Ferroelastic Hybrid Bismuth Bromides with Dual Dielectric Switches

Ferroelastics, as an important member of ferroic materials, play an invaluable role in energy conversion, information processing, and mechanical switches. However, to date, it remains an arduous task to construct molecular ferroelastics with dielectric bistability/switching characteristics. Within this context, moreover, controlling the multiswitching behavior in dielectrics has been a great challenge, while imparting them with other fascinating properties (ferroelasticity and semiconducting features) is even more laborious. Here, through a molecular modification strategy, we successfully designed an organic–inorganic hybrid ferroelastic with a band gap of 2.58 eV, (DMTBA)3Bi2Br9 (DMTBA = N,N-dimethyl-tert-butylaminium), which exhibits dual-dielectric switching characteristics at 425 and 188 K. These attributes make it a multifunctional material for multipurpose sensors, mechanical switches, and photoelectric devices. Compared to other methyl-substituted products, (N,N-dimethyl-tert-butylaminium)3Bi2Br9 and (N,N,N-trimethyl-tert-butylaminium)3Bi2Br9, proper molecular interactions and dynamics of DMTBA cations should be responsible for its ferroelasticity with dual dielectric switches. We expect that this study would throw light on the rational design of new hybrid ferroelastics with multifunctional characteristics.