Improvement of Photosensitivity in Fluorenone Bisazo Pigment/Poly(Methyl Phenyl Silane) Layered Device

Abstract

The low photocarrier generation efficiency of a layered device consisting of an azo-pigment-based carrier generation layer (CGL) and a poly(methyl phenyl silane) (PMPS) layer was investigated. We found that the electron transfer efficiency to generate geminate hole-electron pairs, which are the precursor of free carriers, was quite low, whereas electron transfer efficiently occurs in a layered system using a small carrier transport molecule instead of the large PMPS. These results were explained in terms of the number of electron transfer sites created by the molecular penetration during the overcoating operation. A high electron transfer efficiency was observed in a single layer of mixed PMPS and azo pigment. According to these results, a high carrier generation efficiency has been demonstrated for the layered device using the azo pigment with PMPS in the CGL and only PMPS in the overlayer.