A Mononuclear [PtCl(tpy)]PF6 Complex for a Yellow Emitting Solution-Processable Organic Light Emitting Diode

We report square planar mononuclear Pt(II)-complexes of terpyridines in the form of [PtCl(L1/L2)]PF6 as phosphorescent emitters (where L1 = 4-(3-pyridine)2,2 ':6 ',2 ''-terpyridine and L2 = 4 '-(3-pyridinyl)-4,4 ''-di(tert-butyl)-2,2 ':6 ' 2 ''-terpyridine). Complex 2 showed emission at 534 nm in the DCM solution with photoluminescence quantum efficiency (Phi(PL)) = 14%, while in the mCBP host (5-wt % doped), the emission shifted to 584 nm with Phi(PL) = 37.8% and a phosphorescence lifetime (tau(phos)) of 37.8 mu s. Complex 2 in mCBP was used to fabricate a solution-processed phosphorescent organic light-emitting diode (PhOLED) which showed maximum external quantum efficiency (EQE(max)) = 7.4% with yellow emission at lambda(EL) = 570 nm and exhibited a low efficiency roll-off with an EQE drop to 7.0% at 1000 cd/m(2).