Zero-Dimensional Sn-Based Enantiomeric Phase-Transition Materials with High-Tc and Dielectric Switching.

The combination of chirality and phase-transition materials has broad application prospects. Therefore, based on the quasi-spherical theory and the thought strategy of introducing chirality, we have successfully synthesized a pair of chiral enantiomeric ligands (R/S)-triethyl-(2-hydroxypropyl)ammonium iodide, which can be combined with a tin hexachloride anion to obtain a pair of new organic-inorganic hybrid enantiomeric high-temperature plastic phase-transition materials: (R/S)-[CH3 CH(OH)CH2 N(CH2 CH3 )3 ]2 SnCl6 (1-R/1-S), which have a high temperature phase transition of Tc =384 K, crystallize in the P21 chiral space group at room temperature, and have obvious CD signals. In addition, compounds 1-R and 1-S have a good low-loss dielectric switch and broadband gap. This work is conducive to the research into chiral high-temperature reversible plastic phase-transition materials, and promotes the development of multi-functional phase-transition materials.

High-Tc Quadratic Nonlinear Optical and Dielectric Switchings in Fe-Based Plastic Crystalline Ferroelectric.

Plastic crystals, as a molecular material with multiple functions, have become a research hotspot in the exploration of new ferroelectric crystal compounds, especially due to their unique solid-solid phase transition properties. Based on this, we synthesized a new 0D organic-inorganic hybrid Fe-based plastic ferroelectric [(CH3)3NCH2CHCH2]FeCl4 (1), which has a high-temperature phase transition point of 393 K, obvious ferroelectric domains, and spontaneous polarization and has been tested by dielectric and piezoelectric power microscopy (PFM) and ultraviolet absorption (UV-vis). At room temperature, it crystallizes in the space group Cmc21 and has an obvious SHG switch. In addition, compound 1 also has an optical narrow band gap of 2.45 eV, indicating that compound 1 is a high-quality semiconductor material. This work advances the development of plastic ferroelectrics and provides an avenue for exploring the frequency-doubling response and optoelectronic properties of high-temperature plastic ferroelectrics.

Neutral 1D Perovskite-Type ABX3 Phase Transition Material with a Narrowband Emission and Semiconductor Property.

Cyclic organic amines are emerging as excellent building blocks to assemble organic-inorganic hybrid phase transition materials due to their flexible cyclic structure. Here, we have assembled a 1D organic-inorganic hybrid dielectric material C5 H6 NOPbBr3 (1) by alloying the cyclic organic amine 3-hydroxypyridine. 1 displays a remarkable switchable dielectric response induced by an order-disorder transformation of the organic moiety, this transformation behaviour is confirmed by DSC and Hirshfeld surface measurements. More interestingly, 1 has a narrowband emission (FWHM=4.64 nm) at 590 nm; FWHM is a major quality figure for narrowband photodetectors. In addition, 1 exhibits semiconducting properties with an indirect bandgap of 2.78 eV by the analysis of the UV-Vis absorption results.