Abstract
A novel process to obtain high quality Cu2ZnSn(S,Se)4 (CZTSSe) absorber is proposed by incorporating SnS together with selenium during selenization of stacked precursors. The effects of incorporating SnS powder during selenization are investigated in terms of composition, structure, morphology and electric properties. It is demonstrated that tin loss issue has been solved and S/(Se+S) ratio which ranging from 0 to 0.25 can also be preciously controlled at the same time by tuning the amount of SnS powder during selenization process, in addition, the formation of Mo(S,Se)2 also be suppressed. The solar cells show a significant increment of open circuit voltage and filler factor due to the increasing of CZTSSe band gap and reducing the thickness of Mo(S,Se)2, respectively. Good efficiency achieved with CZTSSe absorber produced through IBSD (Ion beam Sputtering deposition) following selenization is proposed. As a result, solar cell efficiency up to 7.35% was obtained, originating from 3.73% for pure selenization without SnS powder.