The effect of thickness and annealing temperature on the performance of (Ag, Cu)2 ZnSn(S, Se)4 with higher Ag content

Ag-alloying for the kesterite shows many beneficial effects. 1. Enlarge the grain size, 2. Increase the bandgap, 3. Reduction of tailing state and antisite defect, 4. Help type inversion of kesterite. However, if the Ag content in the kesterite is too high (Ag/(Ag+Cu) ≥20%), low efficiency is always demonstrated due to its low carrier concentration and conductivity. In this work, we use the spray pyrolysis to fabricate Ag-alloyed kesterite absorber with higher Ag content. Due to the low conductivity nature of the kesterite with high Ag content, the thickness of the Ag 30 absorber should be reduced. The efficiency of ACZTSSe with higher Ag content can be significantly improved from 5.3% to 7.55% using 0.9 μm absorber under suitable selenization temperature. This results demonstrates the possibility to further increase the Ag content of kesterite for the bandgap engineering and achieve better type inversion.