Reducing Energetic Disorder for High‐Efficiency Perovskite Solar Cells with Low Urbach Energy by in Situ NH3 Generation

Abstract The high disorder in perovskite materials leads to severe carrier non‐radiative recombination, which directly determines the energy loss of photovoltaic devices. Currently, modulation of energetic disorder in perovskite solar cells and its correlation with open‐circuit voltage losses (V OC, loss ) remain insufficiently understood. We regulated the perovskite crystallization process by in situ NH 3 generation, thereby enhancing the perovskite degree of energetic order. Density functional theory calculations reveal that lone‐pair electrons on the N atom of the NH 3 molecule coordinate with Pb 2+ , increasing the defect formation energy of lead vacancies (V Pb ), Pb‐on‐I antisite (Pb I ), and I‐on‐Pb antisite (I Pb ) to 5.61, 0.37, and 4.09 eV, respectively. As a result, we obtained energetic ordered perovskite film with an Urbach energy of 23.7 meV. The champion device exhibited a reduced V OC, loss by over than 50 mV and achieved an open‐circuit voltage (V OC ) of 1.182 V with a power conversion efficiency (PCE) of 26.26%. Under the ISOS‐D protocols, the device maintains over 95% of its initial efficiency after 1100 h of nitrogen storage and over 90% after 700 h at 65 °C. And the 5 × 5 cm 2 mini‐modules achieved a PCE of 21.31%, representing state‐of‐the‐art performance in perovskite photovoltaics.