1
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Ma Y, Li Q, Wang S, Wang Y, Liu H, Wang X, Zhao B, Jiang Z, Ruan W. Observation of tunable surface plasmon resonances and surface enhanced infrared absorption (SEIRA) based on indium tin oxide (ITO) nanoparticle substrates. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 271:120914. [PMID: 35074675 DOI: 10.1016/j.saa.2022.120914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/09/2022] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
The application of surface enhanced infrared absorption (SEIRA) is severely restricted in many fields due to the SEIRA substrates are constructed mainly from expensive noble metals. Therefore, the development of new SEIRA substrates other than the noble metallic ones is very valuable. Here we introduced a new semiconductor SEIRA substrate, the indium tin oxide (ITO) nanoparticles (NPs), to study the SEIRA property. The results demonstrate that the ITO NPs show the SEIRA property and the enhancement is dependent to the doping ratio of the heteroatoms of tin. The ITO NPs with the 5% atomic doping ratio show the highest SEIRA enhancement factor (EF), which is about 24. The limit of detection (LOD) of the 1,1'-dicarboxyferrocene (dcFc) molecule was as low as 10-5 mol/L. The present study proves that the tin-doped indium oxide can be used as a new and inexpensive semiconductor SEIRA substrate. It also proves that the doped semiconductor NPs have strong potentials for being used as emerging SEIRA substrates.
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Affiliation(s)
- Yan Ma
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Qianwen Li
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Siyu Wang
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yanan Wang
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Hongye Liu
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Xu Wang
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Bing Zhao
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Ziping Jiang
- Department of Hand and Foot Surgery, First Hospital of Jilin University, Jilin University, Changchun 130021, P. R. China.
| | - Weidong Ruan
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
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2
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Wahab O, Kang M, Meloni GN, Daviddi E, Unwin PR. Nanoscale Visualization of Electrochemical Activity at Indium Tin Oxide Electrodes. Anal Chem 2022; 94:4729-4736. [PMID: 35255211 PMCID: PMC9007413 DOI: 10.1021/acs.analchem.1c05168] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/11/2022] [Indexed: 01/08/2023]
Abstract
Indium tin oxide (ITO) is a popular electrode choice, with diverse applications in (photo)electrocatalysis, organic photovoltaics, spectroelectrochemistry and sensing, and as a support for cell biology studies. Although ITO surfaces exhibit heterogeneous local electrical conductivity, little is known as to how this translates to electrochemistry at the same scale. This work investigates nanoscale electrochemistry at ITO electrodes using high-resolution scanning electrochemical cell microscopy (SECCM). The nominally fast outer-sphere one-electron oxidation of 1,1'-ferrocenedimethanol (FcDM) is used as an electron transfer (ET) kinetic marker to reveal the charge transfer properties of the ITO/electrolyte interface. SECCM measures spatially resolved linear sweep voltammetry at an array of points across the ITO surface, with the topography measured synchronously. Presentation of SECCM data as current maps as a function of potential reveals that, while the entire surface of ITO is electroactive, the ET activity is highly spatially heterogeneous. Kinetic parameters (standard rate constant, k0, and transfer coefficient, α) for FcDM0/+ are assigned from 7200 measurements at sites across the ITO surface using finite element method modeling. Differences of 3 orders of magnitude in k0 are revealed, and the average k0 is about 20 times larger than that measured at the macroscale. This is attributed to macroscale ET being largely limited by lateral conductivity of the ITO electrode under electrochemical operation, rather than ET kinetics at the ITO/electrolyte interface, as measured by SECCM. This study further demonstrates the considerable power of SECCM for direct nanoscale characterization of electrochemical processes at complex electrode surfaces.
