Dynamic charge mapping in layered polymer films

This paper describes a hybrid algorithm for the solution of the drift-diffusion equations for bipolar charge transport in layered polymer films. Dynamic charge mapping is achieved using a source distribution technique for the solution of the Poisson equation and time-integration using a fourth order total variation diminishing Runge-Kutta scheme that satisfies the Courant-Friedrichs-Levy stability criterion. An integral equation formulation allow conducting and insulating boundaries and material interfaces to be represented by equivalent free and bound charge distributions that collectively satisfy all local and far-field boundary conditions. This hybrid technique solves the drift-diffusion equations that simulate charge injection, field-dependent mobility transport, recombination, and trapping/de-trapping in the bulk and at material and physical interfaces. The resulting charge map is the taxonomy of the different charge types and their abundance; presenting a dynamic view of the temporal and spatial distributions. Results are discussed for single-layer and multi-layered samples with physical and material interfaces. Conditions for creation of charge packets and electroluminescence due to recombination are computed and discussed.