Tunable and Switchable Dielectric Constant in an Amphidynamic Crystal

Abstract

The inclusion compound [(CH3)2NH2]2[KCo(CN)6] exhibits a marked temperature-dependent dielectric constant and can be considered as a model of tunable and switchable dielectric materials. Crystal structure and solid-state NMR studies reveal a switchable property between low and high dielectric states around 245 K. This originates from an order-disorder phase transition of the system, changing the dynamics of the polar dimethylammonium (DMA) cation. Furthermore, the tuning of the dielectric constant at temperatures below the phase transition point is related to increasing angular pretransitional fluctuations of the dipole moment of DMA.

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

“…[1][2][3][4][5] Recently, research on molecular ferroelectrics have attracted much interest since they have great advantages such as being lightweight, easy to prepare and environmentally friendly, in comparison with the conventional inorganic ferroelectric materials. [6][7][8][9][10][11][12][13] Although a great progress has been made in the last few decades, few cases about metallo-organic molecular ferroelectrics have been documented. Moreover, the accurate design and construction of a molecular ferroelectric by facile structural modication on an existing metallo-organic molecule system is still a huge challenge.…”

Structural and electronic properties of hybrid perovskites for high-efficiency thin-film photovoltaics from first-principles

“…29 While no evidence has been reported of this effect in hybrid halide perovskites, it is expected that they will also display some degree of amphidynamic behaviour arising from the collective motion of the constituent polar molecules. Tuning of the molecular dipoles represents a potential route for further improving the performance of this class of materials.…”

Anomalous Dielectric Features and Structural Implications in Gallic Acid–Isoniazid Cocrystal Mediated by Lattice Water

“…It is of interest to note that above 389 K, the dielectric constant drops to about 5.5 and remains invariant on the cooling cycle due to the loss of the water of hydration(Figure 2 inset). Further, loss of water molecule and irreversibility of transition was also captured by in situ powder X-ray diffraction (Figure S4; Supporting Information).Thus, even though this material does not exhibit switchable dielectric phenomenon[5][6][7][8][9][10][11][12] , the appearance of a step like behavior brings out the role of lattice water initially in augmenting the value of the dielectric constant.…”

“…2 In this context, some of the physical properties like dielectric and ferroelectric behaviour [3][4][5][6][7][8][9][10][11][12] of such materials have been correlated with their structural features. In particular, considerable attention has been placed on switchable dielectric materials for data storage and data dissemination applications, resulting from the transition between dynamic/disordered phases in molecular solids.…”