odoh
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, §Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Soumen Ghosh
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, §Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Laura Gagliardi
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, §Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher J. Cramer
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, §Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - C. Daniel Frisbie
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, §Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
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71
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Jafri SHM, Löfås H, Blom T, Wallner A, Grigoriev A, Ahuja R, Ottosson H, Leifer K. Nano-fabrication of molecular electronic junctions by targeted modification of metal-molecule bonds. Sci Rep 2015; 5:14431. [PMID: 26395225 PMCID: PMC5155674 DOI: 10.1038/srep14431] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/25/2015] [Indexed: 11/09/2022] Open
Abstract
Reproducibility, stability and the coupling between electrical and molecular properties are central challenges in the field of molecular electronics. The field not only needs devices that fulfill these criteria but they also need to be up-scalable to application size. In this work, few-molecule based electronics devices with reproducible electrical characteristics are demonstrated. Our previously reported 5 nm gold nanoparticles (AuNP) coated with ω-triphenylmethyl (trityl) protected 1,8-octanedithiol molecules are trapped in between sub-20 nm gap spacing gold nanoelectrodes forming AuNP-molecule network. When the trityl groups are removed, reproducible devices and stable Au-thiol junctions are established on both ends of the alkane segment. The resistance of more than 50 devices is reduced by orders of magnitude as well as a reduction of the spread in the resistance histogram is observed. By density functional theory calculations the orders of magnitude decrease in resistance can be explained and supported by TEM observations thus indicating that the resistance changes and strongly improved resistance spread are related to the establishment of reproducible and stable metal-molecule bonds. The same experimental sequence is carried out using 1,6-hexanedithiol functionalized AuNPs. The average resistances as a function of molecular length, demonstrated herein, are comparable to the one found in single molecule devices.
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Affiliation(s)
- S. Hassan M. Jafri
- Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala SE-75121, Sweden
- Department of Electrical Engineering, Mirpur University of Science and Technology, Mirpur Azad Jammu and Kashmir 10250, Pakistan
| | - Henrik Löfås
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala SE-75120, Sweden
| | - Tobias Blom
- Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala SE-75121, Sweden
| | - Andreas Wallner
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala SE-75123, Sweden
| | - Anton Grigoriev
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala SE-75120, Sweden
| | - Rajeev Ahuja
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala SE-75120, Sweden
- Applied Material Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), Stockholm SE-10044, Sweden
| | - Henrik Ottosson
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala SE-75123, Sweden
| | - Klaus Leifer
- Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala SE-75121, Sweden
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72
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Xie Z, Bâldea I, Smith CE, Wu Y, Frisbie CD. Experimental and Theoretical Analysis of Nanotransport in Oligophenylene Dithiol Junctions as a Function of Molecular Length and Contact Work Function. ACS NANO 2015; 9:8022-8036. [PMID: 26190402 DOI: 10.1021/acsnano.5b01629] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the results of an extensive investigation of metal-molecule-metal tunnel junctions based on oligophenylene dithiols (OPDs) bound to several types of electrodes (M1-S-(C6H4)n-S-M2, with 1 ≤ n ≤ 4 and M1,2 = Ag, Au, Pt) to examine the impact of molecular length (n) and metal work function (Φ) on junction properties. Our investigation includes (1) measurements by scanning Kelvin probe microscopy of electrode work function changes (ΔΦ = ΦSAM - Φ) caused by chemisorption of OPD self-assembled monolayers (SAMs), (2) measurements of junction current-voltage (I-V) characteristics by conducting probe atomic force microscopy in the linear and nonlinear bias ranges, and (3) direct quantitative analysis of the full I-V curves. Further, we employ transition voltage spectroscopy (TVS) to estimate the energetic alignment εh = EF - EHOMO of the dominant molecular orbital (HOMO) relative to the Fermi energy EF of the junction. Where photoelectron spectroscopy data are available, the εh values agree very well with those determined by TVS. Using a single-level model, which we justify via ab initio quantum chemical calculations at post-density functional theory level and additional UV-visible absorption measurements, we are able to quantitatively reproduce the I-V measurements in the whole bias range investigated (∼1.0-1.5 V) and to understand the behavior of εh and Γ (contact coupling strength) extracted from experiment. We find that Fermi level pinning induced by the strong dipole of the metal-S bond causes a significant shift of the HOMO energy of an adsorbed molecule, resulting in εh exhibiting a weak dependence with the work function Φ. Both of these parameters play a key role in determining the tunneling attenuation factor (β) and junction resistance (R). Correlation among Φ, ΔΦ, R, transition voltage (Vt), and εh and accurate simulation provide a remarkably complete picture of tunneling transport in these prototypical molecular junctions.
