Aging-Tolerant Precursor Solution for Perovskite Solar Cells Enabled by Phosphite-Assisted Chemical Protection

Despite rapid advances in the power conversion efficiency of perovskite solar cells, stability issues arising from the degradation of both the perovskite precursor solution and film remain a significant challenge for commercialization. Here, we demonstrate full lifecycle management of perovskite solar cells by introducing triphenyl phosphite as a beneficial additive into the perovskite precursor solution. Triphenyl phosphite not only stabilizes the precursor solution by preventing iodide oxidation and deprotonation of organic cations but also enables the formation of perovskite films with enhanced crystallinity, reduced defect density, and enhanced long-term stability under aging conditions. The optimized n-i-p perovskite solar cells deliver a certified power conversion efficiency of 26.6%. The target device retains 90% of its initial efficiency after 600 h of continuous illumination under maximum power point tracking. Notably, even after aging for 21 days in ambient air, the triphenyl phosphite-containing precursor solution can still yield perovskite solar cells with efficiencies comparable to those fabricated from fresh precursor solutions. These results provide a practical strategy and guiding framework for improving the stability of both perovskite precursor solutions and perovskite films.