OBSERVATION OF CHARGE BEHAVIOR IN ORGANIC PHOTOCONDUCTOR USING PRESSURE-WAVE PROPAGATION METHOD

The charge behavior in an organic photoconductor (OPC), which can be used as an electrophotographic receptor, were observed using the pressure wave propagation method. When a pulse pressure wave passes through the sample, a displacement current is generated. The charge distribution is obtained from the measurement of the displacement current. Two kinds of samples were prepared in this study. One was an aggregate OPC which consisted of one layer (sample A), the other was a layered OPC which consisted of the carrier generation layer (CGL) and the carrier transport layer (CTL) (sample B). The motions of charges in the two samples were observed under the application of dc voltage and of light exposure. In the case of the aggregate OPC, the carriers were generated with light exposure and both hole and electron carriers drifted under the applied electric field, whereas in the case of the layered OPC, the carriers were generated on the CGL by the electric field only and one polarity of carriers, holes, drifted in the CTL. Also in the aggregate OPC, holes and electrons behaved differently under dc stress.