1
|
Chen N, Li S, Zhao P, Liu R, Xie Y, Lin JL, Nijhuis CA, Xu B, Zhang L, Xu H, Li Y. Extreme long-lifetime self-assembled monolayer for air-stable molecular junctions. SCIENCE ADVANCES 2023; 9:eadh3412. [PMID: 37851815 PMCID: PMC10584343 DOI: 10.1126/sciadv.adh3412] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 09/14/2023] [Indexed: 10/20/2023]
Abstract
The molecular electronic devices based on self-assembled monolayer (SAM) on metal surfaces demonstrate novel electronic functions for device minimization yet are unable to realize in practical applications, due to their instability against oxidation of the sulfur-metal bond. This paper describes an alternative to the thiolate anchoring group to form stable SAMs on gold by selenides anchoring group. Because of the formation of strong selenium-gold bonds, these stable SAMs allow us to incorporate them in molecular tunnel junctions to yield extremely stable junctions for over 200 days. A detailed structural characterization supported by spectroscopy and first-principles modeling shows that the oxidation process is much slower with the selenium-gold bond than the sulfur-gold bond, and the selenium-gold bond is strong enough to avoid bond breaking even when it is eventually oxidized. This proof of concept demonstrates that the extraordinarily stable SAMs derived from selenides are useful for long-lived molecular electronic devices and can possibly become important in many air-stable applications involving SAMs.
Collapse
Affiliation(s)
- Ningyue Chen
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Shuwei Li
- Center for Combustion Energy, Tsinghua University, Beijing 100084, China
- School of Vehicle and Mobility, and State Key Laboratory of Intelligent Green Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Peng Zhao
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Ran Liu
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA 30602, USA
| | - Yu Xie
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jin-Liang Lin
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Christian A. Nijhuis
- Hybrid Materials for Opto-Electronics Group, Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Centre and Centre for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, Netherlands
| | - Bingqian Xu
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA 30602, USA
| | - Liang Zhang
- Center for Combustion Energy, Tsinghua University, Beijing 100084, China
- School of Vehicle and Mobility, and State Key Laboratory of Intelligent Green Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Huaping Xu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yuan Li
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| |
Collapse
|
2
|
|
3
|
Shin J, Eo JS, Jeon T, Lee T, Wang G. Advances of Various Heterogeneous Structure Types in Molecular Junction Systems and Their Charge Transport Properties. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202399. [PMID: 35975456 PMCID: PMC9596861 DOI: 10.1002/advs.202202399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/11/2022] [Indexed: 05/31/2023]
Abstract
Molecular electronics that can produce functional electronic circuits using a single molecule or molecular ensemble remains an attractive research field because it not only represents an essential step toward realizing ultimate electronic device scaling but may also expand our understanding of the intrinsic quantum transports at the molecular level. Recently, in order to overcome the difficulties inherent in the conventional approach to studying molecular electronics and developing functional device applications, this field has attempted to diversify the electrical characteristics and device architectures using various types of heterogeneous structures in molecular junctions. This review summarizes recent efforts devoted to functional devices with molecular heterostructures. Diverse molecules and materials can be combined and incorporated in such two- and three-terminal heterojunction structures, to achieve desirable electronic functionalities. The heterojunction structures, charge transport mechanisms, and possible strategies for implementing electronic functions using various hetero unit materials are presented sequentially. In addition, the applicability and merits of molecular heterojunction structures, as well as the anticipated challenges associated with their implementation in device applications are discussed and summarized. This review will contribute to a deeper understanding of charge transport through molecular heterojunction, and it may pave the way toward desirable electronic functionalities in molecular electronics applications.
