Series of Cage-Like Double Perovskite-Type Hybrid Perovskites with Reversible Structural Phase Transition and Switchable Dielectric Constant Property

Abstract

A series of cage-like double perovskite-type hybrid perovskites, (HQ)2[B′Bi(NO3)6] (HQ = quinuclidinium cation, B′ = K, 1; Rb, 2; Cs, 3), were obtained. In the cages, the Bi3+ ions are dodecahedrally coordinated by six NO3 – ligands in a bidentate mode; meanwhile, each alkali metal ion is chelated by six O atoms from neighboring six NO3 – ions. The HQ exists in the anionic cage through intermolecular interactions, which mainly refers to hydrogen-bonding interactions. They display structural phase transitions between 200 and 250 K. Various-temperature (VT) single structural analysis reveals that 1–3 possess similar phase transitions arising from the reorientation of the HQ and the drastic structure changes of the anionic framework. The structural phase transition in 1–3 also arouse striking dielectric transitions. Then, the tunable thermodynamic property, especially the switchable phase transition temperature, was verified by Hirshfeld surface analyses, which is mainly used to describe the changing of the interactions between the HQ and [B′Bi(NO3)6] framework of those compounds. It is found that the intermolecular interactions of 1–3 and the radius of the B′ ion have a linear relationship. This finding will be meaningful for exploring high-performance stimulus-responsive dielectrics in the electronics or electrical industry.

Multiaxial Multiferroicity with Large Spontaneous Polarization in a Hydroxyl-Modified Quinuclidinium Gallium(III) Chloride

“…Similarly, the introduction of chirality will also have an impact on T c . Therefore, smaller void occupancy, stronger hydrogen-bond interactions, and the introduction of chirality all enhance SPT’s energy barrier, resulting in a significant increase in T c . , This reveals that H/OH substitution promotes T c by enhancing the intermolecular interactions.…”

Structural Diversity Design, Four Nucleation Methods Growth and Mechanism of 3D Hollow Box TiO2 Nanocrystals with a Temperature-Controlled High (001) Crystal Facets Exposure Ratio

“…Figure a,b depicts Hirshfeld surface maps and fingerprint plots generated using Crystal Explorer 21.5. These were employed to visualize intermolecular interactions and calculate interatomic contacts within the crystal framework . The blue and red regions represent low and high electron densities, respectively, due to short and long contacts between atoms.…”

Temperature-tunable multiple dielectric switch in hybrid rare-earth perovskites regulated by hierarchical guest dynamics, lanthanide contraction and doping

“…Nevertheless, for practical application, dielectric switches with multiple and/or adjustable T s are more desirable yet challenging to achieve. To overcome this deficiency, we noticed that cage-like hybrid double perovskites (especially the rare-earth double perovskites), 25–39 as a well-known class of phase-change compounds, may be good targets for the design of temperature-tunable multiple dielectric switches. As shown in Chart 1, three combined approaches may be implemented to afford such switches in the hybrid rare-earth perovskite system.…”

“…Till now, only one single phase transition at most was observed for the reported cage-like hybrid rare-earth perovskites. 34–39 The reason may be due to the lack of conformational flexibility/diversity for the incorporated ammonium guests within these perovskites. Here we adopt (Me 2 HC–NHMe 2 ) + , i.e.…”