A nickel(ii)-based one-dimensional organic-inorganic halide perovskite ferroelectric with the highest Curie temperature.

Organic-inorganic halide perovskites (OIHPs) are very eye-catching due to their chemical tunability and rich physical properties such as ferroelectricity, magnetism, photovoltaic properties and photoluminescence. However, no nickel-based OIHP ferroelectrics have been reported so far. Here, we designed an ABX 3 OIHP ferroelectric (3-pyrrolinium)NiCl 3 , where the 3-pyrrolinium cations are located on the voids surrounded by one-dimensional chains composed of NiCl 6 -face-sharing octahedra via hydrogen bonding interactions. Such a unique structure enables the (3-pyrrolinium)NiCl 3 with a high spontaneous polarization ( P s ) of 5.8 μC cm -2 and a high Curie temperature ( T c ) of 428 K, realizing dramatic enhancement of 112 and 52 K compared to its isostructural (3-pyrrolinium)MCl 3 (M = Cd, Mn). To our knowledge, remarkably, (3-pyrrolinium)NiCl 3 should be the first case of nickel(ii)-based OIHP ferroelectric to date, and its T c of 428 K (35 K above that of BaTiO 3 ) is the highest among all reported one-dimensional OIHP ferroelectrics. This work offers a new structural building block for enriching the family of OIHP structures and will inspire the further exploration of new nickel(ii)-based OIHP ferroelectrics.