Collapse
Affiliation(s)
- Jaeho Shin
- KU‐KIST Graduate School of Converging Science and TechnologyKorea UniversitySeoul02841Korea
- Department of ChemistryRice University6100 Main StreetHoustonTexas77005United States
| | - Jung Sun Eo
- KU‐KIST Graduate School of Converging Science and TechnologyKorea UniversitySeoul02841Korea
| | - Takgyeong Jeon
- KU‐KIST Graduate School of Converging Science and TechnologyKorea UniversitySeoul02841Korea
| | - Takhee Lee
- Department of Physics and AstronomyInstitute of Applied PhysicsSeoul National UniversitySeoul08826Korea
| | - Gunuk Wang
- KU‐KIST Graduate School of Converging Science and TechnologyKorea UniversitySeoul02841Korea
- Department of Integrative Energy EngineeringKorea UniversitySeoul02841Korea
- Center for Neuromorphic EngineeringKorea Institute of Science and TechnologySeoul02792Korea
| |
Collapse
|
4
|
Park S, Kim HR, Kim J, Hong BH, Yoon HJ. Enhanced Thermopower of Saturated Molecules by Noncovalent Anchor-Induced Electron Doping of Single-Layer Graphene Electrode. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103177. [PMID: 34453364 DOI: 10.1002/adma.202103177] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Enhancing thermopower is a key goal in organic and molecular thermoelectrics. Herein, it is shown that introducing noncovalent contact with a single-layer graphene (SLG) electrode improves the thermopower of saturated molecules as compared to the traditional gold-thiolate covalent contact. Thermoelectric junction measurements with a liquid-metal technique reveal that the value of Seebeck coefficient in large-area junctions based on n-alkylamine self-assembled monolayers (SAMs) on SLG is increased up to fivefold compared to the analogous junction based on n-alkanethiolate SAMs on gold. Experiments with Raman spectroscopy and field-effect transistor analysis indicate that such enhancements benefit from the creation of new in-gap states and electron doping through noncovalent interaction between the amine anchor and the SLG electrode, which leads to a reduced energy offset between the Fermi level and the transport channel. This work demonstrates that control of interfacial bonding nature in molecular junctions improves the Seebeck effect in saturated molecules.
Collapse
Affiliation(s)
- Sohyun Park
- Department of Chemistry, Korea University, Seoul, 02841, South Korea
| | - Hwa Rang Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Juhee Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Byung-Hee Hong
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul, 02841, South Korea
| |
Collapse
|
5
|
Affiliation(s)
- Yunqiao Ma
- School of Chemical and Biomedical Engineering Nanyang Technological University Singapore Singapore
- Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute Nanyang Technological University Singapore Singapore
| | - Andrew L. Zydney
- Department of Chemical Engineering The Pennsylvania State University University Park Pennsylvania USA
| | - Jia Wei Chew
- School of Chemical and Biomedical Engineering Nanyang Technological University Singapore Singapore
- Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute Nanyang Technological University Singapore Singapore
| |
Collapse
|
6
|
Lecot S, Chevolot Y, Phaner-Goutorbe M, Yeromonahos C. Impact of Silane Monolayers on the Adsorption of Streptavidin on Silica and Its Subsequent Interactions with Biotin: Molecular Dynamics and Steered Molecular Dynamics Simulations. J Phys Chem B 2020; 124:6786-6796. [PMID: 32663028 DOI: 10.1021/acs.jpcb.0c04382] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein adsorption on surfaces is used in analytical tools as an immobilization mean to trap the analyte to be detected. However, protein adsorption can lead to a conformational change in the protein structure, resulting in a loss of bioactivity. Here, we study adsorption of a streptavidin-biotin complex on amorphous SiO2 surfaces functionalized with five different silane self-assembled monolayers by all-atom molecular dynamics simulations. We find that the streptavidin global conformational change, as well as the nature of residues with high mobility, depends on the alkyl chain length and head-group charge of silane molecules. Effects on interactions with biotin are further investigated by steered molecular dynamics (SMD) simulations, which mimics atomic force microscopy (AFM) with the biotin attached on the tip. We show the combined effects of adsorption-induced global conformational changes and of the position of residues with high mobility on the streptavidin-biotin rupture force. By comparing our results to experimental and SMD rupture forces obtained in water, without any surface, we conclude that silane with uncharged and short alkyl chains allows streptavidin immobilization, while keeping biotin interactions better than silanes with long alkyl chains or charged head groups.
