A Semiconducting Organic-Inorganic Hybrid Perovskite-type Non-ferroelectric Piezoelectric with Excellent Piezoelectricity.

Piezoelectric materials are a class of important functional materials applied in high-voltage sources, sensors, vibration reducers, actuators, motors, and so on. Herein, [(CH ₃ ) ₃ S] ₃ [Bi ₂ Br ₉ ](1) is a brilliant semiconducting organic-inorganic hybrid perovskite-type non-ferroelectric piezoelectric with excellent piezoelectricity. Strikingly, the value of the piezoelectric coefficient d ₃₃ is estimated as ≈18 pC N ^-1 . Such a large piezoelectric coefficient in non-ferroelectric piezoelectric has been scarcely reported and is comparable with those of typically one-composition non-ferroelectric piezoelectrics such as ZnO (3pC N ^-1 ) and much greater than those of most known typical materials. In addition, 1 exhibits semiconducting behavior with an optical band gap of ≈2.58 eV that is lower than the reported value of 3.37 eV for ZnO. This discovery opens a new avenue to exploit molecular non-ferroelectric piezoelectric and should stimulate further exploration of non-ferroelectric piezoelectric due to their high stability and low loss characteristics.
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