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Affiliation(s)
- Oluwasegun
J. Wahab
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Minkyung Kang
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
- Institute
for Frontier Materials Deakin University, Burwood, Victoria 3125, Australia
| | - Gabriel N. Meloni
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Enrico Daviddi
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Patrick R. Unwin
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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3
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Ko M, Kim HU, Jeon N. Boosting Electrochemical Activity of Porous Transparent Conductive Oxides Electrodes Prepared by Sequential Infiltration Synthesis. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2105898. [PMID: 35187788 DOI: 10.1002/smll.202105898] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Sequential infiltration synthesis (SIS) is an emerging technique for producing inorganic-organic hybrid materials and templated inorganic nanomaterials. The application space for SIS is expanding rapidly in areas such as lithography, filtration, photovoltaics, antireflection, and triboelectricity, but not in the field of electrochemistry. This study performs SIS for the fabrication of porous, transparent, and electrically conductive films of indium zinc oxide (IZO) to evaluate their potential as an electrode for electrochemistry. The electrochemical activity of IZO-coated electrodes is evaluated when their surfaces are modified with ferrocenecarboxylic acid (FcCOOH), a model redox molecule. Results show a 25-fold enhancement in peak current densities mediated by an Fc/Fc+ redox couple for an IZO-coated electrode in comparison with bare electrodes; this is afforded by the porous morphology of the IZO film and the enhanced binding efficiency of FcCOOH on the IZO film. The results confirm the potential of SIS for the preparation of porous transparent conducting oxide electrodes, which will enable the application of SIS-derived materials in various electrochemical fields.
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Affiliation(s)
- Minkyung Ko
- Department of Materials Science and Engineering, Chungnam National University, 99, Daehak-ro, Yuseong-gu, Daejeon, 34134, Republic of Korea
| | - Hyeong-U Kim
- Department of Plasma Engineering, Korea Institute of Machinery and Materials (KIMM), Daejeon, 34103, Republic of Korea
| | - Nari Jeon
- Department of Materials Science and Engineering, Chungnam National University, 99, Daehak-ro, Yuseong-gu, Daejeon, 34134, Republic of Korea
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4
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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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5
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Bandyopadhyay P, Jana R, Bhattacharyya K, Lebedev OI, Dutta U, Sarkar U, Datta A, Seikh MM. Interaction of a bioactive molecule with surfaces of nanoscale transition metal oxides: experimental and theoretical studies. NEW J CHEM 2019. [DOI: 10.1039/c9nj03124c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Schematic diagram of metal oxide–BTT interaction and the associated changes in experimental UV-Vis spectra. BTT adsorbed α-Fe2O3 is represented by red spectra, while green spectra represent BTT adsorbed NiO. Black spectra represent pure BTT spectra.
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Affiliation(s)
| | - Rajkumar Jana
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | | | | | - Uma Dutta
- Department of Chemistry
- Visva-Bharati
- Santiniketan-731235
- India
| | - Utpal Sarkar
- Department of Physics
- Assam University
- Silchar-788011
- India
| | - Ayan Datta
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Md Motin Seikh
- Department of Chemistry
- Visva-Bharati
- Santiniketan-731235
- India
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6
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Wu JT, Fan YZ, Liou GS. Synthesis, characterization and electrochromic properties of novel redox triarylamine-based aromatic polyethers with methoxy protecting groups. Polym Chem 2019. [DOI: 10.1039/c8py01308j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two series of novel redox aromatic polyethers were synthesized successfully from disilyl ether-containing triphenylamine-based monomers and they display one to three stage electrochromism with interesting and multi-coloured changes.
