Dependence of cell performance on wafer thickness for BSF and non-BSF cells

This paper reports on the results of a set of experiments designed to study the relationship between cell thickness and efficiency for cast polycrystalline silicon solar cells. Cells without back surface field are less efficient as they get thinner. Short circuit current, open circuit voltage and fill factor all decrease as the non-BSF cells get thinner. However, cells made with an aluminum paste back surface field show the opposite relationship; thinner cells are more efficient. This higher efficiency for thinner BSF cells is the result of higher short circuit current and higher fill factor. The physics behind these results are discussed.