Effect of Se‐free Annealing on Cesium Fluoride Treated Cu(In,Ga)Se 2 Thin Films and Corresponding Solar Cells

The effect of selenium-free annealing on cesium fluoride (CsF)-treated Cu(In,Ga)Se2 (CIGS) thin films is investigated and their solar cell performance evaluated. Annealing CsF-treated CIGS changes the surface morphology chemical composition, reduces Urbach energy. However, full benefit reduced energies annealed samples not obtained, because an increased buffer/CIGS interface recombination as a consequence re-evaporation alkali-containing layer from region upon annealing. On other hand, without any after post-deposition treatment (PDT) preserve at surface, thereby leading to improved interface. Consequently, open-circuit voltage (V OC) fill factor improve significantly in these devices. both nonannealed cells are calculated external quantum efficiency measurement understand impact V OC deficit. No correlation between deficit observed.