CURRENT-VOLTAGE CHARACTERISTIC OF ORGANIC LIGHT-EMITTING-DIODES

It has been claimed that the variation of current I with voltage V in an organic light entitling diode (LED), based on either metal chelate complexes or conducting polymers, is explained by shallow traps that t rap carriers propagating in the conduction or valence band. However, b ecause these are disordered materials all states are localized. We sho w that it is possible to lit the dependence of I on V and on film thic kness without explicitly introducing traps, but taking their effect in to account by including the mobility variation with the electric field that arises from the distribution in energy of the localized levels. (C) 1998 American Institute of Physics.