Phase transition arising from order-disorder motion in stable layered two-dimensional perovskite

In recent years, organic-inorganic hybrid materials are widely designed and synthesized as switching materials for temperature response. However, due to the change of molecular arrangement inside the crystal during solid-solid phase transition, the distortion of crystal lattice and the great change of lattice parameters are often caused, which result in a poor repeatability and short life. Thus, designing phase change materials with small lattice changes helps to improve product life. In this article, a novel organic-inorganic hybrid material 3HDMAPAPbBr₄ (1, 3HDMAPA is 3-(hydroxydimethylammonio)propan-1-aminium) was successfully synthesized and characterized. For 1, organic cations filled in the van der Waals gap are connected by hydrogen bonds with halogens in the two-dimensional inorganic layer, forming a stable sandwich structure. During the solid-solid phase transition driven by temperature, the changes of inorganic skeleton are relatively small, and the disorder movement of organic cations does not affect the existence of hydrogen bonds, maintaining a relatively stable crystal structure. In addition, electrical property, optical property and crystal structures are analyzed and discussed in detail. We believe that our work will contribute to the development and application of phase change materials in response materials.