Xerographic and electroabsorption study of primary photocarrier generation process in x-form metal-free phthalocyanine

Using a dual-layered photoconductor, we have investigated the primary photocarrier generation process in x-form metal-free phthalocyanine (x-H₂Pc) over a wide range of illumination wavelengths. According to the results of quantum efficiency measurements, it has been established that the photocarrier generation mechanism in x-H₂Pc occurs via two processes: (i) production of an intermediate that depends solely on the excitation energy, and (ii) subsequent free carrier production in the presence of an electric field. In addition, the spectral quantum efficiency and the electroabsorption spectrum were measured and compared. Based on that, the primary process efficiency was divided into four regions in terms of photon energy, which explained well the relationship between them. The excitation energy dependence of the primary efficiency was semiquantitatively validated based on the electron transfer theory.