Deuterium-Substituted Cations Enhance Perovskite Solar Cell Efficiency and Stability: Article No. 102031

Halide perovskite solar cells with mixed-cation compositions often face instabilities under continuous illumination due to the deprotonation of methylammonium (CH3NH3+, MA+) cations. To address this, we systematically evaluate the partial and complete deuteration of MA+ cations. This approach inhibits deprotonation and degradation, reduces the formation energy of the perovskite phase, improves grain growth, passivates defects, and restrains ion migration. As a result, perovskite solar cells incorporating this deuteration strategy achieve exceptional performance, including a high fill factor (FF) of 82.6% and a power conversion efficiency (PCE) of 25.6%. Their modules with a device area of 56 cm2 demonstrate remarkable stability, maintaining over 93.7% of their initial PCE after 1,000 h at the maximum power point under continuous illumination at 40 degrees C. This novel deuteration strategy presents a promising approach to enhance both the efficiency and stability of perovskite solar cells.