Doping Effects in Transient Radiation-Induced Conductivity of Polymers

Doping effects observed in the transient radiation-induced conductivity of some polymers are investigated. In polymers with predominating free charge carriers (PVK, PEPC, PET, and PS) the effect consists mainly in the reduction of the conductivity depending on the interrelation of ionization potential and electron affinity of the macromolecules and the dopant molecules. These results are in qualitative agreement with time of flight measurements. On the other hand, in polymers like PMMA and perchlorovinyl resin featuring extremely low geminate conductivity, doping enhances (though still selectively) their conductivity and its dependence on the dopant concentration is also discussed.