Suppression–promotion crystallization of wide-bandgap perovskite for efficient and stable perovskite/silicon tandem solar cells

The development of high-quality wide-bandgap perovskites is essential for efficient perovskite/silicon tandem solar cells, yet rapid crystallization induced by bromine incorporation often leads to defective films. To address this, we introduce m-trifluoromethyl phenylamidinium chloride (m-CF 3 -PAH·HCl) as a multifunctional additive, which regulates crystallization via a distinctive “suppression–promotion” mechanism. This process simultaneously reduces defect density and optimizes interfacial energy-level alignment at the perovskite/SnO 2 interface, thereby suppressing non-radiative recombination and enhancing charge extraction. Consequently, single-junction wide-bandgap perovskite solar cells achieve an outstanding efficiency of 22.12% with significantly improved operational stability. When integrated into monolithic perovskite/silicon tandem devices, an efficiency of 29.13% (1 cm 2 ) is achieved. This work underscores the critical role of crystallization control in advancing tandem photovoltaics. • A multifunctional additive m-CF 3 -PAH·HCl is developed to dynamically regulate wide-bandgap perovskite crystallization via a “suppression–promotion” mechanism. • The additive simultaneously passivates defects and optimizes energy-level alignment, thereby suppressing non-radiative recombination and enhancing charge extraction. • The strategy remains effective on high-thermal-conductivity silicon substrates, overcoming key challenges in perovskite/Si tandem fabrication. • Single-junction wide-bandgap perovskite solar cells achieve an efficiency of 22.12%, and monolithic perovskite/silicon tandems reach 29.13% (1 cm 2 ).