Unified Model for Exciton Diffusion and Dissociation in Organic Solar Cells

The performance of organic solar cells is limited by the exciton. However, the theoretical model to study the nature of the exciton is separated into exciton diffusion and dissociation. This article proposes a unified model by combining both exciton diffusion and dissociation. This model can be reduced to the classical model of exciton diffusion or dissociation. Moreover, this model quantitatively explains meaningful experimental data of the short-circuit current characteristic at different active layer thicknesses that cannot be fitted by the two classical models. In sum, this model is useful for researching the mechanism of the exciton in thin organic materials, which make some significant contributions to blend, multilayer, and A-D-A small-molecule acceptor solar cells.