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Affiliation(s)
- Zuoti Xie
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Ioan Bâldea
- Theoretische Chemie, Universität Heidelberg , INF 229, D-69120 Heidelberg, Germany
- National Institute of Lasers, Plasma and Radiation Physics, Institute of Space Science , POB MG-23, RO 077125 Bucharest, Romania
| | - Christopher E Smith
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Yanfei Wu
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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73
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Figueira J, Czardybon W, Mesquita JC, Rodrigues J, Lahoz F, Russo L, Valkonen A, Rissanen K. Synthesis, characterization and solid-state photoluminescence studies of six alkoxy phenylene ethynylene dinuclear palladium(II) rods. Dalton Trans 2015; 44:4003-15. [PMID: 25612106 DOI: 10.1039/c4dt00493k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A rare family of six discrete binuclear [PdCl(PEt3)2] phenylene ethynylene rods with alkoxy side chains (methoxy, ethoxy and heptoxy) have been developed, and their solid-state photoluminescence results have been presented and discussed. The shorter bridging ligands are of the general formula H-C≡C-C6H2(R)2-C≡C-H, where R = H, OCH3, OC2H5, and OC7H15, whereas the longer ones are based on H-C≡C-C6H4-C≡C-C6H2(R)2-C≡C-C6H4-C≡C-H, where R = OCH3, OC2H5. These ligands display increasing length in both the main dimension (backbone length) as well as the number of carbons in the side chains (R, alkoxide side chain) that stem from the central phenylene moiety. The X-ray crystal structures of two of the prepared complexes are reported: one corresponds to a shorter rod, 1,4-bis[trans-(PEt3)2ClPd-C≡C]-2,5-diethoxybenzene (6c), while the second one is associated with a longer rod, the binuclear complex 1,4-bis[trans-(PEt3)2ClPd-4-(-C≡C-C6H4-C≡C)]-2,5-diethoxybenzene (7c). All new compounds were characterized by NMR spectroscopy ((1)H, (13)C{(1)H} and (31)P{(1)H}) as well as ESI-MS(TOF), EA, FTIR, UV-Vis, cyclic voltammetry and solid-state photoluminescence. Our work shows the influence of the alkoxy side chains on the electronic structure of the family of binuclear Pd rods by lowering its oxidation potential. In addition to this, the increase of the length of the bridge results in a higher oxidation potential. Solid state photoluminescence results indicate that Pd complexes are characterized by a marked decrease in both the emission intensity and the fluorescence lifetime values as compared to their ligands. This behaviour could be due to some degree of ligand-to-metal charge transfer.
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Affiliation(s)
- João Figueira
- CQM - Centro de Química da Madeira, MMRG, Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal.
