UV‐Visible Reflectance Spectroscopy of Thin Organic Films at Electrode Surfaces

Sagara, Takamasa

doi:10.1002/9783527616817.ch2

Cited by 15 publications

(35 citation statements)

References 86 publications

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“…2. All three spectra exhibited a difference absorption spectral feature, indicating that the spectral shape represents the absorption spectrum of reduced form in the solution [18,19]. The ER spectra for V-C4-V…”

Section: Cyclic Voltammogramsmentioning

confidence: 95%

“…The details of the instrumentation and measurement procedures are described elsewhere [18,19,23]. Briefly, steady state monochromatic light was irradiated to the electrode surface, the potential of which was modulated by a sinusoidal wave.…”

Section: Electroreflectance (Er) Measurementsmentioning

confidence: 99%

“…(iii) We used ER methods at a macroscopic Au electrode. The ER signal is the ac change of the reflectance of monochromatic light synchronized to the ac potential modulation with an inevitable phase delay [18]. The spectrum of the ER signal (ER spectrum) enables us to see the presence of adsorbed species or deposited film formation, if any, on the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

“…Without these on-surface species, the ER spectrum principally shows a difference absorption spectrum between reduced and oxidized forms in solution [18,19]. Because the oxidized form of viologen in aqueous solution has no light absorption at the wavelength longer than 350 nm [3], we can exclusively see the absorption spectrum of the reduced forms at the electrode|solution interface.…”

Section: Introductionmentioning

confidence: 99%

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Revisiting aqueous redox process of alkyl-linked bis-viologen: Evaluation of redox potential inversion

Sagara

Eguchi

2019

Electrochimica Acta

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Section: Cyclic Voltammogramsmentioning

confidence: 95%

Section: Electroreflectance (Er) Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Revisiting aqueous redox process of alkyl-linked bis-viologen: Evaluation of redox potential inversion

Sagara

Eguchi

2019

Electrochimica Acta

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“…Three possible explanations for the wavelength-dependence shall be considered, (a) changes in the absorption spectrum of the layer which is not included in the analysis, (b) a change in the gold dielectric function in the interfacial region (e.g. because of the presence of surface states, or more generically due to electroreflectance 59,60 ), and (c) the optical anisotropy of the SAMs and a change in anisotropy during the desorption process.…”

Section: Interpretation Of Ellipsometric Datamentioning

confidence: 99%

Electrochemical reductive desorption of alkyl self-assembled monolayers studied in situ by spectroscopic ellipsometry: evidence for formation of a low refractive index region after desorption

Kemnade

Chen

Muglali

et al. 2014

Phys. Chem. Chem. Phys.

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Gold-sulphur bonds holding self-assembled monolayers (SAMs) on their gold substrate can be broken by electrochemical reduction, which typically occurs in an electrode potential range where the electrochemical hydrogen evolution reaction (HER) is thermodynamically possible. This work uses an in situ coupling between cyclic voltammetry and spectroscopic ellipsometry to compare the interfacial structure after desorption of the aliphatic thiols 1-Dodecanethiol (DDT) and 1-Octadecanethiol (ODT), and the ω-hydroxythiol 11-Mercapto-1-undecanol (MUD). For MUD and DDT, the data can only be explained by the presence of a substance with a significantly lower refractive index than the aqueous electrolyte in the interfacial region. This substance is likely to be H2. The hypothesis is put forward here that for MUD and DDT, desorbed molecules stabilise "nanobubbles" of H2. The resulting aggregates form as initial stages of the process of complete disintegration of the SAMs, i.e. the loss of the SAM-forming molecules into solution. On the other hand, desorption and readsorption of ODT are fully reversible - the presence of a layer with low refractive index can neither be excluded nor confirmed in this case. The results indicate that different SAM-stabilities are a consequence of solubility of the thiolates.

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Electrochemistry and Optical Microscopy

Kanoufi

2021

Encyclopedia of Electrochemistry

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Electrochemistry exploits local current heterogeneities at various scales ranging from the micrometer to the nanometer. The last decade has witnessed unprecedented progress in the development of a wide range of electroanalytical techniques allowing to reveal and quantify such heterogeneity through multiscale and multifonctionnal operando probing of electrochemical processes. However most of these advanced electrochemical imaging techniques, employing scanning probes, suffer from either low imaging throughput or limited imaging size. In parallel, optical microscopies, which can image a wide field of view in a single snapshot, have made considerable progress in terms of sensitivity, resolution and implementation of detection modes. Optical microscopies are then mature enough to propose, with basic bench equipment, to probe in a non destructive way a wide range of optical (and therefore structural) properties of a material in situ, in real time: under operating conditions. They offer promising alternative strategies for quantitative high-resolution imaging of electrochemistry. The first sections recall the optical properties of materials and how they can be probed optically. They discuss fluorescence, Raman, surface plasmon resonance, scattering or refractive index. Then the different optical microscopes used to image electrochemical processes are examined along with some strategies to extract quantitative electrochemical information from optical images. Finally the last section reviews some examples of in situ imaging, at micro-to nanometer resolution, and quantification of electrochemical processes ranging from solution diffusion to the conversion of molecular interfaces or solids.]

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UV‐Visible Reflectance Spectroscopy of Thin Organic Films at Electrode Surfaces

Cited by 15 publications

References 86 publications

Revisiting aqueous redox process of alkyl-linked bis-viologen: Evaluation of redox potential inversion

Revisiting aqueous redox process of alkyl-linked bis-viologen: Evaluation of redox potential inversion

Electrochemical reductive desorption of alkyl self-assembled monolayers studied in situ by spectroscopic ellipsometry: evidence for formation of a low refractive index region after desorption

Electrochemistry and Optical Microscopy

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