Surface-defect passivation through complexation with organic molecules leads to enhanced power conversion efficiency and long term stability of perovskite photovoltaics

摘要： Organic-inorganic hybrid lead halide perovskites (e.g., CH3NH3PbX3, X=Cl, Br, I) possess a unique combination of excellent electronic and photoelectrochemical properties including suitable and tunable bandgap, low exciton binding energy in the range of 9–80 meV, high extinction coefficient, and long electron and hole diffusion lengths, which make them excellent photovoltaic materials. The perovskite layer is at the core of perovskite solar cells (PSCs), whose quality would directly determine the device performance. The deficiency of long-term stability of the hybrid perovskite material has been one of the greatest barriers to the commercialization of PSCs. One of the most important strategies to achieve stable solar cells is to improve the intrinsic stability of the materials. Most recently, Wang et al. reported an in-depth systematic study on molecular defect passivation approaches through the interaction between organic functional groups and demonstrated both enhanced PCE and long term stability.