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Affiliation(s)
- Jung-Tsu Wu
- Institute of Polymer Science and Engineering
- National Taiwan University
- Taipei
- Taiwan
| | - Yang-Ze Fan
- Institute of Polymer Science and Engineering
- National Taiwan University
- Taipei
- Taiwan
| | - Guey-Sheng Liou
- Institute of Polymer Science and Engineering
- National Taiwan University
- Taipei
- Taiwan
- Advanced Research Center for Green Materials Science and Technology
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7
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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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8
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Lewtak JP, Landman M, Fernández I, Swarts JC. A DFT-Elucidated Comparison of the Solution-Phase and SAM Electrochemical Properties of Short-Chain Mercaptoalkylferrocenes: Synthetic and Spectroscopic Aspects, and the Structure of Fc-CH2CH2-S-S-CH2CH2-Fc. Inorg Chem 2016; 55:2584-96. [PMID: 26901655 DOI: 10.1021/acs.inorgchem.5b02936] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Facile synthetic procedures to synthesize a series of difficult-to-obtain mercaptoalkylferrocenes, namely, Fc(CH2)nSH, where n = 1 (1), 2 (2), 3 (3), or 4 (4) and Fc = Fe(η(5)-C5H5)(η(5)-C5H4), are reported. Dimerization of 1-4 to the corresponding disulfides 19-22 was observed in air. Dimer 20 (Z = 2) crystallized in the triclinic space group P1̅. Dimers 20-22 could be reduced back to the original Fc(CH2)nSH derivatives with LiAlH4 in refluxing tetrahydrofuran. Density functional theory (DFT) calculations showed that the highest occupied molecular orbital of 1-4 lies exclusively on the ferrocenyl group implying that the electrochemical oxidation observed at ca. -15 < Epa < 76 mV versus FcH/FcH(+) involves exclusively an Fe(II) to Fe(III) process. Further DFT calculations showed this one-electron oxidation is followed by proton loss on the thiol group to generate a radical, Fc(CH2)nS(•), with spin density mainly located on the sulfur. Rapid exothermic dimerization leads to the observed dimers, Fc(CH2)n-S-S-(CH 2)nFc. Reduction of the ferrocenium groups on the dimer occurs at potentials that still showed the ferrocenyl group ΔE = Epa,monomer - Epc,dimer ≤ 78 mV, indicating that the redox properties of the ferrocenyl group on the mercaptans are very similar to those of the dimer. (1)H NMR measurements showed that, like ferrocenyl oxidation, the resonance position of the sulfhydryl proton, SH, and others, are dependent on -(CH2)n- chain length. Self-assembled monolayers (SAMs) on gold were generated to investigate the electrochemical behavior of 1-4 in the absence of diffusion. Under these conditions, ΔE approached 0 mV for the longer chain derivatives at slow scan rates. The surface-bound ferrocenyl group of the metal-thioether, Fc(CH2)n -S-Au, is oxidized at approximately equal potentials as the equivalent CH2Cl2-dissolved ferrocenyl species 1-4. Surface coverage by the SAMs is dependent on alkyl chain length with the largest coverage obtained for 4, while the rate of heterogeneous electron transfer between SAM substrate and electrode was the fastest for the shortest chain derivative, Fc-CH2-S-Au.
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Affiliation(s)
- Jan P Lewtak
- Department of Chemistry, University of the Free State , P.O. Box 339, Bloemfontein 9300, Republic of South Africa
| | - Marilé Landman
- Department of Chemistry, University of Pretoria , Private Bag X20, Hatfield 0028, Republic of South Africa
| | - Israel Fernández
- Departamento de Química Orgánica I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain
| | - Jannie C Swarts
- Department of Chemistry, University of the Free State , P.O. Box 339, Bloemfontein 9300, Republic of South Africa
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9
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Lin CC, Cho CP. Modified photoanodes by amino-containing phosphonate self-assembled monolayers to improve the efficiency of dye-sensitized solar cells. RSC Adv 2016. [DOI: 10.1039/c6ra07810a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Surface modification by selected molecules to form self-assembled monolayers (SAMs) on the surface of TiO2 electrodes could lower the energy barrier of electron transfer and improve DSSC performance efficiently.
