Concentration-insensitive phosphorescent organic light emitting devices (PhOLEDs) for easy manufacturing

Two heteroleptic iridium(III) complexes Ir(piq)2(dbm) and Ir(btp)2(acac) have been tested as emitters for phosphorescent OLEDs (PhOLEDs). Interestingly, device performance exhibited a marked insensitivity to the dopant concentration. In this study, a dibenzoylmethane (dbm)-based complex has also been tested for the first time as dopant for OLEDs. To evaluate the emissive properties of this new emitter belonging to a family of complexes that has not been investigated yet, identical devices were prepared with the well-known red dopant Ir(btp)2(acac) for comparison. The new complex Ir(piq)2(dbm) exhibited comparable performance to that obtained with Ir(btp)2(acac).