Highly Efficient Red Electrophosphorescent Devices Based on Iridium Isoquinoline Complexes: Remarkable External Quantum Efficiency Over a Wide Range of Current

Outstanding performance as an emissive dopant in organic light‐emitting devices is shown by red phosphorescent iridium complexes based on an isoquinoline framework (such as that shown in the Figure). Remarkably high efficiency can be maintained in the devices at high currents with a negligible effect from either triplet–triplet (T–T) annihilation or saturation of the excited states.