Abstract

The utilization of triplet metal-metal-to-ligand-charge-transfer (3MMLCT) emissions of Pt(II) complexes having a large radiative decay rate is a promising strategy to develop efficient red and deep-red emitters for practical organic light-emitting diodes (OLEDs). The panel of robust luminescent dinuclear Pt(II) emitters described here features pyridine-/pyrazine-fused N-heterocyclic carbene-based cyclometalating ligands and ditopic bis-µ2-formamidinate bridging ligands. These complexes show intramolecular Pt–Pt distances of 2.85–2.87 Å, are thermally stable up to 446 °C, and display strong red and deep-red 3MMLCT emission (604–689 nm) with emission quantum yields close to unity. Under laboratory conditions, red and deep-red OLEDs with these complexes show high external quantum efficiencies (up to 21.3%) and prolonged operational lifetimes (LT97 up to 2446 h) at an initial luminance of 1000 cd m−2, highlighting the practicality of these dinuclear Pt(II) emitters in organic optoelectronics application.1

Reference: 

1 Xue. M.Y.; Lam, T.-L.; Cheng, G,; Liu, W.Q.; Low, K.-.H.; Du, L. L.; Xu, S.; Hung, F.-F.; Phillips, D. L.; Che, C.-M. Adv. Optical Mater.2022, 2200741.