Synthesis, properties, and self-polymerization of hole-transporting carbazole- and triphenylamine-based hydrazone monomers

Abstract

Synthesis, optical, thermal, electrochemical, and photoelectrical properties of new carbazole- and triphenylamine-based hydrazones with reactive vinyl groups are reported. Self-polymerization in the solid state of the synthesized monomers was studied by differential scanning calorimetry (DSC) and IR spectrometry. Molecular weights of the soluble polymers were determined by gel chromatography. The synthesized compounds were characterized by 1H and 13C NMR, IR, UV/VIS, fluorescence, and mass spectrometries, as well as by cyclic voltammetry. The synthesized carbazole- and triphenylamine-based hydrazones form glasses with the glass transition temperatures ranging from 83 to 118 °C, as was elucidated by DSC. Their thermal degradation starts above 270 °C, as was revealed by thermogravimetric analysis. The ionization potentials of the films of carbazole- and triphenylamine-based hydrazones, measured by the electron photoemission in air technique, range from 5.32 to 5.65 eV. Hole-drift mobilities in amorphous layers of the monomers, estimated by xerographic time of flight technique, approach 10−3 cm2/Vs at high electric fields.