Characterization of Charge-Transfer Kinetics at Organic/Electrode Interfaces Using Potential-modulated Attenuated Total Reflectance (PM-ATR) Spectroscopy.

Potential-modulated attenuated total reflectance (PM-ATR) spectroscopy is a spectroelectrochemical method that utilizes the potential modulation approach and a waveguide ATR geometry. This unique combination enables measurements of electron-transfer (ET) kinetics of monolayer to submonolayer thin films on waveguide electrode surfaces. Selective probing of molecular subpopulations in a film can be achieved by choosing appropriate combinations of applied potential, wavelength, and polarization of light, which allows subpopulation structure to be correlated with ET kinetics. In this review, the basic theory of PM-ATR is introduced, and examples illustrating characterization of the structure and ET kinetics of organic semiconductor monolayers on electrode surfaces are presented, demonstrating the capabilities and applications of the PM-ATR technique.