High-Temperature Molecular Ferroelectric Tris(2-hydroxyethyl) Ammonium Bromide with Dielectric Relaxation

Abstract

We obtained one new molecular ferroelectric material tris(2-hydroxyethyl) ammonium bromide (TAB) that crystallizes in aqueous solution at room temperature with a space group of R3m which belongs to ten polar space groups. There is a paraelectric-toferroelectric phase transition at 424 K (from hexagonal R3̅ m to hexagonal R3m phase). Such a high transition temperature is close to that of diisopropylamine bromide (426 K) and higher than that of many other molecular ferroelectrics, such as triethylmethylammonium tetrabromoferrate(III) (360 K); some of the organic−inorganic perovskite ferroelectrics, such as (cyclohexylammonium) 2 PbBr 4 (363 K); and some inorganic ferroelectrics, including BaTiO 3 (393 K). The saturated polarization and the coercive field of TAB measured from the ferroelectric hysteresis loop are about 0.54 μC•cm −2 and 0.62 kV/cm, respectively. Given its superior performance, including high phase transition temperature, room-temperature ferroelectricity, small coercive electric field, and adjustable ladder-shaped dielectric constant, TAB will have many potential applications.

Coupling Narrow Band Gap and Switchable SHG Responses in a New Molecule Ferroelectric: Imidazolyl Propylamine Pentabromo Stibium(III)

“…As a special kind of material ferroelectrics can produce spontaneous polarization, and its spontaneous polarization can change with a change in external conditions such as electric field and force field. − With the development of information technology such as 5G communication, people have put forward new requirements for ferroelectric materials. In the past few decades, researchers have discovered many ferroelectric materials based on organic–inorganic hybrid ferroelectrics. , What is more, the combination of ferroelectric properties, semiconductivity, and nonlinear optical properties through organic–inorganic hybrids can not only achieve tunable nonlinear optical properties but also be used in multifunctional ferroelectric devices, − since organic–inorganic hybrid ferroelectric semiconductors combine their ferroelectric and semiconductor properties with their unique structural advantages, such as low cost, ease of processing, mechanical flexibility, etc., which are expected to provide a better solution for the next generation of flexible ferroelectric materials. − …”

“…Because antimony belongs to the VA family of the periodic table of the elements and its transition site is located between metallic and nonmetallic elements, and because the electronegativities of Sb and Bi elements are similar to those of Sn and Pb, the ionic radii are also very close, and their ions are isoelectronic bodies, Sb and Bi have energy band structures similar to those of the divalent Sn- and Pb-based compounds . Furthermore, according to the definition of crystallography, a ferroelectric phase must be in these 10 polar groups: C 1 , C s , C 2 , C 2 v , C 3 , C 3 v , C 4 , C 4 v , C 6 , and C 6 v . ,− 1-(3-Aminopropyl)­imidazole has a flexible structure with low symmetry; therefore, we deduce that the assembly of antimony halide with 1-(3-aminopropyl)­imidazole favors a polar structure.…”

A multifunctional molecular ferroelectric with chiral features, a high Curie temperature, large spontaneous polarization and photoluminescence: (C9H14N)2CdBr4

“…[6][7] On the one hand, organic-inorganic hybrid metal halide not only inherits the advantages of organic part but also inherits the advantages of inorganic part, which makes it have the properties of switching dielectric switch and photoluminescence in a compound; On the other hand, the stable luminescent properties can be obtained by introducing metal ions into inorganic components. [8][9][10] Although great progress has been made in the research of ferroelectrics in recent ten years, the combination of ferroelectric materials and practical applications makes high temperature phase transition materials more ideal, 11 such as DIPAX(DIPA = diisopropylaminium; X = Cl, Br, ClO 4 -)(T c = 426 K); 12 hexane-1,6diammonium pentaiodobismuth (HDA-BiI 5 )(T c = 380 K) has the highest phase transition temperature and the narrowest band gap (E g = 1.89 eV); 13 [(R)-N-(1-phenylethyl)ethane-1,2diaminium]PbI 4 (T c = 378 K); 14 (4,4-Difluoropiperidinium) 4 AgBiI 8 (T c = 422 K). 15 lead-free metal halide has been widely studied in photoelectric and photovoltaic fields.…”

An Organic-Inorganic Hybrid Pyrrolidinium Ferroelectric Based on Solvent Selective Effect

“…OIHFs must crystallize in polar point groups and maintain P s below a certain phase transition temperature, defined as the Curie temperature ( T c ). , In addition, the switchable P s will favor the creation of ferroelectric domains and characteristic hysteretic behavior. Moreover, concomitantly with ferroelectricity, a typical phase transition of paraelectric-to-ferroelectric which is determined to be primarily a disorder-order phase transition occurred for most OIHFs. − Generally, these structural phase transitions are associated with symmetry breaking .…”