The interface of the electrodes that are molecularly modified, such as the case of self-assembled monolayers on metals, is considered a mesoscopic system. This is owing to the fact that the properties of the interface cannot be modeled using solely classical mechanics. Indeed, the state of the interface is in between two mechanical states that comprise the classical and quantum.

Accordingly, mesoscopic electrochemistry is the interpretation of the electrochemistry at the nanoscale as a mesoscopic event, which is an interdisciplinary field that deals with systems at a crucial length scale in which electronic confinement effects are predominant.

For instance, our research group has specifically developed a mesoscopic approach to resolving the capacitive characteristics associated with the electrochemistry of redox-active molecular films. This is the electrochemical capacitance that contains two main contributions: the faradaic and non-faradaic contributions.

The electrochemical capacitance of electro-active molecular films can be theoretically resolved by using first-principle quantum mechanical methods. Using these methods we demonstrated that the pseudo-capacitance characteristics of these interfaces are associated with the charging of the molecular orbitals of the redox states as a component of these interfaces.