Cyclometalated binuclear platinum(II) complexes with an embedded D-A ligand as efficient phosphors for NIR-OLEDs

Two novel binuclear platinum(II) complexes with different embedded units and the same donor (D)/acceptor (A) termini of triphenylamine (TPA) and isoquinoline (iq) in the main ligands, (TPAiq)2Pt2(mu -C8OXT)2 and (TPAniq)2Pt2(mu -C8OXT)2, were designed and synthesized, in which the embedded units are single bond and naphthylidene, respectively. Remarkable photoluminescent properties were observed with photoluminescent quantum yield of 10.5 % at emission peak of 670 nm for (TPAiq)2Pt2(mu -C8OXT)2, and 3.7 % at 732 nm for (TPAniq)2Pt2(mu -C8OXT)2 in the neat films. Their luminescence lifetimes were 840 and 1413 ns, respectively. Meanwhile, the (TPAiq)2Pt2(mu -C8OXT)2 and (TPAniq)2Pt2(mu -C8OXT)2 doped polymer light-emitting devices (PLEDs) further displayed deep-red to near-infrared electroluminescent properties at the emission peaks of 678 nm and 712 nm with the maximum external quantum efficiencies of 2.00 % and 0.26 %, respectively. This work demonstrated new insight for designing deep-red to near-infrared platinum complexes by the embedded strategy in the D-A-type ligands to regulate emission spectrum and efficiency for advanced PLED applications.