Hydrogen-bonding engineering in a 3D cyano-bridged double-perovskite ferroelastic greatly improves the phase-transition temperature

Abstract

Three-dimensional (3D) cyano-bridged double perovskites have attracted increasing attention in recent years for their potential application in optoelectronic materials, such as dielectric, nonlinear optical switches, and ferroelectric. However, due to...

Homochirality to design high-Tclead-free ferroelastic semiconductors

“…33 In addition, the low phase transition temperatures in these hybrid perovskites ferroelastic semiconductors limit their further applications at high temperatures and in special environments. 34–39 Hence, it is imperative to advance the development of lead-free ferroelastic semiconductors with high phase transition temperatures.…”

“…On the one hand, the introduction of hydroxyl groups induces hydrogen bonding, which increases the potential energy barrier for cation motion to raise the T c . 36,45 On the other hand, the introduction of chiral cations alters the microstructure of the crystals, allowing the construction of ferroelasticity, and also enables the compounds to crystallize in non-centrosymmetric space groups, enabling the molecules to be SHG-responsive. 41,42,44,46,47…”

Switchable coordination bonds in 3D cyano-bridged perovskite ferroelastics: achieving the largest leap of symmetry breaking and enhanced dielectric switching performance

“…39–42 The mechanisms of dielectric switching in these cyano-bridged OIHP ferroelastics typically arise from the conventional order–disorder transition of the A-site guests. 43–45 In this transition, the ordered state corresponds to a low dielectric constant (referred to as ‘switching-off’), whereas the disordered state corresponds to an activated high dielectric constant (referred to as ‘switching-on’). However, the larger B′–NC–B′′ framework results in a weaker confinement effect for the A-site cations within the cage, leading to a lower T c and unspectacular symmetry breaking, which makes it difficult to achieve large dielectric switching responses and hinders its application in practical electronic devices.…”