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74
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Optical imaging beyond the diffraction limit by SNEM: Effects of AFM tip modifications with thiol monolayers on imaging quality. Ultramicroscopy 2015; 150:79-87. [DOI: 10.1016/j.ultramic.2014.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 11/18/2014] [Accepted: 12/07/2014] [Indexed: 11/19/2022]
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75
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Juhaniewicz J, Pawlowski J, Sek S. Electron Transport Mediated by Peptides Immobilized on Surfaces. Isr J Chem 2015. [DOI: 10.1002/ijch.201400165] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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76
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Smaali K, Desbief S, Foti G, Frederiksen T, Sanchez-Portal D, Arnau A, Nys JP, Leclère P, Vuillaume D, Clément N. On the mechanical and electronic properties of thiolated gold nanocrystals. NANOSCALE 2015; 7:1809-1819. [PMID: 25518743 DOI: 10.1039/c4nr06180b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a quantitative exploration, combining experiment and simulation, of the mechanical and electronic properties, as well as the modifications induced by an alkylthiolated coating, at the single nanoparticle (NP) level. We determined the response of the NPs to external pressure in a controlled manner using an atomic force microscope tip. We found a strong reduction in their Young's modulus, as compared to bulk gold, and a significant influence of strain on the electronic properties of the alkylthiolated NPs. Electron transport measurements of tiny molecular junctions (NP/alkylthiol/CAFM tip) show that the effective tunnelling barrier through the adsorbed monolayer strongly decreases by increasing the applied load, which translates in a remarkable and unprecedented increase in the tunnel current. These observations are successfully explained using simulations based on the finite element analysis (FEA) and first-principles calculations that permit one to consider the coupling between the mechanical response of the system and the electric dipole variations at the interface.
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Affiliation(s)
- K Smaali
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, Avenue Poincaré, 59652, Villeneuve d'Ascq, France.
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77
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Pace G, Caranzi L, Bucella SG, Canesi EV, Dell'Erba G, Bertarelli C, Caironi M. Electronic transport regimes through an alkoxythiolated diphenyl-2,2'-bithiophene-based molecular junction diodes: critical assessment of the thermal dependence. NANOSCALE 2015; 7:2076-2084. [PMID: 25559138 DOI: 10.1039/c4nr05142d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The detailed understanding of electronic transport through a single molecule or an ensemble of self-assembled molecules embedded between two metallic leads is still a matter of controversy. Multiple factors influence the charge transport in the molecular junction, with particular attention to be given to the band states of the electrodes, molecular orbital energies, bias potential and importantly molecule-electrode electronic coupling. Moreover it is not trivial to disentangle molecular contributions from other possible conduction pathways directly coupling the opposite electrodes. We here investigate the electronic transport properties of an ensemble molecular junction embedding an alkylthiol derivative of a diphenol substituted bithiophene (DPBT) by means of current vs. voltage and temperature dependent measurements. We explored different junction configurations using: micropores (Au//DPBT//Au and Au//DPBT-polymer conductor//Au) and conductive-atomic force microscopy (c-AFM). In all cases, we found a transition voltage V(T) of ∼0.35 V. The consistent presence of a similar V(T) in all the tested configurations is a strong, but not conclusive, indication of a molecular signature in the charge transport, which we assessed and confirmed by temperature dependent measurements. We found a transition from an incoherent resonant tunneling at low biases and close to room temperature, where transport is thermally activated with an activation energy of ∼85 meV, to a coherent tunneling at voltages higher than V(T). Unlike many other molecular junctions reported in the literature, resonant conditions commonly attributed to a hopping transport regime can be found already at room temperature and very low biases for a molecule only ∼1.5 nm long. This paper is the first report to clearly show temperature activated transport through a short and not fully conjugated molecule. Moreover, we could clearly identify a regime at low temperatures and low bias where the transport mechanism is controlled by the thermal conductivity of the metal electrodes rather than the molecule.
