Spectral response and xerographic electrical characteristics of some perylene bisimide pigments

The series of N,N'-disubstituted diimides of perylene-3,4,9,10-tetracarboxylic acid, represented by the general structure shown below, is of interest for two reasons: a) the color of the solid pigment is markedly dependant on the nature of the substituent, R, and can vary from red to brown or black and, b) they are generally well known as effective organic photoconductors. We have synthesized and characterized a series of compounds with a selection of alkyl groups having different degrees of chain branching (R=C5H11, 6 isomers) and chain length. Thin layers of pure material were vacuum deposited onto transparent conductive su bstrates a nd spectroscopically cha racterized. Xerographic photo receptors were prepa red by overcoating these with a charge transport layer and the spectral photosensitivity between 400 and 800 nm was measured. The effect of chain length and chain branching upon solid state absorption spectrum and xerographic spectral photosensitivity will be presented and compared with the properties of previously described perylene bisimide photocond uctors.