Electronic Structures and Photoelectric Properties in Cs3Sb2X9 (X = Cl, Br, or I) under High Pressure: A First Principles Study

Yanwen Wu; Guangbiao Xiang; Man Zhang; Dongmei Wei; Chen Cheng; Jiancai Leng; Hong Ma

doi:10.3390/nano12172982

Electronic Structures and Photoelectric Properties in Cs₃Sb₂X₉ (X = Cl, Br, or I) under High Pressure: A First Principles Study

Nanomaterials (Basel). 2022 Aug 29;12(17):2982. doi: 10.3390/nano12172982.

Authors

Yanwen Wu¹, Guangbiao Xiang¹, Man Zhang¹, Dongmei Wei¹, Chen Cheng¹, Jiancai Leng², Hong Ma¹

Affiliations

¹ Shandong Provincial Key Laboratory of Optics, Photonic Device and Collaborative Innovation Center of Light Manipulations and Applications, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
² Department of Physics, School of Electronic and Information Engineering, Qilu University of Technology (Shandong Academy of Science), Jinan 250353, China.

Abstract

Lead-free perovskites of Cs₃Sb₂X₉ (X = Cl, Br, or I) have attracted wide attention owing to their low toxicity. High pressure is an effective and reversible method to tune bandgap without changing the chemical composition. Here, the structural and photoelectric properties of Cs₃Sb₂X₉ under high pressure were theoretically studied by using the density functional theory. The results showed that the ideal bandgap for Cs₃Sb₂X₉ can be achieved by applying high pressure. Moreover, it was found that the change of the bandgap is caused by the shrinkage of the Sb-X long bond in the [Sb₂X₉]^3- polyhedra. Partial density of states indicated that Sb-5s and X-p orbitals contribute to the top of the valence band, while Sb-5p and X-p orbitals dominate the bottom of the conduction band. Moreover, the band structure and density of states showed significant metallicity at 38.75, 24.05 GPa for Cs₃Sb₂Br₉ and Cs₃Sb₂I₉, respectively. Moreover, the absorption spectra showed the absorption edge redshifted, and the absorption coefficient of the Cs₃Sb₂X₉ increased under high pressure. According to our calculated results, the narrow bandgap and enhanced absorption ability under high pressure provide a new idea for the design of the photovoltaic and photoelectric devices.

Keywords: Cs3Sb2Br9; band structures; high pressure; photoelectric properties; the first principles.

Grants and funding

This work was funded by the National Natural Science Foundation of China (NFSC) (grant No. 11904212). This work also received the financial support from by the project ZR2020MA081, ZR2019MA037 and ZR2018BA031 supported by Shandong Provincial Nature Science Foundation and the Research Leader Program of Jinan Science and Technology Bureau (2019GXRC061).