“…In the past 10 years, high quality conducting polymer films have been obtained by choosing boron trifluoride diethyl etherate (BFEE) as solvent and supporting electrolyte [20][21][22][23][24][25], especially when fused ring compounds were used as the monomers, such as indole and its derivatives [26,27], anthracene [28], naphthalene [29,30], benzofuran [31], dibenzofuran [32] etc. The interaction between BFEE and the aromatic monomers can lower the monomer oxidation potentials, and high quality freestanding polymer films can be obtained.…”