Generation and Trapping of Charge Carriers in a Localized Model for Dye Photoconductors

In solid photoconductive dyes the energy of the conduction electron is appreciably greater than that of the excited ``optical electron.'' In favorable cases, the energy levels of the dye are almost unaffected by its state of aggregation, so that the ionization energy of the bulk dye is only slightly less than that of a single molecule. Both these facts argue for a localized-process model for photoconductivity in dyes. Some of the implications of such a model for quantum yields of charge carriers and for the kinetics of photoconductivity are discussed.