Stable Perovskite-Organic Tandem Solar Cells Enabled by Chloride-Doped Evaporated Wide-Bandgap Perovskites

Abstract

Wide-bandgap perovskites are critical for achieving high-efficiency perovskite-based tandem solar cells, yet their practical deployment remains limited by stability challenges such as ion migration and halide phase segregation. Here, we demonstrate that introducing ~1% PbCl2 as a vapor-phase additive during thermal evaporation effectively stabilizes wide-bandgap perovskite devices. Detailed characterizations reveal strong chemical interactions between chloride anions and formamidinium cations, resulting in improved crystallinity and enhanced photoluminescence quantum yield. The Cl-doped wide-bandgap perovskite films exhibit suppressed halide phase segregation and mitigated ionic losses. As a result, a 1.75 eV single-junction perovskite cell achieves a T80 lifetime of 1,639 hours under continuous maximum power point tracking, along with improved efficiency and open-circuit voltage. When integrated with an organic subcell (PCE-10:P2EH-2V), the resulting perovskite-organic tandem solar cell achieves a power conversion efficiency of 24.86% and a maximum T80 of 1,979 hours, surpassing the stability of all the previously reported perovskite-organic and perovskite-perovskite tandem devices.