Low‐potential facile electrosynthesis of free‐standing poly(1H‐benzo[g]indole) film as a yellow‐light‐emitter

High‐quality free‐standing poly(1H‐benzo[g]indole) (PBIn) films were synthesized electrochemically by direct anodic oxidation of 1H‐benzo[g]indole (BIn) in boron trifluoride diethyl etherate. PBIn films obtained from this medium showed good electrochemical behavior and better thermal stability with a conductivity of 0.29 S cm^?1. PBIn films with low band gap value (1.59 eV) were insoluble in acetone and tetrahydrofuran. The structure and morphology of the polymer were studied by UV–vis, FTIR, and scanning electron microscopy, respectively. The results of quantum chemistry calculations and the spectroscopies of dedoped PBIn indicate that the polymerization of BIn mainly occurs via C₍₂₎ and C₍₅₎ position. The polymer film was compact with regular nanoparticles on the surface. Fluorescent spectral studies indicate that solid‐state PBIn film is a good yellow‐light‐emitter. Thermal stability of PBIn film is higher than poly(indole‐6‐carboxylic acid), poly(5‐formylindole), and polyindole. To the best of our knowledge, this is the first report on the electrosynthesis of free‐standing polyindole derivatives as yellow‐light‐emitter. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2730–2738