Organic photoconductive layers sensitized with triarylcarbonium salts

The electrophotographic layer consisting of poly-3,6-dibromo-N-vinylcarbazole was sensitized with twenty-seven kinds of triarylcarbonium salts. The carbonium salt compounds used have the formula: [equation] The novel sensitizers differ in two points from the well-known triphenylmethane dyestuffs sensitizers for the organic electrophotoconductors. First, the triphenylmethane dyestuffs have at least two radicals such as amino or dimethylamino radical. The novel sensitizers have not such a radical. Second, the novel sensitizers have an extreme ability to increase the photosensitivity of organic photoconductors. When the photoconductive polymer sensitized with carbonium salts is applied to semitransparent paper, cellophane papers or plastic sheet, a transparent electrophotographic material can be obtained. These materials are superior to sensitized zinc oxide paper in photosensitivity. Such a transparent material can be used as a master for diazo copy, for overhead projection copy, or for slides.