Collapse
Affiliation(s)
- Solène Lecot
- Université de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
| | - Yann Chevolot
- Université de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
| | - Magali Phaner-Goutorbe
- Université de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
| | - Christelle Yeromonahos
- Université de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
| |
Collapse
|
7
|
Xia J, Zhu Y, He Z, Wang F, Wu H. Superstrong Noncovalent Interface between Melamine and Graphene Oxide. ACS APPLIED MATERIALS & INTERFACES 2019; 11:17068-17078. [PMID: 30998319 DOI: 10.1021/acsami.9b02971] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
There have been growing academic interests in the study of strong organic molecule-graphene [or graphene oxide (GO)] systems, owing to their essential noncovalent nature and the consequent chemomechanical behavior within the interface. A more recent experimental measurement [ Chem 2018, 4, 896-910] reported that the melamine-GO interface exhibits a remarkable noncovalent binding strength up to ∼1 nN, even comparable with typical covalent bonds. But the poor understanding on the complex noncovalent nature in particular makes it challenging to unveil the mystery of this high-performance interface. Herein, we carry out first-principles calculations to investigate the atomistic origin of ultrastrong noncovalent interaction between the melamine molecule and the GO sheet, as well as the chemomechanical synergy in interfacial behavior. The anomalous O-H···N hydrogen bonding, formed between the triazine moiety of melamine and the -OH in GO, is found cooperatively enhanced by the pin-like NH2-π interaction, which is responsible for the strong interface. Following static pulling simulations validates the 1 nN level rupture strength and the contribution of each noncovalent interaction within the interface. Moreover, our results show that the -OH hydrogen bonding will mainly augment the interfacial adhesion strength, whereas the -NH2 group cooperating with the -OH hydrogen bonding and conjugating with the GO surface will greatly improve the interfacial shear performance. Our work deepens the understanding on the chemomechanical behaviors within the noncovalent interface, which is expected to provide new potential strategies in designing high-performance graphene-based artificial nacreous materials.
Collapse
Affiliation(s)
- Jun Xia
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics , University of Science and Technology of China , Hefei 230027 , China
| | - YinBo Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics , University of Science and Technology of China , Hefei 230027 , China
| | - ZeZhou He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics , University of Science and Technology of China , Hefei 230027 , China
| | - FengChao Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics , University of Science and Technology of China , Hefei 230027 , China
| | - HengAn Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics , University of Science and Technology of China , Hefei 230027 , China
| |
Collapse
|
8
|
Abstract
Surfaces and interfaces are ubiquitous in nature and are involved in many biological processes. Due to this, natural organisms have evolved a number of methods to control interfacial and surface properties. Many of these methods involve the use of specialised protein biosurfactants, which due to the competing demands of high surface activity, biocompatibility, and low solution aggregation may take structures that differ from the traditional head–tail structure of small molecule surfactants. As well as their biological functions, these proteins have also attracted interest for industrial applications, in areas including food technology, surface modification, and drug delivery. To understand the biological functions and technological applications of protein biosurfactants, it is necessary to have a molecular level description of their behaviour, in particular at surfaces and interfaces, for which molecular simulation is well suited to investigate. In this review, we will give an overview of simulation studies of a number of examples of protein biosurfactants (hydrophobins, surfactin, and ranaspumin). We will also outline some of the key challenges and future directions for molecular simulation in the investigation of protein biosurfactants and how this can help guide future developments.
Collapse
|
9
|
Song P, Guerin S, Tan SJR, Annadata HV, Yu X, Scully M, Han YM, Roemer M, Loh KP, Thompson D, Nijhuis CA. Stable Molecular Diodes Based on π-π Interactions of the Molecular Frontier Orbitals with Graphene Electrodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1706322. [PMID: 29356141 DOI: 10.1002/adma.201706322] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/01/2017] [Indexed: 06/07/2023]
Abstract
In molecular electronics, it is important to control the strength of the molecule-electrode interaction to balance the trade-off between electronic coupling strength and broadening of the molecular frontier orbitals: too strong coupling results in severe broadening of the molecular orbitals while the molecular orbitals cannot follow the changes in the Fermi levels under applied bias when the coupling is too weak. Here, a platform based on graphene bottom electrodes to which molecules can bind via π-π interactions is reported. These interactions are strong enough to induce electronic function (rectification) while minimizing broadening of the molecular frontier orbitals. Molecular tunnel junctions are fabricated based on self-assembled monolayers (SAMs) of Fc(CH2 )11 X (Fc = ferrocenyl, X = NH2 , Br, or H) on graphene bottom electrodes contacted to eutectic alloy of gallium and indium top electrodes. The Fc units interact more strongly with graphene than the X units resulting in SAMs with the Fc at the bottom of the SAM. The molecular diodes perform well with rectification ratios of 30-40, and they are stable against bias stressing under ambient conditions. Thus, tunnel junctions based on graphene with π-π molecule-electrode coupling are promising platforms to fabricate stable and well-performing molecular diodes.
