Pyromellitic diimide-mediated bulk passivation for efficient perovskite solar cells with low energy loss

Perovskite solar cells have attracted considerable attention due to their remarkable efficiency and potential for low-cost production. However, their performance is still impeded by defect states and non-radiative recombination. To mitigate this issue, pyromellitic diimide (PD) is employed as an additive to passivate bulk defects in perovskite materials, effectively inhibiting non-radiative recombination and minimizing energy loss within the system. Experimental investigations demonstrate that PD forms hydrogen bonds with formamidinium (FA+) ions and coordinates with Pb2+ ions, thereby effectively passivating defects. After being treated with PD, the perovskite film exhibits enhanced crystallinity and improved uniformity. As a result of suppressed non-radiative recombination, the solar cell achieves a high open-circuit voltage of 1.193 V along with a power conversion efficiency of 25.79% in 1.55 eV perovskite solar cells. Furthermore, the PD-treated unpackaged device shows improved stability, retaining 96% of its initial efficiency after 2000 h under a nitrogen atmosphere. This study offers valuable insights into developing effective passivation strategies that address defects in perovskite materials.