1
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Kim M, Mangolini L. Using Surface-Enhanced Raman Spectroscopy to Probe Surface-Localized Nonthermal Plasma Activation. J Phys Chem Lett 2024; 15:4136-4141. [PMID: 38593364 PMCID: PMC11033932 DOI: 10.1021/acs.jpclett.4c00747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/01/2024] [Accepted: 04/04/2024] [Indexed: 04/11/2024]
Abstract
Low-temperature, nonthermal plasmas generate a complex environment even when operated in nonreactive gases. Plasma-produced species impinge on exposed surfaces, and their thermalization is highly localized at the surface. Here we present a Raman thermometry approach to quantifying the resulting degree of surface heating. A nanostructured silver substrate is used to enhance the Raman signal and make it easily distinguishable from the background radiation from the plasma. Phenyl phosphonic acid is used as a molecular probe. Even under moderate plasma power and density, we measure a significant degree of vibrational excitation for the phenyl group, corresponding to an increase in surface temperature of ∼80 °C at a plasma density of 2 × 1010 cm-3. This work confirms that surface-localized thermal effects can be quantified in low-temperature plasma processes. Their characterization is needed to improve our understanding of the plasma-induced activation of surface reactions, which is highly relevant for a broad range of plasma-driven processes.
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Affiliation(s)
- Minseok Kim
- Department
of Mechanical Engineering, University of
California, Riverside, Riverside, California 92521, United States
| | - Lorenzo Mangolini
- Department
of Mechanical Engineering, University of
California, Riverside, Riverside, California 92521, United States
- Materials
Science & Engineering Program, University
of California, Riverside, Riverside, California 92521, United States
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2
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Bölke S, Früh A, Trilling F, Forster M, Scherf U, Chassé T, Peisert H. Influence of Backbone Ladderization and Side Chain Variation on the Orientation of Diketopyrrolopyrrole-Based Donor-Acceptor Copolymers. Molecules 2023; 28:6435. [PMID: 37764211 PMCID: PMC10535938 DOI: 10.3390/molecules28186435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/29/2023] Open
Abstract
Ladder polymers with poly(diketopyrrolopyrrole) (DPP) moieties have recently attracted enormous interest for a large variety of opto-electronic applications. Since the rigidity of the backbone increases with ladderization, a strong influence on the self-organization of thin films is expected. We study the molecular orientation of DPP-based ladder polymers in about 50 nm thin films using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS). Exemplarily, for one polymer, the orientation in thicker films is qualitatively investigated by infrared spectroscopy in transmission. Further, this method allows us to rule out the effects of a possible azimuthal ordering, which would affect the analysis of the orientation by PM-IRRAS. For all polymers, the long axis of the polymer backbone is preferentially oriented parallel to the substrate surface, pointing to a high degree of ordering. It is suggested that the choice of the side chains might be a promising way to tune for face-on and edge-on orientations. The exemplarily performed investigation of interface properties on substrates with different work functions suggests that the choice of the side chains has a minor effect on the interfacial electronic interface structure.
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Affiliation(s)
- Sven Bölke
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany (A.F.)
| | - Andreas Früh
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany (A.F.)
| | - Florian Trilling
- Makromolekulare Chemie (buwMakro) und Wuppertal Center for Smart Materials and Systems (CM@S), Bergische Universität Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany (M.F.)
| | - Michael Forster
- Makromolekulare Chemie (buwMakro) und Wuppertal Center for Smart Materials and Systems (CM@S), Bergische Universität Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany (M.F.)
| | - Ullrich Scherf
- Makromolekulare Chemie (buwMakro) und Wuppertal Center for Smart Materials and Systems (CM@S), Bergische Universität Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany (M.F.)
| | - Thomas Chassé
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany (A.F.)
| | - Heiko Peisert
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany (A.F.)
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3
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Pattadar D, Arcidiacono A, Beery D, Hanson K, Saavedra SS. Molecular Orientation and Energy Transfer Dynamics of a Metal Oxide Bound Self-Assembled Trilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:10670-10679. [PMID: 37466635 DOI: 10.1021/acs.langmuir.3c01323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Self-assembly of molecular multilayers via metal ion linkages has become an important strategy for interfacial engineering of metalloid and metal oxide (MOx) substrates, with applications in numerous areas, including energy harvesting, catalysis, and chemical sensing. An important aspect for the rational design of these multilayers is knowledge of the molecular structure-function relationships. For example, in a multilayer composed of different chromophores in each layer, the molecular orientation of each layer, both relative to the adjacent layers and the substrate, influences the efficiency of vectorial energy and electron transfer. Here, we describe an approach using UV-vis attenuated total reflection (ATR) spectroscopy to determine the mean dipole tilt angle of chromophores in each layer in a metal ion-linked trilayer self-assembled on indium-tin oxide. To our knowledge, this is the first report demonstrating the measurement of the orientation of three different chromophores in a single assembly. The ATR approach allows the adsorption of each layer to be monitored in real-time, and any changes in the orientation of an underlying layer arising from the adsorption of an overlying layer can be detected. We also performed transient absorption spectroscopy to monitor interlayer energy transfer dynamics in order to relate structure to function. We found that near unity efficiency, sub-nanosecond energy transfer between the third and second layer was primarily dictated by the distance between the chromophores. Thus, in this case, the orientation had minimal impact at such proximity.
