Donor-Substituted 1,3,5-Triazines as Host Materials for Blue Phosphorescent Organic Light-Emitting Diodes

A series of new donor-substituted 1,3,5-triazines (TRZ 1−7) has been prepared by nucleophilic substitution of cyanuric chloride with carbazole, 3-methylcarbazole, phenol, and 3,5-dimethylphenol. These s-triazines have been investigated as host material for blue phosphorescent light-emitting diodes (OLEDs). All triazine based hosts were characterized regarding their optical and thermal properties. Different substitution patterns resulted in high glass-transition temperatures (T g) of up to 170 °C and triplet energies (ΔE(T1−S0)) of up to 2.96 eV. The application as host material for the blue phosphor bis(4,6-difluorophenylpyridinato-N,C2)picolinato-iridium(III) (FIrpic) yielded maximum current efficiencies up to 21 cd/A.