Electric-Field-Dependent Percolation Model Of Charge-Carrier Mobility In Amorphous Organic Semiconductors

Understanding the electric field dependence of charge-carrier mobility is central to the rational design of organic semiconductor devices. We present an analytic description of mobility by considering nonequilibrium carrier distributions within a percolation framework. The theory is compared to measurements by Brutting [Org. Electron. 2, 1 (2001)] of the current-voltage and mobility of the archetype small molecule tris(8-hydroxyquinoline) aluminum. The theory accurately reproduces the temperature, carrier density, and electric field dependences of the experimental data.