context: Electrochemical measurements. All electrochemical measurements were made using an Autolab potentiostat (PGSTAT) and the custom-made three electrode electrochemical cell. The cells components are as follows: thin film deposited on FTO coated glass (working electrode), platinum dispersed on FTO coated glass (counter electrode), silver (Ag) wire (pseudo reference electrode), and 0.1 M tBuNH PF6 in acetonitrile (inert electrolyte). Cyclic voltammetry was measured by applying an oxidising potential to the working electrode and scanning the potential from −0.5 V to 1.2 V vs. Ag at a scan rate of 20 mV s−1, followed by reversing the direction. The current response waveform was measured simultaneously. Chronoamperometry was used to oxidise the polymer film during in situ spectroscopy measurements. It was performed by applying an excitation square-wave potential to the working electrode in the following configuration: 0 V for 20 seconds (neutral state), an oxidising potential (Vox) for 40 seconds (oxidised state), and 0 V for 20 seconds (back to neutral state). In situ Raman and UV-vis measurements were taken during the application of an oxidising potential when the current response reached steady state (usually after 5–10 seconds).
answer: 0.1 M tBuNH PF6 in acetonitrile