Dyes, Sensitizing

AbstractSpectral sensitizing dyes extend the wavelengths of light to which semiconductors or chemical reactions can respond. The silver halides in photography require special sensitizers to respond to blue, green, red, and infrared wavelengths. Colorless organic semiconductors in electrophotography require dyes to sensitize the electrophotographic response to red and infrared wavelengths. Infrared dyes in general serve both biological and data storage markets. Biological photochemical or photothermal effects require dyes that match the infrared transmission wavelengths of body tissue. Spectral sensitizing dyes are considered functional dyes to distinguish their photosensitizing actions from light absorbing (filtering) action.There are several broad classes of these dyes, eg, cyanine dyes, merocyanine dyes, azine dyes, polymethine dyes, xanthene dyes, etc.Uses for these dyes include photography, eletrophotography, lasers, optical disks, medicine and in solar cells. High purity dyes are required for most of these applications.