Negative Longitudinal Piezoelectricity Coexisting with both Negative and Positive Transverse Piezoelectricity in a Hybrid Formate Perovskite
Negative Longitudinal Piezoelectricity Coexisting with both Negative and Positive Transverse Piezoelectricity in a Hybrid Formate Perovskite
复制标题
混合甲酸盐钙钛矿中负纵向压电与负和正横向压电共存
DOI：
10.1021/acsami.2c09828
复制
发表时间：
2022
影响因子：
9.5
通讯作者：
Ponomareva, Inna
中科院分区：
文献类型：
--
作者：
Ghosh, Partha Sarathi;Lisenkov, Sergey;Ponomareva, Inna
纵向负压电响应是一种罕见的特性，主要存在于无机材料中。我们使用第一性原理密度泛函理论模拟来预测[NH 2NH 3]Co（HCOO）3中的这种不寻常的响应，[NH 2NH 3]Co（HCOO）3是一个大家族的混合有机-无机甲酸钙钛矿的代表。与具有负纵向压电响应的无机化合物不同的是，[NH 2 NH3]Co（HCOO）3的一个特征是，这种罕见的性质与负横向压电响应和正横向压电响应共存，这对于可调应用来说是非常理想的。原子分析表明，这种不寻常的机电耦合源于材料对单轴应力的高各向异性响应。这样的变形产生氧八面体倾斜的框架，其幅度强烈依赖于所施加的应变的方向。对于硬方向，倾斜度的主要贡献的变形引起的极化变化，而对于较软的方向，它是NH 2NH 3+阳离子的倾斜度占主导地位的极化响应。后者是由于复杂的氢键网络对八面体倾斜的响应而发生的。由于机械性能的高各向异性是整个甲酸钙钛矿的共同特征，我们希望我们的研究结果能够刺激这个家族中不寻常的机电耦合的更多发现。
Negative longitudinal piezoelectric response is a rare property, which has been found mostly in inorganic materials. We use first-principles density functional theory simulations to predict such an unusual response in [NH2NH3]Co(HCOO)3─a representative of a large family of hybrid organic–inorganic formate perovskites. A feature that sets aside [NH2NH3]Co(HCOO)3from inorganic compounds with a negative longitudinal piezoelectric response is that this rare property coexists with both negative and positive transverse piezoelectric responses, which is highly desirable for tunable applications. Atomistic analysis reveals that this unusual electromechanical coupling originates from the high anisotropy of materials response to uniaxial stress. Such a deformation produces oxygen octahedral tilts in the framework, whose magnitude depends strongly on the direction of the applied strain. For hard directions, the tilts make the dominant contribution to the deformation-induced change in polarization, while for the softer direction, it is the tilts of the NH2NH3+cation that dominate the polarization response. The latter occur as the complex hydrogen bond network responds to the octahedral tilts. As high anisotropy of mechanical properties is a common feature across the formate perovskites, we expect our findings to stimulate more discoveries of unusual electromechanical couplings in this family.