Layer number dependent ferroelasticity in 2D Ruddlesden–Popper organic-inorganic hybrid perovskites

Abstract Ferroelasticity represents material domains possessing spontaneous strain that can be switched by external stress. Three-dimensional perovskites like methylammonium lead iodide are determined to ferroelastic. Layered have been applied in optoelectronic devices with outstanding performance. However, the understanding of lattice and ferroelasticity layered is still lacking. Here, using in-situ observation switching perovskite single crystals under strain, we discover evidence layer number more than one, while octahedra do not show ferroelasticity. Density functional theory calculation shows originates from distortion inorganic resulting rotation aspherical cations. The absence cations accounts for lack These ferroelastic induce non-radiative recombination or reduce photoluminescence quantum yield.