Electron transfer kinetics across derivatized self-assembled monolayers on platinum: a cyclic voltammetry and electrochemical impedance spectroscopy study

Brito, Rosa; Tremont, Rolando; Cabrera, Carlos R.

doi:10.1016/j.jelechem.2004.05.031

Cited by 27 publications

(16 citation statements)

References 28 publications

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“…The blocking behavior towards the hexacyanoferrate(III) reduction was used to characterize the mixed SAM, as shown in Figure 3. A SAM of MPA adsorbed on the entire poly-Au shows no blocking ability towards Fe(CN) 6 3À , in agreement with the findings for MPA on Au [17] and Pt electrodes [24]. Voltammogram (a) in Figure 3 does not differ from the voltammogram using a bare gold electrode.…”

Section: Formation Of Mixed Monolayerssupporting

confidence: 87%

Microstructures by Selective Desorption of Self‐Assembled Monolayer from Polycrystalline Gold Electrodes

Strutwolf

O’Sullivan

2007

Electroanalysis

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Potential-controlled partial reductive desorption of a self-assembled monolayer of mercaptopropionic acid (MPA) formed on polycrystalline gold electrodes is used to expose subdomains of bare gold to the electrolyte solution. Two sets of cathodic waves are observed in the reduction scan with MPA self-assembled on a polycrystalline gold electrode. The origin of the two waves is ambiguous but there are indications that the waves are correlated with reductive desorption from the (111) and then simultaneously (100) and (110) index faces of a polycrystalline gold electrode. Consecutive reduction scans with reversing the potential direction after the first peak (but before the onset of the second wave) results in disappearance of the first wave. The exposed domains are then blocked by an assembling process of longer chain alkanethiols to create a mixed self-assembled monolayer on polycrystalline gold electrodes. Desorption of the remaining MPA creates a partially blocked electrode and the blocking behavior towards hexacyanoferrate(III) is analyzed using the theory of partially blocked electrodes and indicates an array of interacting centers. The approach of partial reductive desorption may be exploited for use in biosensing applications where the exposed gold domains could be used for anchoring of DNA probes.

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Section: Formation Of Mixed Monolayerssupporting

confidence: 87%

Microstructures by Selective Desorption of Self‐Assembled Monolayer from Polycrystalline Gold Electrodes

Strutwolf

O’Sullivan

2007

Electroanalysis

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“…SAMs of alkanethiols and alkanedithiols on gold [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] are the most extensively studied due to the formation of well packed structures with relatively high stability, which can suppress supress electrochemical processes directly at the metal-solution interface. SAMs have, additionally, been prepared by chemisorption of organic molecules containing various functional groups such as -SH, [28] -COOH, [29] -NH2, [30,31] etc. and are also known on a variety of electrode surfaces other than gold, such as platinum, [31,[44][45][46] copper, [47][48] silver [49] and silicon.…”

Section: Introductionmentioning

confidence: 99%

Modification of Electrode Surfaces by Self‐Assembled Monolayers of Thiol‐Terminated Oligo(Phenyleneethynylene)s

et al. 2013

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The wire‐like properties of four S‐(4‐{2‐[4‐(2‐phenylethynyl)phenyl]ethynyl}phenyl) thioacetate derivatives, PhC≡CC6H4C≡CC6H4SAc (1), H2NC6H4C≡CC6H4C≡CC6H4SAc (2), PhC≡CC6H2(OMe)2C≡CC6H4SAc (3) and AcSC6H4C≡CC6H4C≡CC6H4SAc (4) (Figure 1), all of which possess a high degree of conjugation along the oligo(phenyleneethynylene) (OPE) backbone, were investigated as self‐assembled monolayers (SAMs) on gold and platinum electrodes by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The redox probe [Fe(CN)6]4− was used in both the CV and impedance experiments. The results indicate that the thiolates derived from thioacetate‐protected precursor molecules 1 and 2 form well‐ordered monolayers on a gold electrode, whereas SAMs derived from 3 and 4 exhibit randomly distributed pinholes. The electron tunnelling resistance and fractional coverage of SAMs of all four compounds were examined using electron tunnelling theory. The analysis of the results reveal that the well‐ordered SAMs of 1 and 2 exhibit higher charge‐transfer resistance in comparison to the defect‐ridden SAMs of 3 and 4. The additional steric bulk offered by the methoxy groups in 3 is likely to prevent efficient packing within the SAM, leading to a microelectrode behaviour, when assembled on a gold electrode surface. The protected dithiol derivative 4 probably binds to the surface through both terminal groups which prevents dense packing and leads to the formation of a monolayer with randomly distributed pinholes. Atomic force microscopy (AFM) was used to examine the morphology of the monolayers, and height images gave root‐mean‐square (RMS) roughness′s which are in agreement with the proposed SAM structures.

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“…Cyclic voltammetry has been used to calculate the size, number and chemical characteristics of defects produced at monolayers on the basis of the changes in electron transfer kinetics [30][31][32]. This method estimates pinhole parameters by determining the scan rate at which the peak current was no longer lineal with the square root of the scan rate [30][31][32][33][34] or in the cases where radial diffusion becomes the dominant regime, by the use of a numerical simulation computer program [35]. However, the fractional coverage estimated from the cyclic voltammetric peak current is quantitatively different from values obtained by other methods.…”

Section: Introductionmentioning

confidence: 99%

“…In this sense, electrochemical impedance spectroscopy is particularly valuable for pinhole characterization because the effects of solution resistance, double-layer charging and currents due to diffusion or to other processes occurring in the SAM can be separated [37,38]. This approximation has then been used to characterized the pinhole size and distribution together with the surface coverage of different SAMs [32,37,[39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical characterization of a 1,8-octanedithiol self-assembled monolayer (ODT-SAM) on a Au(111) single crystal electrode

García-Raya

Madueño

Sevilla

et al. 2008

Electrochimica Acta

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Electron transfer kinetics across derivatized self-assembled monolayers on platinum: a cyclic voltammetry and electrochemical impedance spectroscopy study

Cited by 27 publications

References 28 publications

Microstructures by Selective Desorption of Self‐Assembled Monolayer from Polycrystalline Gold Electrodes

Microstructures by Selective Desorption of Self‐Assembled Monolayer from Polycrystalline Gold Electrodes

Modification of Electrode Surfaces by Self‐Assembled Monolayers of Thiol‐Terminated Oligo(Phenyleneethynylene)s

Electrochemical characterization of a 1,8-octanedithiol self-assembled monolayer (ODT-SAM) on a Au(111) single crystal electrode

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