High‐Efficiency Sn‐Pb Perovskite Solar Cells via Nucleation and Crystallization Control

substrate. The approach is also applicable to wide bandgap PSCs, normal bandgap PSCs, and all-perovskite tandem solar cells, delivering a PCE >27% for the antisolvent-free and additive-free tandem device. This work establishes a scalable and versatile approach for developing large-area Sn-Pb and all-perovskite tandem devices, advancing the field toward practical applications.