We report on the analytical description of high-efficiency Cu(In,Ga)Se2-based solar cells produced with a static coevaporation process. We discuss classic quality markers such as grain morphology, composition, vertical compositional gradings, and grain orientation in these cells. We then describe the successful transfer of such results to industrially relevant inline processes in our module production line. Finally, we explicate one of the many optimisation routes for the further improvement of these Cu(In,Ga)Se2-based solar cells: Zn(O,S) buffer layers. •Quality markers of high-efficiency Cu(In,Ga)Se2 (CIGS) cells re-examined.•Efficiency development of CIGS modules.•Zn(O,S) alternative buffer optimization.•Technology transfer from lab to industry