Effect of non-ohmic contacts on the light-intensity dependence of the open-circuit voltage in organic solar cells

The effect of contact barriers on the light-intensity dependence of the open-circuit voltage of organic solar cells is investigated in experiments and simulations. Reduced light-intensity dependence is found when the open-circuit voltage surpasses the built-in voltage, leading to a slope of kT/2q for a device with one non-ohmic contact and a slope of zero for a device with two non-ohmic contacts. The reduced light-intensity dependence of the open-circuit voltage is not caused by entering a contact-recombination-limited regime but by the absence of band bending in the vicinity of a non-ohmic contact.