Tin–lead halide perovskites with improved thermal and air stability for efficient all-perovskite tandem solar cells

We report the fabrication of monolithic all-perovskite tandem solar cells with a stabilized power conversion efficiency of 19.1% and demonstrate improved thermal, atmospheric, and operational stability of the tin–lead perovskite (FA0.75Cs0.25Sn0.5Pb0.5I3) used as the low gap absorber.