Abstract
The memory mechanisms of conductivity and charge acceptance change for a photoreceptor consisting of ionic dye or colored spiropyran and Poly-N-vinyl carbazole (PVK) were studied by measurement of corona charge acceptance, current-voltage characteristics with a sandwich cell and ESR measurement. And it is concluded that the memory is formed by two different cases.
1) When the memory layer is based on ohmic contacting substrate (Au), the photogenerated dye radicals in the bulk seemed to be responsible for memory formation by changing the conductivity. In other words, it is cosidered that the change of dye condition from ionic to non-ionic by exposure caused the elimination of hole trapping site and increased the bulk conductivity.
2) When non-ohmic contacting substrates (ITO, Al) are used, it was also considered that the radicals at the interface could act the key role to assist hole injection from the electrode into memory layer.
