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

Abstract

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 w ere created by utilizing a rigid 4-coordination configuration, where the ligands w ere formed by linking electron-donor of triphenylamine (TPA) moieties with electron-acceptor of pyridine, isoquinoline, and/or δ-carboline units. The thermal stability, electrochemical, and photophysical properties of the complexes w ere thoroughly examined. The complexes display efficient red phosphorescence, with high photoluminescence quantum yields and short excited lifetimes. The OLEDs doped 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 demonstrated exceptional long operational lifetime, with a T90 lifetime of over 14000 hours at initial luminance of 1000cd m-2 , indicating the potential for these complexes to be practically utilized. This article is protected by copyright. All rights reserved.