Anisotropic dielectric behavior of layered perovskite-like Cs3Bi2I9 crystals in the terahertz region

被引：11

作者：

Sun, Qihao ^{[1
,2
]}

Yang, Wenhui ^{[1
,2
]}

Cheng, Yuanbo ^{[1
,2
]}

Dong, Jiangpeng ^{[1
,2
]}

Zhu, Mengqin ^{[1
,2
]}

Zhang, BinBin ^{[1
,2
]}

Dubois, Alain ^{[1
,2
,3
]}

Zhu, Menghua ^{[1
,2
]}

Jie, Wanqi ^{[1
,2
]}

Xu, Yadong ^{[1
,2
,3
]}

机构：

[1] Northwestern Polytech Univ, Sch Mat Sci & Engn, MIIT, Key Lab Radiat Detect Mat & Devices, Xian 710072, Shaanxi, Peoples R China

[2] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Shaanxi, Peoples R China

[3] Sorbonne Univ, Lab Phys Chem Matter & Radiat, Paris, France

来源：

PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 2020年 / 22卷 / 42期

基金：

中国国家自然科学基金;

关键词：

THZ ABSORPTION; RB; CS; A(3)M(2)I(9); BI;

D O I：

10.1039/d0cp04485g

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The ternary metal halide perovskites have gradually attracted attention for application in the optoelectronic field, owing to their tunable crystal structure and appropriate bandgap. Lead free Cs3Bi2I9 perovskite, with a 0D layered structure containing molecular [Bi2I9](3-) dimers, exhibits prominent optical and electrical anisotropies. Here, the anisotropic properties of the Cs3Bi2I9 crystals were evaluated using terahertz time-domain spectroscopy (THz-TDS); meanwhile, the effect of phonon vibration on the THz transmission was confirmed using density functional perturbation theory (DFPT). Accordingly, the refractive index and extinction coefficient are estimated using THz-TDS, thanks to the high transmission in the range of 0.2-0.9 THz. The anisotropic refractive index was observed for the Cs3Bi2I9 crystals, and was found to be 3.2-3.7 for the (100) plane (CBI(100)) in contrast to 2.8-3.2 for the (001) plane (CBI(001)). Furthermore, the Lorentz model was employed to extract the dielectric constant of Cs3Bi2I9, in which anisotropy is obviously indicated by the static dielectric constant and the high-frequency dielectric constant. These anisotropic behaviors are determined by the dipole moment, which is attributed to the anisotropic packing density of [Bi2I9](3-) dimers. This study is significant and provides a deeper insight into the anisotropic photoelectric properties of Cs3Bi2I9, thus contributing to the development of metal halide perovskites in the field of optoelectronics.

引用

页码：24555 / 24560

页数：6

共 34 条

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