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Affiliation(s)
- Dhruba Pattadar
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Ashley Arcidiacono
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Drake Beery
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Kenneth Hanson
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - S Scott Saavedra
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, United States
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4
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Pattadar D, Zheng L, Robb AJ, Beery D, Yang W, Hanson K, Scott Saavedra S. Molecular Orientation of -PO 3H 2 and -COOH Functionalized Dyes on TiO 2, Al 2O 3, ZrO 2, and ITO: A Comparative Study. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:2705-2715. [PMID: 36908684 PMCID: PMC9996377 DOI: 10.1021/acs.jpcc.2c08632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Modification of transparent metal oxide (MOx) surfaces with organic monolayers is widely employed to tailor the properties of interfaces in organic electronic devices, and MOx substrates modified with light-absorbing chromophores are a key component of dye-sensitized solar cells (DSSCs). The effects of an organic modifier on the performance of a MOx-based device are frequently assessed by performing experiments on model monolayer|MOx interfaces, where an "inert" MOx (e.g., Al2O3) is used as a control for an "active" MOx (e.g., TiO2). An underlying assumption in these studies is that the structure of the MOx-monolayer complex is similar between different metal oxides. The validity of this assumption was examined in the present study. Using UV-Vis attenuated total reflection spectroscopy, we measured the mean dipole tilt angle of 4,4'-(anthracene-9,10-diyl)bis(4,1-phenylene)diphosphonic acid (A1P) adsorbed on indium tin oxide (ITO), TiO2, ZrO2, and Al2O3. When the surface roughness of the MOx substrate and the surface coverage (𝛤) of the A1P film were constant, the molecular orientation of A1P was the same on these substrates. The study was extended to 4,4'-(anthracene-9,10-diyl)bis(4,1-phenylene)dicarboxylic acid (A1C) adsorbed on the same group of MOx substrates. The mean tilt angle of A1C and A1P films on ITO was the same, which is likely due the intermolecular interactions resulting from the high and approximately equal 𝛤 of both films. Comparing A1C films at the same 𝛤 on TiO2 and Al2O3 having the same surface roughness, there was no difference in the mean tilt angle. MD simulations of A1C and A1P on TiO2 produced nearly identical tilt angle distributions, which supports the experimental findings. This study provides first experimental support for the assumption that the structure of the MOx-modifer film is the same on an "active" substrate vs. a "inert" control substrate.
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Affiliation(s)
- Dhruba Pattadar
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
| | - Lianqing Zheng
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA
| | - Alex J. Robb
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Drake Beery
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Wei Yang
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Kenneth Hanson
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - S. Scott Saavedra
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
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5
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Kajihara K, Takahashi D, Kobayashi H, Mandai T, Imai H, Kanamura K. Phenylphosphonate surface functionalisation of MgMn 2O 4 with 3D open-channel nanostructures for composite slurry-coated cathodes of rechargeable magnesium batteries operated at room temperature. RSC Adv 2021; 11:19076-19082. [PMID: 35478634 PMCID: PMC9033493 DOI: 10.1039/d1ra02598h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/19/2021] [Indexed: 12/13/2022] Open
Abstract
Spinel-type MgMn2O4, prepared by a propylene-oxide-driven sol–gel method, has a high surface area and structured bimodal macro- and mesopores, and exhibits good electrochemical properties as a cathode active material for rechargeable magnesium batteries. However, because of its hydrophilicity and significant water adsorption properties, macroscopic aggregates are formed in composite slurry-coated cathodes when 1-methyl-2-pyrrolidone (NMP) is used as a non-aqueous solvent. Functionalising the surface with phenylphosphonate groups was found to be an easy and effective technique to render the structured MgMn2O4 hydrophobic and suppress aggregate formation in NMP-based slurries. This surface functionalisation also reduced side reactions during charging, while maintaining the discharge capacity, and significantly improved the coulombic efficiency. Uniform slurry-coated cathodes with active material fractions as high as 93 wt% can be produced on Al foils by this technique employing carbon nanotubes as an electrically conductive support. A coin-type full cell consisting of this slurry-coated cathode and a magnesium alloy anode delivered an initial discharge capacity of ∼100 mA h g−1 at 25 °C. Phenylphosphonate functionalisation is an easy, highly effective strategy to fabricate slurry-coated nanostructured MgMn2O4 cathodes for rechargeable magnesium batteries at active material fractions up to 93 wt% for rechargeable magnesium batteries cycled at 25 °C.![]()
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Affiliation(s)
- Koichi Kajihara
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University 1-1 Minami-Osawa Hachioji Tokyo 192-0397 Japan
| | - Daisuke Takahashi
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University 1-1 Minami-Osawa Hachioji Tokyo 192-0397 Japan
| | - Hiroaki Kobayashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University 2-1-1 Katahira, Aoba-ku Sendai Miyagi 980-8577 Japan
| | - Toshihiko Mandai
- Center for Green Research on Energy and Environmental Materials, National Institute for Materials Science (NIMS) 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan
| | - Hiroaki Imai
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University 3-14-1 Hiyoshi, Kohoku-ku Yokohama Kanagawa 223-8522 Japan
| | - Kiyoshi Kanamura
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University 1-1 Minami-Osawa Hachioji Tokyo 192-0397 Japan
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6
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Zheng Y, Giordano AJ, Marder SR, Saavedra SS. Potential-Modulated Total Internal Reflection Fluorescence for Measurement of the Electron Transfer Kinetics of Submonolayers on Optically Transparent Electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6728-6735. [PMID: 32453577 DOI: 10.1021/acs.langmuir.0c00817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An electroreflectance method to determine the electron transfer rate constant of a film of redox-active chromophores immobilized on an optically transparent electrode when the surface coverage of the film is very low (<0.1 monolayer) is described herein. The method, potential-modulated total internal reflection fluorescence (PM-TIRF) spectroscopy, is a fluorescence version of potential-modulated attenuated total reflection (PM-ATR) spectroscopy that is applicable when the immobilized chromophores are luminescent. The method was tested using perylene diimide (PDI) molecules functionalized with p-phenylene phosphonic acid (PA) moieties that bind strongly to indium-tin oxide (ITO). Conditions to prepare PDI-phenyl-PA films that exhibit absorbance and fluorescence spectra characteristic of monomeric (i.e., nonaggregated) molecules were identified; the electrochemical surface coverage was approximately 0.03 monolayer. The tilt angle of the long axis of the PDI molecular plane is 58° relative to the ITO surface normal, 25° greater than the tilt angle of aggregated PDI-phenyl-PA films, which have a surface coverage of approximately one monolayer. The more in-plane orientation of monomeric films is likely due to the absence of cofacial π-π interactions present in aggregated films and possibly a difference in PA-ITO binding modes. The electron transfer rate constant (ks,opt) of monomeric PDI-phenyl-PA films was determined using PM-TIRF and compared with PM-ATR results obtained for aggregated films. For PDI monomers, ks,opt = 3.8 × 103 s-1, which is about 3.7-fold less than ks,opt for aggregated films. The slower kinetics are attributed to the absence of electron self-exchange between monomeric PDI molecules. Differences in the electroactivity of the binding sites on the ITO electrode surface also may play a role. This is the first demonstration of PM-TIRF for determining electron transfer rate constants at an electrode/organic film interface.
