Investigation of the photoconductive AZO-AS/TiOPc composites

Abstract The relationship between photoconductivity and composition has been studied in double-layered photoreceptor devices where AZO-AS/TiOPc composites were used as the charge generation materials (CGMs) and DENH served as the charge transporting material (CTM). It was found that AZO-AS/TiOPc composites have high photosensitivity not only in the visible region but also in the near-IR region and their xerographic properties vary with the ratio of AZO-AS to TiOPc. The composites exhibit better sensitivity at ∼500 nm than at other wavelengths at the ratio of 6 : 4 (by weight) while the best sensitivity was found at ∼570 nm and in the near-IR region at the ratio of 1 : 9 (by weight). The absorption spectra and X-ray powder diffraction patterns were investigated and some changes were found in the composites. For the first time, a charge transfer from AZO-AS to TiOPc was revealed by the measurements of XPS and ESR. Various xerographic properties of the composites result from different degrees of charge transfer as the content of TiOPc varies.