The Effect of Electric Field on Carrier Mobility in Organic Semiconductors Based on Exponential Type Density of States and Genuine Transport Energy

Carrier mobility plays a crucial role in organic semiconductors because it limits the efficiency of organic devices. Based on the exponential type density of states (EC DOS) and genuine transport energy, we introduce a model to describe the dependence of electric field and carrier mobility in organic semiconductors by using effective medium approximation. The theoretical results show that the carrier concentration is a key factor to influence the carrier mobility, which increases with the increasing carrier concentration. The Poole-Frenkel behavior is reproduced in our model. The calculated carrier mobility as functions of electric field at different temperatures are in good agreement with analytical data for [40'-(3,7-dimethyloctyloxy)-1,1'-biphenylene-2, 5-vinylene] (NRS-PPV).