Unified Mobility Model for Amorphous Organic Materials

The influence of temperature, carrier concentration and electric field on the hopping transport in disordered organic semiconductors is studied theoretically, and a simple and accurate analytical model is worked out. The model is based on the concept of percolation in a variable range hopping system and the calculations are worked out exploiting the effective temperature approach. At room temperature the dependence on carrier density plays a major role, whereas at low temperatures or high fields the electric field dependence becomes relevant. Neglecting only one of those effects, depending on the operating conditions, leads to an evident underestimation of the hopping mobility.