Bandgap Tunable Two-Step Vapor-Deposited Perovskite Absorbers for Perovskite-Silicon Tandem Solar Cells

We report a two-step thermal evaporation–close space sublimation deposition method for tunable bandgap lead halide perovskites with single junction solar cell efficiencies exceeding 20%. These absorbers are integrated into perovskite–silicon tandem solar cells with stabilized efficiencies of >29%.