A Poling-Free Supramolecular Crown Ether Compound with Large Piezoelectricity

Area of Science:

• Materials Science
• Solid-State Physics
• Supramolecular Chemistry

Background:

• Supramolecular host-guest ferroelectrics are desirable for their intrinsic piezoelectricity and lack of need for poling.
• Existing materials often exhibit limited piezoelectric performance.
• Poly(vinylidene fluoride) (PVDF) requires poling to achieve piezoelectricity.

Purpose of the Study:

• To develop a novel supramolecular host-guest ferroelectric with enhanced piezoelectric properties.
• To investigate the effect of H/F substitution on piezoelectric performance.
• To provide a poled-free piezoelectric material exceeding current benchmarks.

Main Methods:

• Synthesis of a novel supramolecular host-guest compound: [(CF3-C6H4-NH3)(18-crown-6)][TFSA].
• Characterization of the material's structural and electrical properties.
• Measurement of piezoelectric coefficients (d33, g33) and mechanical quality factor (Qm).

Main Results:

• The compound [(CF3-C6H4-NH3)(18-crown-6)][TFSA] demonstrated a remarkable piezoelectric response of 42 pC/N without poling.
• Fluorine incorporation enhanced phase transition temperature, polar axes, and second harmonic generation (SHG) intensity.
• Achieved d33, g33, and Qm values surpassed those of previously reported supramolecular ferroelectrics and PVDF.

Conclusions:

• The developed material represents a significant advancement in poled-free piezoelectric supramolecular compounds.
• Fluorine substitution is an effective strategy for optimizing piezoelectricity in such materials.
• This work inspires the design of next-generation molecular piezoelectric materials.