Piezoelectric hybrid organic–inorganic perovskites have attracted significant attention due to their outstanding piezoelectricity comparable to perovskite oxides. However, their elastic properties, which determine the piezoelectric performance, have not yet been explored. Here, the elastic properties of a perovskite ferroelectric TMCM-CdCl3 (TMCM = trimethylchloromethyl ammonium) with a large piezoelectric effect are comprehensively investigated. High-pressure synchrotron powder x-ray diffraction experiments reveal that it exhibits a low bulk modulus of 14.58 GPa, which is an order of magnitude lower than those of perovskite oxides. In addition, Young’s moduli and shear moduli were calculated using density functional theory, and their values are significantly smaller than perovskite piezoceramics. Furthermore, the acoustic properties of TMCM-CdCl3 were calculated. Its longitudinal wave velocity is 3.86 km s−1–4.94 km s−1, and the corresponding specific acoustic impedance is 8.28 MRayl–10.21 MRayl. These maximum values are, respectively, 31.5%, 74.4%, and 8.4%, 73.1% lower than those from BaTiO3 and PbTiO3. Our findings disclose the soft nature and low acoustic impedance of hybrid perovskite piezoelectrics, which are critical to their applications in energy conversion devices.

中文翻译：

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具有大压电性的混合有机-无机钙钛矿 TMCM-CdCl3 的机械和声学特性

压电杂化有机-无机钙钛矿由于其与钙钛矿氧化物相当的出色压电性能而引起了极大的关注。然而，决定压电性能的弹性特性尚未得到探索。在这里，综合研究了具有大压电效应的钙钛矿铁电 TMCM-CdCl3（TMCM = 三甲基氯甲基铵）的弹性特性。高压同步加速器粉末 X 射线衍射实验表明，它具有 14.58 GPa 的低体积模量，比钙钛矿氧化物低一个数量级。此外，杨氏模量和剪切模量是使用密度泛函理论计算的，它们的值明显小于钙钛矿压电陶瓷。此外，计算了TMCM-CdCl3的声学特性。其纵波速度为3.86 km s−1–4.94 km s−1，对应的比声阻抗为8.28 MRayl–10.21 MRayl。这些最大值分别比 BaTiO3 和 PbTiO3 的最大值低 31.5%、74.4% 和 8.4%，分别低 73.1%。我们的研究结果揭示了混合钙钛矿压电材料的柔软特性和低声阻抗，这对其在能量转换设备中的应用至关重要。