The applied potential values of all measurements were converted to the formal potential of the external redox couple Ferrocene/Ferrocenium (Fc/Fc + ), which was measured at 83 mV versus Ag/Ag + within the same cell setup used for DPV measurements. The DPV measurements of the blank FTO-coated glass substrates (Solaronix, TCO22-15, thickness 2.2 mm, sheet resistance 15 Ω/sq; Sigma Aldrich, 735167, thickness 2.2 mm, sheet resistance 7 Ω/sq) and IHO substrates were performed inside the EMAS cell filled with LiClO 4 /MeCN-d 3 and referenced to the respective Ferrocene values given in the SI (see Figure ) and below.