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Affiliation(s)
- Yilong Zheng
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Anthony J Giordano
- School of Chemistry & Biochemistry and the Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Seth R Marder
- School of Chemistry & Biochemistry and the Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - S Scott Saavedra
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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7
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Bertram M, Schuschke C, Waidhas F, Schwarz M, Hohner C, Montero MA, Brummel O, Libuda J. Molecular anchoring to oxide surfaces in ultrahigh vacuum and in aqueous electrolytes: phosphonic acids on atomically-defined cobalt oxide. Phys Chem Chem Phys 2019; 21:23364-23374. [PMID: 31637373 DOI: 10.1039/c9cp03779a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this work, we investigated the interaction of phenylphosphonic acid (PPA, C6H5PO3H2) with atomically-defined Co3O4(111) thin films, grown on Ir(100), under ultrahigh vacuum (UHV) conditions and in the electrochemical environment. In the first step, we employed infrared reflection absorption spectroscopy (IRAS) and followed the formation of a saturated monolayer (380 K) in UHV. We observed that the binding motif changes from a chelating tridentate in the sub-monolayer regime to a chelating bidentate at full monolayer coverages. In the electrochemical environment, we analyzed the interaction of PPA with the same Co3O4(111) surface by electrochemical infrared reflection absorption spectroscopy (EC-IRRAS) (0.3 VRHE-1.3 VRHE). When adsorbed at pH 10 from an ammonia buffered aqueous solution, PPA binds to the surface in form of a fully deprotonated chelating bidentate. With increasing electrode potential, we observed two fully reversible processes. At low buffer concentration, protons are released upon oxidation of surface Co2+ ions and lead to protonation of the anchored phosphonates. At high buffer concentration, most of the protons released are accepted by NH3. Simultaneously, the surface phosphonate changes its adsorption motif from bidentate to tridentate while adopting a more upright geometry.
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Affiliation(s)
- Manon Bertram
- Interface Research and Catalysis, Erlangen Catalysis Resource Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, D-91058 Erlangen, Germany.
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8
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Mervinetsky E, Alshanski I, Buchwald J, Dianat A, Lončarić I, Lazić P, Crljen Ž, Gutierrez R, Cuniberti G, Hurevich M, Yitzchaik S. Direct Assembly and Metal-Ion Binding Properties of Oxytocin Monolayer on Gold Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11114-11122. [PMID: 31361147 DOI: 10.1021/acs.langmuir.9b01830] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Peptides are very common recognition entities that are usually attached to surfaces using multistep processes. These processes require modification of the native peptides and of the substrates. Using functional groups in native peptides for their assembly on surfaces without affecting their biological activity can facilitate the preparation of biosensors. Herein, we present a simple single-step formation of native oxytocin monolayer on gold surface. These surfaces were characterized by atomic force spectroscopy, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy. We took advantage of the native disulfide bridge of the oxytocin for anchoring the peptide to the Au surface, while preserving the metal-ion binding properties. Self-assembled oxytocin monolayer was used by electrochemical impedance spectroscopy for metal-ion sensing leading to subnanomolar sensitivities for zinc or copper ions.
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Affiliation(s)
| | | | - Jörg Buchwald
- Institute for Materials Science and Max Bergmann Center of Biomaterials , Hallwachsstraße 3 , 01062 Dresden , Germany
| | - Arezoo Dianat
- Institute for Materials Science and Max Bergmann Center of Biomaterials , Hallwachsstraße 3 , 01062 Dresden , Germany
| | - Ivor Lončarić
- Ruđer Bošković Institute , Bijenička cesta 54 , 10000 Zagreb , Croatia
| | - Predrag Lazić
- Ruđer Bošković Institute , Bijenička cesta 54 , 10000 Zagreb , Croatia
| | - Željko Crljen
- Ruđer Bošković Institute , Bijenička cesta 54 , 10000 Zagreb , Croatia
| | - Rafael Gutierrez
- Institute for Materials Science and Max Bergmann Center of Biomaterials , Hallwachsstraße 3 , 01062 Dresden , Germany
| | - Gianaurelio Cuniberti
- Institute for Materials Science and Max Bergmann Center of Biomaterials , Hallwachsstraße 3 , 01062 Dresden , Germany
- Dresden Center for Computational Materials Science , TU Dresden , 01062 Dresden , Germany
- Center for Advancing Electronics Dresden , TU Dresden , 01062 Dresden , Germany
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9
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Venkata Jagadeesh R, Lakshminarayanan V. Effect of solvents on the self-assembly of long chain alkylphosphonic acids on indium tin oxide surface - In situ studies on the adsorption kinetics and electron transfer process. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Benneckendorf FS, Hillebrandt S, Ullrich F, Rohnacher V, Hietzschold S, Jänsch D, Freudenberg J, Beck S, Mankel E, Jaegermann W, Pucci A, Bunz UHF, Müllen K. Structure-Property Relationship of Phenylene-Based Self-Assembled Monolayers for Record Low Work Function of Indium Tin Oxide. J Phys Chem Lett 2018; 9:3731-3737. [PMID: 29923411 DOI: 10.1021/acs.jpclett.8b01242] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Studying the structure-property relations of tailored dipolar phenyl and biphenylphosphonic acids, we report self-assembled monolayers with a significant decrease in the work function (WF) of indium-tin oxide (ITO) electrodes. Whereas the strengths of the dipoles are varied through the different molecular lengths and the introduction of electron-withdrawing fluorine atoms, the surface energy is kept constant through the electron-donating N, N-dimethylamine head groups. The self-assembled monolayer formation and its modification of the electrodes are investigated via infrared reflection absorption spectroscopy, contact angle measurements, and photoelectron spectroscopy. The WF decrease in ITO correlates with increasing molecular dipoles. The lowest ever recorded WF of 3.7 eV is achieved with the fluorinated biphenylphosphonic acid.
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Affiliation(s)
- Frank S Benneckendorf
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
| | - Sabina Hillebrandt
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
| | - Florian Ullrich
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Institute of Materials Science , Technische Universität Darmstadt , Petersenstraße 32 , 64287 Darmstadt , Germany
| | - Valentina Rohnacher
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
| | - Sebastian Hietzschold
- Institut für Hochfrequenztechnik , Technische Universität Braunschweig , Schleinitzstr. 22 , 38106 Braunschweig , Germany
| | - Daniel Jänsch
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
| | - Jan Freudenberg
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
| | - Sebastian Beck
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
| | - Eric Mankel
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Institute of Materials Science , Technische Universität Darmstadt , Petersenstraße 32 , 64287 Darmstadt , Germany
| | - Wolfram Jaegermann
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Institute of Materials Science , Technische Universität Darmstadt , Petersenstraße 32 , 64287 Darmstadt , Germany
| | - Annemarie Pucci
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Kirchhoff-Institut für Physik , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
- Centre for Advanced Materials , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 225 , 69120 Heidelberg , Germany
| | - Uwe H F Bunz
- Organisch-Chemisches Institut , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
- Centre for Advanced Materials , Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 225 , 69120 Heidelberg , Germany
| | - Klaus Müllen
- InnovationLab , Speyerer Straße 4 , 69115 Heidelberg , Germany
- Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
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11
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Schuschke C, Schwarz M, Hohner C, Silva TN, Fromm L, Döpper T, Görling A, Libuda J. Phosphonic Acids on an Atomically Defined Oxide Surface: The Binding Motif Changes with Surface Coverage. J Phys Chem Lett 2018; 9:1937-1943. [PMID: 29595985 DOI: 10.1021/acs.jpclett.8b00668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have studied the anchoring mechanism of a phosphonic acid on an atomically defined oxide surface. Using time-resolved infrared reflection absorption spectroscopy, we investigated the reaction of deuterated phenylphosphonic acid (DPPA, C6H5PO3D2) with an atomically defined Co3O4(111) surface in situ during film growth by physical vapor deposition. We show that the binding motif of the phosphonate anchor group changes as a function of coverage. At low coverage, DPPA binds in the form of a chelating tridentate phosphonate, while a transition to a chelating bidentate occurs close to monolayer saturation coverage. However, the coverage-dependent change in the binding motif is not associated with a major change of the molecular orientation, suggesting that the rigid phosphonate linker always maintains the DPPA in a strongly tilted orientation irrespective of the surface coverage.
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Affiliation(s)
- Christian Schuschke
- Lehrstuhl für Physikalische Chemie II , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Matthias Schwarz
- Lehrstuhl für Physikalische Chemie II , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Chantal Hohner
- Lehrstuhl für Physikalische Chemie II , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Thais N Silva
- Lehrstuhl für Physikalische Chemie II , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Lukas Fromm
- Lehrstuhl für Theoretische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Tibor Döpper
- Lehrstuhl für Theoretische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Andreas Görling
- Lehrstuhl für Theoretische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
- Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface Controlled Processes , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
| | - Jörg Libuda
- Lehrstuhl für Physikalische Chemie II , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
- Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface Controlled Processes , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3 , D-91058 Erlangen , Germany
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12
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Hasan N, Schwieger C, Tee HT, Wurm FR, Busse K, Kressler J. Crystallization of a polyphosphoester at the air-water interface. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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13
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Ehamparam R, Oquendo LE, Liao MW, Brynnel AK, Ou KL, Armstrong NR, McGrath DV, Saavedra SS. Axially Bound Ruthenium Phthalocyanine Monolayers on Indium Tin Oxide: Structure, Energetics, and Charge Transfer Properties. ACS APPLIED MATERIALS & INTERFACES 2017; 9:29213-29223. [PMID: 28795562 DOI: 10.1021/acsami.7b07394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The efficiency of charge collection at the organic/transparent conducting oxide (TCO) interface in organic photovoltaic (OPV) devices affects overall device efficiency. Modifying the TCO with an electrochemically active molecule may enhance OPV efficiency by providing a charge-transfer pathway between the electrode and the organic active layer, and may also mitigate surface recombination. The synthesis and characterization of phosphonic acid-ruthenium phthalocyanine (RuPcPA) monolayer films on indium tin oxide (ITO), designed to facilitate charge harvesting at ITO electrodes, is presented in this work. The PA group was installed axially relative to the Pc plane so that upon deposition, RuPcPA molecules were preferentially aligned with the ITO surface plane. The tilt angle of 22° between the normal axes to the Pc plane and the ITO surface plane, measured by attenuated total reflectance (ATR) spectroscopy, is consistent with a predominately in-plane orientation. The effect of surface roughness on RuPcPA orientation was modeled, and a correlation was obtained between experimental and theoretical mean tilt angles. Based on electrochemical and spectroelectrochemical studies, RuPcPA monolayers are composed predominately of monomers. Electrochemical impedance spectroscopy (EIS) and potential modulated-ATR (PM-ATR) spectroscopy were used to characterize the electron-transfer (ET) kinetics of these monolayers. A rate constant of 4.0 × 103 s-1 was measured using EIS, consistent with a short tunneling distance between the chromophore and the electrode surface. Using PM-ATR, ks,opt values of 2.2 × 103 and 2.4 × 103 s-1 were measured using TE and TM polarized light, respectively; the similarity of these values is consistent with a narrow molecular orientation distribution and narrow range of tunneling distances. The ionization potential of RuPcPA-modified ITO was measured using ultraviolet photoelectron spectroscopy and the results indicate favorable energetics for hole collection at the RuPcPA/ITO interface, indicating that this type of TCO modification may be useful for enhancing charge collection efficiency in OPV devices.
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Affiliation(s)
- Ramanan Ehamparam
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Luis E Oquendo
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Michael W Liao
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Ambjorn K Brynnel
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Kai-Lin Ou
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Neal R Armstrong
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Dominic V McGrath
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - S Scott Saavedra
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
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14
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Vilan A, Cahen D. Chemical Modification of Semiconductor Surfaces for Molecular Electronics. Chem Rev 2017; 117:4624-4666. [PMID: 28230354 DOI: 10.1021/acs.chemrev.6b00746] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Inserting molecular monolayers within metal/semiconductor interfaces provides one of the most powerful expressions of how minute chemical modifications can affect electronic devices. This topic also has direct importance for technology as it can help improve the efficiency of a variety of electronic devices such as solar cells, LEDs, sensors, and possible future bioelectronic ones. The review covers the main aspects of using chemistry to control the various aspects of interface electrostatics, such as passivation of interface states and alignment of energy levels by intrinsic molecular polarization, as well as charge rearrangement with the adjacent metal and semiconducting contacts. One of the greatest merits of molecular monolayers is their capability to form excellent thin dielectrics, yielding rich and unique current-voltage characteristics for transport across metal/molecular monolayer/semiconductor interfaces. We explain the interplay between the monolayer as tunneling barrier on the one hand, and the electrostatic barrier within the semiconductor, due to its space-charge region, on the other hand, as well as how different monolayer chemistries control each of these barriers. Practical tools to experimentally identify these two barriers and distinguish between them are given, followed by a short look to the future. This review is accompanied by another one, concerning the formation of large-area molecular junctions and charge transport that is dominated solely by molecules.
