European Conference on Organic Electronics and Related Phenomena - ECOER location:Kent, UK date:21/09/03
Device simulators are capable of numerically solving sets of coupled linear and non-linear differential equations, like Poissons equation and the continuity equations for holes and electrons, in two- or three dimensional device geometries. We have extended a commercial device simulator to include the Langevin recombination term in the continuity equations for holes and electrons. Moreover we have implemented continuity equations for singlet and triplet excitons which use this Lagevin term as a source for excitons, and which include radiative and on-radiative decay, intersystem crossing, triplet-triplet annihilation, as well as singlet-singlet, singlet-triplet, singlet-polaron and triplet-polaron quenching mechanisms. Energy transfer is implemented as a diffusion term, since the molecular nature of this process is ill-compatible with the continuum nature of the differential equations. Those singlet and triplet continuity equations form a set of coupled non-linear differential equations that can be solved in addition to the Poissons and charge carrier continuity equations. Exciton dissociation has not been implemented yet. As a case study, we simulate and analyse the working of a tetracene light-emitting field effect transistor using our organic device simulator. Tetracene is an archetype organic semiconductor of which most optoelectronic constants have been determined or at least estimated. The field effect transistor has been suggested as a potentially interesting device structure to build an organic laser, provided appropriate optical feedback.