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Affiliation(s)
- Giuseppina Pace
- Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
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78
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Caranzi L, Pace G, Guarnera S, Canesi EV, Brambilla L, Raavi SSK, Petrozza A, Caironi M. Photoactive molecular junctions based on self-assembled monolayers of indoline dyes. ACS APPLIED MATERIALS & INTERFACES 2014; 6:19774-82. [PMID: 25365534 DOI: 10.1021/am5049465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We demonstrate the feasibility of a photodetector based on an ensemble molecular junction, where a self-assembled monolayer of an organic donor-acceptor dye is directly sandwiched between two electrodes. In such a device, upon photoexcitation and generation of a charge-transfer state on the molecule, charges are dissociated and directly collected at the electrodes without the need of transport through a bulk phase, as in usual photodetectors. We show that the device can work in photovoltaic regime and the spectral response can be tuned by varying the light absorbing dye. Therefore, the electro-optical properties of the downscaled device can be unambiguously related to the physical-chemical properties of the molecules, a commonly difficult point to demonstrate in a molecular junction device, because of the uncertainties of the interplay between molecules and electrodes. The proposed device, which relies on a simple self-assembly process, has a strong potentiality for fast responding, downscaled detectors, ultimately limited by charge dissociation dynamics, and can be considered also as a useful tool to investigate fundamental electro-optical processes in molecular monolayers.
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Affiliation(s)
- Lorenzo Caranzi
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia , Via Pascoli 70/3, 20133 Milano, Italy
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79
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Diebold RM, Gordon MJ, Clarke DR. Effect of silane coupling agent chemistry on electrical breakdown across hybrid organic-inorganic insulating films. ACS APPLIED MATERIALS & INTERFACES 2014; 6:11932-11939. [PMID: 25010384 DOI: 10.1021/am504305k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dielectric breakdown measurements were conducted on self-assembled monolayer (SAM)/native silicon oxide hybrid dielectrics using conductive atomic force microscopy (C-AFM). By depositing silane coupling agents (SCAs) through a diffusional barrier layer, SAM roughness was decoupled from chemistry to compare the chemical effects of exposed R-group functionality on dielectric breakdown. Using Weibull and current-voltage (I-V) analysis, the breakdown strength was observed to be independent of SCA R-group length, and the addition of a SAM was seen to improve the breakdown strength relative to native silicon oxide by up to 158%. Fluorinated SCAs were observed to suppress tunneling leakage and exhibited increased breakdown strength relative to their hydrocarbon analogs. Electron trapping, scattering, or attachment processes inherent to the fluorinated moieties are thought to be the origin of the improved breakdown properties.
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Affiliation(s)
- Roger M Diebold
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
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80
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Alfonta L, Meckes B, Amir L, Schlesinger O, Ramachandran S, Lal R. Measuring localized redox enzyme electron transfer in a live cell with conducting atomic force microscopy. Anal Chem 2014; 86:7674-80. [PMID: 24979064 PMCID: PMC4215851 DOI: 10.1021/ac5015645] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bacterial systems are being extensively studied and modified for energy, sensors, and industrial chemistry; yet, their molecular scale structure and activity are poorly understood. Designing efficient bioengineered bacteria requires cellular understanding of enzyme expression and activity. An atomic force microscope (AFM) was modified to detect and analyze the activity of redox active enzymes expressed on the surface of E. coli. An insulated gold-coated metal microwire with only the tip conducting was used as an AFM cantilever and a working electrode in a three-electrode electrochemical cell. Bacteria were engineered such that alcohol dehydrogenase II (ADHII) was surface displayed. A quinone, an electron transfer mediator, was covalently attached site specifically to the displayed ADHII. The AFM probe was used to lift a single bacterium off the surface for electrochemical analysis in a redox-free buffer. An electrochemical comparison between two quinone containing mutants with different distances from the NAD(+) binding site in alcohol dehydrogenase II was performed. Electron transfer in redox active proteins showed increased efficiency when mediators are present closer to the NAD(+) binding site. This study suggests that an integrated conducting AFM used for single cell electrochemical analysis would allow detailed understanding of enzyme electron transfer processes to electrodes, the processes integral to creating efficiently engineered biosensors and biofuel cells.
