High-Temperature and Large-Polarization Ferroelectric with Second Harmonic Generation Response in a Novel Crown Ether Clathrate.
Chemistry
; 27(54): 13575-13581, 2021 Sep 24.
Article
em En
| MEDLINE
| ID: mdl-34322911
ABSTRACT
Molecular ferroelectrics of high-temperature reversible phase transitions are very rare and have attracted increasing attention in recent years. In this paper is described the successful synthesis of a novel high-temperature host-guest inclusion ferroelectric [(C6 H5 NF3 )(18-crown-6)][BF4 ] (1) that shows a pair of reversible peaks at 348â
K (heating) and 331â
K (cooling) with a heat hysteresis about 17â
K by differential scanning calorimetry measurements, thus indicating that 1 undergoes a reversible structural phase transition. Variable-temperature PXRD and temperature-dependent dielectric measurements further prove the phase-transition behavior of 1. The second harmonic response demonstrates that 1 belongs to a non-centrosymmetric space group at room temperature and is a good nonlinear optical material. In its semiconducting properties, 1 shows a wide optical band gap of about 4.43â
eV that comes chiefly from the C, H and O atoms of the crystals. In particular, the ferroelectric measurements of 1 exhibit a typical polarization-electric hysteresis loop with a large spontaneous polarization (Ps ) of about 4.06â
µC/cm2 . This finding offers an alternative pathway for designing new ferroelectric-dielectric and nonlinear optical materials and related physical properties in organic-inorganic and other hybrid crystals.
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MEDLINE
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En
Ano de publicação:
2021
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Article