Molecular Design for Better Charge Tansporting Organic Materials (II)

— Hole Drift Mobility and Chemical Structure of Arylamine Derivatives —

Abstract

A series of arylamine derivatives consisting of only N-phenyl units, which can be taken as a structural minimum unit for hole carrier, was synthesized and their hole drift mobilities in the polymer dispersions were inter related with their chemical structures. As a result, the validity of the previously proposed guiding concept for developing better charge transporting organic materials [Electrophotography, 25, 16(1985)] was demonstrated and furthermore the dependence of the mobility on the chemical structure was newly found relating to the substitution site of N-phenyl group on benzene ring. The dependence was interpreted by the more concrete concept of poly-functionality and intramolecular-mobility based on the molecular orbital calculations. Among the compounds investigated a new arylamine derivative, N, N, N', N'-tetrakis (3-methylphenyl)-m-phenylenediamine (m-PDA), was nominated for high hole mobility compounds.