Bonding Optimization Strategies for Flexibly Preparing Multi-Component Piezoelectric Crystals.

Bai, Yuan; Tang, Gang; Xie, Lei; Lian, He; Wang, Shihao; Liu, Chaopeng; Yu, Qiao; Ji, Jianying et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

Flexible films with optimal piezoelectric performance and water-triggered dissolution behavior are fabricated using the co-dissolution-evaporation method by mixing trimethylchloromethyl ammonium chloride (TMCM-Cl), CdCl<sub>2</sub>, and polyethylene oxide (PEO, a water-soluble polymer). The resultant TMCM trichlorocadmium (TMCM-CdCl<sub>3</sub>) crystal/PEO film exhibited the highest piezoelectric coefficient (d<sub>33</sub>) compared to the films employing other polymers because PEO lacks electrophilic or nucleophilic side-chain groups and therefore exhibits relatively weaker and fewer bonding interactions with the crystal components. Furthermore, upon slightly increasing the amount of one precursor of TMCM-CdCl<sub>3</sub> during co-dissolution, this component gained an advantage in the competition against PEO for bonding with the other precursor. This in turn improved the co-crystallization yield of TMCM-CdCl<sub>3</sub> and further enhanced d<sub>33</sub> to ≈71 pC/N, exceeding that of polyvinylidene fluoride (a commercial flexible piezoelectric) and most other molecular ferroelectric crystal-based flexible films. This study presents an important innovation and progress in the methodology and theory for maintaining a high piezoelectric performance during the preparation of flexible multi-component piezoelectric crystal films.