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Wang X, Lamantia A, Jay M, Sadeghi H, Lambert CJ, Kolosov OV, Robinson BJ. Determination of electric and thermoelectric properties of molecular junctions by AFM in peak force tapping mode. NANOTECHNOLOGY 2023; 34:385704. [PMID: 37336192 DOI: 10.1088/1361-6528/acdf67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/19/2023] [Indexed: 06/21/2023]
Abstract
Molecular thin films, such as self-assembled monolayers (SAMs), offer the possibility of translating the optimised thermophysical and electrical properties of high-Seebeck-coefficient single molecules to scalable device architectures. However, for many scanning probe-based approaches attempting to characterise such SAMs, there remains a significant challenge in recovering single-molecule equivalent values from large-area films due to the intrinsic uncertainty of the probe-sample contact area coupled with film damage caused by contact forces. Here we report a new reproducible non-destructive method for probing the electrical and thermoelectric (TE) properties of small assemblies (10-103) of thiol-terminated molecules arranged within a SAM on a gold surface, and demonstrate the successful and reproducible measurements of the equivalent single-molecule electrical conductivity and Seebeck values. We have used a modified thermal-electric force microscopy approach, which integrates the conductive-probe atomic force microscope, a sample positioned on a temperature-controlled heater, and a probe-sample peak-force feedback that interactively limits the normal force across the molecular junctions. The experimental results are interpreted by density functional theory calculations allowing quantification the electrical quantum transport properties of both single molecules and small clusters of molecules. Significantly, this approach effectively eliminates lateral forces between probe and sample, minimising disruption to the SAM while enabling simultaneous mapping of the SAMs nanomechanical properties, as well as electrical and/or TE response, thereby allowing correlation of the film properties.
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Affiliation(s)
- Xintai Wang
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
- School of Information Science and Technology, Dalian Maritime University, Dalian, 116026, People's Republic of China
| | - Angelo Lamantia
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Michael Jay
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Hatef Sadeghi
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Oleg V Kolosov
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Benjamin J Robinson
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
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Küllmer M, Endres P, Götz S, Winter A, Schubert US, Turchanin A. Solution-Based Self-Assembly and Stability of Ruthenium(II) Tris-bipyridyl Monolayers on Gold. ACS APPLIED MATERIALS & INTERFACES 2021; 13:60544-60552. [PMID: 34878243 DOI: 10.1021/acsami.1c10989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ruthenium(II) polypyridyl complexes are commonly applied as photosensitizers in the fields of artificial photosynthesis and light harvesting. Their immobilization on gold surfaces is also of interest for sensing and biological applications. Here, we report the self-assembly of [Ru(dmbpy)2(dcbpy)](PF6)2 complexes on gold substrates from solution (dmbpy: 4,4'-dimethyl-2,2'-bipyridine; dcbpy: 2,2'-bipyridine-4,4'-dicarboxylic acid). Applying X-ray photoelectron spectroscopy, we demonstrate the formation of self-assembled monolayers (SAMs) of the Ru(II) complexes upon loss of counterions with carboxylate groups oriented toward the gold surface. We investigate the stability of the formed SAMs toward the substitution in solvents with competing aliphatic and aromatic thiols such as 4'-nitro[1,1'-biphenyl]-4-thiol, [1,1'-biphenyl]-4-thiol, and 1-hexadecanethiol. We show that the exchange reactions may lead to both complete replacement of the Ru(II) complexes and controlled formation of mixed SAMs. Moreover, we demonstrate that thiol-based SAMs can also be replaced completely from gold via their immersion into solutions of [Ru(dmbpy)2(dcbpy)](PF6)2, indicating a relatively high stability for the Ru(II) complex SAMs. Our findings open up a variety of opportunities for applications of carboxylate-based SAMs on gold in nanotechnology.
