Regulating Surface Metal Abundance via Lattice‐Matched Coordination for Versatile and Environmentally‐Viable Sn‐Pb Alloying Perovskite Solar Cells

• Published in: Advanced materials (Weinheim) Vol. 36; no. 39; pp. e2405860 - n/a
• Main Authors: Liu, Gengling, Yang, Guo, Feng, Wenhuai, Li, Hui, Yang, Meifang, Zhong, Yang, Jiang, Xianyuan, Wu, Wu‐Qiang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.09.2024
• Subjects: Abundance; Alloying; Biocompatibility; Buried structures; Carrier density; chemical coordination; Chemical damage; Crystallization; Energy conversion efficiency; Homogeneity; ion distribution; Lattice matching; Lead; Leakage; pb leakage; Perovskites; Photovoltaic cells; Porphyrins; sn‐pb perovskites; Solar cells; Tensile strain; Tin; Water damage; chemical coordination; ion distribution; sn‐pb perovskites; pb leakage; solar cells
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202405860

Narrow‐bandgap Sn‐Pb alloying perovskites showcased great potential in constructing multiple‐junction perovskite solar cells (PSCs) with efficiencies approaching or exceeding the Shockley‐Queisser limit. However, the uncontrollable surface metal abundance (Sn2+ and Pb2+ ions) hinders their efficiency and versatility in different device structures. Additionally, the undesired Pb distribution mainly at the buried interface accelerates the Pb leakage when devices are damaged. In this work, a novel strategy is presented to modulate crystallization kinetics and surface metal abundance of Sn‐Pb perovskites using a cobweb‐like quadrangular macrocyclic porphyrin material, which features a molecular size compatible with the perovskite lattice and robustly coordinates with Pb2+ ions, thus immobilizing them and increasing surface Pb abundance by 61%. This modulation reduces toxic Pb leakage rates by 24‐fold, with only ∼23 ppb Pb in water after severely damaged PSCs are immersed in water for 150 h.This strategy can also enhance chemical homogeneity, reduce trap density, release tensile strain and optimize carrier dynamics of Sn‐Pb perovskites and relevant devices. Encouragingly, the power conversion efficiency (PCEs) of 23.28% for single‐junction, full‐stack devices and 21.34% for hole transport layer‐free Sn‐Pb PSCs are achieved.Notably, the related monolithic all‐perovskite tandem solar cell also achieves a PCE of 27.03% with outstanding photostability. Lattice‐matched coordination of Sn‐Pb alloying perovskites by cobweb‐like quadrangular macrocyclic porphyrin chelators beneficially regulates the surface metal abundance for versatile construction of high‐efficiency single‐junction and tandem solar cells with extended lifespan and minimized toxic Pb leakage.