As illustrated in Fig. (i)-(v), PEDOT thin film interfacial electrosynthesis progresses along five distinct stages with time. Initially, IET occurs between the aqueous Ce 4+ oxidant and EDOT organic monomer forming monomeric radical cations (EDOT •+ ) in the diffusion layer on the organic side of the ITIES (Fig. (i)). For IET to proceed with appreciable kinetics, the ITIES must be polarised positively (as discussed vide infra) with Δ o w 𝜙 set to a value near the positive extreme of the Galvani polarisable potential window. EDOT •+ species are stabilised by the weakly coordinating organic anion, tetrakis(pentafluorophenyl)borate (TB -), and further couple with each other or EDOT monomers to form dimers in the diffusion layer.