Fig. 1. (a) Absorption spectra of Spiro-OMeTAD (abbreviated as Spiro) in chlorobenzene (30 mM), FeCl3 in chlorobenzene/acetonitrile (v/v, 1/1) mixture (24 mM), Spiro-OMeTAD (30 mM) and FeCl3 (24 mM) (abbreviated as Spiro + FeCl3) dissolved in chlorobenzene/acetonitrile (v/v, 1/1) mixture. (b) Wavelength-dependent absorption change upon applying a positive potential bias to a Spiro-OMeTAD deposited FTO film. (c) CV of Spiro-OMeTAD (abbreviated as Spiro) and FeCl3 doped Spiro-OMeTAD (abbreviated as Spiro + FeCl3) deposited on FTO film immersed in EMITFSI as the supporting electrolyte. CV was measured using a three-electrode system, Pt as the counter electrode, and Ag/AgCl as the reference electrode. Scan rate: 10 mV s−1. The onset potential is 0.75 V for Spiro-OMeTAD, and 0.77 V for FeCl3 doped Spiro-OMeTAD. The oxidation potential is 0.86 V for Spiro-OMeTAD, and 0.89 V for FeCl3 doped Spiro-OMeTAD.
