Efficient Flexible Perovskite Solar Cells With Over 2000 h T 90 Operational Lifetime via 2,4,6‐Triphenyl‐1,3,5‐Triazine Anchoring

ABSTRACT The defect passivation of the perovskite and the mitigation of nonradiative recombination losses substantially contribute to the enhancement of power conversion efficiency (PCE) and operational stability of flexible perovskite solar cells (PSCs). In this study, 2,4,6‐triphenyl‐1,3,5‐triazine, characterized by its multifunctional molecular groups, is selected for the perovskite defect passivation. The molecular anchoring suppresses the undercoordinated lead (Pb), iodine (I), and formamidinium defects, and the Pb I antisite defects. Consequently, the resulting PSCs achieve a PCE of 24.85%. Under the maximum power point tracking measurement, the T 95 , T 91, and T 90 lifetime (time for the device's efficiency that decreases to 95%, 91%, and 90% of its initial efficiency, respectively) of the flexible PSCs is 1423, 1682, and 2181 h, which are the best results among these flexible PSCs reported so far. The work highlights a promising buried interface anchoring strategy to guide the development of high‐performance flexible PSCs.