Uracil Induced Simultaneously Strengthening Grain Boundaries and Interfaces Enables High‐Performance Perovskite Solar Cells with Superior Operational Stability

Abstract The operational stability is a huge obstacle to further commercialization of perovskite solar cells. To address this critical issue, in this work, uracil is introduced as a “binder” into the perovskite film to simultaneously improve the power conversion efficiency (PCE) and operational stability. Uracil can efficiently passivate defects and strengthen grain boundaries to enhance the stability of perovskite films. Moreover, the uracil also strengthens the interface between the perovskite and the Tin oxide (SnO 2 ) electron transport layer to increase the binding force. The uracil‐modified devices deliver a champion PCE of 24.23% (certificated 23.19%) with negligible hysteresis at active area of 0.0625 cm 2 . In particular, the optimal device exhibits over 90% of its initial PCE after tracking for ≈6000 h at its maximum power point under continuous light, indicating its superior operational stability. Moreover, the devices also show great reproducibility in both PCE and operational stability.