A Spiro-Driven Ferroelectric Coordination Polymer Exhibiting Distinct Phase Transitions under Thermal and Pressure Stimuli.

Controllable strategies for the design of molecular ferroelectrics have been actively pursued in recent years due to their promising applications in modern electronic devices. In this work, we present a spiro-driven approach for the design of a new class of molecular ferroelectrics. Using 2-morpholinoethanol (MEO) as a bidentate chelating ligand and the SCN- anion as a bridging co-ligand, we obtained a neutral chain-like ferroelectric coordination polymer, [Cd(MEO)(SCN)2].

Controlling the Orientation-Dependent Second Harmonic Generation in Hybrid Germanium Perovskites.

Manipulating the crystal orientation plays a crucial role in the conversion efficiency during second harmonic generation (SHG). Here, we provide a new strategy in controlling the surface-dependent anisotropic SHG with the precise design of (101) and (2 0) MAGeI facets. Based on the SHG measurement, the (101) MAGeI single crystal exhibits larger SHG (1.

Three-Step Ferroelastic Transitions from Hexagonal to Triclinic Phases in a Hybrid Perovskite: (1-Fluoromethyl-1-methylpyrrolidine)[CdCl].

Hybrid ferroelastic crystals have emerged as a hot research topic in recent years owing to their prospective applications in piezoelectric sensors, mechanical switches, and optoelectronic devices. Nevertheless, most of the documented materials exhibit one-step or two-step ferroelastic phase transition(s), and those with multistep ferroelastic transitions are extremely scarce. We present a new hexagonal molecular perovskite based on a fluoro-substituted flexible cyclic ammonium cation, (1-fluoromethyl-1-methylpyrrolidine)[CdCl] (), undergoing unusual three-step ferroelastic phase transitions from hexagonal paraelastic phase to orthorhombic, monoclinic, and triclinic ferroelastic phases at 388, 376, and 311 K, respectively, with Aizu notation of 6/F, F2/, and 2/F-1, featuring spontaneous strain of 0.

Halogen-regulating induced reversible high-temperature dielectric and thermal transitions in novel layered organic-inorganic hybrid semiconducting crystals.

Organic-inorganic hybrid metal halides for high-temperature phase transition have become increasingly popular owing to their wide operating temperature range in practical applications, , energy storage, permittivity switches and opto-electronic devices. This paper describes the subtle assembly of two new hybrid perovskite crystals, [Cl-CH-(CH)NH]CdX (X = Br 1; Cl 2), undergoing high- reversible phase transformations around 335 K/356 K. Differential scanning calorimetry (DSC), differential thermal analysis (DTA) and VT PXRD tests uncover their reversible first-order phase transition behaviors.

High-Temperature Phase Transition Containing Switchable Dielectric Behavior, Long Fluorescence Lifetime, and Distinct Photoluminescence Changes in a 2D Hybrid CuBr Perovskite.

A novel organic-inorganic hybrid perovskite crystal, [ClCH(CH)NH]CuBr (), having experienced an invertible high-temperature phase transition near (the Curie temperature = 355 K), has been successfully synthesized. The phase-transition characteristics for compound are thoroughly revealed by specific heat capacity (), differential thermal analysis, and differential scanning calorimetry tests, possessing 16 K broad thermal hysteresis. Multiple-temperature powder X-ray diffraction analysis further proves the phase-transition behavior of compound .

A multifunctional molecular ferroelectric with chiral features, a high Curie temperature, large spontaneous polarization and photoluminescence: (CHN)CdBr.

Low-dimensional chiral organic-inorganic hybrid metal halides have attracted a lot of attention in recent years due to their unique intrinsic properties, including having potential applications in optoelectronic and spintronic devices. However, low-dimensional chiral molecular ferroelectrics are very rare. In this paper, we report a novel zero-dimensional molecular ferroelectric (CHN)CdBr (CHN = protonated 3-phenylpropylamine), which has obvious dielectric and thermal anomalies and shows a high Curie temperature at 395 K.

Ferroelectric properties, narrow band gap and ultra-large reversible entropy change in a novel nonlinear ionic chromium(VI) compound.

A novel chromium(VI)-based compound, [(CHCH)N(CHCl)][CrOCl] (1), undergoes a high-temperature phase transition at around 340.9 K, accompanied by an ultra-large entropy change of 63.49 J mol K.

A Narrow Bandgap of 2D Ruddlesden-Popper Bilayer Perovskite with Giant Entropy Change and Photoluminescence.

The multifunctional two-dimensional (2D) organic-inorganic hybrid perovskites have potential applications in many fields, such as, semiconductor, energy storage and fluorescent device etc. Here, a 2D Ruddlesden-Popper (RP) perovskite (IPA) (FA)Pb I (1, IPA =C H NI , FA =CN H ) is determined for its photophysical properties. Strikingly, 1 reveals a solid reversible phase transition with T of 382 K accompanied by giant entropy change of 40 J mol  K .

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

Due to the existence of some cross properties such as SHG (second-harmonic generation), ferroelectricity, piezoelectricity, and thermoelectricity, molecular ferroelectrics have been widely used as a composite multipurpose material. Particularly, organic-inorganic molecular ferroelectrics have received much interest recently because of their unique flexible structures, friendly environment, ease of synthesis, etc. Also, these hybrids show great flexibility in band-gap engineering.