Bond engineering of molecular ferroelectrics renders soft and high-performance piezoelectric energy harvesting materials

• Published in: Nature communications Vol. 13; no. 1; pp. 5607 - 10
• Main Authors: Hu, Yuzhong, Parida, Kaushik, Zhang, Hao, Wang, Xin, Li, Yongxin, Zhou, Xinran, Morris, Samuel Alexander, Liew, Weng Heng, Wang, Haomin, Li, Tao, Jiang, Feng, Yang, Mingmin, Alexe, Marin, Du, Zehui, Gan, Chee Lip, Yao, Kui, Xu, Bin, Lee, Pooi See, Fan, Hong Jin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.09.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 142/136; 639/301/119/1002; 639/301/119/996; 639/4077/4072/4062; 639/638/298/917; Bonding strength; Chemical bonds; Crystal structure; Electric potential; Energy; Energy harvesting; Engineering; Ferroelectric materials; Ferroelectricity; Ferroelectrics; Humanities and Social Sciences; Laboratories; Metal halides; multidisciplinary; Phase transitions; Piezoelectricity; Science; Science (multidisciplinary); Shear strain; Softness; Solid solutions; Strain; Voltage; Wearable computers; Wearable technology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-33325-6

Piezoelectric materials convert mechanical stress to electrical energy and thus are widely used in energy harvesting and wearable devices. However, in the piezoelectric family, there are two pairs of properties that improving one of them will generally compromises the other, which limits their applications. The first pair is piezoelectric strain and voltage constant, and the second is piezoelectric performance and mechanical softness. Here, we report a molecular bond weakening strategy to mitigate these issues in organic-inorganic hybrid piezoelectrics. By introduction of large-size halide elements, the metal-halide bonds can be effectively weakened, leading to a softening effect on bond strength and reduction in polarization switching barrier. The obtained solid solution C 6 H 5 N(CH 3 ) 3 CdBr 2 Cl 0.75 I 0.25 exhibits excellent piezoelectric constants ( d 33  = 367 pm/V, g 33  = 3595 × 10 −3  Vm/N), energy harvesting property (power density is 11 W/m 2 ), and superior mechanical softness (0.8 GPa), promising this hybrid as high-performance soft piezoelectrics. Improving piezoelectric strain and voltage constant generally compromises piezoelectric performance and mechanical softness. Here, the authors report a bond weakening strategy for organic-inorganic hybrid piezoelectrics and mitigated these issues.