Self-Consistent Cation-Anion Integration Eliminates Passivation Crosstalk for Inverted Perovskite Solar Cells.

Abstract

The wide-bandgap (WBG) absorber in silicon/perovskite tandem solar cells face persistent challenges of interfacial defects and energy-level misalignment. Although dual-cation passivators have demonstrated the potential to address these issues simultaneously, their efficacy is hindered by cation competition for binding sites and modification conflicts, which limit further device improvement. To overcome these limitations, we introduce a self-consistent cation-anion integrated passivation (SCAP) strategy, designing a multifunctional passivator, PDA(TFA)₂, where the bipolar trifluoroacetate (TFA) anion is paired with 1,3-propanediamine (PDA) cations. This SCAP approach eliminates cation competition by enabling defect and field-effect passivation in a unified framework. Specifically, the bipolar TFA anion efficiently passivates halide vacancies and bridges the perovskite and C₆₀ interface, while the PDA cations induce surface dipoles and optimize band alignment. Therefore, optimized 1.68 eV WBG perovskite solar cells achieve a high power conversion efficiency (PCE) of 23.23% with an exceptional open-circuit voltage of 1.27 V. Furthermore, this strategy achieves a 32.33% PCE (31.47% certified stabilized PCE) for a 0.945 cm² monolithic perovskite/silicon tandem cell, delivering an ultra-high 1.992 V open-circuit voltage. These findings underscore the transformative potential of the SCAP strategy in advancing the efficiency and stability of WBG perovskite photovoltaics, paving the way for next-generation tandem solar cells.