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Affiliation(s)
- Chun-Chu Lin
- Department of Applied Materials and Optoelectronic Engineering
- National Chi Nan University
- Nantou County 54561
- Taiwan
| | - Chun-Pei Cho
- Department of Applied Materials and Optoelectronic Engineering
- National Chi Nan University
- Nantou County 54561
- Taiwan
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10
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Wei B, Liu J, Ouyang L, Kuo CC, Martin DC. Significant enhancement of PEDOT thin film adhesion to inorganic solid substrates with EDOT-acid. ACS APPLIED MATERIALS & INTERFACES 2015; 7:15388-94. [PMID: 26052833 DOI: 10.1021/acsami.5b03350] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
With its high conductivity, tunable surface morphology, relatively soft mechanical response, high chemical stability, and excellent biocompatibility, poly(3,4-ethylenedioxythiophene) (PEDOT) has become a promising coating material for a variety of electronic biomedical devices. However, the relatively poor adhesion of PEDOT to inorganic metallic and semiconducting substrates still poses challenges for long-term applications. Here, we report that 2,3-dihydrothieno(3,4-b)(1,4)dioxine-2-carboxylic acid (EDOT-acid) significantly improves the adhesion between PEDOT thin films and inorganic solid electrodes. EDOT-acid molecules were chemically bonded onto activated oxide substrates via the chemisorption of the carboxylic groups. PEDOT was then polymerized onto the EDOT-acid modified substrates, forming covalently bonded coatings. The adsorption of EDOT-acid onto the electrode surfaces was characterized by cyclic voltammetry (CV), contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy. The electrical properties of the subsequently coated PEDOT films were studied by electrochemical impedance spectroscopy and CV. An aggressive ultrasonication test confirmed the significantly improved adhesion and mechanical stability of the PEDOT films on electrodes with EDOT-acid treatment over those without treatment.
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Affiliation(s)
- Bin Wei
- †Department of Materials Science and Engineering, The University of Delaware, Newark, Delaware 19716, United States
| | - Jinglin Liu
- †Department of Materials Science and Engineering, The University of Delaware, Newark, Delaware 19716, United States
| | - Liangqi Ouyang
- †Department of Materials Science and Engineering, The University of Delaware, Newark, Delaware 19716, United States
| | - Chin-Chen Kuo
- †Department of Materials Science and Engineering, The University of Delaware, Newark, Delaware 19716, United States
| | - David C Martin
- †Department of Materials Science and Engineering, The University of Delaware, Newark, Delaware 19716, United States
- ‡Department of Biomedical Engineering, The University of Delaware, Newark, Delaware 19716, United States
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11
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Cui BB, Zhong YW, Yao J. Three-state near-infrared electrochromism at the molecular scale. J Am Chem Soc 2015; 137:4058-61. [PMID: 25775114 DOI: 10.1021/jacs.5b00586] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Self-assembled monolayer films of a cyclometalated ruthenium complex with a redox-active amine substituent and three carboxylic acid groups have been prepared on ITO electrode surfaces. The obtained thin films show three-state electrochromic switching with low electrochemical potential inputs and high near-infrared absorbance outputs. Thanks to the long retention time of each oxidation states, these films have been used to demonstrate surface-confined flip-flop memory functions with high ON/OFF ratios at the molecular scale.
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Affiliation(s)
- Bin-Bin Cui
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yu-Wu Zhong
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Jiannian Yao
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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12
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Joubert CC, van As L, Jakob A, Speck JM, Lang H, Swarts JC. Intramolecular electronic communication in ferrocene-based β-diketonato copper(II) complexes as observed by an electrochemical study. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.02.059] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Kühnert J, Hahn H, Rüffer T, Walfort B, Lang H. Silver(I) ferrocenylcarboxylate: Reactivity and reaction behavior toward phosphines and phosphites. J Organomet Chem 2013. [DOI: 10.1016/j.jorganchem.2012.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Gao Z, Deng H, Shen W, Ren Y. A Label-Free Biosensor for Electrochemical Detection of Femtomolar MicroRNAs. Anal Chem 2013; 85:1624-30. [DOI: 10.1021/ac302883c] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Zhiqiang Gao
- Department of Chemistry, National University of Singapore, Singapore 117543
| | - Huimin Deng
- Department of Chemistry, National University of Singapore, Singapore 117543
| | - Wei Shen
- Department of Chemistry, National University of Singapore, Singapore 117543
| | - Yuqian Ren
- Department of Chemistry, National University of Singapore, Singapore 117543
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15
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Chen X, Luais E, Darwish N, Ciampi S, Thordarson P, Gooding JJ. Studies on the effect of solvents on self-assembled monolayers formed from organophosphonic acids on indium tin oxide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:9487-9495. [PMID: 22621243 DOI: 10.1021/la3010129] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The preparation of self-assembled monolayers (SAMs) of organophosphonic acids on indium tin oxide (ITO) surfaces from different solvents (triethylamine, ethyl ether, tetrahydofuran (THF), pyridine, acetone, methanol, acetonitrile, dimethyl sulfoxide (DMSO), or water) has been performed with some significant differences observed. Cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and contact angle measurement demonstrated that the quality of SAMs depends critically on the choice of solvents. Higher density, more stable monolayers were formed from solvents with low dielectric constants and weak interactions with the ITO. It was concluded low dielectric solvents that were inert to the ITO gave monolayers that were more stable with a higher density of surface bound molecules because higher dielectric constant solvents and solvents that coordinate with the surface disrupted SAM formation.
