A Numerical Scheme to Model Current and Voltage Excitation of Organic Light-Emitting Diodes

We present a method to model organic light-emitting devices driven by a current source in the context of drift-diffusion models. The method is extended to the case of voltage excitation, and calculations with current and voltage excitation are compared. An advantage over the application of Poisson´s equation is that standard numerical solvers can be used for the ordinary differential equations that result from the spatial discretization of the model equations. We employ the model to calculate I- V characteristics and to examine the transient response of an organic light-emitting diode under pulsed current operation. The approach is generalized to the case of an arbitrary number of layers.