All-Vacuum-Deposited Bifacial Cu₂ZnSnSe₄ Photovoltaic Cells with Sputtered Cd-Free Buffer Layer

Figure 9

The efficiencies of CZTSe solar cells prepared on FTO substrates obtained during the weatherability DH test. The inset figure is a cross-sectional view of a 4-cycle CZTSe solar cell measured by SEM before and after damp heat treatment.