Substrate configuration CdTe solar cells

Cadmium Telluride (CdTe) thin film solar cells technology is prominent because of optimum theoretical conversion efficiency and low manufacturing cost. CdTe solar cells are fabricated in two configurations namely superstrate and substrate. The latter has many advantages over the former, such as the feasibility to replace rigid glass with flexible metal or polymers, and it is much easier to study the interface. However, substrate configuration still has lots of challenges with record power conversion efficiency of ~14% while superstrate has already reached 22.1%. The issues for substrate configuration is the poor ohmic contact with the substrate. Molybdenum(Mo) is found to be the best back contact because of its high thermal expansion, good conductivity, and adequate reflection. To make better ohmic contact, we worked with various contact layers and found that molybdenum diselenide (MoSe₂) boosts better performance for copper (Cu) free CdTe solar cells and a comparative analysis of these contact layers will be presented. The differences between different CdS deposition methods and the effect of heat treatment before and after CdS deposition will also be discussed for substrate configuration.