A bright single layer non-doped orange-red light emitting diode using a symmetric starburst material via solution process

Abstract

A symmetric starburst orange-red emitter, 2,4,6-tris((E)-2-(10-butyl-10H-phenothiazin-2-yl)vinyl)-1,3,5-triazine (TP3T) incorporating phenothiazine as the electron donor and triazine as the electron acceptor, was synthesized. It shows high fluorescence quantum yield (0.42 in toluene) because of the existence of strong intramolecular charge transfer between the phenothiazine and the triazine moieties. The smaller dipole moment for the molecule resulted from its symmetric starburst conformation and larger alkyl group substituents induce weaker interaction of molecules, thus fluorescence quenching can be effectively reduced. Owing to its bipolar structure, both hole and electron transport could be facilitated. A single layer non-doped stable orange-red emission with CIE coordinates at (0.59, 0.41) and a low turn-on voltage of 2.5 V and a maximum luminance of 2935 cd m⁻² was obtained by using TP3T as the single combination layer of charge transporting and emitter via solution process.