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Affiliation(s)
- Lital Alfonta
- Department of Life Sciences, ‡Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , P.O. Box 653, Beer-Sheva, 84105, Israel
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81
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Bowers CM, Liao KC, Yoon HJ, Rappoport D, Baghbanzadeh M, Simeone FC, Whitesides GM. Introducing ionic and/or hydrogen bonds into the SAM//Ga2O3 top-interface of Ag(TS)/S(CH2)nT//Ga2O3/EGaIn junctions. NANO LETTERS 2014; 14:3521-3526. [PMID: 24840009 DOI: 10.1021/nl501126e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Junctions with the structure Ag(TS)/S(CH2)nT//Ga2O3/EGaIn (where S(CH2)nT is a self-assembled monolayer, SAM, of n-alkanethiolate bearing a terminal functional group T) make it possible to examine the response of rates of charge transport by tunneling to changes in the strength of the interaction between T and Ga2O3. Introducing a series of Lewis acidic/basic functional groups (T = -OH, -SH, -CO2H, -CONH2, and -PO3H) at the terminus of the SAM gave values for the tunneling current density, J(V) in A/cm(2), that were indistinguishable (i.e., differed by less than a factor of 3) from the values observed with n-alkanethiolates of equivalent length. The insensitivity of the rate of tunneling to changes in the terminal functional group implies that replacing weak van der Waals contact interactions with stronger hydrogen- or ionic bonds at the T//Ga2O3 interface does not change the shape (i.e., the height or width) of the tunneling barrier enough to affect rates of charge transport. A comparison of the injection current, J0, for T = -CO2H, and T = -CH2CH3--two groups having similar extended lengths (in Å, or in numbers of non-hydrogen atoms)--suggests that both groups make indistinguishable contributions to the height of the tunneling barrier.
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Affiliation(s)
- Carleen M Bowers
- Department of Chemistry and Chemical Biology, Harvard University , 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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82
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Fokin AA, Yurchenko RI, Tkachenko BA, Fokina NA, Gunawan MA, Poinsot D, Dahl JEP, Carlson RMK, Serafin M, Cattey H, Hierso JC, Schreiner PR. Selective Preparation of Diamondoid Phosphonates. J Org Chem 2014; 79:5369-73. [DOI: 10.1021/jo500793m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Andrey A. Fokin
- Department
of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine
| | - Raisa I. Yurchenko
- Department
of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine
| | | | | | - Maria A. Gunawan
- Institut
de Chimie Moléculaire de l’Université de Bourgogne
(ICMUB), UMR CNRS 6302, Université de Bourgogne, 9 avenue
Alain Savary, 21078 cedex, Dijon, France
| | - Didier Poinsot
- Institut
de Chimie Moléculaire de l’Université de Bourgogne
(ICMUB), UMR CNRS 6302, Université de Bourgogne, 9 avenue
Alain Savary, 21078 cedex, Dijon, France
| | - Jeremy E. P. Dahl
- Stanford Institute for Materials & Energy Science, Stanford University, 476 Lomita Mall, Stanford, California 94305, United States
| | - Robert M. K. Carlson
- Stanford Institute for Materials & Energy Science, Stanford University, 476 Lomita Mall, Stanford, California 94305, United States
| | | | - Hélène Cattey
- Institut
de Chimie Moléculaire de l’Université de Bourgogne
(ICMUB), UMR CNRS 6302, Université de Bourgogne, 9 avenue
Alain Savary, 21078 cedex, Dijon, France
| | - Jean-Cyrille Hierso
- Institut
de Chimie Moléculaire de l’Université de Bourgogne
(ICMUB), UMR CNRS 6302, Université de Bourgogne, 9 avenue
Alain Savary, 21078 cedex, Dijon, France
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83
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Hu J, Tanabe M, Sato J, Uosaki K, Ikeda K. Effects of Atomic Geometry and Electronic Structure of Platinum Surfaces on Molecular Adsorbates Studied by Gap-Mode SERS. J Am Chem Soc 2014; 136:10299-307. [DOI: 10.1021/ja502008t] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jian Hu
- Division
of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Masahiro Tanabe
- Division
of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Jun Sato
- Division
of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | | | - Katsuyoshi Ikeda
- Division
of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
- Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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84
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Zhang Y, Zhao Z, Fracasso D, Chiechi RC. Bottom-Up Molecular Tunneling Junctions Formed by Self-Assembly. Isr J Chem 2014. [DOI: 10.1002/ijch.201400033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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85
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Kleijn SEF, Lai SCS, Koper MTM, Unwin PR. Electrochemistry of Nanoparticles. Angew Chem Int Ed Engl 2014; 53:3558-86. [DOI: 10.1002/anie.201306828] [Citation(s) in RCA: 304] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Indexed: 01/01/2023]
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86
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87
