High temperature hybrid perovskite multifunctional switching materials constructed through precise molecular design†
Abstract
Organic–inorganic hybrid perovskite (OIHP) multifunctional molecular switching materials have been widely studied as excellent supplements to the conventional all-inorganic perovskites due to their structural diversity and property adjustability. However, considering their practical application, the phase transition temperature (Tp) of the system is a crucial evaluation standard and meanwhile it remains an arduous challenge to construct phase transition materials with three kinds of switching characteristics. Therefore, the design of high Tp multifunctional switching materials is a huge task. Herein, we have reported a chiral OIHP multifunctional semiconductor 2 ([(R)-N-fluoroethyl-3-quinuclidinol]PbBr3) with dielectric switching, nonlinear switching and ferroelastic switching characteristics and an ultrahigh Tp of 498 K, which is obtained from compound 1 ([(R)-N-ethyl-3-quinuclidinol]PbBr3) with a Tp of 445 K through the strategy of H/F substitution. The substitution of F atoms for H atoms not only changes the coordination environment of Pb, but also increases the molecular interactions due to the stronger electronegativity of the F atoms, which raises the barrier of rotation of the fluorinated organic cations, (R)-N-fluoroethyl-3-quinuclidinol, and finally leads to a remarkable increase in Tp. Ultimately, through accurate molecular design, the Tp of compound 2 has been increased by 53 K and compound 2 exhibits three kinds of switching characteristics, which also makes it a superior switching material for practical application.