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 (T_p) 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 T_p 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 T_p of 498 K, which is obtained from compound 1 ([(R)-N-ethyl-3-quinuclidinol]PbBr₃) with a T_p 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 T_p. Ultimately, through accurate molecular design, the T_p 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.