Control of electronic polarization via charge ordering and electron transfer: electronic ferroelectrics and electronic pyroelectrics

Abstract

Ferroelectric, pyroelectric, and piezoelectric compounds whose electric polarization properties can be controlled by external stimuli such as electric field, temperature, and pressure have various applications, including ferroelectric memory materials, sensors,...

Electrically Detectable Photoinduced Polarization Switching in a Molecular Prussian Blue Analogue

“…To explore the polarization switching of the single crystals, the current during the phase transition before and after irradiation were evaluated with the pyroelectric measurement system. − A single-crystal sample was sandwiched between silver pastes on its (001) and (00–1) surfaces, which are perpendicular to the long axis of the single crystal (Figure S7a). During the thermodynamic phase transition, a negative peak for the pyroelectric current was observed at T (↓) = 145 K in the cooling process, and a peak in the opposite direction was detected in the heating process at T (↑) = 168 K, which is indicative of a polarization change.…”

Polar Crystals Using Molecular Chirality: Pseudosymmetric Crystallization toward Polarization Switching Materials

“…Ferroelectrics − and pyroelectrics − are important materials, which are widely applied to memory and sensors, owing to a change in their spontaneous electric polarization. − The current challenge is to synthesize new compounds that exhibit an electron transfer-based polarization switching − compared to the more typical mechanism of ion displacement or molecular motion. Molecules that exhibit stimulated electron transfer , behavior (e.g., valence tautomeric VT) complexes − are good candidates for such purposes.…”

“…However, a strategy to prepare polar compounds has not been established. We report a rational synthesis of a polar CoGa crystal using chiral cth ligands cth = 5,7,7,12,14,4,8,. Both the original homo metal Co crystal and Ga crystal exhibit a centrosymmetric isostructure, where the dipole moment of metal complexes with the SS-cth ligand and those with the RR-cth ligand are canceled out.…”

Solvent-dependent valence tautomerism and polarization switching in a heterodinuclear [CrCo] complex

“…To date, there have been only a few non-ferroelectric molecular crystals exhibiting macroscopic polarization switching via electron transfer owing to the difficulties in crystal engineering to align molecules in polar space groups. 14,18,[49][50][51] The acquisition of such crystals still largely relies on serendipity. Hence, it is still full of challenges in synthesizing polar crystals through an appropriate molecular design to enhance the probability of arranging target molecules in a polar space group.…”