Achieving saturated red photoluminescence and electroluminescence with readily synthesized maleimide-arylamine copolymers

Abstract

Maleimide-based red fluorescent copolymers were easily synthesized from palladium catalyzed polycondensation of N-alkyl-3,4-bis(4-bromophenyl)maleimide with commercially available or readily prepared secondary aryldiamines. The copolymers were characterized by gel permeation chromatography, differential scanning calorimetry, cyclic voltammetry, UV–vis absorption, and fluorescence spectroscopy. They showed brilliant red fluorescence in solution (toluene) with emission maximum in the range of 617–638 nm, although severely red-shifted in thin films. With judicious selection of aryldiamine monomers, the red-shifting of the thin film fluorescence can be largely diminished. The structure and property (molecular weight, glass transition temperature, and fluorescence) relationships were analyzed and deciphered as well. A light-emitting device has been fabricated with maleimide-arylamine copolymer in demonstrating the potentials for saturated red polymer light-emitting diodes (PLEDs).