Phase behavior and substitution limit of mixed cesium-formamidinium lead triiodide perovskites

Charles, Bethan, Weller, Mark T., Rieger, Sebastian, Hatcher, Lauren E. ORCID: https://orcid.org/0000-0002-1549-9727, Henry, Paul F., Feldmann, Jochen, Wolverson, Daniel and Wilson, Chick C. 2020. Phase behavior and substitution limit of mixed cesium-formamidinium lead triiodide perovskites. Chemistry of Materials 32 (6) , pp. 2282-2291. 10.1021/acs.chemmater.9b04032

Preview

PDF - Accepted Post-Print Version Download (829kB) | Preview

Abstract

The mixed cation lead iodide perovskite photovoltaics show improved stability following site substitution of cesium ions (Cs+) onto the formamidinium cation sites (FA+) of (CH(NH2)2PbI3 (FAPbI3) and increased resistance to formation of the undesirable ∂-phase. The structural phase behavior of Cs0.1FA0.9PbI3 has been investigated by neutron powder diffraction (NPD), complemented by single crystal and power X-ray diffraction and photoluminescence spectroscopy. The Cs-substitution limit has been determined to be less than 15%, and the cubic α-phase, Cs0.1FA0.9PbI3, is shown to be synthesizable in bulk and stable at 300 K. On cooling the cubic Cs0.1FA0.9PbI3, a slow, second-order cubic to tetragonal transition is observed close to 290 K, with variable temperature NPD indicating the presence of the tetragonal β-phase, adopting the space group P4/mbm between 290 and 180 K. An orthorhombic phase or twinned tetragonal phase is formed below 180 K, and the temperature for further transition to a disordered state is lowered to 125 K compared to that seen in phase pure α-FAPbI3 (140 K). These results demonstrate the importance of understanding the effect of cation site substitution on structure–property relationships in perovskite materials.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Publisher:	American Chemical Society
ISSN:	0897-4756
Funders:	EPSRC
Date of First Compliant Deposit:	19 March 2020
Date of Acceptance:	27 February 2020
Last Modified:	02 Dec 2024 03:30
URI:	https://orca.cardiff.ac.uk/id/eprint/130516

Citation Data

Cited 18 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item