1
|
Li W, Hao M, Baktash A, Wang L, Etheridge J. The role of ion migration, octahedral tilt, and the A-site cation on the instability of Cs 1-xFA xPbI 3. Nat Commun 2023; 14:8523. [PMID: 38129416 PMCID: PMC10739958 DOI: 10.1038/s41467-023-44235-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Organic-inorganic hybrid perovskites are promising materials for the next generation photovoltaics and optoelectronics; however, their practical application has been hindered by poor structural stability mainly caused by ion migration and external stimuli. Understanding the mechanism(s) of ion migration and structure decomposition is thus critical. Here we observe the sequence of structural changes at the atomic level that precede structural decomposition in the technologically important Cs1-xFAxPbI3 using ultralow dose transmission electron microscopy. We find that these changes differ, depending upon the A-site composition. Initially, there is a random loss of FA+, complemented by the loss of I-. The remaining FA+ and I- ions then migrate, unit cell by unit cell, into an ordered and more stable phase with a √2 x √2 superstructure. Further ion loss is accompanied by A-site dependent octahedral tilt modes and associated tetragonal phases with different stabilities. These observations of the loss of FA+/I- ion pairs, ion migration, octahedral tilt modes, and the role of the A-cation, provide insights into the atomic-scale structural mechanisms that drive and block ion loss and ion migration, opening pathways to inhibit ion loss, migration and improve structural stability.
Collapse
Affiliation(s)
- Weilun Li
- School of Physics and Astronomy, Monash University, Clayton, VIC, 3800, Australia.
| | - Mengmeng Hao
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Ardeshir Baktash
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Lianzhou Wang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia.
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4072, Australia.
| | - Joanne Etheridge
- School of Physics and Astronomy, Monash University, Clayton, VIC, 3800, Australia.
- Monash Centre for Electron Microscopy, Monash University, Clayton, VIC, 3800, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia.
| |
Collapse
|