Realizing Double Graded CIGSe Absorbers With the R2R Hybrid-CIGSe-Process

This article presents an approach for industrial roll-to-roll (R2R) deposition of Cu(In,Ga)Se-2 (CIGSe) thin films on stainless steel foil for use as absorber layers in flexible thin-film solar cells. The hybrid-CIGSe-deposition-process combines magnetron sputtering with evaporation techniques and allows the realization of a double graded CIGSe layer, reaching a conversion efficiency of currently up to 14.0% (w/o antireflective coating). The influence of different power settings of the individual magnetrons on the gallium profile is described. For a deeper understanding of differences between a static and an R2R process, a calculated flux diagram is presented. In the second part of this contribution, the homogeneity of the industrial scale samples is discussed by comparing the change in CGI and GGI over the foil width of 30 cm. The hybrid-CIGSe-deposition-process excels in a straightforward scalability for industrial usage due to the application of planar magnetron sputtering sources as metal vapor supply.

Automated summary

This article presents a method for industrial roll-to-roll deposition of Cu(In,Ga)Se-2 thin films on stainless steel foil for use in flexible thin-film solar cells, achieving high conversion efficiency. The influence of different power settings of magnetron sputtering sources on gallium distribution and differences between static and R2R processes are studied.