Modification of Transparent Conducting Oxide (
            <scp>TCO</scp>
            ) Electrodes through Silanization and Chemisorption of Small Molecules

Brumbach, Michael T.; Armstrong, Neal R.

doi:10.1002/9783527610426.bard100101

Cited by 7 publications

(11 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For this purpose, we employed N,N ′-bis(2-phosphonoethyl)-3,4,9,10-perylenediimide (PPDI), a PDI derivative substituted with phosphonic acid groups (Scheme A). Phosphonic acid functionalities have been shown recently to be among the best ligands for ITO modification. − We studied the PPDI monolayer employing both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which is a very powerful AC technique, since it can resolve phenomena occurring at different time scales. The studies include the effect of applied bias on the EIS spectra of the PPDI monolayer.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Perylenediimide Self-Assembled Monolayer on Indium Tin Oxide Electrodes Using Electrochemical Impedance Spectroscopy

2014

View full text Add to dashboard Cite

Self-assembled monolayers (SAMs) of N,N′bis(2-phosphonoethyl)-3,4,9,10-perylenediimide (PPDI), a perylene dye substituted with phosphonic acid groups, were deposited on indium tin oxide (ITO) substrates. Dye deposition was confirmed by UV−visible absorption spectroscopy and by electrochemical methods. Electrochemical characterization of the SAM was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Two reversible redox waves were observed by CV for the PPDI monolayer, corresponding to E 1/2 = −0.49 V (radical anion formation) and E 1/2 = −0.90 V (dianion formation). The effect of applied bias on the EIS response was studied, comparing a region where PPDI was not reduced (applied bias = 0 V) with a region within the redox window of the imide (applied bias = −0.6 V). The EIS results were analyzed using either impedance (Nyquist and Bode) or capacitance (Cole−Cole) diagrams. Capacitance plots were shown to be by far more sensitive to study the faradaic activity of the SAM, allowing the determination of both the pseudocapacitance (C pc ) for charging the monolayer and the heterogeneous electron transfer rate constant (k et ) from the electrode to the SAM. A molecular coverage of 7 × 10 −11 mol/cm 2 was calculated for the SAM from the pseudocapacitance. A value of k et = 41 s −1 was obtained, consistent with literature data for similar systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterization of a Perylenediimide Self-Assembled Monolayer on Indium Tin Oxide Electrodes Using Electrochemical Impedance Spectroscopy

2014

View full text Add to dashboard Cite

show abstract

“…Such reactions involve silanes, 31−33 phosphonic acids, 34 or other small molecules. 24,30 There are evidences, for instance, that indium tin oxide (ITO) modified surface increases electron transfer properties, 35 optimizes light trapping, 36,37 allows tuning surface roughness and tribological properties via any plasma activation. 38,39 However, there are still unsolved problems mainly related to long-term and thermal stability, reproducibility of the treatment, chemical surface homogeneity after modification, and controlled protocols for monolayer formation.…”

Section: ■ Introductionmentioning

confidence: 99%

Surface Functionalization of Fluorine-Doped Tin Oxide Samples through Electrochemical Grafting

Lamberti

Agnoli

Brigo

et al. 2013

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Transparent conductive oxides are emerging materials in several fields, such as photovoltaics, photoelectrochemistry, and optical biosensing. Their high chemical inertia, which ensured long-term stability on one side, makes challenging the surface modification of transparent conductive oxides; long-term robust modification, high yields, and selective surface modifications are essential prerequisite for any further developments. In this work, we aim at inducing chemical functionality on fluorine-doped tin oxide surfaces (one of the most inexpensive transparent conductive oxide) by means of electrochemical grafting of aryl diazonium cations. The grafted layers are fully characterized by photoemission spectroscopy, cyclic voltammetry, and atomic force microscopy showing linear correlation between surface coverage and degree of modification. The electrochemical barrier effect of modified surfaces was studied at different pH to characterize the chemical nature of the coating. We showed immuno recognition of biotin complex built onto grafted fluorine-doped tin oxides, which opens the perspective of integrating FTO samples with biological-based devices.