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Abstract
Electrons have so little mass that in less than a second they can tunnel through potential energy barriers that are several electron-volts high and several nanometers wide. Electron tunneling is a critical functional element in a broad spectrum of applications, ranging from semiconductor diodes to the photosynthetic and respiratory charge transport chains. Prior to the 1970s, chemists generally believed that reactants had to collide in order to effect a transformation. Experimental demonstrations that electrons can transfer between reactants separated by several nanometers led to a revision of the chemical reaction paradigm. Experimental investigations of electron exchange between redox partners separated by molecular bridges have elucidated many fundamental properties of these reactions, particularly the variation of rate constants with distance. Theoretical work has provided critical insights into the superexchange mechanism of electronic coupling between distant redox centers. Kinetics measurements have shown that electrons can tunnel about 2.5 nm through proteins on biologically relevant time scales. Longer-distance biological charge flow requires multiple electron tunneling steps through chains of redox cofactors. The range of phenomena that depends on long-range electron tunneling continues to expand, providing new challenges for both theory and experiment.
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Affiliation(s)
- Jay R. Winkler
- Beckman Institute, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Harry B. Gray
- Beckman Institute, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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88
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Arielly R, Vadai M, Kardash D, Noy G, Selzer Y. Real-Time Detection of Redox Events in Molecular Junctions. J Am Chem Soc 2014; 136:2674-80. [DOI: 10.1021/ja412668f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Rani Arielly
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Michal Vadai
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dina Kardash
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gilad Noy
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yoram Selzer
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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89
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Valkenier H, Guédon CM, Markussen T, Thygesen KS, van der Molen SJ, Hummelen JC. Cross-conjugation and quantum interference: a general correlation? Phys Chem Chem Phys 2014; 16:653-62. [DOI: 10.1039/c3cp53866d] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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90
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He Z, Phan H, Liu J, Nguyen TQ, Tan TTY. Understanding TiO(2) size-dependent electron transport properties of a graphene-TiO(2) photoanode in dye-sensitized solar cells using conducting atomic force microscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:6900-6904. [PMID: 24114931 DOI: 10.1002/adma.201303327] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/09/2013] [Indexed: 06/02/2023]
Abstract
Conducting AFM reveals a continuous conduction network of a TiO2 -graphene composite in DSSC due to a more intimate contact between the smaller sized TiO2 -graphene composite nanosheets,which reduces the internal resistance at TiO2 /TiO2 and TiO2 /FTO interfaces and ultimately leads to a faster and more efficient electron transport in the photoanode.
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Affiliation(s)
- Ziming He
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore
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91
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Mei J, Diao Y, Appleton AL, Fang L, Bao Z. Integrated Materials Design of Organic Semiconductors for Field-Effect Transistors. J Am Chem Soc 2013; 135:6724-46. [DOI: 10.1021/ja400881n] [Citation(s) in RCA: 1165] [Impact Index Per Article: 105.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Jianguo Mei
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Ying Diao
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Anthony L. Appleton
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Lei Fang
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Zhenan Bao
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
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92
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Pobelov IV, Mohos M, Yoshida K, Kolivoska V, Avdic A, Lugstein A, Bertagnolli E, Leonhardt K, Denuault G, Gollas B, Wandlowski T. Electrochemical current-sensing atomic force microscopy in conductive solutions. NANOTECHNOLOGY 2013; 24:115501. [PMID: 23448801 DOI: 10.1088/0957-4484/24/11/115501] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Insulated atomic force microscopy probes carrying gold conductive tips were fabricated and employed as bifunctional force and current sensors in electrolyte solutions under electrochemical potential control. The application of the probes for current-sensing imaging, force and current-distance spectroscopy as well as scanning electrochemical microscopy experiments was demonstrated.
