Synthesis and properties of bipolar derivatives of 1,3,5-triazine and carbazole

• Three carbazolyl containing 1,3,5-triazine derivatives were synthesized.
• The compounds exhibited superior thermal characteristics.
• The solvatochromic behavior was demonstrated.
• High photoluminescence quantum yields were observed for solutions and films.
• Blue and green OLEDs were fabricated.

Three new bipolar star-shaped derivatives of 2,4,6-triphenyl-1,3,5-triazine containing carbazolyl groups were designed, synthesized and characterized. All the materials possess high thermal stability and high glass transition temperatures ranging 97–226 °C. Photophysical study of the dilute solutions and neat films of the synthesized compounds was performed. Lippert–Mataga plots revealed linear dependence of Stokes shifts on the orientation polarizability for all the compounds. The dilute solutions of the triazine derivatives exhibited high photoluminescence quantum yields reaching 0.85, while for the neat films photoluminescence efficiency of 0.20–0.33 was observed. Ionization potentials of the solid layers of carbazole-triazine adducts estimated by photoelectron spectroscopy were found to be in the range of 5.49–5.97 eV. Hole drift mobility of the materials well exceeded the magnitude of 10−3 cm2 V−1 s−1 at an electric field of 6.4 · 105 V/cm. The selected compounds were tested as light emitting materials in organic light emitting diodes based on host-guest systems.

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