Parametrical study of multilayer structures for CIGS solar cells

In this paper, a numerical analysis of relevant electrical parameters of multilayer structures for CIGS-based solar cells was carried out, employing the simulation software wxAMPS. In particular, we have focused on thin film cells having a ZnO:Al/ZnO/CdS/CIGS structure with a Molybdenum back contact. The aim of this work is to establish good theoretical reference values for an ongoing experimental activity, where our technology of choice is the single-step electrodeposition. In detail, we have analyzed how the main electrical properties change with the bang gap and the thickness of the absorber layer, for such a type of solar cell structure. Our results show that both efficiency and fill factor strongly depend on the energy gap. Instead, the absorber thickness plays a role up to a few microns, after which the cell parameters remain almost constant. As expected, the theoretical peak efficiency was found for a band gap value of 1.40 eV, corresponding to a Ga/(In+Ga) ratio of 0.66.