Superior ferroelectricity and nonlinear optical response in a hybrid germanium iodide hexagonal perovskite

Kun Ding; Haoshen Ye; Changyuan Su; Yu-An Xiong; Guowei Du; Yu-Meng You; Zhi-Xu Zhang; Shuai Dong; Yi Zhang; Da-Wei Fu

doi:10.1038/s41467-023-38590-7

Superior ferroelectricity and nonlinear optical response in a hybrid germanium iodide hexagonal perovskite

Nat Commun. 2023 May 19;14(1):2863. doi: 10.1038/s41467-023-38590-7.

Authors

Kun Ding^#^{1

2}, Haoshen Ye^#³, Changyuan Su^#¹, Yu-An Xiong¹, Guowei Du¹, Yu-Meng You¹, Zhi-Xu Zhang^{4

5}, Shuai Dong⁶, Yi Zhang⁷, Da-Wei Fu⁸

Affiliations

¹ Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, China.
² Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, 321019, China.
³ Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China.
⁴ Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, China. zhixu@seu.edu.cn.
⁵ Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, 321019, China. zhixu@seu.edu.cn.
⁶ Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China. sdong@seu.edu.cn.
⁷ Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, 321019, China. yizhang1980@seu.edu.cn.
⁸ Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, 321019, China. dawei@seu.edu.cn.

^# Contributed equally.

Abstract

Abundant chemical diversity and structural tunability make organic-inorganic hybrid perovskites (OIHPs) a rich ore for ferroelectrics. However, compared with their inorganic counterparts such as BaTiO₃, their ferroelectric key properties, including large spontaneous polarization (P_s), low coercive field (E_c), and strong second harmonic generation (SHG) response, have long been great challenges, which hinder their commercial applications. Here, a quasi-one-dimensional OIHP DMAGeI₃ (DMA = Dimethylamine) is reported, with notable ferroelectric attributes at room temperature: a large P_s of 24.14 μC/cm² (on a par with BaTiO₃), a low E_c below 2.2 kV/cm, and the strongest SHG intensity in OIHP family (about 12 times of KH₂PO₄ (KDP)). Revealed by the first-principles calculations, its large P_s originates from the synergistic effects of the stereochemically active 4s² lone pair of Ge²⁺ and the ordering of organic cations, and its low kinetic energy barrier of small DMA cations results in a low E_c. Our work brings the comprehensive ferroelectric performances of OIHPs to a comparable level with commercial inorganic ferroelectric perovskites.

Abstract

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