Investigation of modified stacking sequences of metallic precursors and pre-annealing process without Se vapor at low temperature

Modified stacking sequence of precursors and pre-annealing process on Se vapor at low temperature were applied to Cu(In,Ga)Se2 (CIGS) solar. The remarkable improvement of efficiency (5.53–10.10% and further 11.04%) and open circuit voltage (0.41 V–0.53 V and further 0.56 V) comes from a compact, smooth microstructure, and modified depth profile of Ga with suitable thickness of CuGa multi-stacking layers in the top of precursors as well as surface bandgap enhancement via preannealing process without Se vapor followed by a specific non-toxic hydrogen-assisted solid Se vapor selenization process. The effects of microstructural, compositional and electrical characteristics of Ga distribution including accumulation and interdiffusion were examined in detail. Finally, al arge-area (4030 cm 2 )C IGS solar cell efficiency with improved open circuit voltage (VOC )a ndfill factor (FF) of 36% and 14% has been demonstrated, yielding a promising efficiency of 11.04%.