Conductivity photoquenching effect in polymer–ferrocene composites

Abstract

Based on a nonpolar polymer—i.e., high-density polyethylene, polar polyvinylidene fluoride, and di-π-cyclopentadienyl iron (π-(C5H5)2Fe, ferrocene)—matrix composites are obtained that exhibit the conductivity photoquenching effect. Charge states and photoelectret and photoconductive properties of films of these composites are studied. In the visible region, the degree of conductivity photoquenching of matrix composites depends heavily on charge transport features in the heterogeneous polymer-ferrocene system and on reversible changes in electrical and chemical properties of ferrocene structures upon exposure to the electric field and light. A possible mechanism of the conductivity photoquenching effect in polymer-ferrocene composites is proposed that adequately accounts for experimental results. As light is turned off, the dark current is restored, which indicates the reversibility of the observed effect. The negative photoconductivity does not appear when CdS is used instead of ferrocene in composites of polymers under study. The negative photoconductivity effect increases when the third component, i.e., CdS photosensitive semiconductor, is introduced into the polymer-ferrocene composite.