Discrete Mononuclear Platinum(II) Complexes Realize High-Performance Red Phosphorescent OLEDs with EQEs of up to 31.8% and Superb Device Stability

Designing mononuclear platinum(II) complexes that do not rely on intermolecular aggregation for high-performance red organic light-emitting diodes remains a formidable challenge. In this work, three robust red-emitting Pt(II) complexes are created by utilizing a rigid 4-coordination configuration, where the ligands are formed by linking electron-donor of triphenylamine (TPA) moieties with electron-acceptor of pyridine, isoquinoline, and/or & delta;-carboline units. The thermal stability, electrochemical, and photophysical properties of the complexes are thoroughly examined. The complexes display efficient red phosphorescence, with high photoluminescence quantum yields and short excited lifetimes. The OLEDs dope with these complexes exhibit high maximum external quantum efficiencies (EQEs) of up to 31.8% with minimal efficiency roll-off even at high brightness. Significantly, the devices demonstrate exceptional long operational lifetime, with a T-90 lifetime of over 14000 h at initial luminance of 1000 cd m(-2), indicating the potential for these complexes to be practically utilizes.

Automated summary

Creating robust red-emitting Pt(II) complexes with a rigid 4-coordination configuration, formed by linking triphenylamine (TPA) electron-donors with pyridine, isoquinoline, and/or & delta;-carboline electron-acceptors, shows potential for high-performance red OLEDs. The complexes exhibit efficient red phosphorescence, high photoluminescence quantum yields, and short excited lifetimes. The OLEDs doped with these complexes show high maximum external quantum efficiencies (EQEs) and exceptional long operational lifetime.