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Affiliation(s)
- Maria Küllmer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Patrick Endres
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Stefan Götz
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Andreas Winter
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Ulrich S Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, 07743 Jena, Germany
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Tang Z, Chulanova E, Küllmer M, Winter A, Picker J, Neumann C, Schreyer K, Herrmann-Westendorf F, Arnlind A, Dietzek B, Schubert US, Turchanin A. Photoactive ultrathin molecular nanosheets with reversible lanthanide binding terpyridine centers. NANOSCALE 2021; 13:20583-20591. [PMID: 34874038 DOI: 10.1039/d1nr05430a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In recent years, functional molecular nanosheets have attracted much attention in the fields of sensors and energy storage. Here, we present an approach for the synthesis of photoactive metal-organic nanosheets with ultimate molecular thickness. To this end, we apply low-energy electron irradiation induced cross-linking of 4'-(2,2':6',2''-terpyridine-4'-yl)-1,1'-biphenyl-4-thiol self-assembled monolayers on gold to convert them into functional ∼1 nm thick carbon nanomembranes possessing the ability to reversibly complex lanthanide ions (Ln-CNMs). The obtained Ln-CNMs can be prepared on a large-scale (>10 cm2) and inherit the photoactivity of the pristine terpyridine lanthanide complex (Ln(III)-tpy). Moreover, they possess mechanical stability as free-standing sheets over micrometer sized openings. The presented methodology paves a simple and robust way for the preparation of ultrathin nanosheets with tailored photoactive properties for application in photocatalytic and energy conversion devices.
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Affiliation(s)
- Zian Tang
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
| | - Elena Chulanova
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
- Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Maria Küllmer
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
| | - Andreas Winter
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Philosophenweg 7a, 07743 Jena, Germany
| | - Julian Picker
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
| | - Christof Neumann
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
| | - Kristin Schreyer
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Philosophenweg 7a, 07743 Jena, Germany
| | - Felix Herrmann-Westendorf
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
- Leibniz Institute of Photonic Technology, Research Department Functional Interfaces, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Andreas Arnlind
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
| | - Benjamin Dietzek
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Philosophenweg 7a, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology, Research Department Functional Interfaces, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Ulrich S Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Philosophenweg 7a, 07743 Jena, Germany
| | - Andrey Turchanin
- Institute of Physical Chemistry (IPC), Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany.
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Philosophenweg 7a, 07743 Jena, Germany
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Olejnik B, Kozioł A, Brzozowska E, Ferens-Sieczkowska M. Application of selected biosensor techniques in clinical diagnostics. Expert Rev Mol Diagn 2021; 21:925-937. [PMID: 34289786 DOI: 10.1080/14737159.2021.1957833] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Examination of disease biomarkers mostly performed on crude materials, such as serum, meets some obstacles, resulting from sample complexity and the wide range of concentrations and sizes of the components. Techniques currently used in clinical diagnostics are usually time-consuming and expensive. The more sensitive and portable devices are needed for early diagnostics. Chemical sensors are devices that convert chemical information into parameters suitable for fast and precise processing and measurement. AREA COVERED We review the use of biosensors and their possible application in early diagnostics of some diseases like cancer or viral infections. We focus on different types of biorecognition and some technical modifications, lowering the limit of detection potentially attractive to medical practitioners. EXPERT OPINION Among the new diagnostic strategies, the use of biosensors is of increasing interest. In these techniques, the capture ligand interacts with the analyte of interest. Measuring interactions between partners in real time by surface plasmon resonance yields valuable information about kinetics and affinity in a short time and without labels. Importantly, the tendency in such techniques is to make biosensor devices smaller and the test results apparent with the naked eye, so they can be used in point-of-care medicine.
