  Photo-induced charge transfer of positive and negative charges across the
interface between an ordered organic semiconductor and a polymeric insulator is
observed in the field-effect experiments. Immobilization of the transferred
charge in the polymer results in a shift of the field-effect threshold of
polaronic conduction along the interface in the semiconductor, which allows for
direct measurements of the charge transfer rate. The transfer occurs when the
photon energy exceeds the absorption edge of the semiconductor. The direction
of the transverse electric field at the interface determines the sign of the
transferred charge; the transfer rate is controlled by the field magnitude and
light intensity.
