Synthesis and properties of photocross-linkable carbazole dimers

Abstract

New carbazole-based monomers with two reactive functional groups such as epoxypropyl, oxetanyl and vinyloxethyl were synthesized and their cationic photopolymerization was performed. The monomer containing epoxypropyl groups exhibited the highest conversion in photopolymerization (78%). The monomers and polymers exhibited ability of glass formation with the glass transition temperatures up to 98°C for low-molecular-weight compounds and those observed for polymers ranging from 89 to 150°C. The synthesized derivatives absorb electromagnetic irradiation in the range of 200–390nm with the band gaps of 3.14–3.16eV. The compounds exhibit blue photoluminescence with the intensity maxima at 400nm. The compounds were found to have high triplet energies of ca. 2.78eV. The electron photoemission spectra of the layers of the synthesized compounds revealed ionization potentials of 5.20–5.37eV. The time-of-flight hole drift mobilities of the layers of the compounds exceed 10−5cm2/V×s at high electric fields.