show abstract

“…10,18 Several successful strategies have been developed for the modification of ITO and related oxide surfaces, including the addition of modifiers through covalent bond formation (e.g., silanes) [28][29][30] and the chemisorption of carboxylic acids, phosphonic acids, and thiols. 22,[31][32][33] The recent studies of Zotti and co-workers, 34 involving carboxylic acid-and phosphonic acidterminated thiophene monomers on ITO, are particularly notable. Their modification method starts with thiophene monomers that are functionalized at the 2-position with alkyl-COOH or alkyl-PO 3 groups, which provide for attachment at the ITO surface and ensure that polymerization occurs perpendicular to the ITO surface, forming "brush-like" polymer chains.…”

Section: Introductionmentioning

confidence: 99%

Modification of Indium−Tin Oxide Electrodes with Thiophene Copolymer Thin Films: Optimizing Electron Transfer to Solution Probe Molecules

et al. 2006

Self Cite

View full text Add to dashboard Cite

We describe the modification of indium-tin oxide (ITO) electrodes via the chemisorption and electropolymerization of 6-{2,3-dihydrothieno[3,4-b]-1.4-dioxyn-2-yl methoxy}hexanoic acid (EDOTCA) and the electrochemical co-polymerization of 3,4-ethylenedioxythiophene (EDOT) and EDOTCA to form ultrathin films that optimize electron-transfer rates to solution probe molecules. ITO electrodes were first activated using brief exposure to strong haloacids, to remove the top approximately 8 nm of the electrode surface, followed by immediate immersion into a 50:50 EDOT/EDOTCA co-monomer solution. Potential step electrodeposition for brief deposition times was used to grow copolymer films of thickness 10-100 nm. The composition of these copolymer films was characterized by solution depletion studies of the monomers and atomic force microscopy (AFM), X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy (reflection-absorption infrared spectroscopy (RAIRS)) of the product films. The spectroscopic data suggest that the composition of the copolymer approaches 80% EDOTCA when electropolymerization occurs from concentrated (10 mM) solutions. AFM characterization shows that electrodeposited poly(EDOT)/poly(EDOTCA) (PEDOT/PEDOTCA) films are quite smooth, with texturing on the nanometer scale. RAIRS studies indicate that these films consist of a combination of EDOTCA units with noninteracting -COOH groups and adjacent hydrogen-bonded -COOH groups. The EDOTCA-containing polymer chains appear to grow as columnar clusters from specific regions, oriented nearly vertically to the substrate plane. As they grow, these columnar clusters overlap to form a nearly continuous redox active polymer film. ITO activation and formation of these copolymer films enhances the electroactive fraction of the electrode surface relative to a nonactivated, unmodified "blocked" ITO electrode. Outer-sphere solution redox probes (dimethylferrocene) give standard rate coefficients, kS > or = 0.4 cm.s-1, at 10 nm thick copolymer films of PEDOT/PEDOTCA, which is 3 orders of magnitude greater than that on the unmodified ITO surface and approaches the values for kS seen on clean gold surfaces.

show abstract

Modification of Transparent Conducting Oxide ( TCO ) Electrodes through Silanization and Chemisorption of Small Molecules

Abstract: The sections in this article are Introduction The Metal Oxide Electrode and Modification Schemes Commonly Encountered TCO Electrodes Variability in TCO Electrodes Factors that Control the Surface… Show more

Cited by 7 publications

References 78 publications

Characterization of a Perylenediimide Self-Assembled Monolayer on Indium Tin Oxide Electrodes Using Electrochemical Impedance Spectroscopy

Characterization of a Perylenediimide Self-Assembled Monolayer on Indium Tin Oxide Electrodes Using Electrochemical Impedance Spectroscopy

Surface Functionalization of Fluorine-Doped Tin Oxide Samples through Electrochemical Grafting

Modification of Indium−Tin Oxide Electrodes with Thiophene Copolymer Thin Films: Optimizing Electron Transfer to Solution Probe Molecules

Contact Info

Product

Resources

About