PtON-TBBI is a tetradentate platinum(II) complex with N-heterocyclic carbene (NHC) ligand. As a blue phosphorescent dopant, PtON-TBBI is commonly used as a phosphor material and sensitizer in deep-blue phosphorescent and hyperfluorescent OLEDs. N-heterocyclic carbene-based complex is known for enabling deep-blue light emission with a narrow spectrum and high external quantum efficiency. The Introduction of bulky 3,5-di-tert-butyl-phenyl into the N-heterocyclic carbene moiety in the platinum complex can further enhance the photochemical stability of the high-lying metal-centred triplet state. Also the steric effect created by the three tert-butyl groups can prevent undesirable host–guest interactions to enhance device colour purity and stability with narrow FWMH and longer device lifetime.
Stable deep-blue phosphorescent organic light-emitting device (PhOLED) based on PtON-TBBI as the dopant and SiCzCz:SiTrZCz2 as the exciplex host demonstrates a maximum external quantum efficiency (EQEmax) of 25.4% with a y co-ordinate of 0.197 and a long device lifetime of LT70 = 1,113 h at L0 = 1,000 cd m-2.