Numerical simulation of the effect of the free carrier motilities on light-soaked a-Si:H p–i–n solar cell

Abstract

Using a previous model, which was developed to describe the light-induced creation of the defect density in the a-Si:H gap states, we present in this work a computer simulation of the a-Si:H p–i–n solar cell behavior under continuous illumination. We have considered the simple case of a monochromatic light beam nonuniformly absorbed. As a consequence of this light-absorption profile, the increase of the dangling bond density is assumed to be inhomogeneous over the intrinsic layer (i-layer). We investigate the internal variable profiles during illumination to understand in more detail the changes resulting from the light-induced degradation effect. Changes in the cell external parameters including the open circuit voltage, Voc, the short circuit current density, Jsc, the fill factor, FF, and the maximum power density, Pmax, are also presented. This shows, in addition, the free carrier mobility influence. The obtained results show that Voc seems to be the less affected parameter by the light-induced increase of the dangling bond density. Moreover, its degradation is very weak-sensitive to the free carrier mobility. Finally, the free hole mobility effect is found to be more important than that of electrons in the improvement of the solar cell performance. DOI: 10.1088/1674-4926/36/7/074002