High-quality and excellent green-light-emitting poly(acenaphthylene) film: electrosynthesis and characterization

Conducting poly(acenaphthylene) (PAcN) films were synthesized electrochemically by direct anodic oxidation of acenaphthylene (AcN) in boron trifluoride diethyl etherate (BFEE) containing additional 20% anhydrous ethyl ether (by volume). The oxidation potential onset of AcN in this medium was measured to be 0.92 V, which was much lower than that determined in CH3CN containing 0.1 mol L−1 tetra butylammonium tetrafluoroborate (Bu4NBF4, 1.34 V). PAcN films obtained from BFEE + 20% EE showed good electrochemical behavior and good thermal stability with an electrical conductivity of 0.43 S cm−1. The average molecular weight with a polydispersity index of 1.06 was determined by gel permeation chromatography to be Mw = 426,000 g mol−1 for the electrochemically synthesized polymer. The structure and morphology of the polymer were investigated by ultraviolet-visible spectroscopy, infrared spectroscopy, nuclear molecular resonance spectroscopy and scanning electron microscopy, respectively. Fluorescent spectra indicated that the electrochemically polymerized PAcN was an excellent green light-emitting material (fluorescence quantum yield as high as 0.3). All these results indicate that the striking PAcN films obtained have potential applications in various fields.