Charge transport compounds are described that have a multiple number of
hydrazone-bridged heterocyclic groups (especially julolidine,
carbazole and / or triarylmethane groups) connected by a central bridging group. An example of charge transport compounds are those having the following generic formula:(R-Q)n-Y Formula Iwherein R is selected from the group consisting of julolidine ring groups,
carbazole ring groups, and triarylmethane ring groups; Q comprises an aromatic
hydrazone linking group, such as Y comprises a bridging group between R-Q- groups, such as a bond,
carbon atom,
nitrogen atom,
oxygen atom,
sulfur atom, a
methylene group; Z is an
aryl group, preferably a
phenyl group or naphthyl group; X is a linking group, preferably amethylene group, and for example having the formula -(CH2)m- (branched or linear), where m is an integer between 0 and 20, inclusive, and one or more of the
methylene groups is optionally replaced by an
oxygen atom, a
carbonyl group, urethane,
urea, an ester group, a -NR6 group, a CHR7 group, or a CR8R9 group where R6, R7, R8, and R9 are, independently, H, an
alkyl group, or
aryl group; and n is an integer between 2 and 6, inclusive. An organic photoreceptor includes that compound and (b) a charge generating compound; and (c) an
electrically conductive substrate.