Swiss scientists have built a 4T tandem perovskite/CIGS mini-panel with a geometric fill factor of over 93%. It combines a 10.8%-efficient mini perovskite module and a 15.1%-efficient CIGS device.

The module was fabricated with methylammonium lead iodide (MAPbI3) perovskite solar cells via low-cost spin coating. The panel also achieved an open-circuit voltage of 16.07 V, a short-circuit current ...