Rigid Bridge‐Confined Double‐Decker Platinum(II) Complexes Towards High‐Performance Red and Near‐Infrared Electroluminescence

Abstract

AbstractA molecular design to high‐performance red and near‐infrared (NIR) organic light‐emitting diodes (OLEDs) emitters remains demanding. Herein a series of dinuclear platinum(II) complexes featuring strong intramolecular Pt⋅⋅⋅Pt and π–π interactions has been developed by using N‐deprotonated α‐carboline as a bridging ligand. The complexes in doped thin films exhibit efficient red to NIR emission from short‐lived (τ=0.9–2.1 μs) triplet metal‐metal‐to‐ligand charge transfer (3MMLCT) excited states. Red OLEDs demonstrate high maximum external quantum efficiencies (EQEs) of up to 23.3 % among the best PtII‐complex‐doped devices. The maximum EQE of 15.0 % and radiance of 285 W sr−1 m−2 for NIR OLEDs (λEL=725 nm) are unprecedented for devices based on discrete molecular emitters. Both red and NIR devices show very small efficiency roll‐off at high brightness. Appealing operational lifetimes have also been revealed for the devices. This work sheds light on the potential of intramolecular metallophilicity for long‐wavelength molecular emitters and electroluminescence.