A charge transport molecule contains four radical polymerizable functional groups of the general structure exemplified below: where R1 and R2 contain a spacer group and a radical polymerizable functional group, R3 and R4 are hydrogen atoms, and R5 and R6 contain a spacer group and a radical polymerizable functional group wherein the spacer group of R1, R2, R5 and R6 is an ethyl group and the radical polymerizable functional group of R1, R2, R5 and R6 is an acrylate group.