Photo induced memory devices using conducting polymer, poly(3-hexylthiophene) thin films

Photo induced memory devices have been fabricated utilizing conducting polymer, head-to-tail coupled poly(3-hexylthiophene), PHT. The PHT film with Au electrodes at the bottom was coated with ultra thin Al by the thickness of 1 nm on the top. A large increase of conductivity was observed upon light illumination. The increased photoconductivity lasted for several hours after turn off of illumination, indicating photo induced memory effect. The phenomenon is discussed in terms of the persistent photoconduction, which resulted from the electron trapping at Al donor sites in the depletion layer formed near the top of film.