Photoreceptors fabrication techniques

The photoreceptors of the eye utilize "dyes" to convert the incoming light into at least the precursor to a nervous system signal. The field of dye chemistry is extremely well developed and broad. It is also extremely complex. For many years, dye chemistry delineated itself between natural dyes and man-made dyes. This was done for a number of reasons the natural dyes were generally inferior in absorption, stability and applicability to all but the first few manmade counterparts and the natural dyes involved grossly different fabrication techniques. However, the chemical rules derived during the development of man-made dyes are also applicable to the natural dyes. In recent years, the separation between natural dye chemistry and man-made dye chemistry has begun to disappear. Many natural dyes can now be classified in the same tables as the man-made dyes. This will be demonstrated below. 

Organic photoreceptors are prepared by solvent coating techniques and can be fabricated in a drum or web configuration. These can be prepared in the single- or dual-layer arrangement. In the dual-layer arrangement, the generation... 

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