Xiang Guangbiao, Wu Yanwen, Zhang Man, Cheng Chen, Leng Jiancai, Ma Hong
Shandong Provincial Key Laboratory of Optics and Photonic Device, Collaborative Innovation Center of Light Manipulations and Applications, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
Nanomaterials (Basel). 2021 Oct 14;11(10):2712. doi: 10.3390/nano11102712.
Low-toxicity, air-stable cesium bismuth iodide CsBiX (X = I, Br, and Cl) perovskites are gaining substantial attention owing to their excellent potential in photoelectric and photovoltaic applications. In this work, the lattice constants, band structures, density of states, and optical properties of the CsBiX under high pressure perovskites are theoretically studied using the density functional theory. The calculated results show that the changes in the bandgap of the zero-dimensional CsBiI, one-dimensional CsBiCl, and two-dimensional CsBiBr perovskites are 3.05, 1.95, and 2.39 eV under a pressure change from 0 to 40 GPa, respectively. Furthermore, it was found that the optimal bandgaps of the Shockley-Queisser theory for the CsBiI, CsBiBr, and CsBiCl perovskites can be reached at 2-3, 21-26, and 25-29 GPa, respectively. The CsBiI perovskite was found to transform from a semiconductor into a metal at a pressure of 17.3 GPa. The lattice constants, unit-cell volume, and bandgaps of the CsBiX perovskites exhibit a strong dependence on dimension. Additionally, the CsBiX perovskites have large absorption coefficients in the visible region, and their absorption coefficients undergo a redshift with increasing pressure. The theoretical calculation results obtained in this work strengthen the fundamental understanding of the structures and bandgaps of CsBiX perovskites at high pressures, providing a theoretical support for the design of materials under high pressure.
低毒性、空气稳定的铯铋碘化物CsBiX（X = I、Br和Cl）钙钛矿因其在光电和光伏应用中的优异潜力而备受关注。在这项工作中，利用密度泛函理论对高压钙钛矿下CsBiX的晶格常数、能带结构、态密度和光学性质进行了理论研究。计算结果表明，在压力从0变化到40 GPa时，零维CsBiI、一维CsBiCl和二维CsBiBr钙钛矿的带隙变化分别为3.05、1.95和2.39 eV。此外，发现CsBiI、CsBiBr和CsBiCl钙钛矿的肖克利-奎塞尔理论的最佳带隙分别在2 - 3、21 - 26和25 - 29 GPa时可以达到。发现CsBiI钙钛矿在17.3 GPa的压力下从半导体转变为金属。CsBiX钙钛矿的晶格常数、晶胞体积和带隙对维度表现出强烈的依赖性。此外，CsBiX钙钛矿在可见光区域具有较大的吸收系数，并且它们的吸收系数随着压力的增加而发生红移。这项工作中获得的理论计算结果加强了对高压下CsBiX钙钛矿结构和带隙的基本理解，为高压下材料的设计提供了理论支持。
