Studies On The Single Layer Photoreceptor Of Fluorenone Bisazo/phthalocyanine Composites

Single layer organic photoreceptor, one of the trends of photoreceptors development, has aroused great researching efforts due to its high performance and low cost. Blending photoconductive materials with different structure and function can lead to both complementary and coenhancement effects of increasing photosensitivity. However, the mechanism of the effects is still keep unknown.Based on a molecular design on bisazo photoconductive material, three kinds of Fluorenone-based bisazos (F-Mo) with different substitutive group (-Cl,-H,-OCH3) were synthesized. Based on the principle of energy level matching, F-Azos, phthalocyanines (Pc) and hydrazone were chose to blend together through a special procedure to prepare a new type of single layer photoreceptor. The xerographic properties are improved while the spectral response range is broadened in the composites by 1:1 mol ratio of F-Azos and Pcs.The mechanism of photoconductivity in F-Azo/TiOPc composites was preliminarily studied using UV/Vis absorption spectra (UV/Vis), X-ray powder diffraction pattern (XRD), X-ray photoelectric spectroscopy (XPS) and Surface photovoltaic spectrometers (SPS). F-Azo/TiOPc composites exhibited broadened absorption range and red-shift in term of photosensitivity when compared to their UV/Vis spectra. XRD suggested changes of aggregate states in the composites. XPS studies indicated charge transfer form F-Mo to titanium oxide phthalocyanine (TiQPc). A new peak was found in SPS spectrum in the composites when compared to their UV/Vis absorption. It was also found that the photovoltaic polarity of F-Azo/TiOPc composites might alternate between positive and negative when exposed to light with different wavelength or changing the proportion of F-Azos and TiQPc.When external electric field is applied, the SPS results showed strong enhanced signal in both F-Azos and TiQPc while only minimal discrepancies was found in their composites, which might due to the photoinduced charge transfer between F-Azoa and TiQPc. Based on the above characterizations results, a model of charge transfer step by step mechanism in F-Azo/TiOPc composites was proposed.4~4~ ~Finally, the research focused on the F-Azo Ase based single layer photoreceptor aiming at finding out best experimental conditions for photoreceptor preparation. The optimized conditions were found as following: 1% TiOPc as sensitizer, 0.5% TN7F as electron transport material, a proportion of CGM:CTM:PC1:80:120 and a mixing solvent of TIfF and dioxane. An IFL and a protective layer can be adopted to enhance surface charging abilities and decrease dark decay.