Investigation of different buffer layers, front and back contacts for CdS/CdTe PV from numerical analysis

Polycrystalline thin film CdTe shows great promise for efficient, low-cost photovoltaics (PV) cell. A numerical analysis was conducted utilizing AMPS simulator to explore the possibility of higher efficiency and stable CdS/CdTe cell among seven different cell structures with tin oxide (SnO₂) and cadmium stannate (Cd₂SnO₄) as front contact layer, zinc oxide (ZnO) and zinc stannate (Zn₂SnO₄) as buffer layer and Ag or antimony telluride (Sb₂Te₃) with Mo as back contact material. It was found that the structure of CTO/ZTO/CdS/CdTe/Ag produced best efficiency over 17%. This analysis has also shown that Cd₂SnO₄ front contact, Zn₂SnO₄ buffer layer and Sb₂Te₃ back contact materials are suitable for high efficiency (>15.5%) and stable CdTe based cells. Moreover, it was found that the cell normalized efficiency linearly decreased at the temperature gradient of -0.3%/°C.