biostudies-literatureUnknown16(48)Su CYFerroelastics, as a key branch of ferroic materials, are vital for mechanical switches, energy conversion, <i>etc.</i> While research on ferroelastic organic-inorganic hybrid perovskites has laid a preliminary foundation, in-depth exploration is still needed to expand their material system and functional integration. In this work, we constructed two perovskite ferroelastics using cyclobutylmethanaminium (CBA⁺) as the cationic template. First, the lead-based (CBA)₂PbBr₄ exhibits a ferroelastic phase transition at Curie temperature (<i>T</i> _c) = 383.4 K (<i>mmm</i>F2/<i>m</i>). To address lead toxicity, we developed the lead-free double perovskite (CBA)₄AgBiBr₈ (<i>T</i> _c = 346.7 K, 4/<i>mmm</i>F2/<i>m</i>), whichChemical science23385-23393https://www.ebi.ac.uk/biostudies/studies/S-EPMC12598617biostudies-literatureTwo-dimensional lead-free double perovskite ferroelastics with dynamic thermochromism.PMC12598617Xia SQLiu ZSu CYFu DWZhang ZXNi HFYi HGDu GWfalseTwo-dimensional lead-free double perovskite ferroelastics with dynamic thermochromism.Ferroelastics, as a key branch of ferroic materials, are vital for mechanical switches, energy conversion, <i>etc.</i> While research on ferroelastic organic-inorganic hybrid perovskites has laid a preliminary foundation, in-depth exploration is still needed to expand their material system and functional integration. In this work, we constructed two perovskite ferroelastics using cyclobutylmethanaminium (CBA⁺) as the cationic template. First, the lead-based (CBA)₂PbBr₄ exhibits a ferroelastic phase transition at Curie temperature (<i>T</i> _c) = 383.4 K (<i>mmm</i>F2/<i>m</i>). To address lead toxicity, we developed the lead-free double perovskite (CBA)₄AgBiBr₈ (<i>T</i> _c = 346.7 K, 4/<i>mmm</i>F2/<i>m</i>), which2025-01-01T00:00:00Z2025 Dec2026-06-06T01:13:38.247Z2026-05-24T03:12:19.174ZS-EPMC125986174122111010.1039/d5sc05158d