ELECTRON-TRANSPORT IN -BUTYL-9,10-N,N'-DICYANOANTHRAQUINONEDIIMINE-DOPED POLYMERS

Electron mobilities have been measured in 2-t-butyl-9,10-N,N,N'-dicyan oanthraquinonediimine (DCAQ)-doped bisphenol-A-polycarbonate and poly( styrene) over a range of fields, temperatures, and DCAQ concentrations . The results agree with predictions of a model based on disorder, acc ording to Bassler and coworkers. The model is premised on the assumpti on that charge transport occurs by hopping through a manifold of local ized states with superimposed energetic and positional disorder. The k ey parameters of the model are the energy width of the hopping site ma nifold, the degree of positional disorder, and a prefactor mobility. D escribing the results by the disorder model leads to the conclusion th at the width of the hopping site manifold is 0.136 eV and independent of both the host polymer and DCAQ concentration. The width comprises a dipolar component of 0.085 eV and a van der Waals component of 0.106 eV. Agreement with experimental requires that the dipolar effect be pu rely intramolecular and the van der Waals component be independent of both the DCAQ concentration and the host polymer. The degree of positi onal disorder is between 3.0 and 4.2, increasing with decreasing DCAQ concentration, and is independent of the polymer. The prefactor mobili ties are between 10(-3) and 10(-9) cm(2)/Vsec and can be described by wavefunction decay constants of approximately 1 Angstrom that are also independent of the polymer.