Juan Bisquert, Peter Cendula, Luca Bertoluzzi, and Sixto Gimenez
J. Phys. Chem. Lett. 5, pp 205–207, 2014.
In photoelectrochemistry, the voltage is measured with respect to a reference electrode, or in a two electrode cell, but only the points at the surface of a semiconductor electrode are measured. In solid state devices and surface physics it is important to trace variations of energy and electrostatic potential across different semiconductor layers, as well as the dipoles at their interfaces, which is achieved by plotting all energies with respect to the local vacuum level.
We have noticed that this type of diagram causes some problems for the representation of combinations of materials used for solar fuels, for example, that are becoming increasingly complex. To facilitate the representation and calculation of multiple layer semiconductor electrodes used in solar fuels and photocatalysis, we provide a unified representation of the two conventions in a single diagram. The paper establishes a link between the conventions of electrochemistry and solid state physics, and defines some central quantities as the built-in potential and flatband potential.