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Affiliation(s)
- Ilya V Pobelov
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
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93
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Vilan A, Cahen D, Kraisler E. Rethinking transition voltage spectroscopy within a generic Taylor expansion view. ACS NANO 2013; 7:695-706. [PMID: 23236949 DOI: 10.1021/nn3049686] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Transition voltage spectroscopy (TVS) has become an accepted quantification tool for molecular transport characteristics, due to its simplicity and reproducibility. Alternatively, the Taylor expansion view, TyEx, of transport by tunneling suggests that conductance-voltage curves have approximately a generic parabolic shape, regardless of whether the tunneling model is derived from an average medium view (e.g., WKB) or from a scattering view (e.g., Landauer). Comparing TVS and TyEx approaches reveals that TVS is closely related to a bias-scaling factor, V(0), which is directly derived from the third coefficient of TyEx, namely, the second derivative of the conductance with respect to bias at 0 V. This interpretation of TVS leads to simple expressions that can be compared easily across primarily different tunneling models. Because the basic curve shape is mostly generic, the quality of model fitting is not informative on the actual tunneling model. However internal correlation between the conductance near 0 V and V(0) (TVS) provides genuine indication on fundamental tunneling features. Furthermore, we show that the prevailing concept that V(0) is proportional to the barrier height holds only in the case of resonant tunneling, while for off-resonant or deep tunneling, V(0) is proportional to the ratio of barrier height to barrier width. Finally, considering TVS as a measure of conductance nonlinearity, rather than as an indicator for energy level spectroscopy, explains the very low TVS values observed with a semiconducting (instead of metal) electrode, where transport is highly nonlinear due to the relatively small, bias-dependent density of states of the semiconducting electrode.
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Affiliation(s)
- Ayelet Vilan
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel.
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94
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Sek S. Review peptides and proteins wired into the electrical circuits: An SPM-based approach. Biopolymers 2013; 100:71-81. [DOI: 10.1002/bip.22148] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/26/2012] [Accepted: 08/08/2012] [Indexed: 12/30/2022]
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95
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Kim CM, Bechhoefer J. Conductive probe AFM study of Pt-thiol and Au-thiol contacts in metal-molecule-metal systems. J Chem Phys 2013; 138:014707. [DOI: 10.1063/1.4773436] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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96
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Li W, Sepunaru L, Amdursky N, Cohen SR, Pecht I, Sheves M, Cahen D. Temperature and force dependence of nanoscale electron transport via the Cu protein azurin. ACS NANO 2012; 6:10816-10824. [PMID: 23136937 DOI: 10.1021/nn3041705] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Solid-state electron transport (ETp) via a monolayer of immobilized azurin (Az) was examined by conducting probe atomic force microscopy (CP-AFM), as a function of both temperature (248-373K) and applied tip force (6-15 nN). At low forces, ETp via holo-Az (with Cu(2+)) is temperature-independent, but thermally activated via the Cu-depleted form of Az, apo-Az. While this observation agrees with those of macroscopic-scale measurements, we find that for holo-Az the mechanism of ETp at high temperatures changes upon an increase in the force applied by the tip to the proteins; namely, above 310 K and forces >6 nN ETp becomes thermally activated. This is in contrast to apo-Az, where increasing applied force causes only small monotonic increases in currents due to decreased electrode separation. The distinct ETp temperature dependence of holo- and apo-Az is assigned to a difference in structural response to pressure between the two protein forms. An important implication of these CP-AFM results (of measurements over a significant temperature range) is that for reliable ETp measurements on flexible macromolecules, such as proteins, the pressure applied during the measurements should be controlled or at least monitored.
