A unified understanding of charge transport in organic semiconductors: the importance of attenuated delocalization for the carriers
The variety of charge transport theories for organic semiconductors (OSCs) raises the question of which models should be selected for each case, and it is in lack of generalized understanding to cover various OSCs over the full range of crystallinity from single crystal to amorphous. Here, we report that the generalized Einstein relation (GER) can unify various theoretical models and predict charge transport in OSCs with various crystallinity, by altering the variance of density of states and delocalization degree in a Gaussian-distributed density of states. The GER also provides good fitting to much of the experimental data of temperature- and gate-voltage-dependent mobility for different OSCs in transistors. Consequently, disorders of charge transport in various OSCs can be directly compared in the same map, which reveals how energetic disorder and delocalization degree determine charge transport in organic devices.