Beyond Self‐Assembled Molecules: Hydrogen‐Bonding‐Regulated Crystallization of Wide‐Bandgap Perovskite for High‐Performance Perovskite‐Silicon Tandem Photovoltaics

Wide-bandgap (WBG) perovskites crystallization is essential for high-efficiency perovskite-silicon tandem solar cells (TSCs), yet their fabrication on self-assembled molecules (SAMs) is often challenged by solvent-induced damage and uncontrolled packing. Here, we report an interfacial engineering strategy that goes beyond conventional SAM modification by introducing a thiophen-3-ylmethanamine hydrochloride (3-TMA) molecular layer between the SAM and perovskite photo-active layer. The aromatic thiophene units establish strong π‑π stacking interactions with the underlying SAM, forming a solvent-resistant interlayer that stabilizes the anchored SAM structure during solution processing. Meanwhile, hydrogen-bonding interactions between 3-TMA and the perovskite precursors effectively decelerate crystallization, promoting uniform nucleation and high-quality WBG perovskite films. The resulting interface exhibits improved energy-level alignment and reduced interfacial stress, facilitating efficient charge transport and enhanced device stability. Consequently, single-junction WBG perovskite devices with bandgaps of 1.67 and 1.84 eV achieve champion power conversion efficiencies (PCEs) of 23.17% and 19.61%, respectively. When integrated into monolithic perovskite‒silicon TSCs, the strategy enables PCEs of 33.21% (certified 32.13%) for rigid tandems and 31.03% (certified 30.34%) for flexible tandems. Encapsulated devices retain 92.3% of their initial performance after 1000 h of continuous 1 sun illumination at room temperature.