ELECTRON-TRANSPORT IN VAPOR-DEPOSITED LAYERS OF 2-METHYL-2-PENTYL-1,3-BIS(DICYANOMETHYLENE)INDANE

Electron mobilities are measured in vapor-deposited amorphous layers o f 2-melhyl-2-pentyl-1,3-bis(dicyanomethylene)indane, a highly polar ac ceptor compound with a dipole moment of 3.9 D. The results are describ ed within the framework of a formalism based on disorder, due to Bassl er and coworkers. The parameters of the formalism are sigma, the varia nce of the hopping site energies, mu(0), a prefactor mobility, and Sig ma, the degree of positional disorder. Experimental values of sigma, m u(0), and Sigma. are 0.112 eV, 1.6 x 10(-3) cm(2)/Vs, and 1.6. The var iance of site energies can be described by a model based on dipolar di sorder. A comparison of the prefactor mobility with literature values for vapor-deposited acceptor glasses suggests that the prefactor is de pendent on dipole moment, decreasing with increasing moment. The degre e of positional disorder is similar to that observed in a wide range o f vapor-deposited molecular glasses and attributed to packing constrai nts.