An organic-inorganic hybrid thermochromic ferroelastic with multi-channel switches

Multifunctional switchable materials are attracting tremendous interest because of their great application potential in signal processing, information encryption, and smart devices. Here, we reported an organic-inorganic hybrid thermochromic ferroelastic crystal, [TMIm][CuCl4] (TMIm = 1,1,3,3-tetramethylimidazolidinium), which undergoes two reversible phase transitions at 333 K and 419 K, respectively. Intriguingly, these three phases experience a remarkable ferroelastic-paraelastic-ferroelastic (2/m-mmm-2/m) transition, which remains relatively unexplored in ferroelastics. Moreover, the ferroelastic domains can be simultaneously switched under temperature and stress stimuli. Meanwhile, [TMIm][CuCl4] exhibits thermochromic phenomenon, endowing it with extra spectral encryption possibilities during information processing. Combined with dielectric switching behavior, [TMIm][CuCl4] are promising for practical applications in memory devices, next-generation sensors, and encryption technology.