A Mononuclear [PtCl(tpy)]PF 6 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 )]PF 6 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 (Φ PL ) = 14%, while in the mCBP host (5-wt % doped), the emission shifted to 584 nm with Φ PL = 37.8% and a phosphorescence lifetime (τ phos ) of 37.8 μs. 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 λ EL = 570 nm and exhibited a low efficiency roll-off with an EQE drop to 7.0% at 1000 cd/m 2 .