Optical and Recombination Losses in Cu2ZnSn(S,Se)4-Based Thin-Film Solar Cells with CdS, ZnSe, ZnS Window and ITO, ZnO Charge-Collecting Layers

We report the investigation on the optical and recombination losses in the solar cells based on n-CdS(ZnSe, ZnS)/p-Cu2ZnSn(S,Se)(4) heterojunctions with n-ITO(ZnO) frontal charge-collecting contacts. The calculation of the optical losses was carried out taking into account the light reflection from the interfaces of the contacted layers and absorption of the window and frontal charge-collecting layers. The recombination losses of the photogenerated charge carriers at the interface between the window and absorber layer, in the space charge and in the quasineutral regions of the semiconductor films was determined using the solution of the continuity equation. We investigated the effect of the optical and recombination losses on the internal (Q(int)), external (Q(ext)) quantum yields, short-circuit current density (J(sc)) and maximum efficiency (eta) of solar cells.