For instance, in some DFT codes E SC,DF T f is equal to valence band edge energy whereas other codes place E SC,DF T f in a band gap. Therefore, the single electrode potential scales from the different conventions are clearly different. Furthermore, slab models omit metallic connections and (charged) bulk with defects as well as their effect on the Fermi level to reduce computational burden (see also Section S5). Different definitions of E SC f used for semiconductor electrodes in experiments and calculations have led some authors to argue that the semiconductor electrode potential cannot be continuously altered in GCE-DFT simulations due to the presence of a finite band gap. The electrode potential discontinuities are, however, a computational artefact related to the use of E SC,DF T f definition of electrode potentials, and the confusion between the system and bath electrochemical potentials in GCE-DFT calculations. A more robust description of semiconductor electrode potentials without discontinuities can be obtained by using the semiconductor inner potential as the basic variable of GCE-DFT. The applied electrode potential, ∆U , can then be written in terms of the local electrostatic potentials and material-dependent constants and it is directly proportional to the bulk electrostatic potentials i.e. inner potentials at different charge states: