Structure–properties relationship of hydrazones containing methoxy-substituted triphenylamino groups

Abstract

We have synthesized a series of hole-transporting dimethoxytriphenylamine-based hydrazones and studied the influence of the position of methoxy groups on the thermal, optical, electrochemical, and photoelectrical properties of the materials. The synthesized compounds form glasses with glass transition temperatures ranging from 32 to 64 °C. Compounds having methoxy groups in the ortho positions of triphenylamino moiety show higher glass transition temperatures than the corresponding derivatives having methoxy substituents in meta or para positions. Ionization potentials of the solid samples of hydrazones range from 5.18 to 5.27 eV. Hydrazones having methoxy substituents in para positions of triphenylamino moiety show superior charge-transporting properties with respect to hydrazones containing methoxy substituents in ortho and meta positions respectively. Molecularly doped bisphenol Z polycarbonate containing 50 wt.% of hydrazones with methoxy substituents in para positions of triphenylamino moiety show time-of-flight hole-drift mobilities approaching 10 −4 cm 2/(V s) at high electric fields.