Ultrahigh Pyroelectric Figures of Merit Associated with Distinct Bistable Dielectric Phase Transition in a New Molecular Compound: Di‐n‐Butylaminium Trifluoroacetate

Abstract

Ultrahigh pyroelectric figures of merit are achieved in a new phase-transition material, di-n-butylaminium trifluoroacetate, of which the peak values are an order of magnitude larger than those of their inorganic counterparts. Such an attractive behavior of pyroelectric detectivity is strongly related to its distinct bistable dielectric behavior, which recalls excellent thermoelectric response in organic molecular phase-transition systems.

Reversible structural phase transition, ferroelectric and switchable dielectric properties of an adduct molecule of hexamethylenetetramine ferrocene carboxylic acid

“…This is because a ferroelectric is required to satisfy some specic conditions: (i) their lower symmetrical structures must fall into one of the 10 noncentrosymmetric and polar space groups (1, 2, m, mm2, 3, 3m, 4, 4mm, 6 and 6mm), 21 and (ii) the dipole moments that can generate remnant spontaneous polarization should exist in the ferroelectric structures. [22][23][24][25][26][27][28] However, in a molecular system with reversible phase transitions, if we x a body part that can afford the "driving/controlling force" of the structural transition and carry out certain structural modications to create polarization, can we design and construct a new ferroelectric through this molecular system? Ferrocene, the rst reported sandwich complex, possesses two typical reversible structures, the overlapping (D 5h ) and interlaced (D 5d ) cyclopentadienyl rings (Scheme 1).…”

Exploring a Polar Two‐dimensional Multi‐layered Hybrid Perovskite of (C5H11NH3)2(CH3NH3)Pb2I7 for Ultrafast‐Responding Photodetection

“…Besides organic cations, the shift of lead atoms away from the center of PbI 6 octahedra also contributes to its electric polarization. Using the point electric charge model, the spontaneous polarization of EMA is estimated to be 1.34 × 10 −1 C m −2 along a ‐axis and 1.76 × 10 −3 C m −2 along c ‐axis, respectively ( and ) . Further, the second harmonic generation (SHG) effects of EMA were performed by using the fundamental laser beam of 1400 nm at room temperature.…”

Tuning Order‐Disorder Phase Transition through Regulating the Substituent Group of Anion

“…There is a thermal hysteresis of 2 K between two reversible peaks, which suggests that 1 undergoes a first-order and reversible phase transition. [2,[13][14][15] Based on the DSC curves of 1, the average enthalpy change ∆H is estimated to be 7169.2 J•mol 1 . According to the entropy change ∆S＝∆H/T c , ∆S is obtained as 25.88…”

“…As shown in Figure 1b, an endothermic peak and an exothermic peak appear at 251 and 249 K, respectively. There is also a thermal hysteresis of about 2 K, and such a thermal hysteresis will enlarge when the heating and cooling rate increases ( Figure S3), indicating that 2 undergoes a first-order phase transition at 251 K. [2,[13][14][15] At around 282 K, another pair of sharp peaks appears, which is a feature of phase transition. [23] Since the phase transitions at 290 and 282 K occur close to each other, it is difficult to analyze the structural phase between them.…”

“…[1][2][3][4][5][6][7][8] These applications are mostly related with their phase transitions such as the latent heat of transition, phase transition temperature point. Therefore, effectively controlling these phase transition processes is very important for their applications.…”