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Affiliation(s)
- Ayelet Vilan
- Department of Materials & Interfaces, Weizmann Institute of Science , Rehovot, Israel 76100
| | - David Cahen
- Department of Materials & Interfaces, Weizmann Institute of Science , Rehovot, Israel 76100
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15
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McNichols BW, Koubek JT, Sellinger A. Single-step synthesis of styryl phosphonic acids via palladium-catalyzed Heck coupling of vinyl phosphonic acid with aryl halides. Chem Commun (Camb) 2017; 53:12454-12456. [DOI: 10.1039/c7cc05909d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have developed a single step palladium-catalyzed Heck coupling of aryl halides with vinyl phosphonic acid to produce functionalized (E)-styryl phosphonic acids.
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Affiliation(s)
- Brett W. McNichols
- Department of Chemistry
- Colorado School of Mines
- Golden
- USA
- Department of Chemistry
| | | | - Alan Sellinger
- Department of Chemistry
- Colorado School of Mines
- Golden
- USA
- Materials Science Program
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16
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Ostapenko A, Klöffel T, Eußner J, Harms K, Dehnen S, Meyer B, Witte G. Etching of Crystalline ZnO Surfaces upon Phosphonic Acid Adsorption: Guidelines for the Realization of Well-Engineered Functional Self-Assembled Monolayers. ACS APPLIED MATERIALS & INTERFACES 2016; 8:13472-13483. [PMID: 27159837 DOI: 10.1021/acsami.6b02190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Functionalization of metal oxides by means of covalently bound self-assembled monolayers (SAMs) offers a tailoring of surface electronic properties such as their work function and, in combination with its large charge carrier mobility, renders ZnO a promising conductive oxide for use as transparent electrode material in optoelectronic devices. In this study, we show that the formation of phosphonic acid-anchored SAMs on ZnO competes with an unwanted chemical side reaction, leading to the formation of surface precipitates and severe surface damage at prolonged immersion times of several days. Combining atomic force microscopy (AFM), X-ray diffraction (XRD), and thermal desorption spectroscopy (TDS), the stability and structure of the aggregates formed upon immersion of ZnO single crystal surfaces of different orientations [(0001̅), (0001), and (101̅0)] in phenylphosphonic acid (PPA) solution were studied. By intentionally increasing the immersion time to more than 1 week, large crystalline precipitates are formed, which are identified as zinc phosphonate. Moreover, the energetics and the reaction pathway of this transformation have been evaluated using density functional theory (DFT), showing that zinc phosphonate is thermodynamically more favorable than phosphonic acid SAMs on ZnO. Precipitation is also found for phosphonic acids with fluorinated aromatic backbones, while less precipitation occurs upon formation of SAMs with phenylphosphinic anchoring units. By contrast, no precipitates are formed when PPA monolayer films are prepared by sublimation under vacuum conditions, yielding smooth surfaces without noticeable etching.
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Affiliation(s)
- Alexandra Ostapenko
- Fachbereich Physik, Molekulare Festkörperphysik and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Renthof 7, 35032 Marburg, Germany
| | - Tobias Klöffel
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg , Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Jens Eußner
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany
| | - Klaus Harms
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany
| | - Stefanie Dehnen
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg , Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Gregor Witte
- Fachbereich Physik, Molekulare Festkörperphysik and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Renthof 7, 35032 Marburg, Germany
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17
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Paniagua SA, Giordano AJ, Smith OL, Barlow S, Li H, Armstrong NR, Pemberton JE, Brédas JL, Ginger D, Marder SR. Phosphonic Acids for Interfacial Engineering of Transparent Conductive Oxides. Chem Rev 2016; 116:7117-58. [DOI: 10.1021/acs.chemrev.6b00061] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sergio A. Paniagua
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Anthony J. Giordano
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - O’Neil L. Smith
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Stephen Barlow
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Hong Li
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
- Division
of Physical Sciences and Engineering, King Abdullah University of Science and Technology, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Neal R. Armstrong
- Department
of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jeanne E. Pemberton
- Department
of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jean-Luc Brédas
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
- Division
of Physical Sciences and Engineering, King Abdullah University of Science and Technology, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - David Ginger
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Seth R. Marder
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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18
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Ostapenko A, Klöffel T, Meyer B, Witte G. Formation and Stability of Phenylphosphonic Acid Monolayers on ZnO: Comparison of In Situ and Ex Situ SAM Preparation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5029-5037. [PMID: 27145215 DOI: 10.1021/acs.langmuir.6b00487] [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
Self-assembled monolayers (SAMs) enable an electronic interface tailoring of conductive metal oxides and offer an alternative to common transparent electrodes in optoelectronic devices. Here, the influence of surface orientation and pretreatment on the formation and stability of SAMs has been studied for the case of phenylphosphonic acid (PPA) on ZnO single crystals. Using thermal desorption spectroscopy (TDS), X-ray photoelectron spectroscopy (XPS), near-edge X-ray adsorption fine structure spectroscopy (NEXAFS) and density-functional theory (DFT) calculations, the thermal stability and orientational ordering of PPA-SAMs on the polar and mixed-terminated ZnO surfaces were analyzed. On all surfaces, PPA-SAMs remain stable up to 550 K, while at higher temperatures a C-P bond cleavage and dissociative desorption takes place yielding two distinct desorption peaks. Based on DFT calculations, these desorption channels are attributed to protonated and deprotonated chemisorbed PPA molecules, which can be related to tri- and bidentate species, hence allowing to determine their relative abundance from the intensity ratio. Beside immersion, an alternative monolayer preparation based on vacuum deposition in combination with controlled desorption of excess multilayers is demonstrated. This enables a SAM preparation on bare ZnO surfaces without any precoating due to exposure to ambient air, which is further compared with SAM formation on intentionally hydroxylated substrates. Corresponding TDS data indicate that initial hydroxylation favors the formation of tridentate and deprotonated bidentate, while the OMBD preparation on bare surfaces yields a larger fraction of protonated bidentate species. The orientation of PPA molecules adopted in the SAMs was determined from the dichroism of K-edge NEXAFS measurements and reveals an almost upright orientation for the deprotonated species, while a slight tilting is obtained for monolayer films with a large fraction of protonated bidentate molecules.
