Studying electron transfer through alkanethiol self-assembled monolayers on a hanging mercury drop electrode using potentiometric measurements

A new approach based on measuring the change of the open-circuit potential (OCP) of a hanging mercury drop electrode (HMDE), modified with alkanethiols of different chain length conducted in a solution containing a mixture of Ru(NH₃)₆²⁺ and Ru(NH₃) ₆³⁺ is used for studying electron transfer across the monolayer. Following the time dependence of the OCP allowed the extraction of the kinetic parameters, such as the charge transfer resistance (R_ct) and the electron transfer rate constant (k_et), for different alkanethiol monolayers. An electron tunneling coefficient, β, of 0.9 Å^-1 was calculated for the monolayers on Hg.