Molecular Extrusion Drives Polymer Dynamic Soft Encapsulation to Inhibit Lead Leakage for Efficient Inverted Perovskite Solar Cells and Modules

Polymer additives exhibit unique advantages in suppressing lead leaching from perovskite solar cells (PSCs). However, polymers tend to excessively aggregate in the perovskite film, which hinders comprehensive encapsulation and disrupts charge transport efficiency, degrading lead leakage inhibition and device performance. Herein, a polymer dynamic soft encapsulation strategy driven by molecular extrusion is introduced to mitigate lead leakage in PSCs, achieved through the incorporation of poly(propylene adipate) (PPA) as a multifunctional additive in the perovskite formulation. The PPA-modified inverted perovskite solar cell (aperture area: 0.04 cm²) and module with dimensions of 30 × 30 cm² (aperture area: 651.42 cm²) achieve superior power conversion efficiencies of 26.37% and 20.06% (certified 19.68%), respectively. Furthermore, the PPA anchors Pb²⁺ via chemical coordination and physically blocks moisture ingress, resulting in lead leakage suppression efficiencies of 95.0% in the perovskite solar cell and 91.4% in the module, with a concomitant 93.1% reduction in environmental biotoxicity compared to the control device. This work addresses the critical challenge of lead leakage in PSCs and offers a scalable strategy for advancing the development of environmentally friendly and high-performance perovskite photovoltaic technology.