Dilution-induced current-density increase in disordered organic semiconductor devices: A kinetic Monte Carlo study

Dilution of certain disordered organic semiconductors with an inert material can significantly improve current density in devices, but so far the design conditions for a large effect have not been elucidated, hampering application to e.g. OLEDs. In this work, three-dimensional kinetic Monte Carlo simulations are used to study the counterintuitive effect. The results show that dilution is a double-edged sword: The observed effect reflects a balance between a beneficial rise in current density due to reduction of charge traps, and a detrimental fall due to reduction of conducting material in the system. The simulation results are furthermore described well by an analytical model.