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Affiliation(s)
- Wenjie Li
- Department of Materials & Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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97
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Rakshit T, Mukhopadhyay R. Solid-state electron transport in Mn-, Co-, holo-, and Cu-ferritins: Force-induced modulation is inversely linked to the protein conductivity. J Colloid Interface Sci 2012; 388:282-92. [DOI: 10.1016/j.jcis.2012.08.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/02/2012] [Accepted: 08/14/2012] [Indexed: 10/28/2022]
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98
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MacDonald GA, Veneman PA, Placencia D, Armstrong NR. Electrical property heterogeneity at transparent conductive oxide/organic semiconductor interfaces: mapping contact ohmicity using conducting-tip atomic force microscopy. ACS NANO 2012; 6:9623-9636. [PMID: 23030667 DOI: 10.1021/nn303043y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We demonstrate mapping of electrical properties of heterojunctions of a molecular semiconductor (copper phthalocyanine, CuPc) and a transparent conducting oxide (indium-tin oxide, ITO), on 20-500 nm length scales, using a conductive-probe atomic force microscopy technique, scanning current spectroscopy (SCS). SCS maps are generated for CuPc/ITO heterojunctions as a function of ITO activation procedures and modification with variable chain length alkyl-phosphonic acids (PAs). We correlate differences in small length scale electrical properties with the performance of organic photovoltaic cells (OPVs) based on CuPc/C(60) heterojunctions, built on these same ITO substrates. SCS maps the "ohmicity" of ITO/CuPc heterojunctions, creating arrays of spatially resolved current-voltage (J-V) curves. Each J-V curve is fit with modified Mott-Gurney expressions, mapping a fitted exponent (γ), where deviations from γ = 2.0 suggest nonohmic behavior. ITO/CuPc/C(60)/BCP/Al OPVs built on nonactivated ITO show mainly nonohmic SCS maps and dark J-V curves with increased series resistance (R(S)), lowered fill-factors (FF), and diminished device performance, especially near the open-circuit voltage. Nearly optimal behavior is seen for OPVs built on oxygen-plasma-treated ITO contacts, which showed SCS maps comparable to heterojunctions of CuPc on clean Au. For ITO electrodes modified with PAs there is a strong correlation between PA chain length and the degree of ohmicity and uniformity of electrical response in ITO/CuPc heterojunctions. ITO electrodes modified with 6-8 carbon alkyl-PAs show uniform and nearly ohmic SCS maps, coupled with acceptable CuPc/C(60)OPV performance. ITO modified with C14 and C18 alkyl-PAs shows dramatic decreases in FF, increases in R(S), and greatly enhanced recombination losses.
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Affiliation(s)
- Gordon A MacDonald
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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99
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Sek S, Breczko J, Plonska-Brzezinska ME, Wilczewska AZ, Echegoyen L. STM-based molecular junction of carbon nano-onion. Chemphyschem 2012; 14:96-100. [PMID: 23129103 DOI: 10.1002/cphc.201200624] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Indexed: 11/11/2022]
Affiliation(s)
- Slawomir Sek
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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100
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Synthesis of one-molecule-thick single-crystalline nanosheets of energetic material for high-sensitive force sensor. Sci Rep 2012; 2:698. [PMID: 23019519 PMCID: PMC3458245 DOI: 10.1038/srep00698] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/03/2012] [Indexed: 11/08/2022] Open
Abstract
Energetic material is a reactive substance that contains a great amount of potential energy, which is extremely sensitive to external stimuli like force. In this work, one-molecule-thick single-crystalline nanosheets of energetic material were synthesized. Very small force applied on the nanosheet proves to lead to the rotation of the tilted nitro groups, and subsequently change of current of the nanosheet. We apply this principle to design high-sensitive force sensor. A theoretical model of force-current dependence was established based on the nanosheets' molecular packing structure model that was well supported with the high resolution XPS, AFM analysis results. An ultra-low-force with range of several picoNewton to several nanoNewton can be measured by determination of corresponding current value.
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