Collapse
Affiliation(s)
- Peng Song
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Sarah Guerin
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Sherman Jun Rong Tan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Harshini Venkata Annadata
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - Micheál Scully
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Ying Mei Han
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Max Roemer
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
| |
Collapse
|
10
|
Abstract
Recognition and manipulation of graphene edges enable the control of physical properties of graphene-based devices. Recently, the authors have identified a peptide that preferentially binds to graphene edges from a combinatorial peptide library. In this study, the authors examine the functional basis for the edge binding peptide using experimental and computational methods. The effect of amino acid substitution, sequence context, and solution pH value on the binding of the peptide to graphene has been investigated. The N-terminus glutamic acid residue plays a key role in recognizing and binding to graphene edges. The protonation, substitution, and positional context of the glutamic acid residue impact graphene edge-binding. Our findings provide insights into the binding mechanisms and the design of peptides for recognizing and functionalizing graphene edges.
Collapse
|
11
|
Abstract
Understanding protein-inorganic surface interactions is central to the rational design of new tools in biomaterial sciences, nanobiotechnology and nanomedicine. Although a significant amount of experimental research on protein adsorption onto solid substrates has been reported, many aspects of the recognition and interaction mechanisms of biomolecules and inorganic surfaces are still unclear. Theoretical modeling and simulations provide complementary approaches for experimental studies, and they have been applied for exploring protein-surface binding mechanisms, the determinants of binding specificity towards different surfaces, as well as the thermodynamics and kinetics of adsorption. Although the general computational approaches employed to study the dynamics of proteins and materials are similar, the models and force-fields (FFs) used for describing the physical properties and interactions of material surfaces and biological molecules differ. In particular, FF and water models designed for use in biomolecular simulations are often not directly transferable to surface simulations and vice versa. The adsorption events span a wide range of time- and length-scales that vary from nanoseconds to days, and from nanometers to micrometers, respectively, rendering the use of multi-scale approaches unavoidable. Further, changes in the atomic structure of material surfaces that can lead to surface reconstruction, and in the structure of proteins that can result in complete denaturation of the adsorbed molecules, can create many intermediate structural and energetic states that complicate sampling. In this review, we address the challenges posed to theoretical and computational methods in achieving accurate descriptions of the physical, chemical and mechanical properties of protein-surface systems. In this context, we discuss the applicability of different modeling and simulation techniques ranging from quantum mechanics through all-atom molecular mechanics to coarse-grained approaches. We examine uses of different sampling methods, as well as free energy calculations. Furthermore, we review computational studies of protein-surface interactions and discuss the successes and limitations of current approaches.
Collapse
|
12
|
Song P, Sangeeth CSS, Thompson D, Du W, Loh KP, Nijhuis CA. Noncovalent Self-Assembled Monolayers on Graphene as a Highly Stable Platform for Molecular Tunnel Junctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:631-9. [PMID: 26618274 DOI: 10.1002/adma.201504207] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/02/2015] [Indexed: 05/16/2023]
Abstract
Monolayer graphene is used as the bottom electrode to fabricate stable and high-quality self-assembled monolayer (SAM)-based tunnel junctions. The SAMs are formed on graphene via noncovalent bonds without altering the structure of the graphene. This work paves the way to new types of molecular electronic junctions based on 2D materials.
Collapse
Affiliation(s)
- Peng Song
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - C S Suchand Sangeeth
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Damien Thompson
- Materials and Surface Science Institute and Department of Physics and Energy, University of Limerick, Co. Limerick, Ireland
| | - Wei Du
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| |
Collapse
|
13
|
Liu SH, Balankura T, Fichthorn KA. Self-assembled monolayer structures of hexadecylamine on Cu surfaces: density-functional theory. Phys Chem Chem Phys 2016; 18:32753-32761. [DOI: 10.1039/c6cp07030b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We used dispersion-corrected density-functional theory to probe possible structures for adsorbed layers of hexadecylamine (HDA) on Cu(111) (left) and Cu(100) (right).
