Interface Modulation by Macromolecules for Enhancing the Efficiency and Stability of Perovskite Solar Cells.

Both high-power conversion efficiency (PCE) and long-term stability are critical needs for a reliable perovskite solar cell (PSC). In this work, a polyamidoamine (PAMAM) dendrimer is employed to enhance the efficiency and stability of double-cation-based PSCs via different fabrication scenarios. Based on our experimental results and numerical analysis, the application of a thin layer of PAMAM macromolecules at the interface of the perovskite absorber and the hole transport layer gives rise to enhanced performance, including both efficiency and stability due to reduced interface defects and lower carrier recombination. The results suggest that PAMAM as a capping layer can effectively passivate the surface defects of the perovskite film. As a result, a PCE of 22.8% has been achieved, while the reference devices without the PAMAM passivation layer exhibit a PCE of 20.9%. The operational stability at maximum power point (MPP) under continuous 1 sun illumination and dark storage stability show that the target perovskite/PAMAM device retains 80% of its initial PCE after 1000 h. Our research could significantly impact the field by providing valuable insights into surface passivation using macromolecules to improve the performance of perovskite-based photovoltaic devices.