Perovskite-organic tandem solar cells with superior reverse-bias stability.

The industrial deployment of thin-film solar cells faces challenges under reverse bias, particularly concerning perovskite materials with poor reverse-bias stability. Meanwhile, the reverse-bias characteristics of organic solar cells (OSCs) remain underexplored. This study first elucidates the mechanism that reverse tunnelling in OSCs, fundamentally dominated by deep trap state within a bulk heterojunction, triggering reversible/irreversible breakdowns under reverse bias. Building on this, we demonstrated high-performance OSCs with superior irreversible breakdown voltage exceeding -35 V by modulating the deep trap state through suppressing an isolated acceptor cluster in the donor-acceptor intermix region. Moreover, through strategically shielding perovskite by OSC with suppressed reverse tunnelling, n-i-p perovskite-organic tandem solar cells maintain over 90% of the initial efficiency when subjected to -40 V. These tandem devices retain 90% and 97% of the initial efficiency after stressing at -20 V for 12 h and -4.5 V for 2,000 h, respectively, outperforming all existing thin-film solar technologies. The exceptional reverse-bias stability under shadowing conditions was further demonstrated in scalable perovskite-organic tandem solar cell minimodules.