Consolidating a Pb–X framework via multifunctional passivation with fluorinated zwitterions for efficient and stable perovskite solar cells. Issue 19 (25th April 2022)

• Record Type: Journal Article
• Authors: Wang, Hanyu; Zou, Wenjing; Ouyang, Yukun; Deng, Xiong; Luo, Hu; Xu, Juehao; Liu, Xingchong; Li, Haimin; Gong, Xiaoli; Lei, Yue; Ni, Yafei; Peng, Yongshan
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 19(2022)
• Page Start: 10750
• Page End: 10758
• Publication Date: 2022-04-25
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta00653g
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Multifunctional fluorinated D-PFPAA zwitterions can reduce the number of ionic defects and consolidate Pb–X framework, suppressing ion migration, and form a hydrophobic barrier, significantly improving the power conversion efficiency and stability. Abstract : Ionic defects in perovskite films decrease both the power conversion efficiency (PCE) and stability of a perovskite solar cell (PSC). Herein, fluorinated D-pentafluoro-phenylalanine (D-PFPAA) zwitterions are introduced into a perovskite to passivate the ionic defects and effectively consolidate the Pb–X framework to suppress ion migration. The results demonstrate that the amino, carboxyl, and fluorine groups in D-PFPAA can support the multifunctional passivation of both positive and negative ionic defects, including uncoordinated Pb 2+ ions and halogen (X − ) defects in the perovskites, thereby effectively suppressing charge recombination. Consequently, a D-PFPAA-modified device shows a highest PCE of 21.56% with an increased open circuit voltage of 1.15 V. Apart from the consolidated Pb–X framework, resulting from multifunctional passivation, the fluorine groups in D-PFPAA can also form an effective hydrophobic barrier to protect the perovskite film from moisture-related erosion. As a consequence, the D-PFPAA-modified device retains more than 85% of its original PCE after undergoing 500 h of aging at 45% relative humidity under ambient conditions. This work provides a promising strategy for the realization of efficient and stable PSCs via the selection of fluorinated zwitterions to passivate the ionic defects, inhibit ion migration, and protect against moisture damage.