Record high-Tc and large practical utilization level of electric polarization in metal-free molecular antiferroelectric solid solutions

Metal-free antiferroelectric materials are holding a promise for energy storage application, owing to their unique merits of wearability, environmental friendliness, and structure tunability. Despite receiving great interests, metal-free antiferroelectrics are quite limited and it is a challenge to acquire new soft antiferroelectric candidates. Here, we have successfully exploited binary CMBrxI1-x and CMBrxCl1-x solid solution as single crystals (0 ≤ x ≤ 1, where CM is cyclohexylmethylammonium). A molecule-level modification can effectively enhance Curie temperature. Emphatically, the binary CM-chloride salt shows the highest antiferroelectric-to-paraelectric Curie temperature of ~453 K among the known molecular antiferroelectrics. Its characteristic double electrical hysteresis loops provide a large electric polarization up to ~11.4 μC/cm2, which endows notable energy storage behaviors. To our best knowledge, this work provides an effective solid-solution methodology to the targeted design of new metal-free antiferroelectric candidates toward biocompatible energy storage devices.

The role of attractive and repulsive interactions in the stabilization of ammonium salts structures

A series of ammonium salts was used to propose a step-by-step approach to obtain the stabilization energy and contact area data of supramolecular clusters in charged molecules. A new parameter was presented to assess the cluster energy efficiency.

Synthesis and crystal structure of a new polymorph of diisopropylammonium trichloroacetate, C8H16Cl3NO2

C8H16Cl3NO2, monoclinic, P21 (no. 4), a = 9.1804(5), Å, b = 19.4133(10) Å, c = 13.9191(7) Å, β = 90.593(3)°, V = 2480.6(2) Å3, Z = 8, R gt(F) = 0.0605, wR ref(F 2) = 0.1387, T = 296(2) K.

Hierarchical Frameworks of Metal-Organic Cages with Axial Ferroelectric Anisotropy

Designing molecular crystals with switchable dipoles for ferroelectric applications is challenging and often serendipitous. Herein, we show a systematic approach toward hierarchical 1D, 2D and 3D frameworks that are assembled through successive linkage of metal-organic cages [Cu₆ (H₂ O)₁₂ (TPTA)₈ ]¹²⁺ with chloride ions. Their ferroelectric properties are due to the displacement of channel-bound nitrate counterions and solvated water molecules relative to the framework of cages. Ferroelectric measurements of crystals of discrete and 1D-framework assemblies showed axial ferroelectric anisotropy with high remnant polarisation. Both, the reversible formation of cage-connected networks and the observation of ferroelectric anisotropic behaviour are rare among metal-ligand cage assemblies.

Ferroelasticity and piezoelectricity of organic–inorganic hybrid materials with a one-dimensional anionic structure: so similar, yet so different

The synthesis, structural aspects, and thermal and dielectric analysis for new members of the ferroic family, polynuclear Bi(iii) and Sb(iii) halide complexes based on a pyrazolium cation with the formulas (C₃N₂H₅)[BiCl₄]·H₂O and (C₃N₂H₅)[SbCl₄]·H₂O, are presented.