Efficient monolithic perovskite/perovskite tandem solar cells are fabricated using two perovskite absorbers with complementary bandgaps. By employing doped organic semiconductors, an efficient and selective extraction of the charge carriers is ensured. This study demonstrates perovskite/perovskite tandem cells delivering a maximum efficiency of 18%, highlighting the potential of vacuum‐deposited multilayer structures in overcoming the efficiency of single‐junction perovskite devices.

The addition of Sr in CH NH PbI perovskite films enhances the charge carrier collection efficiency of solar cells leading to very high fill factors, up to 85%. The charge carrier lifetime of Sr -containing perovskites is in excess of 40 μs, longer than those reported for perovskite single crystals.

A low temperature approach for the fabrication of p-i-n perovskite solar cells is presented. Using lead acetate-based precursors, flat and homogeneous CH 3 NH 3 PbI 3 films, compatible with the use of thin organic charge transport layers, can be obtained. The correspondent solar cells showed power conversion efficiency up to 12.5%, with remarkable reproducibility and very low hysteresis.