Organic enantiomeric high-T_c ferroelectrics

Area of Science:

• Materials Science
• Solid-State Physics
• Organic Chemistry

Background:

• Homochiral ferroelectrics have historically been multicomponent organic amine salts or metal coordination compounds.
• Single-component homochiral organic ferroelectrics with high Curie temperatures (Tc) are rare.
• The first discovered ferroelectric, Rochelle salt, is a homochiral metal coordination compound.

Purpose of the Study:

• To report a new class of single-component organic enantiomorphic ferroelectrics.
• To investigate the ferroelectric properties and phase transitions of (R)-3-quinuclidinol, (S)-3-quinuclidinol, and their racemic mixture.
• To demonstrate the advantages of homochirality in designing high-Tc ferroelectric materials.

Main Methods:

• Synthesis and crystallization of (R)-3-quinuclidinol, (S)-3-quinuclidinol, and (Rac)-3-quinuclidinol.
• X-ray diffraction and vibrational circular dichroism spectroscopy to determine crystal structure and enantiomorphism.
• Dielectric measurements and ferroelectric domain observation to characterize phase transitions and ferroelectric properties.

Main Results:

• The homochiral enantiomers (R)- and (S)-3-quinuclidinol crystallize in the polar point group 6 (C6).
• Both enantiomers exhibit a 622F6-type ferroelectric phase transition with a high Curie temperature (Tc) of 400 K.
• The enantiomers show high saturation polarization (7 μC/cm2), low coercive field (15 kV/cm), and identical ferroelectric domains, while the racemic mixture is non-ferroelectric.

Conclusions:

• Single-component homochiral organic compounds can exhibit high-Tc ferroelectricity.
• Homochirality is crucial for achieving high-Tc ferroelectric phase transitions in organic materials.
• These findings open avenues for developing novel homochiral ferroelectrics for various applications.