Dual Interface Exciplex Emission of Quinoline and Carbazole Derivatives for Simplified Non-Doped White OLEDs

Isomeric quinoline and 9-phenylcarbazole derivatives with different linking topology were synthesized as versatile exciplex-forming materials. Their exciplex forming properties were examined. The studied compounds showed dual electron-donating or accepting nature and formed blue emitting excited complexes with acceptor 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine and orange emitting exciplexes with the donor 4,4′,4′′-tris[3-methylphenyl(phenyl)amino]- triphenylamine. The solutions and solid films of both the synthesized compounds showed violet fluorescence. Compound with meta-substitution exhibited higher energy of triplet level (2.64 eV) and higher ionization potential value (6.21 eV) in comparison to para-substituted one. Higher 5 % weight loss and glass transition temperatures of 339 °C and 84 °C were observed for para-isomer. The studied compounds were characterized by bipolar charge-transport properties with hole- and electron mobilities exceeding 10-4 cm2V-1s-1 at electric fields exceedin...