Spectroelectrochemistry, electroactive

Dunphy DR, Mendes SB et al (1997) The electroactive integrated optical waveguide ultrasensitive spectroelectrochemistry of submonolayer adsorbates. Anal Chem 69(15) 3086-3094... 

Dunphy DR, Mendes SB, et al (1999) Spectroelectrochemistry of monolayer and submonolayer films using an electroactive integrated optical waveguide. Chapter 29. In Wieckowski A (Ed) Interfacial electrochemistry. Marcel Dekker, New York... 

This same R T state equilibrium model can also be used to interpret the non-Nernstian behaviour of Fib redox monitored by spectroelectrochemistry. Reduction or oxidation of interacting electroactive centres in Fib gives rise to a nonlinear Nernst plot. The changing slope of the Nernst plot, n, can no longer be simply interpreted as the number of electrons transferred. Nonlinear Nernstian plots obtained from such spectroelectrochemical data require a special treatment. 

In the case of channel electrodes, the solution containing the electroactive species flows in a channel such as that shown in Figure 8.3 where a rectangular electrode of length Xe and width w is placed on the channel floor. The mass transport by convection can be controlled through the channel design, the electrode size and the flow rate. Moreover, this setup enables the incorporation of electrochemical measurements to flow systems as well as its use in spectroelectrochemistry and photoelectrochemistry [4]. 

Charge transfer in electroactive polymers is usually investigated by techniques such as cyclic voltammetry, spectroelectrochemistry, and AC impedance. Using these techniques, one can extract information such as standard potentials, number of electrons transferred, rates of charge transfer, and intermediates, if any, in the redox reaction. These techniques are explained in some detail in Appendix 11,... 

IR spectroelectrochemistry has been the subject of a sizeable amount of early reviews, where the experimental details and applications have been described [5-7]. Regardless the fact that electrochemistry is an extremely broad field, the following discussion will be restricted to classical electrochemical systems where a solid electrode is in contact with a liquid electrolyte solution which may contain electroactive species. Since the typically used electrolyte solutions (mostly aqueous solutions) are strongly IR absorbing, it is not possible to use a standard laboratory electrochemical cell, but for spectroelectrochemical experiments, special cell designs and beam paths have to be employed. There are two general principles on how the IR beam is directed to the electrode surface called internal reflection and external reflection, respectively. 

Time-resolved luminescence spectroelectrochemistry (TRLS) is less common than but complementary to luminescence spectroelectrochemistry. TRLS can be used to monitor the lifetime of a luminescent species, provided it is sufficiently long-lived. TRLS may be useful in studying the photophysics of an electroactive species to understand its temporal behavior under application of potential and can be used to provide a unique perspective on the electrochemical interface. 

---