Scalable Growth of Stable Wide‐Bandgap Perovskite towards Large‐Scale Tandem Photovoltaics

Upscaling and stabilizing efficient wide‐bandgap perovskite solar cells (PSCs) are critical for the commercialization of tandem photovoltaics. Herein, solvent engineering is applied for scalable deposition of wide‐bandgap (≈1.72 eV) perovskite by the introduction of N ‐methyl‐2‐pyrrolidone (NMP) additives, which enables compact and phase‐stable FA 0.83 Cs 0.17 Pb(I 0.7 Br 0.3 ) 3 perovskite even without the use of antisolvent. By further passivation with a 2‐thiophenemethylammonium bromide (2‐ThMABr)‐based quasi‐2D perovskite ( n = 2 ) on the surface of 3D perovskite, a champion power conversion efficiency (PCE) of 19.46% with a higher open‐circuit voltage of 1.219 V for a small‐sized wide‐bandgap PSC is achieved. It also exhibits excellent long‐term stability, maintaining 93% of its initial PCE after 2000 h storage in the air without encapsulation. In addition, this wide‐bandgap perovskite is also easy to be upscaled via a blade‐coating strategy, which demonstrates high PCEs of 16.07% and 13.03% with active areas of 46.5 and 123.0 cm 2 , respectively. Furthermore, the application of this wide‐bandgap perovskite for four‐terminal (4‐T) perovskite/silicon (Si) tandem solar cells also demonstrates high PCEs of 23.85% and 19.51% with active areas of 0.16 and 1.0 cm 2 . The work demonstrates a great potential toward large‐area efficient and stable wide‐bandgap PSCs and perovskite/Si tandem cells.