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Affiliation(s)
- Xin Chen
- School of Chemistry, University of New South Wales, Sydney NSW 2052, Australia
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16
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Chockalingam M, Darwish N, Le Saux G, Gooding JJ. Importance of the indium tin oxide substrate on the quality of self-assembled monolayers formed from organophosphonic acids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:2545-2552. [PMID: 21314169 DOI: 10.1021/la104464w] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The role of indium tin oxide (ITO) surface structure and chemistry on the formation of self-assembled monolayers (SAM) derived from organophosphonic acids has been investigated. The surface hydroxide content, crystal structure, and roughness of unmodified ITO surfaces were analyzed with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and contact angle measurements. Organophosphonic acid monolayer modified ITO surfaces were then characterized using electrochemistry, contact angle measurements and impedance spectroscopy. To ascertain the extent of defects, Pb was underpotentially deposited (UPD) onto the monolayer modified ITO surfaces at defect sites and regions where the monolayer was weakly bound. The extent of defects, and the location of defects, in monolayers formed on different ITO surfaces were determined from the amount of charge passed during UPD of Pb at identical conditions, followed by XPS analysis of the Pb 4f peak and imaging with scanning tunnelling microscopy (STM). The results demonstrate that the crystal structure and hydroxide ion concentration of ITO surfaces significantly influence the quality of self-assembled monolayer formation as does the surface roughness. The most well-packed stable monolayers formed only on smooth amorphous ITO substrates with homogeneous grains and high hydroxide content. Lower quality SAMs with significant defects formed on polycrystalline surfaces and the higher the roughness the more the defects. STM defect mapping revealed that the location of defects in monolayers occurred at the boundaries between grain edges on the polycrystalline surfaces. This shows that the substrate characteristics have a strong influence on the quality of monolayers formed on ITO surfaces.
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Hains AW, Liang Z, Woodhouse MA, Gregg BA. Molecular Semiconductors in Organic Photovoltaic Cells. Chem Rev 2010; 110:6689-735. [PMID: 20184362 DOI: 10.1021/cr9002984] [Citation(s) in RCA: 464] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Alexander W. Hains
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Ziqi Liang
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Michael A. Woodhouse
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Brian A. Gregg
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
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Shallcross RC, D’Ambruoso GD, Pyun J, Armstrong NR. Photoelectrochemical Processes in Polymer-Tethered CdSe Nanocrystals. J Am Chem Soc 2010; 132:2622-32. [DOI: 10.1021/ja907782f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Jeffrey Pyun
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Neal R. Armstrong
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
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Li H, Paramonov P, Bredas JL. Theoretical study of the surface modification of indium tin oxide with trifluorophenyl phosphonic acid molecules: impact of coverage density and binding geometry. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b921768a] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Paradinas M, Garzón L, Sánchez F, Bachelet R, Amabilino DB, Fontcuberta J, Ocal C. Tuning the local frictional and electrostatic responses of nanostructured SrTiO3—surfaces by self-assembled molecular monolayers. Phys Chem Chem Phys 2010; 12:4452-8. [DOI: 10.1039/b924227a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Armstrong NR, Veneman PA, Ratcliff E, Placencia D, Brumbach M. Oxide contacts in organic photovoltaics: characterization and control of near-surface composition in indium-tin oxide (ITO) electrodes. Acc Chem Res 2009; 42:1748-57. [PMID: 19728725 DOI: 10.1021/ar900096f] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The recent improvements in the power