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Affiliation(s)
- Alexandra Ostapenko
- Fachbereich Physik, Molekulare Festkörperphysik and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Renthof 7, 35032 Marburg, Germany
| | - Tobias Klöffel
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg , Nägelsbachstraße 25, 91052 Erlangen, Germany
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg , Nägelsbachstraße 25, 91052 Erlangen, Germany
| | - Gregor Witte
- Fachbereich Physik, Molekulare Festkörperphysik and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Renthof 7, 35032 Marburg, Germany
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19
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Sang L, Mudalige A, Sigdel AK, Giordano AJ, Marder SR, Berry JJ, Pemberton JE. PM-IRRAS Determination of Molecular Orientation of Phosphonic Acid Self-Assembled Monolayers on Indium Zinc Oxide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:5603-5613. [PMID: 25924006 DOI: 10.1021/acs.langmuir.5b00129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Self-assembled monolayers (SAMs) of phosphonic acids (PAs) on transparent conductive oxide (TCO) surfaces can facilitate improvement in TCO/organic semiconductor interface properties. When ordered PA SAMs are formed on oxide substrates, interface dipole and electronic structure are affected by the functional group properties, orientation, and binding modes of the modifiers. Choosing octylphosphonic acid (OPA), F13-octylphosphonic acid (F13OPA), pentafluorophenyl phosphonic acid (F5PPA), benzyl phosphonic acid (BnPA), and pentafluorobenzyl phosphonic acid (F5BnPA) as a representative group of modifiers, we report polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) of binding and molecular orientation on indium-doped zinc oxide (IZO) substrates. Considerable variability in molecular orientation and binding type is observed with changes in PA functional group. OPA exhibits partially disordered alkyl chains but on average the chain axis is tilted ∼57° from the surface normal. F13OPA tilts 26° with mostly tridentate binding. The F5PPA ring is tilted 23° from the surface normal with a mixture of bidentate and tridentate binding; the BnPA ring tilts 31° from normal with a mixture of bidentate and tridentate binding, and the F5BnPA ring tilts 58° from normal with a majority of bidentate with some tridenate binding. These trends are consistent with what has been observed previously for the effects of fluorination on orientation of phosphonic acid modifiers. These results from PM-IRRAS are correlated with recent results on similar systems from near-edge X-ray absorption fine structure (NEXAFS) and density functional theory (DFT) calculations. Overall, these results indicate that both surface binding geometry and intermolecular interactions play important roles in dictating the orientation of PA modifiers on TCO surfaces. This work also establishes PM-IRRAS as a routine method for SAM orientation determination on complex oxide substrates.
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Affiliation(s)
- Lingzi Sang
- †Department of Chemistry and Biochemistry University of Arizona, 1306 E. University Boulevard, Tucson, Arizona 85721, United States
| | - Anoma Mudalige
- †Department of Chemistry and Biochemistry University of Arizona, 1306 E. University Boulevard, Tucson, Arizona 85721, United States
| | - Ajaya K Sigdel
- ‡Department of Physics and Astronomy, University of Denver, Denver, Colorado 80208, United States
- §National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Anthony J Giordano
- ∥School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Seth R Marder
- ∥School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Joseph J Berry
- §National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Jeanne E Pemberton
- †Department of Chemistry and Biochemistry University of Arizona, 1306 E. University Boulevard, Tucson, Arizona 85721, United States
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20
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Forget A, Limoges B, Balland V. Efficient chemisorption of organophosphorous redox probes on indium tin oxide surfaces under mild conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1931-1940. [PMID: 25611977 DOI: 10.1021/la503760x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report a mild and straightforward one-step chemical surface functionalization of indium tin oxide (ITO) electrodes by redox-active molecules bearing an organophosphoryl anchoring group (i.e., alkyl phosphate or alkyl phosphonate group). The method takes advantage of simple passive adsorption in an aqueous solution at room temperature. We show that organophosphorus compounds can adsorb much more strongly and stably on an ITO surface than analogous redox-active molecules bearing a carboxylate or a boronate moiety. We provide evidence, through quantitative electrochemical characterization (i.e., by cyclic voltammetry) of the adsorbed organophosphoryl redox-active molecules, of the occurrence of three different adsorbate fractions on ITO, exhibiting different stabilities on the surface. Among these three fractions, one is observed to be strongly chemisorbed, exhibiting high stability and resistance to desorption/hydrolysis in a free-redox probe aqueous buffer. We attribute this remarkable stability to the formation of chemical bonds between the organophosphorus anchoring group and the metal oxide surface, likely occurring through a heterocondensation reaction in water. From XPS analysis, we also demonstrate that the surface coverage of the chemisorbed molecules is highly affected by the degree of surface hydroxylation, a parameter that can be tuned by simply preconditioning the freshly cleaned ITO surfaces in water. The lower the relative surface hydroxide density on ITO, the higher was the surface coverage of the chemisorbed species. This behavior is in line with a chemisorption mechanism involving coordination of a deprotonated phosphoryl oxygen atom to the non-hydroxylated acidic metal sites of ITO.
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Affiliation(s)
- Amélie Forget
- Laboratoire d'Electrochimie Moléculaire, UMR CNRS 7591, Université Paris Diderot , Sorbonne Paris Cité, 15 rue Jean-Antoine de Baïf, F-75205 Paris, Cedex 13, France
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21
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Li JW, Liu YY, Xie LH, Shang JZ, Qian Y, Yi MD, Yu T, Huang W. Revealing the interactions between pentagon–octagon–pentagon defect graphene and organic donor/acceptor molecules: a theoretical study. Phys Chem Chem Phys 2015; 17:4919-25. [DOI: 10.1039/c4cp04900d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cyano group interacts strongly with 5–8–5 defect graphene, changes the bands near the Fermi level and enhances the infrared light absorption.
