Regulating intermolecular interaction of passivators for controllable surface energetics of photovoltaic perovskites.

Abstract

Tackling nonradiative recombination at the perovskite surface is critical yet challenging for unlocking the full potential of perovskite solar cells (PSCs). Although conventional surface passivation effectively reduces trap state density, providing crucial benefits, it will inevitably modify surface energetics that may compromise carrier dynamics and then constrain device performance. Here, we develop a strategy to control the energy-level shifting by passivators through modulation of intermolecular hydrogen bond formation (N─H…N) between the two effective passivators, enabling effective n-type shift at the perovskite surface while sustaining sufficient defect passivation. This strategy featuring tunable energy levels demonstrates versatile compatibility across various perovskite compositions, indicating universal applicability. Consequently, surface trap-mediated nonradiative charge recombination is suppressed, resulting in a champion single-junction inverted wide-bandgap (1.68 electron volts) PSC with a power conversion efficiency (PCE) of 24.04%. We thereby demonstrate a champion PCE of 33.63% in 1-square centimeter two-terminal monolithic perovskite/silicon tandem (certified 33.48%). These results validate tunable energy levels in passivators as an essential solution for interfacial recombination, improving the efficiency and stability of single-junction PSCs and their tandem devices.