Symmetric “Double Spiro” Wide Energy Gap Hosts for Blue Phosphorescent OLED Devices

Wide energy gap materials dispiro[fluorene-9,9?-anthracene-10?,9?-fluorene] (SAS) and dispiro[xanthene-9,9?-anthracene-10?,9?-xanthene] (XAX) containing double spiro–carbons, are introduced as hosts for blue phosphorescent organic light-emitting diodes (PHOLEDs). Both SAS XAX free of heteroatomic exocyclic bonds, which implicated in limiting the stability PHOLEDs. The synthesized gram-scale quantities through short efficient paths. They have large gaps (?5.0 eV) between highest occupied molecular orbital (HOMO) lowest unoccupied (LUMO) correspondingly high triplet energies solid state (ET ? 3.0 eV). Analysis devices using host with dopant fac-tris(N,N-di-p-tolyl-pyrizinoimidazol-2-yl)iridium(III) (Ir(tpz)3), shows that charges transported trapped by dopant, subsequently forms excitons directly on phosphor. As a result, luminescence quenching pathways suppressed leads to (?18%) external quantum efficiency. Thus, serve promising materials, suitable