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Affiliation(s)
- Jie-Wei Li
- Center for Molecular Systems and Organic Devices (CMSOD)
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)
- National Synergistic Innovation Center for Advanced Materials (SICAM)
- Nanjing University of Posts & Telecommunications
- Nanjing 210023
| | - Yu-Yu Liu
- Center for Molecular Systems and Organic Devices (CMSOD)
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)
- National Synergistic Innovation Center for Advanced Materials (SICAM)
- Nanjing University of Posts & Telecommunications
- Nanjing 210023
| | - Ling-Hai Xie
- Center for Molecular Systems and Organic Devices (CMSOD)
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)
- National Synergistic Innovation Center for Advanced Materials (SICAM)
- Nanjing University of Posts & Telecommunications
- Nanjing 210023
| | - Jing-Zhi Shang
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - Yan Qian
- Center for Molecular Systems and Organic Devices (CMSOD)
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)
- National Synergistic Innovation Center for Advanced Materials (SICAM)
- Nanjing University of Posts & Telecommunications
- Nanjing 210023
| | - Ming-Dong Yi
- Center for Molecular Systems and Organic Devices (CMSOD)
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)
- National Synergistic Innovation Center for Advanced Materials (SICAM)
- Nanjing University of Posts & Telecommunications
- Nanjing 210023
| | - Ting Yu
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM)
| | - Wei Huang
- Center for Molecular Systems and Organic Devices (CMSOD)
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)
- National Synergistic Innovation Center for Advanced Materials (SICAM)
- Nanjing University of Posts & Telecommunications
- Nanjing 210023
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22
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Pemberton JE, Mudalige A, Yoo H. Thickness, composition, and molecular structure of residual thin films formed by forced dewetting of Ag from glycerol/D₂O solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:15181-15192. [PMID: 25453908 DOI: 10.1021/la503863t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The thickness, composition, and interfacial molecular structure of residual thin films retained on the surface of polycrystalline Ag substrates after being forcibly dewet from glycerol/D2O solutions are investigated using contact angle measurements, ellipsometry, and polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS). Residual film thicknesses are rationalized on the basis of the relevant long-range van der Waals and structural forces leading to residual film formation along with the interfacial glycerol and D2O structure. Unique interfacial composition, wherein glycerol preferentially segregates to the residual film interfaces, is substantiated by PM-IRRAS. Thus, the residual films possess composition and molecular structure that differ from those of bulk solution. Specifically, in the thinnest residual films, glycerol interacts strongly with the Ag substrate, leading to glycerol that is more ordered than the bulk liquid that coexists with bulk-like D2O. In thicker residual films, the glycerol mole fraction is still enhanced relative to the bulk solution, but both ordered and liquid-like glycerol species are observed along with D2O that is more strongly hydrogen-bonded than in the bulk. The creation of residual films by forced dewetting and their interrogation by spectroscopic methods are thus demonstrated to represent a powerful approach for characterizing interfacial liquid molecular structure near solid surfaces but beyond the first monolayer under ambient conditions.
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Affiliation(s)
- Jeanne E Pemberton
- Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721, United States
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23
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Mangolini F, McClimon JB, Rose F, Carpick RW. Accounting for Nanometer-Thick Adventitious Carbon Contamination in X-ray Absorption Spectra of Carbon-Based Materials. Anal Chem 2014; 86:12258-65. [DOI: 10.1021/ac503409c] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Filippo Mangolini
- Department
of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - J. Brandon McClimon
- Department
of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Franck Rose
- HGST, a Western Digital Company, San
Jose, California 95135, United States
| | - Robert W. Carpick
- Department
of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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24
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Braid JL, Koldemir U, Sellinger A, Collins RT, Furtak TE, Olson DC. Conjugated phosphonic acid modified zinc oxide electron transport layers for improved performance in organic solar cells. ACS APPLIED MATERIALS & INTERFACES 2014; 6:19229-19234. [PMID: 25329245 DOI: 10.1021/am505182c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Phosphonic acid modification of zinc oxide (ZnO) electron transport layers in inverted P3HT:ICBA solar cells was studied to determine the effect of conjugated linkages between the aromatic and phosphonic acid attachment groups. For example, zinc oxide treated with 2,6-difluorophenylvinylphosphonic acid, having a conjugated vinyl group connecting the aromatic moiety to the phosphonic acid group, showed a 0.78 eV decrease in the effective work function versus unmodified ZnO, whereas nonconjugated 2,6-difluorophenylethylphosphonic acid resulted in a 0.57 eV decrease, as measured by Kelvin probe. This resulted in an average power conversion efficiency of 5.89% for conjugated 2,6-difluorophenyvinylphosphonic acid modified solar cells, an improvement over unmodified (5.24%) and nonconjugated phosphonic acid modified devices (5.64%), indicating the importance of the conjugated linkage.
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Affiliation(s)
- Jennifer L Braid
- Department of Physics and §Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
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25
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Shao G, Glaz MS, Ma F, Ju H, Ginger DS. Intensity-modulated scanning Kelvin probe microscopy for probing recombination in organic photovoltaics. ACS NANO 2014; 8:10799-10807. [PMID: 25207675 DOI: 10.1021/nn5045867] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We study surface photovoltage decays on sub-millisecond time scales in organic solar cells using intensity-modulated scanning Kelvin probe microscopy (SKPM). Using polymer/fullerene (poly[N-9"-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]/[6,6]-phenyl C71-butyric acid methyl ester, PCDTBT/PC71BM) bulk heterojunction devices as a test case, we show that the decay lifetimes measured by SKPM depend on the intensity of the background illumination. We propose that this intensity dependence is related to the well-known carrier-density-dependent recombination kinetics in organic bulk heterojunction materials. We perform transient photovoltage (TPV) and charge extraction (CE) measurements on the PCDTBT/PC71BM blends to extract the carrier-density dependence of the recombination lifetime in our samples, and we find that the device TPV and CE data are in good agreement with the intensity and frequency dependence observed via SKPM. Finally, we demonstrate the capability of intensity-modulated SKPM to probe local recombination rates due to buried interfaces in organic photovoltaics (OPVs). We measure the differences in photovoltage decay lifetimes over regions of an OPV cell fabricated on an indium tin oxide electrode patterned with two different phosphonic acid monolayers known to affect carrier lifetime.
