ELECTRIC-FIELD AND TEMPERATURE-DEPENDENCE OF THE HOLE MOBILITY IN POLY(P-PHENYLENE VINYLENE)

The current-voltage characteristics of poly(dialkoxy p-phenylene vinyl ene)-based hole-only devices are measured as a function of temperature . The hole current is space-charge limited, which provides a direct me asurement of the hole mobility mu(p) as a function of electric field E and temperature. The hole mobility exhibits a field dependence In mu( p) infinity root E as has also been observed from time-of-flight exper iments in many molecularly doped polymers and amorphous glasses. For t he zero-field hole mobility an activation energy of 0.48 eV is obtaine d. The combination of a field-dependent mobility and space-charge effe cts provides a consistent description of the hole conduction in conjug ated polymer films as a function of voltage, temperature, and layer th ickness.