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Affiliation(s)
- Beata Olejnik
- Department of Chemistry and Immunochemistry, Medical University of Wroclaw, Wrocław, Poland
| | - Agata Kozioł
- Department of Chemistry and Immunochemistry, Medical University of Wroclaw, Wrocław, Poland
| | - Ewa Brzozowska
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Laboratory of Medical Microbiology, Wrocław, Poland
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Riedel R, Frese N, Yang F, Wortmann M, Dalpke R, Rhinow D, Hampp N, Gölzhäuser A. Fusion of purple membranes triggered by immobilization on carbon nanomembranes. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:93-101. [PMID: 33564606 PMCID: PMC7849249 DOI: 10.3762/bjnano.12.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
A freestanding ultrathin hybrid membrane was synthesized comprising two functional layers, that is, first, a carbon nanomembrane (CNM) produced by electron irradiation-induced cross-linking of a self-assembled monolayer (SAM) of 4'-nitro-1,1'-biphenyl-4-thiol (NBPT) and second, purple membrane (PM) containing genetically modified bacteriorhodopsin (BR) carrying a C-terminal His-tag. The NBPT-CNM was further modified to carry nitrilotriacetic acid (NTA) terminal groups for the interaction with the His-tagged PMs forming a quasi-monolayer of His-tagged PM on top of the CNM-NTA. The formation of the Ni-NTA/His-tag complex leads to the unidirectional orientation of PM on the CNM substrate. Electrophoretic sedimentation was employed to optimize the surface coverage and to close gaps between the PM patches. This procedure for the immobilization of oriented dense PM facilitates the spontaneous fusion of individual PM patches, forming larger membrane areas. This is, to our knowledge, the very first procedure described to induce the oriented fusion of PM on a solid support. The resulting hybrid membrane has a potential application as a light-driven two-dimensional proton-pumping membrane, for instance, for light-driven seawater desalination as envisioned soon after the discovery of PM.
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Affiliation(s)
- René Riedel
- Faculty of Chemistry and Materials Sciences Center, University of Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
| | - Natalie Frese
- Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Fang Yang
- Nano Biomaterials Group, Ningbo Institute of Industrial Technology, Chinese Academy of Science, China
| | - Martin Wortmann
- Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Interaktion 1, D-33619 Bielefeld, Germany
| | - Raphael Dalpke
- Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Daniel Rhinow
- Faculty of Chemistry and Materials Sciences Center, University of Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
- Max Planck Institute of Biophysics, Department of Structural Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt, Germany
| | - Norbert Hampp
- Faculty of Chemistry and Materials Sciences Center, University of Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
| | - Armin Gölzhäuser
- Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Universitätsstraße 25, D-33615 Bielefeld, Germany
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Kankate L, Hamann T, Li S, Moskaleva LV, Gölzhäuser A, Turchanin A, Swiderek P. Tracking down the origin of peculiar vibrational spectra of aromatic self-assembled thiolate monolayers. Phys Chem Chem Phys 2018; 20:29918-29930. [PMID: 30475374 DOI: 10.1039/c8cp03651a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Several studies have previously observed surprisingly low frequencies for the C-H stretching modes of self-assembled monolayers (SAMs) prepared from aromatic thiols. The reason for this property has so far remained elusive. Therefore, we report a novel study of the vibrational spectra of SAMs prepared on Au from two different aromatic thiols, namely, 4'-nitro-1,1'-biphenyl-4-thiol (NBPT) and 4-aminothiophenol (ATP). The SAMs were prepared by vapor deposition (VD) in ultrahigh vacuum (UHV) as well as by the solution method (SM) and their quality was controlled by X-ray photoelectron spectroscopy (XPS). In addition, amino terminated SAMs were also obtained by electron irradiation and by chemical reduction of NBPT SAMs. Beside infrared reflection absorption spectroscopy (IRRAS), we have employed high resolution electron energy loss spectroscopy (HREELS), by which VD SAMs can be studied in situ, i.e. without exposing them to air. Hence, we can exclude possible contributions of solvent molecules to the vibrational spectra. Nonetheless, HREELS in fact reveals the same large red shift of the C-H stretching modes in the SAMs as also observed in ex situ IRRAS experiments. In contrast, HREELS for physisorbed ATP and ATP in a KBr pellet measured by transmission infrared spectroscopy exhibit the expected aromatic bands. Using a computational approach, we can exclude molecular packing effects as origin of this shift. Therefore, we propose chemical changes in the aromatic rings during SAM formation as an alternative explanation for the observed frequency shift. As another striking effect, the N-H stretching vibrational modes of the amino-terminated SAMs are extremely weak in both IRRAS and HREELS despite the fact that XPS confirms the presence of amino groups. A very weak signal is observed only in the case of an electron irradiated NBPT SAM. In contrast, an energy loss ascribed to the N-H stretching vibrations is clearly observed in HREELS of ATP physisorbed on an ATP SAM and on graphite as well as in the transmission infrared spectrum of ATP in KBr. The extremely low intensity of these vibrations in the SAM is traced back to the inherently low transition dipole moment for the excitation of N-H stretching modes in free N-H groups. Furthermore, the calculations suggest that the much stronger signals of N-H stretching modes involved in hydrogen-bonding with adjacent amino groups are suppressed because these vibrations are oriented parallel to the surface.
