Multifunctional materials based on the double-perovskite organic–inorganic hybrid (CH₃NH₃)₂[KCr(CN)₆] showing switchable dielectric, magnetic, and semiconducting behaviour

Abstract

Herein, we have synthesised and characterised a novel organic–inorganic hybrid crystal, [CH3NH3]2KCr(CN)6 (MACr).

Near-Infrared Phosphorescent Hybrid Organic–Inorganic Perovskite with High-Contrast Dielectric and Third-Order Nonlinear Optical Switching Functionalities

“…Another point worth commenting on is that the phase transition temperature from the cubic disordered phase is much lower for Pyr 2 KCr(CN) 6 (237.8 K on cooling) than for its MA analogue (447 K). 39 A study of double perovskite cyanides comprising MA + cations showed that the phase transition temperature decreases with an increasing TF, and the cubic phase would be stable below 298 K when the TF > 0.873. 68 Therefore, the large increase in the phase transition temperature when going from Pyr 2 KCr(CN) 6 to MA 2 KCr(CN) 6 can be attributed to the large decrease in the TF for the latter compound (the TF of MA 2 KCr(CN) 6 is 0.825).…”

“… 3 , 36 − 38 In that context, the most promising family of 3D switchable perovskites constitutes cyanides of the general formula A 2 M I M III (CN) 6 (A = organic cation; M I = Na, K, or Rb; M III = Co, Fe, or Cr). A step-like change of dielectric permittivity was reported for a few cobalt 39 − 45 and iron 42 , 43 , 46 , 47 cyanides, but a reversible change between on and off states by a thermal stimulus was demonstrated only for cobalt analogues comprising methylammonium (MA + ) and iron analogues comprising MA + and dimethylammonium (DMA + ) cations. 39 , 47 It is worth noting that we have discovered switchable properties controlled by temperature also for a nonperovskite cobalt cyanide network comprising pyrrolidinium (Pyr + ) cations.…”

“…A step-like change of dielectric permittivity was reported for a few cobalt 39 − 45 and iron 42 , 43 , 46 , 47 cyanides, but a reversible change between on and off states by a thermal stimulus was demonstrated only for cobalt analogues comprising methylammonium (MA + ) and iron analogues comprising MA + and dimethylammonium (DMA + ) cations. 39 , 47 It is worth noting that we have discovered switchable properties controlled by temperature also for a nonperovskite cobalt cyanide network comprising pyrrolidinium (Pyr + ) cations. 48 Furthermore, we demonstrated for the first time that the change between on and off states in this compound may also be achieved by applying external pressure.…”

Organic‐Inorganic Hybrid Crystal [1‐methylpiperidinium]2[ZnCl4] with High Tc Phase Transition and Dielectric Switches

“…In the process of phase transition, the latent heat of phase transition is absorbed or released. Among them, dielectric phase transition materials can switch the dielectric constant between low dielectric state and high dielectric state under the stimulation of external temperature, and have potential applications in the fields of information storage, sensors, signal processing and storage equipment [23–35] . In the past few years, they have received great attention and became a hotspot of multifunctional materials research.…”

Temperature‐Induced Reversible Phase Transition with Switchable Dielectric Response in a A2BX4‐Type Hybrid Compound: [TEAMA]2[CdBr4] (TEAMA=(CH3CH2)3NCH3)

“…Switchable dielectric materials, which usually exhibit a reversible dielectric transition between low‐ and high‐dielectric states under external stimuli, have attracted increasing attention due to they possess rich potential applications in the field of smart electrical and electronic devices [1–5] . From the microscopic viewpoint, the dipolar motions such as molecular rotations contributes greatly to dielectric constant in hybrid organic‐inorganic materials, compared with the electronic and ionic displacements [6–9] .…”