Photogeneration and excitons distribution function in organic bulk heterojunction solar cells

Abstract

In this work, the excitons distribution function in organic bulk heterojunction solar cells, at a depth z has been determined from solving the charge continuity equation, by exploiting the Laplace transform with an appropriate boundary conditions. Next, the influence of the electron-hole pair separation distance on the excitons dissociation probability, the internal quantum efficiency and the binding energy, has been studied. The simulated results show that the probability density of the carriers photogenerated depend on the generation rate, excitons dissociation and the charge carriers in the cells. The potential improvement of the internal quantum efficiency of charge generation depends on electron-hole pair separation distance, the excitons dissociation probability into free charges and depends strongly on the optical absorption of the photons in the active layer.