Application of Unsymmetrical Diphenoquinone Derivatives to Xerography (I)

— Molecular Design of a Novel Class of Polymerdispersible Electron-transport-active Compounds —

Abstract

A novel class of electron-acceptive compomds, unsymmetrically substituted diphenoquinones with two kinds of alkyl groups, was designed and synthesized for electron transport materials. The unsymmetrical substitution produced extraordinarily high solubility in organic solvents and dispersibility in a wide range of polymers. In the polymeric dispersion of 3,5-dimethyl-3',5'-di-tert-butyl-4,4'-diphenoquinone (DMDB), a representative member of these compounds, high electron mobilities over 10^-6 cm²/Vs were obtained, which are comparable to those of the hole transport materials in practical use.Its electron transport properties were characterized according to the Schein's analytical technique. The results indicated that the electron mobility in the limit of zero-field is consistent with the non-adiabatic small-polaron hopping mechanism. It was also found that electrons can be photo-injected from phthalocyanine pigments into the DMDB-based electron transport layer, suggesting the promising application to xerographic photoreceptors that can work in the positive charging mode.