Fig. 1

CIGS solar cell. Set-up of a standard CIGS solar cell on flexible PI. The layer stack consists of the following layers from bottom to top: PI substrate (\(\sim\)25 µm), Mo back contact (\(\sim\)600 nm), co-evaporated CIGS absorber layer (\({\sim}\)2 µm), CdS buffer layer (\({\sim}\)2 nm), i-ZnO (\(\sim\)50–60 nm), and ZnO:Al (\({\sim}\)200 nm) bilayer front contact, MgF\(_{2}\) anti-reflection coating (\({\sim}100\) nm)