Limitation of the mobility of charge carriers in a nanoscaled heterogeneous system by dynamical Coulomb screening

The limitation of the mobility of charge carriers by dynamical Coulomb screening due to mobile ions has been analyzed for a heterogeneous system with spatially separated interpenetrating conducting paths. A finite time of charge screening has been taken into account. An expression connecting the mobility of charge carriers with the ionic conductivity in the other conducting channels and with the screening has been derived. The correlation between the electron mobility and the ion conductivity has been demonstrated experimentally by time-of-flight and impedance spectroscopy measurements for electron injection into a porous network of sintered TiO2 nanoparticles.