Cementitious grain-boundary passivation for flexible perovskite solar cells with superior environmental stability and mechanical robustness

• Published in: Science bulletin (Beijing) 2021-03, Vol.66 (6), p.527-535
• Main Authors: Hu, Xiaotian, Meng, Xiangchuan, Yang, Xia, Huang, Zengqi, Xing, Zhi, Li, Pengwei, Tan, Licheng, Su, Meng, Li, Fengyu, Chen, Yiwang, Song, Yanlin
• Format: Article
• Language: English
• Subjects: Cementitious grain boundary; Mechanical robustness; Perovskites solar cells; Sulfonated graphene oxide
• ISSN: 2095-9273
• DOI: 10.1016/j.scib.2020.10.023

Sulfonated graphene oxide (s-GO) is employed to form the cementitious GBs, which passivates the defects of VI and enhances the ductility of perovskites. The as-optimized flexible PSCs shows a record PCE of 20.56% for 1.01 cm2 and exhibits excellent flexibility, which retains about 88% efficiency even the bending angle reaches 70 degree [Display omitted] The power conversion effciency (PCE) of flexible perovskite solar cells (PSCs) has increased rapidly, while the mechanical flexibility and environmental stability are still far from satisfactory. Previous studies show the environmental degradation and ductile cracks of perovskite films usually begin at the grain boundaries (GBs). Herein, sulfonated graphene oxide (s-GO) is employed to construct a cementitious GBs by interacting with the [PbI6]4– at GBs. The resultant s-GO-[PbI6]4– complex can effectively passivate the defects of vacant iodine, and the devices with s-GO exhibit remarkable waterproofness and flexibility due to the tough and water-insoluble GBs. The champion PCE of 20.56% (1.01 cm2) in a device treated with s-GO is achieved. This device retains 90% of its original PCE after 180 d stored in the ambient condition, as well as over 80% retention after 10,000 bending cycles at a curvature radius of 3 mm.