Dehydration-activated structural phase transition in a two-dimensional hybrid double perovskite.

As a feasible lead-free scheme, organic-inorganic hybrid double perovskites show many excellent properties, including ferroelectricity, ferroelasticity, self-powered circularly polarized light detection and so on. In this work, the solid-to-solid structural phase transition of a two-dimensional hybrid double perovskite (CHA)CuBiI was successfully activated the dehydration of (CHA)CuBiI·HO, which was proven by differential scanning calorimetry (DSC) and temperature-dependent dielectric measurements. Using variable-temperature single-crystal X-ray diffractometry, the cause behind the phase transition of (CHA)CuBiI was determined to be the overall coordination of distortion and movement of the inorganic skeleton and thermal deformation of the cationic structure.

Metal ion modulation triggers dielectric double switching and green fluorescence in AMX-type compounds.

Multifunctional switching materials show great potential for applications in sensors, smart switches, and other fields due to their ability to integrate different physical channels in one single device. However, multifunctional responsive materials with multiple switching and luminescence properties have rarely been reported. Here, we report three organic-inorganic hybrids: [TMAA][CoCl] (compound 1), [TMAA][CdBr] (compound 2) and [TMAA][MnCl] (compound 3).

Observation of Transition from Ferroelasticity to Ferroelectricity by Solvent Selective Effect in Anilinium Bromide.

Organic ferroelectrics are highly desirable for their light weight, mechanical flexibility and biocompatibility. However, the rational design of organic ferroelectrics has always faced great challenges. Anilinium bromide (AB) has two structures reported in the Cambridge Crystallographic Data Centre, which might be an mmmF2/m type ferroelastic (AB-1).