Steric Impediment of Ion Migration Contributes to Improved Operational Stability of Perovskite Solar Cells. Issue 11 (4th February 2020)

• Record Type: Journal Article
• Authors: Tan, Shaun; Yavuz, Ilhan; De Marco, Nicholas; Huang, Tianyi; Lee, Sung‐Joon; Choi, Christopher S.; Wang, Minhuan; Nuryyeva, Selbi; Wang, Rui; Zhao, Yepin; Wang, Hao‐Cheng; Han, Tae‐Hee; Dunn, Bruce; Huang, Yu; Lee, Jin‐Wook; Yang, Yang
• Is Part Of: Advanced materials. Volume 32:Issue 11(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-02-04
• Subjects: acetamidinium -- ion migration -- perovskite solar cells -- stability -- steric engineering; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201906995
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: The operational instability of perovskite solar cells (PSCs) is known to mainly originate from the migration of ionic species (or charged defects) under a potential gradient. Compositional engineering of the "A" site cation of the ABX3 perovskite structure has been shown to be an effective route to improve the stability of PSCs. Here, the effect of size‐mismatch‐induced lattice distortions on the ion migration energetics and operational stability of PSCs is investigated. It is observed that the size mismatch of the mixed "A" site composition films and devices leads to a steric effect to impede the migration pathways of ions to increase the activation energy of ion migration, which is demonstrated through multiple theoretical and experimental evidence. Consequently, the mixed composition devices exhibit significantly improved thermal stability under continuous heating at 85 °C and operational stability under continuous 1 sun illumination, with an extrapolated lifetime of 2011 h, compared to the 222 h of the reference device. Abstract : A steric engineering strategy to impede ion migration in perovskite thin films is demonstrated where ion migration is effectively hindered by localized lattice distortions induced by incorporation of oversized A site cations. The steric engineering approach improves the operational lifetime of perovskite solar cells by more than nine‐fold from 222 h to 2011 h.