Collapse
Affiliation(s)
- Shih-Hsien Liu
- Department of Chemical Engineering
- The Pennsylvania State University
- University Park
- USA
| | - Tonnam Balankura
- Department of Chemical Engineering
- The Pennsylvania State University
- University Park
- USA
| | - Kristen A. Fichthorn
- Department of Chemical Engineering
- The Pennsylvania State University
- University Park
- USA
| |
Collapse
|
14
|
Sprenger KG, He Y, Pfaendtner J. Probing How Defects in Self-assembled Monolayers Affect Peptide Adsorption with Molecular Simulation. FOUNDATIONS OF MOLECULAR MODELING AND SIMULATION 2016. [DOI: 10.1007/978-981-10-1128-3_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
15
|
Pykal M, Jurečka P, Karlický F, Otyepka M. Modelling of graphene functionalization. Phys Chem Chem Phys 2016; 18:6351-72. [DOI: 10.1039/c5cp03599f] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This perspective describes the available theoretical methods and models for simulating graphene functionalization based on quantum and classical mechanics.
Collapse
Affiliation(s)
- Martin Pykal
- Regional Centre of Advanced Technologies and Materials
- Department of Physical Chemistry
- Faculty of Science
- Palacký University Olomouc
- 771 46 Olomouc
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials
- Department of Physical Chemistry
- Faculty of Science
- Palacký University Olomouc
- 771 46 Olomouc
| | - František Karlický
- Regional Centre of Advanced Technologies and Materials
- Department of Physical Chemistry
- Faculty of Science
- Palacký University Olomouc
- 771 46 Olomouc
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials
- Department of Physical Chemistry
- Faculty of Science
- Palacký University Olomouc
- 771 46 Olomouc
| |
Collapse
|
16
|
Chen J, Wang Z, Oyola-Reynoso S, Gathiaka SM, Thuo M. Limits to the Effect of Substrate Roughness or Smoothness on the Odd-Even Effect in Wetting Properties of n-Alkanethiolate Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:7047-54. [PMID: 26065482 DOI: 10.1021/acs.langmuir.5b01662] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This study investigates the effect of roughness on interfacial properties of an n-alkanethiolate self-assembled monolayer (SAM) and uses hydrophobicity to demonstrate the existence of upper and lower limits. This article also sheds light on the origin of the previously unexplained gradual increase in contact angles with increases in the size of the molecule making the SAM. We prepared Au surfaces with a root-mean-square (RMS) roughness of ∼0.2-0.5 nm and compared the wetting properties of n-alkanethiolate (C10-C16) SAMs fabricated on these surfaces. Static contact angles, θ(s), formed between the SAM and water, diethylene glycol, and hexadecane showed an odd-even effect irrespective of the solvent properties. The average differences in subsequent SAM(E) and SAM(O) are Δθ(s|n – (n+1)|) ≈ 1.7° (n = even) and Δθ(s|n – (n+1)|) ≈ 3.1° (n = odd). A gradual increase in θ(s) with increasing length of the molecule was observed, with values ranging from water 104.7-110.7° (overall Δθ(s) = 6.0° while for the evens Δθ(s)(E) = 4.4° and odds Δθ(s)(O) = 3.5°) to diethylene glycol 72.9-80.4° (overall Δθ(s) = 7.5° while for the evens Δθ(s)(E) = 2.9° and odds Δθ(s)(O) = 2.4°) and hexadecane 40.4–49.4° (overall Δθ(s) = 9.0° while for the evens Δθ(s)(E) = 3.7° and odds Δθ(s)(O) = 2.1°). This article establishes that the gradual increase in θ(s) with increasing molecular size in SAMs is due to asymmetry in the zigzag oscillation in the odd-even effect. Comparison of the magnitude and proportion differences in this asymmetry allows us to establish the reduction in interfacial dispersive forces, due to increasing SAM crystallinity with increasing molecular size, as the origin of this asymmetry. By comparing the dependence of θ(s) on surface roughness we infer that (i) RMS roughness ≈ 1 nm is a theoretical limit beyond which the odd-even effect cannot be observed and (ii) on a hypothetically flat surface the maximum difference in hydrophobicity, as expressed in θ(s), is ∼3°.
