Characteristics of small- and large-polaron motion in organic crystals

Based on a generalized theory of charge transport in organic crystals we investigate the motion of polarons of arbitrary size. Within this theory, we analyze the influence of characteristic electronic, vibronic, and thermal energies and their role for the transport regimes. The polaron bandwidth is identified as the central temperature-dependent quantity. The size of the dressed charge carriers is used to analyze the correlation between the polaron size and transport mechanism. In addition, we propose that the band and hopping transport can be distinguished by investigating the mobility anisotropy. To do this only electronic structure parameters are necessary for comparison.