Thermally stable aromatic amine derivative with symmetrically substituted double spirobifluorene core as a hole transport material for green phosphorescent organic light-emitting diodes

A thermally stable aromatic amine derivative with a symmetrically substituted double spirobifluorene core was synthesized as a hole transport material for green phosphorescent organic light-emitting diodes. A high glass transition temperature of 142 °C was obtained and a film morphology of the hole transport material was kept stable up to 120 °C. The hole transport material showed a high triplet energy of 2.53 eV and a quantum efficiency of 17.4% in green phosphorescent organic light-emitting diodes. - Highlights: ► Synthesis of symmetrically substituted double spirobifluorene core ► Stable film morphology up to 120 °C ► High quantum efficiency in green phosphorescent organic light emitting diode