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Affiliation(s)
- Guozheng Shao
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
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26
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Zhu J, Mu L, Chen L, Shi Y, Wang H, Feng X, Lu X. Interface-Strengthened Polyimide/Carbon Nanofibers Nanocomposites with Superior Mechanical and Tribological Properties. MACROMOL CHEM PHYS 2014. [DOI: 10.1002/macp.201400194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Jiahua Zhu
- State Key Laboratory of Materials-oriented Chemical Engineering; Nanjing Tech University; Nanjing 210009 P. R. China
- Department of Chemical and Biomolecular Engineering; The University of Akron; Akron OH 44221 USA
| | - Liwen Mu
- State Key Laboratory of Materials-oriented Chemical Engineering; Nanjing Tech University; Nanjing 210009 P. R. China
- School of Materials Engineering; Nanjing Institute of Technology; Nanjing 211167 P. R. China
| | - Long Chen
- Department of Chemical and Biomolecular Engineering; The University of Akron; Akron OH 44221 USA
| | - Yijun Shi
- Division of Machine Elements; Lulea University of Technology; Lulea 97187 Sweden
| | - Huaiyuan Wang
- School of Chemistry & Chemical Engineering; Northeast Petroleum University; Daqing 163318 P. R. China
| | - Xin Feng
- State Key Laboratory of Materials-oriented Chemical Engineering; Nanjing Tech University; Nanjing 210009 P. R. China
| | - Xiaohua Lu
- State Key Laboratory of Materials-oriented Chemical Engineering; Nanjing Tech University; Nanjing 210009 P. R. China
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27
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Pujari SP, Scheres L, Marcelis ATM, Zuilhof H. Covalent Surface Modification of Oxide Surfaces. Angew Chem Int Ed Engl 2014; 53:6322-56. [DOI: 10.1002/anie.201306709] [Citation(s) in RCA: 583] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Indexed: 12/26/2022]
Affiliation(s)
- Sidharam P. Pujari
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (The Netherlands)
| | - Luc Scheres
- Surfix B.V. Dreijenplein 8, 6703 HB Wageningen (The Netherlands)
| | - Antonius T. M. Marcelis
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (The Netherlands)
| | - Han Zuilhof
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (The Netherlands)
- Department of Chemical and Materials Engineering, King Abdulaziz University, Jeddah (Saudi Arabia)
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28
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Pujari SP, Scheres L, Marcelis ATM, Zuilhof H. Kovalente Oberflächenmodifikationen von Oxiden. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201306709] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Sidharam P. Pujari
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (Niederlande)
| | | | - Antonius T. M. Marcelis
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (Niederlande)
| | - Han Zuilhof
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (Niederlande)
- Department of Chemical and Materials Engineering, King Abdulaziz University, Jeddah (Saudi‐Arabien)
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29
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Cornil D, Van Regemorter T, Beljonne D, Cornil J. Work function shifts of a zinc oxide surface upon deposition of self-assembled monolayers: a theoretical insight. Phys Chem Chem Phys 2014; 16:20887-99. [DOI: 10.1039/c4cp02811b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have investigated at the DFT level the way the work function of ZnO is affected upon deposition of self-assembled monolayers made of 4-tert-butylpyridine and various benzoic acids.
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Affiliation(s)
- D. Cornil
- Laboratory for Chemistry of Novel Materials
- University of Mons (UMons)
- Mons 7000, Belgium
| | - T. Van Regemorter
- Laboratory for Chemistry of Novel Materials
- University of Mons (UMons)
- Mons 7000, Belgium
| | - D. Beljonne
- Laboratory for Chemistry of Novel Materials
- University of Mons (UMons)
- Mons 7000, Belgium
| | - J. Cornil
- Laboratory for Chemistry of Novel Materials
- University of Mons (UMons)
- Mons 7000, Belgium
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30
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Everaerts K, Emery JD, Jariwala D, Karmel HJ, Sangwan VK, Prabhumirashi PL, Geier ML, McMorrow JJ, Bedzyk MJ, Facchetti A, Hersam MC, Marks TJ. Ambient-Processable High Capacitance Hafnia-Organic Self-Assembled Nanodielectrics. J Am Chem Soc 2013; 135:8926-39. [DOI: 10.1021/ja4019429] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Antonio Facchetti
- Polyera Corporation, 8045
Lamon Avenue, Skokie, Illinois 60077, United States
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31
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Wang H, Coss CS, Mudalige A, Polt RL, Pemberton JE. A PM-IRRAS investigation of monorhamnolipid orientation at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4441-4450. [PMID: 23406083 DOI: 10.1021/la3051725] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The rhamnolipid biosurfactants have been considered as possible "green" alternatives to synthetic surfactants due to their greater compatibility with the environment and excellent surface active properties. In order to understand the molecular orientation of rhamnolipids at the air-water interface, a new monorhamnolipid with two octadecyl chains, Rha-C18-C18, has been studied at the air-water interface with polarization modulated-infrared reflection absorption spectroscopy (PM-IRRAS). Since rhamnolipids possess a carboxylic acid, and hence exhibit pH-dependent properties, their water surface orientation is studied in solutions of pH 2, 5, and 8. Rhamnolipids have also been reported to form strong complexes with Pb(2+); thus, the effect of the presence of Pb(2+) on molecular orientation at the interface is also investigated. PM-IRRA spectra indicate an increase in alkyl chain order and a decrease in alkyl chain tilt angle as the surface pressure of the monolayer increases, with pH-independent tilt angles ranging from 63° to 45°. Molecular modeling using Spartan provides insight into the cause of this large tilt angle as being due to the nature of the monorhamnolipid packing at the air-water interface as dictated by its large hydrophilic headgroup.
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Affiliation(s)
- Hui Wang
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Boulevard, Tucson, Arizona 85721, USA
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32
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Guerrero G, Alauzun JG, Granier M, Laurencin D, Mutin PH. Phosphonate coupling molecules for the control of surface/interface properties and the synthesis of nanomaterials. Dalton Trans 2013; 42:12569-85. [DOI: 10.1039/c3dt51193f] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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