HOLE TRANSPORT IN 1-PHENYL-3-((DIETHYLAMINO)STYRYL)-5-(P-(DIETHYLAMINO)PHENYL)PYRAZOLINE-DOPED POLYMERS

Hole mobilities have been measured in 1-phenyl-3-((diethylamino)styryl)-5-(p-(diethylamino)phenyl)pyrazoline (DEASP)-doped polycarbonate (PC) and polystyrene (PS) over a wide range of fields, temperatures, and DEASP concentrations. At low concentrations mobilities of DEASP-doped PS are significantly higher than for DEASP-doped PC. At high concentrations, the mobilities are largely independent of the polymer. A key result is that the activation energies of the mobilities are independent of both the DEASP concentration and the polymer. The results have been compared to predictions of the disorder formalism, due to Bassler and co-workers, and models based on polaron formation. Describing the results by the disorder formalism leads to the conclusion that the width of the hopping site manifold is determined by dipole moments associated with the DEASP molecule. Agreement with experiment requires that the dipole effect be purely intramolecular. Interpretation of the results by models based on polaron formation requires that the polaron be intramolecular with a binding energy of approximately 1.2 eV