HOLE TRANSPORT IN HYDRAZONE-DOPED POLYMER-FILMS

Hole drift mobilities were measured in hydrazone-doped polycarbonate f ilms under various concentrations, temperatures and electric fields. H ydrazone molecules used were 9-ethylcarbazole-3-carbaldehyde diphenylh ydrazone (CTM1), 9-ethylcarbazole-3-carbaldehyde methylphenylhydrazone (CTM2); and 1-pyrenecarbaldehyde diphenylhydrazone (CTM3). Charge tra nsport in the films obeyed the nonadiabatic small-polaron hopping form alism with almost the same activation energies at concentrations inves tigated. CTM2 exhibited a different concentration dependency and relat ively small mobility especially at high concentrations. Analysis by di sorder formalism indicated that the energetic disorder parameter (a) i s almost the same and the non-energetic disorder parameter (Sigma) is different. We found some correlations between the mobilities of the CT Ms and molecular overlap and orientation in the single crystalline sta te of CTMs.