Collapse
Affiliation(s)
- Jiahao Chen
- †Department of Materials Science and Engineering, Iowa State University, 2220 Hoover Hall, Ames, Iowa 50011, United States
- ‡Micro-Electronic Research Center, Iowa State University, 133 Applied Sciences Complex I, 1925 Scholl Road, Ames, Iowa 50011, United States
| | - Zhengjia Wang
- †Department of Materials Science and Engineering, Iowa State University, 2220 Hoover Hall, Ames, Iowa 50011, United States
| | - Stephanie Oyola-Reynoso
- †Department of Materials Science and Engineering, Iowa State University, 2220 Hoover Hall, Ames, Iowa 50011, United States
| | - Symon M Gathiaka
- §Department of Chemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Martin Thuo
- †Department of Materials Science and Engineering, Iowa State University, 2220 Hoover Hall, Ames, Iowa 50011, United States
- ‡Micro-Electronic Research Center, Iowa State University, 133 Applied Sciences Complex I, 1925 Scholl Road, Ames, Iowa 50011, United States
- ∥Biopolymer and Biocomposites Research Team, Center for Bioplastics and Biocomposites, Iowa State University, 1041 Food Sciences Building, Ames, Iowa 50011, United States
| |
Collapse
|
17
|
Kong L, Enders A, Rahman TS, Dowben PA. Molecular adsorption on graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:443001. [PMID: 25287516 DOI: 10.1088/0953-8984/26/44/443001] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Current studies addressing the engineering of charge carrier concentration and the electronic band gap in epitaxial graphene using molecular adsorbates are reviewed. The focus here is on interactions between the graphene surface and the adsorbed molecules, including small gas molecules (H(2)O, H(2), O(2), CO, NO(2), NO, and NH(3)), aromatic, and non-aromatic molecules (F4-TCNQ, PTCDA, TPA, Na-NH(2), An-CH(3), An-Br, Poly (ethylene imine) (PEI), and diazonium salts), and various biomolecules such as peptides, DNA fragments, and other derivatives. This is followed by a discussion on graphene-based gas sensor concepts. In reviewing the studies of the effects of molecular adsorption on graphene, it is evident that the strong manipulation of graphene's electronic structure, including p- and n-doping, is not only possible with molecular adsorbates, but that this approach appears to be superior compared to these exploiting edge effects, local defects, or strain. However, graphene-based gas sensors, albeit feasible because huge adsorbate-induced variations in the relative conductivity are possible, generally suffer from the lack of chemical selectivity.
Collapse
Affiliation(s)
- Lingmei Kong
- Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 North 16th Street, University of Nebraska, PO Box 880299, Lincoln, NE 68588-0299, USA
| | | | | | | |
Collapse
|
18
|
Peng C, Liu J, Zhao D, Zhou J. Adsorption of hydrophobin on different self-assembled monolayers: the role of the hydrophobic dipole and the electric dipole. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11401-11. [PMID: 25185838 DOI: 10.1021/la502595t] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In this work, the adsorptions of hydrophobin (HFBI) on four different self-assembled monolayers (SAMs) (i.e., CH3-SAM, OH-SAM, COOH-SAM, and NH2-SAM) were investigated by parallel tempering Monte Carlo and molecular dynamics simulations. Simulation results indicate that the orientation of HFBI adsorbed on neutral surfaces is dominated by a hydrophobic dipole. HFBI adsorbs on the hydrophobic CH3-SAM through its hydrophobic patch and adopts a nearly vertical hydrophobic dipole relative to the surface, while it is nearly horizontal when adsorbed on the hydrophilic OH-SAM. For charged SAM surfaces, HFBI adopts a nearly vertical electric dipole relative to the surface. HFBI has the narrowest orientation distribution on the CH3-SAM, and thus can form an ordered monolayer and reverse the wettability of the surface. For HFBI adsorption on charged SAMs, the adsorption strength weakens as the surface charge density increases. Compared with those on other SAMs, a larger area of the hydrophobic patch is exposed to the solution when HFBI adsorbs on the NH2-SAM. This leads to an increase of the hydrophobicity of the surface, which is consistent with the experimental results. The binding of HFBI to the CH3-SAM is mainly through hydrophobic interactions, while it is mediated through a hydration water layer near the surface for the OH-SAM. For the charged SAM surfaces, the adsorption is mainly induced by electrostatic interactions between the charged surfaces and the oppositely charged residues. The effect of a hydrophobic dipole on protein adsorption onto hydrophobic surfaces is similar to that of an electric dipole for charged surfaces. Therefore, the hydrophobic dipole may be applied to predict the probable orientations of protein adsorbed on hydrophobic surfaces.
