Photophysical properties and electroluminescent applications of donor–acceptor–donor functionalized red electroactive fluorescent materials

Four electroactive molecular materials with donor-π-acceptor-π-donor structures have been synthesized for investigation of structure–properties relationships, and used as dopant for electroluminescent applications. The optical and electrical properties of these materials are electronically manipulated by attaching different donors. The twisted intramolecular charge transfer (TICT) model is proposed by photophysical behaviors observed with increasing solvent polarity. Red electroluminescence devices were fabricated by spin coating the blend of polymer host and fluorescent guest. Highly efficient energy transfer leads to a saturated red emission with emission peak at 623 nm, narrow bandwidth of 75 nm and an external quantum efficiency of 0.38%.