Star-shaped trinuclear cyclometalated platinum(II) complexes as single-component emitters in white-emitting PLEDs

Two star-shaped phosphorescent small molecules, Ph-3FPt(pic) and 4Ph-3FPt(pic), are single-component emitters in polymer white-light-emitting diodes (WPLEDs) that are comprised of three blue-light-emitting phosphorescent chromophores of FPt(pic) and are attached to benzene-1,3,5-trioxy- and 1,3,5-tri(4-oxyphenyl)benzene cores through a hexyloxy chain, respectively. Compared to their corresponding mono- or dinuclear platinum complexes, this class of star-shaped homotrinuclear cyclometalated platinum(II) complexes exhibited controllable excimer emission. Stable white/near-white emission was obtained in single-emissive-layer PLEDs by using the Ph-3FPt(pic) or 4Ph-3FPt(pic) as a single dopant and a blend of poly(vinylcarbazole) and 2-(4-biphenyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole as a host matrix at dopant concentrations of 1-4 wt.%. Our results provide an efficient way to control excimer formation and to obtain a single-component emitter for use in WPLEDs.