conversion efficiencies of organic photovoltaic devices (OPVs) promise to make these technologies increasingly attractive alternatives to more established photovoltaic technologies. OPVs typically consist of photoactive layers 20-100 nm thick sandwiched between both transparent oxide and metallic electrical contacts. Ideal OPVs rely on ohmic top and bottom contacts to harvest photogenerated charges without compromising the power conversion efficiency of the OPV. Unfortunately, the electrical contact materials (metals and metal oxides) and the active organic layers in OPVs are often incompatible and may be poorly optimized for harvesting photogenerated charges. Therefore, further optimization of the chemical and physical stabilities of these metal oxide materials with organic materials will be an essential component of the development of OPV technologies. The energetic and kinetic barriers to charge injection/collection must be minimized to maximize OPV power conversion efficiencies. In this Account, we review recent studies of one of the most common transparent conducting oxides (TCOs), indium-tin oxide (ITO), which is the transparent bottom contact in many OPV technologies. These studies of the surface chemistry and surface modification of ITO are also applicable to other TCO materials. Clean, freshly deposited ITO is intrinsically reactive toward H(2)O, CO, CO(2), etc. and is often chemically and electrically heterogeneous in the near-surface region. Conductive-tip atomic force microscopy (C-AFM) studies reveal significant spatial variability in electrical properties. We describe the use of acid activation, small-molecule chemisorption, and electrodeposition of conducting polymer films to tune the surface free energy, the effective work function, and electrochemical reactivity of ITO surfaces. Certain electrodeposited poly(thiophenes) show their own photovoltaic activity or can be used as electronically tunable substrates for other photoactive layers. For certain photoactive donor layers (phthalocyanines), we have used the polarity of the oxide surface to accelerate dewetting and "nanotexturing" of the donor layer to enhance OPV performance. These complex surface chemistries will make oxide/organic interfaces one of the key focal points for research in new OPV technologies.
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Affiliation(s)
- Neal R. Armstrong
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - P. Alex Veneman
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Erin Ratcliff
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
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Brumbach MT, Boal AK, Wheeler DR. Metalloporphyrin assemblies on pyridine-functionalized titanium dioxide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10685-10690. [PMID: 19678616 DOI: 10.1021/la901130a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Porphyrin adsorption on TiO2 nanoparticles has been achieved for multiple porphyrins, and in mixed porphyrin assemblies, via axial ligation to surface-bound pyridine anchored by either para carboxylic or phosphonic functionalizations. Homogenous assemblies were prepared and characterized, while mixed metalloporphyrin assemblies were demonstrated by controlling the concentration ratios of respective porphyrins in the modifying solution. Evaluation of the assemblies using spectroscopic techniques and electrochemistry confirms high porphyrin retention, while exhibiting their surface bound optical and electrochemical properties. A thorough study is discussed where several metalloporphyrins have been evaluated (Ru(CO)OEP, Ru(CO)TPP, and ZnTPP) for relative comparisons and relationships to pyridyl axial binding strengths. The systematic study evaluates multiple background cases using either H2TPP, TiO2 modification with benzoic acid, or unmodified TiO2 to confirm the high affinity of Ru and Zn porphyrins for surface-anchored pyridyl sites. The simple method of step-by-step coordinative anchoring of porphyrins to TiO2 using small, commercially available molecules is highly adaptable for use in dye-sensitized solar cells (DSSC) where intimate contact between the absorbing dye and the semiconductor is required. DSSC devices with novel mixed porphyrin assemblies were shown to give higher power performance than DSSCs utilizing sensitization with only one type of porphyrin.
