A High-Temperature Order-Disorder Phase Transition Coupled With Conformational Change in the Hybrid Material [C6H13NH]2⋅ZnBr4

Ferroelastic Phase Transition with Large Spontaneous Strain Caused by Freezing the Conformational Dynamics of Ammonium

By adjusting the substituent group of the organic ammonium in three molecular ionic complexes, [A][Fe3O(O2CH)8(H2O)]2 (A = NH3(CH2)3NH3 for 1, CH3NH2(CH2)3NH3 for 2 and CH3CH2NH2(CH2)3NH2CH2CH3 for 3) crystallized in 2/m...

Exploring a lead-free organic-inorganic semiconducting hybrid with above-room-temperature dielectric phase transition

Recently, organic-inorganic hybrid lead halide perovskites have attracted great attention for optoelectronic applications, such as light-emitting diodes, photovoltaics and optoelectronics. Meanwhile, the flexible organic components of these compounds give rise to a large variety of important functions, such as dielectric phase transitions. However, those containing Pb are harmful to the environment in vast quantities. Herein, a lead-free organic-inorganic hybrid, (C6H14N)2BiCl5 (CHA; C6H14N+ is cyclohexylaminium), has been successfully developed. As expected, CHA exhibits an above-room-temperature solid phase transition at 325 K (T c), which was confirmed by the differential scanning calorimetry measurement and variable temperature single crystal X-ray diffraction analyses. Further analyses indicate the phase transition is mainly governed by the order-disorder transformation of organic cyclohexylaminium cations. Interestingly, during the process of phase transition, the dielectric constant (ε') of CHA shows an obvious step-like anomaly, which displays a low dielectric constant state below T c and a high dielectric constant state above T c. Furthermore, variable temperature conductivity combined with theoretical calculations demonstrate the notable semiconducting feature of CHA. It is believed that our work will provide useful strategies for exploring lead-free organic-inorganic semiconducting hybrid materials with above room temperature dielectric phase transitions.

[C6H14N]PbI3: a one-dimensional perovskite-like order–disorder phase transition material with semiconducting and switchable dielectric attributes

Here we report a new one-dimensional organic–inorganic hybrid, adopting an ABX₃ perovskite-like architecture, which exhibits semiconducting and switchable dielectric attributes.

Sequential dielectric phase transitions induced by the vibrations of water molecules in an organic-inorganic hybrid halide (N-(2-ammoniumethyl)piperazinium) CuCl5·2H2O

Organic-inorganic hybrids represent a new type of material showing promising properties. In this report, sequential dielectric transitions have been studied in an organic-inorganic hybrid halide, (N-2-AP)CuCl₅·2H₂O (N-2-AP = N-(2-ammoniumethyl)piperazinium) (1). The packing structure of 1 displays discrete [CuCl₅]^3- rectangular pyramids and N-2-AP cations, which are linked by two water molecules, forming infinite hydrogen bond networks with inorganic and organic components along the b-axis. Characterization studies containing differential scanning calorimetry (DSC) measurements, variable-temperature X-ray diffraction and dielectric measurements were performed to investigate the phase transitions in 1. The deuterated sample of 1 (named 2) also exhibits a similar behavior to that in 1, but shows different phase transition temperatures in dielectric transitions. The arresting deuterated effect strongly confirms that the phase transitions in 1 are attributable to the local vibrations of water molecules resulting from the variation of hydrogen-bonding interactions.

N-Methylpyrrolidinium hydrogen tartrate (NMPHT): an above-room-temperature order–disorder molecular switchable dielectric material

A new above-room-temperature molecular switchable dielectric material, which undergoes a first-order phase transition induced by the order-disorder transformation of cation, has been reported.

[C5H12N]CdCl3: an ABX3 perovskite-type semiconducting switchable dielectric phase transition material

We report a new lead-free ABX₃ perovskite-type hybrid, which displays high thermal stability, semiconducting and striking switchable dielectric properties.

Modulating molecular structures and dielectric transitions in organic–inorganic hybrid crystals

Three hybrids display tunable structural transitions, achieving the regulation of phase transition temperature and dielectric characteristics.

Prominent dielectric transitions in layered organic–inorganic hybrids: (isoamyl-ammonium)2CdX4 (X = Cl and Br)

Two new organic–inorganic layered perovskite-type hybrid compounds demonstrate different dynamic motions of cations, contributing to a significant difference in dielectric transitions.