Analytical description of the current-voltage relationship in organic-semiconductor diodes

The description of the current-voltage relationship in disordered organic-semiconductor diodes is complicated by the effects of diffusion and a charge-carrier mobility that depends on charge concentration, electric field and temperature. Here, an analytical model is presented that accurately describes the drift-diffusion current through disordered organic semiconductors over the full voltage range. The model applies to single-carrier devices in which the organic-semiconductor layer is situated between an Ohmic injecting contact and an extracting contact of which the barrier can be varied. The analytical description can be used to extract charge-transport parameters, such as mobility and energetic disorder, from experimental current-voltage characteristics of devices of virtually any layer thickness.