Thin film CdS/CdTe and CdS/PbS photovoltaic solar cells

The current review article has focused on studying the effect of some losses such as the optical and recombination losses on the calculated short-circuit current density, cell efficiency and other cell parameters (such as: fill factor, open-circuit voltage, output power) of CdS/CdTe and CdS/PbS solar cells. The effect of the thickness of front electrode layer, the thickness of window layer (CdS), the thickness of absorber layer (CdTe or PbS), the width of space-charge region, the electron lifetime and the reflectivity from back contact were considered in this study. The optical losses which include the absorption in window layer and front electrode as well as the reflection at various interfaces recorded a value of 23-33% dependence on the thickness and optical properties of the window and front electrode layers. The front surface recombination losses are about 8% depend on the width of space charge region. The back surface recombination losses are mainly depending on the thickness of the absorber layer. The recombination losses in space charge region can be neglected at long electron lifetime of about 10(-8) sec. The reflectivity of metallic back contact plays a significant role in enhancing the short current density particularly at low thickness of the absorber layer. The calculated efficiency of CdS/CdTe of 16.5 % agrees with the corresponding experimental values. The maximum efficiency of CdS/PbS of 6.1% is considered greater than those measured experimentally of this type of solar cells.