Collapse
Affiliation(s)
- Chunwang Peng
- School of Chemistry and Chemical Engineering, Guangdong Provincial Key Lab for Green Chemical Product Technology, South China University of Technology , Guangzhou, Guangdong 510640, P. R. China
| | | | | | | |
Collapse
|
19
|
Yimer YY, Jha KC, Tsige M. Epitaxial transfer through end-group coordination modulates the odd-even effect in an alkanethiol monolayer assembly. NANOSCALE 2014; 6:3496-3502. [PMID: 24553572 DOI: 10.1039/c3nr05671f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Short spacer length and high end-group coordination lead to the top network acting as a template for the buried sulfur-gold interface of n-alkanethiols (SH-(CH2)n-OH or SH-(CH2)n-CH3) on gold {111}. Annealing and templating both drive toward a higher sampling of the spatially favorable bridge adsorption sites. The hydrogen-bonded network increases in strength by increasing the number of hydrogens participating per oxygen, from 1.75 to 1.98 for n = 14-30. Higher n leads to better packing (five times for hydroxyl-terminated and seven times for methyl-terminated for n = 14-30) and stability of monolayers, while lower n results in better epitaxial transfer (transfer coefficient ratio = 13.5 for {SH-(CH2)14-OH}/{SH-(CH2)30-CH3}) and actuation. Odd values of n for the hydroxyl-terminated n-alkanethiols lead to lattice spacing of an average of 0.04 ± 0.01 Å higher than even values. There is a structural transition in properties around spacer length n = 24-27. Characterization of monolayer assembly through correlation between adatom and network layers provides recursive design principles for actuation and sensing applications.
Collapse
Affiliation(s)
- Yeneneh Y Yimer
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, USA.
| | | | | |
Collapse
|
20
|
Jiang L, Yuan L, Cao L, Nijhuis CA. Controlling leakage currents: the role of the binding group and purity of the precursors for self-assembled monolayers in the performance of molecular diodes. J Am Chem Soc 2014; 136:1982-91. [PMID: 24401113 DOI: 10.1021/ja411116n] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This paper describes that the performance of molecular diodes based on self-assembled monolayers (SAMs) depends on the type of anchoring group and purity of the precursors of these SAMs. The SAMs were formed on ultrasmooth template-stripped silver (Ag(TS)) surfaces, which served as the bottom-electrode, and a eutectic alloy of gallium-indium was used as the top-electrode. When these junctions incorporate SAMs of the form S(CH2)11Fc (≡ SC11Fc) derived from HSC11Fc, they are good molecular diodes and rectify currents with rectification ratios R (≡ |J(-1.0 V)|/|J(+1.0 V)|) of ∼1.0 × 10(2). Replacing the thiol by disulfide or thioacetate functionalities in the precursor resulted in molecular diodes with values of R close to unity. Cyclic voltammetry and angle resolved X-ray photoelectron spectroscopy indicated that the SAMs derived from the disulfide or thioacetate precursors have lower surface coverages and are more defective than SAMs derived from thiols. In the junctions these defective SAMs caused defects and increased the leakage currents. The purity of the thiol-precursor is also crucial: 3 or 5% of disulfide present in the thiol caused a 28 or 61% decrease in R, respectively, and >15% of disulfide lowered R to unity, while the yield in nonshorting junctions remained unchanged. Our results show that the type of binding group, and the puritiy of the thiols, are crucial parameters in the experimental design of molecular electronic devices to ensure optimal device performance by keeping leakage currents to a minimum.
Collapse
Affiliation(s)
- Li Jiang
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543
| | | | | | | |
Collapse
|