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Sone K, Yagi M. Chemical Adsorption onto an ITO Substrate of Single-Wall Carbon Nanotube Functionalized by Carboxylic Groups as an Efficient Support for Electrocatalyst. ELECTROANAL 2009. [DOI: 10.1002/elan.200804412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Li J, Wang L, Liu J, Evmenenko G, Dutta P, Marks TJ. Characterization of transparent conducting oxide surfaces using self-assembled electroactive monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:5755-5765. [PMID: 18457433 DOI: 10.1021/la704038g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The electronic properties of various transparent conducting oxide (TCO) surfaces are probed electrochemically via self-assembled monolayers (SAMs). A novel graftable probe molecule having a tethered trichlorosilyl group and a redox-active ferrocenyl functionality (Fc(CH2) 4SiCl3) is synthesized for this purpose. This molecule can be self-assembled via covalent bonds to form monolayers on various TCO surfaces. On as-received ITO, saturation coverage of 6.6 x 10(-10) mol/cm2 by a close-packed monolayer and an electron-transfer rate of 6.65 s(-1) is achieved after 9 h of chemisorption, as determined by cyclic voltammetry (CV) and synchrotron X-ray reflectivity. With this molecular probe, it is found that O2 plasma-treated ITO has a significantly greater electroactive coverage of 7.9 x 10 (-10) mol/cm2 than as-received ITO. CV studies of this redox SAM on five different TCO surfaces reveal that MOCVD-derived CdO exhibits the greatest electroactive coverage (8.1 x 10(-10) mol/cm2) and MOCVD-derived ZITO (ZnIn2.0Sn1.5O) exhibits the highest electron transfer rate (7.12 s(-1)).
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Affiliation(s)
- Jianfeng Li
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
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Brumbach M, Veneman PA, Marrikar FS, Schulmeyer T, Simmonds A, Xia W, Lee P, Armstrong NR. Surface composition and electrical and electrochemical properties of freshly deposited and acid-etched indium tin oxide electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:11089-99. [PMID: 17880253 DOI: 10.1021/la701754u] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We compare the near-surface composition and electroactivity of commercial indium tin oxide (ITO) thin films, activated by plasma cleaning or etching with strong haloacids, with ITO films that have been freshly deposited in high vacuum, before and after exposure to the atmosphere or water vapor. Conductive-tip AFM, X-ray photoelectron spectroscopy (XPS), and the electrochemistry of probe molecules in solution were used to compare the relative degrees of electroactivity and the near-surface composition of these materials. Brief etching of commercial ITO samples with concentrated HCl or HI significantly enhances the electrical activity of these oxides as revealed by C-AFM. XPS was used to compare the composition of these activated surfaces, focusing on the intrinsically asymmetric O 1s line shape. Energy-loss processes associated with photoemission from the tin-doped, oxygen-deficient oxides complicate the interpretation of the O 1s spectra. O 1s spectra from the stoichiometric indium oxide lattice are accompanied by higher-binding-energy peaks associated with hydroxylated forms of the oxide (and in some cases carbonaceous impurities) and overlapping photoemission associated with energy-loss processes. Characterization of freshly sputter-deposited indium oxide (IO) and ITO films, transferred under high vacuum to the surface analysis environment, allowed us to differentiate the contributions of tin doping and oxygen-vacancy doping to the O 1s line shape, relative to higher-binding-energy O 1s components associated with hydroxyl species and carbonaceous impurities. Using these approaches, we determined that acid activation and O2 plasma etching create an ITO surface that is still covered with an average of one to two monolayers of hydroxide. Both of these activation treatments lead to significantly higher rates of electron transfer to solution probe molecules, such as dimethyferrocene in acetonitrile. Solution electron-transfer events appear to occur at no more than 4x10(7) electroactive sites per cm2 (each with diameters of ca. 50-200 nm) (i.e., a small fraction of the geometric area of the electrode). Electron-transfer rates correlate with the near-surface tin dopant concentration, suggesting that these electroactive sites arise from near-surface tin enrichment.
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Affiliation(s)
- Michael Brumbach
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
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