Regulating wide-bandgap perovskite face-on stacking in hybrid-deposited perovskite/organic tandem solar cells

Vacuum-assisted hybrid deposition for wide-bandgap (WBG) perovskites has been widely recognized for its advantages, including convenience for scaling up and conformal growth, while avoiding toxic solvents. However, the growth of WBG perovskites (>1.8 eV), which is critical for advancing the performance of thin-film-based tandem solar cells, remains insufficiently controlled under hybrid deposition. In this work, we introduce n-propylamine hydrochloride (PACl), which shows enhanced face-on stacking of (100) plane, effectively regulating the oriented crystal growth of 1.84 eV WBG perovskites during the annealing process. This approach reduces defect density and, consequently, improves carrier diffusion length. As a result, the hybrid-deposited WBG perovskite (>1.8 eV) solar cells realize a maximum efficiency of 17.48% and an open-circuit voltage (V_oc) exceeding 1.315 V. When integrated with organic sub-cell in a two-terminal tandem configuration, the tandem device demonstrates a record efficiency of 26.46%, with a certified efficiency of 25.82% over an active area of 0.05 cm².