Dual-functional interfacial engineering with Portulaca oleracea phytochemicals enables efficient and eco-safe perovskite solar cells

Abstract

Perovskite solar cells (PSCs) represent a transformative renewable energy technology, leveraging their low-cost fabrication, high efficiency, and scalable production. However, persistent challenges of operational instability and lead leakage still hinder their practical deployment. Here, we address these dual issues through synergistic interfacial engineering and lead-sequestering strategies. By introducing Oleracein E (OE), a naturally derived phytochemical from Portulaca oleracea (hereinafter referred to as PO) with moderate Pb²⁺-binding affinity, at the SnO₂/perovskite interface, we achieve concurrent defect passivation, perovskite crystallization regulation, and lead leakage suppression. The multifunctional groups of OE passivate surface defects of SnO₂, enhance interfacial conductivity, and promote hydrogen-bond-assisted growth of large-grained perovskite films, minimizing nonradiative recombination. The resulting PSCs deliver a champion power conversion efficiency of 25.02 % with enhanced operational stability. Furthermore, integrating OE-modified interface with a bio-based encapsulation layer containing PO extracts enables dual lead sequestration. Under severe mechanical damage, this hierarchical design suppresses >99.8 % of lead leakage, limiting Pb²⁺ release to 8.33 ppb in a real-world condition, which is far below regulatory thresholds for drinking water (15 ppb) and sewage discharge (50 ppb). Our work establishes a sustainable, cost-effective roadmap for eco-safe and high-performance PSCs, advancing their practical application.