Homochiral Nickel Nitrite ABX (X = NO) Perovskite Ferroelectrics.

Chiral organic-inorganic perovskites (COIPs) have recently attracted increasing interest due to their unique inherent chirality and potential applications in next-generation optoelectronic and spintronic devices. However, COIP ferroelectrics are very sparse. In this work, for the first time, we present the nickel-nitrite ABX COIP ferroelectrics, [( and )--fluoromethyl-3-quinuclidinol]Ni(NO) ([( and )-FMQ]Ni(NO)), where the X-site is the rarely seen NO bridging ligand. [( and )-FMQ]Ni(NO) display mirror-relationship in the crystal structure and vibrational circular dichroism signal. It is emphasized that [( and )-FMQ]Ni(NO) show splendid ferroelectricity with both an extremely high phase-transition point of 405 K and a spontaneous polarization of 12 μC/cm. To our knowledge, [( and )-FMQ]Ni(NO) are the first examples of nickel-nitrite based COIP ferroelectrics. This finding expands the COIP family and throws light on exploration of high-performance COIP ferroelectrics.