Carbazole derivatives containing one or two tetra-/triphenylethenyl units as efficient hole-transporting OLED emitters

Abstract New efficient carbazole-based emitters containing tetra-/triphenylethene units were developed for boosting efficiency of non-doped fluorescent organic light-emitting diodes. Comparable study of the properties of derivatives containing one or two tetra-/triphenylethenyl units was performed using various experimental and theoretical techniques. Depending on the substitution pattern, emitters exhibited strong blue or green emission, which was enhanced by aggregation. Compounds with two substituents showed higher glass transition temperatures (up to 120 °C) and lower ionization potentials (of ca. 5.15 eV) comparing to mono substituted derivatives. Time-of-flight hole drift mobility values of the studied compounds with two substituents reached 10 −3  cm 2 /V at high electric fields. Non-doped fluorescent OLEDs based on carbazole derivative containing two tetraphenylethenyl units demonstrated extremely high external quantum efficiency as for simple fluorescent organic light-emitting devices, which reached 5.32%.