Tunable dielectric transitions in layered organic–inorganic hybrid perovskite-type compounds: [NH₃(CH₂)₂Cl]₂[CdCl_4−4xBr_4x] (x= 0, 1/4, 1)

Abstract

Molecular bistable dielectric switches represent a class of highly desirable intelligent materials due to their sensitive switchable responses, simple and environmentally friendly processing, light weights, and mechanical flexibility. However, most of these switches can only work at a very low temperature, extremely limiting their potential applications. Herein, three layered organic-inorganic hybrid perovskite-type compounds of the general formula A2BX4, [NH3(CH2)2Cl]2[CdCl3Br] (1), [NH3(CH2)2Cl]2[CdCl4] (2) and [NH3(CH2)2Cl]2[CdBr4] (3), which display sensitive dielectric switching reversibility and remarkable switching anti-fatigue, have been successfully designed. Differential scanning calorimetry and dielectric measurements for 1 confirm its reversible phase transition at around 166 K. Through anion modulation, the phase transition temperatures of 2 and 3 can be greatly improved up to 237 K and 254 K, respectively. Structural analysis discloses that the phase transition temperature's shifts may result from the differences among the inorganic frameworks. Moreover, due to the significant order-disorder transitions of ammonium cations, the permittivities of 1, 2 and 3 change abruptly at around the phase transition points, making them excellent stimuli-responsive electrical switches. Such an anion-modulated method will open up new possibilities of highly efficiently tuning the phase transition temperature of molecular bistable dielectric switches.

Highly Efficient and Uncommon Photoluminescence Behavior Combined with Multiple Dielectric Response in Manganese(II) Based Hybrid Phase Transition Compounds

“…Therefore, we collected and obtained structures of compounds 1 and 2 near the phase transition temperature (compound 1 at 350 K and compound 2 at 354 K) (Table S1). As shown in Figure S1, upon heating, the thermal vibration of the cationic atoms become more intense . For the inorganic frameworks of compound 1 , at 350 K, the Mn–Br distances [2.455(5)–2.495(3) Å] and Br–Mn–Br [105.01(19)°–112.6(2)°] are similar to those in RTP (Table S2).…”

Tunable Dielectric Switching of (Quinuclidinium)[MnCl4] Hybrid Compounds

“…The rapid decrease in ε′ from 23.5 to 17 corresponds to the low-dielectric state (Phase II). Generally, the behavior of switching of dielectric constant can be characterized as a rapid switchable (nearly no-time response) and with some nonzero delay time. , The rapid switchable materials show rapid system response during the switch ON/OFF process. With the temperature decrease, the rapid response of QMnCl from high-dielectric state (ON) to low-dielectric state (OFF) indicates a nearly no-time delay process.…”

Acentric Organic–Inorganic Hybrid Halide [N(CH3)4]2HgBr2I2 Featuring an Isolated [HgBr2I2]2– Tetrahedron and Second-Order Nonlinearity

“…Therefore, new compounds containing novel anionic groups are a mainstream trend in the exploration of organic–inorganic hybrid halides. Current studies on OIMHs are mainly in transition metals and heavy metals with lone pairs, leading to the development of a number of corresponding complexes. − …”