H/OH substitution, construction of K–O coordinated bonds and introduction of homochirality for the design of a 3D hybrid double perovskite multiferroic†

Abstract

Three-dimensional (3D) hybrid metal-halogen perovskite multiferroic materials have great advantages in the application of ferroic-photoelectric devices because of their excellent physical properties, including ferroelectricity, ferroelasticity, large piezoelectric response, and high carrier mobility. Currently, relatively few types of 3D hybrid metal-halogen perovskite multiferroic materials are known, as their construction requires their organic structure to conform to the Goldschmidt tolerance factor. Moreover, their performance potential is limited by their lower Curie temperature (T_c). Herein, we successfully designed a novel 3D hybrid double perovskite (R-3P)₂KBiCl₆ (R-3P = (R)-3-hydroxypyrrolidinium, R3PBKC) using the synthesis strategy of generating K–O coordination bonds through H/OH substitution and introducing homochirality. Notably, R3PBKC exhibited an unusually high T_c (376 K) structural phase transition of P1–P1–P2₁–P6₃22, and the ferroelectric–ferroelastic multiferroicity of R3PBKC was verified using typical polarization electric field (P–E) hysteresis loops and temperature-dependent evolution of ferroelastic domains. This study presents a simple and efficient molecular strategy to realize the construction of 3D hybrid perovskite ferroelectrics, opening up a new research path for the design and development of 3D multiferroic materials.