Diffusion and Drift of Charge Carriers in Molecularly Doped Polymers

The diffusion coefficient $\left(D\right)$ and drift mobility $\left(\mu \right)$ of molecularly doped polymers have been obtained by Monte Carlo parameter fitting of a theoretical equation to time-of-flight transient photocurrent signals. The logarithm of μ increased linearly with $\sqrt{E}$. The negative field dependence of the mobility that has been observed at low electric field appeared to a superimposition of drift and diffusion. An anomalous field-assisted $D$ was observed. The logarithm of $D$ decreased linearly with $T^{-2\mathrm{}}$.