The sensitization and the spectral sensitization of the photoconductivity of an organic derivative, 2,5-bis (p-diethyl-aminophenyl) - 1,3, 4-oxadiazole, was studied once an electrostatic sensitometer had been built. Among 27 dyes tested representing 8 different classes, only the triarylmethane-type dyes and rhodamine-type dyes have a sensitizing effect which does not seem to be correlated with energy level considerations. The main effect of the sensitizers, once they have formed charge-transfer complexes, is to increase the dark decay reaction, and, thus, they are not suitable as practical products
