Analysis of Irregular Morphologies and Mobilities of Organic Solar Cells by Simulation

Irregular morphologies of organic solar cells with different donor:acceptor ratios and mobilities are explored. In this work, a simple algorithm that generates random disordered morphologies as a function of weight ratios from different nucleation points located randomly within the active layer and growing radially is used. By solving in two spatial dimensions the system of three coupled differential equations: Poisson’s equation, and the continuity equations for the electron and hole current densities; the current density−voltage characteristics of bulk heterojunction solar cells with different donor:acceptor ratios for different mobilities are calculated. The results show that the transport properties of the materials influence the optimal value of the weight ratio of the mixture.