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Affiliation(s)
- Laxman Kankate
- University of Bremen, Faculty 2 (Chemistry/Biology), Institute of Applied and Physical Chemistry, Leobener Straße 5 (NW2), Postfach 330440, 28334 Bremen, Germany.
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7
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Koch S, Kaiser CD, Penner P, Barclay M, Frommeyer L, Emmrich D, Stohmann P, Abu-Husein T, Terfort A, Fairbrother DH, Ingólfsson O, Gölzhäuser A. Amplified cross-linking efficiency of self-assembled monolayers through targeted dissociative electron attachment for the production of carbon nanomembranes. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2562-2571. [PMID: 29259871 PMCID: PMC5727824 DOI: 10.3762/bjnano.8.256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
The determination of the negative ion yield of 2'-chloro-1,1'-biphenyl (2-Cl-BP), 2'-bromo-1,1'-biphenyl (2-Br-BP) and 2'-iodo-1,1'-biphenyl (2-I-BP) upon dissociative electron attachment (DEA) at an electron energy of 0 eV revealed cross section values that were more than ten times higher for iodide loss from 2-I-BP than for the other halogenides from the respective biphenyls (BPs). Comparison with dissociative ionization mass spectra shows that the ratio of the efficiency of electron impact ionization induced fragmentation of 2-I-BP, 2-Br-BP, and 2-Cl-BP amounts to approximately 1:0.7:0.6. Inspired by these results, self-assembled monolayers (SAMs) of the respective biphenyl-4-thiols, 2-Cl-BPT, 2-Br-BPT, 2-I-BPT as well as BPT, were grown on a Au(111) substrate and exposed to 50 eV electrons. The effect of electron irradiation was investigated by X-ray photoelectron spectroscopy (XPS), to determine whether the high relative DEA cross section for iodide loss from 2-I-BPT as compared to 2-Br-BP and 2-Cl-BP is reflected in the cross-linking efficiency of SAMs made from these materials. Such sensitization could reduce the electron dose needed for the cross-linking process and may thus lead to a significantly faster conversion of the respective SAMs into carbon nanomembranes (CNMs) without the need for an increased current density. XPS data support the notation that DEA sensitization may be used to achieve more efficient electron-induced cross-linking of SAMs, revealing more than ten times faster cross-linking of 2-I-BPT SAMs compared to those made from the other halogenated biphenyls or from native BPT at the same current density. Furthermore, the transfer of a freestanding membrane onto a TEM grid and the subsequent investigation by helium ion microscopy (HIM) verified the existence of a mechanically stable CNM created from 2-I-BPT after exposure to an electron dose as low as 1.8 mC/cm2. In contrast, SAMs made from BPT, 2-Cl-BPT and 2-Br-BPT did not form stable CNMs after a significantly higher electron dose of 9 mC/cm2.
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Affiliation(s)
- Sascha Koch
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
| | - Christopher D Kaiser
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
| | - Paul Penner
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
| | - Michael Barclay
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Lena Frommeyer
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
| | - Daniel Emmrich
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
| | - Patrick Stohmann
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
| | - Tarek Abu-Husein
- Department of Chemistry, Institute of Inorganic and Analytical Chemistry, Goethe-University, 60438 Frankfurt, Germany
| | - Andreas Terfort
- Department of Chemistry, Institute of Inorganic and Analytical Chemistry, Goethe-University, 60438 Frankfurt, Germany
| | - D Howard Fairbrother
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Oddur Ingólfsson
- Department of Chemistry and Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavik, Iceland
| | - Armin Gölzhäuser
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33613 Bielefeld, Germany
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