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Theoretical insight into the optoelectronic properties of lead-free perovskite derivatives of Cs3Sb2X9 (X = Cl, Br, I)

Liu, Yu-Liang, Yang, Chuan-Lu, Wang, Mei-Shan, Ma, Xiao-Guang, Yi, You-Gen
Journal of materials science 2019 v.54 no.6 pp. 4732-4741
absorption, bromine, carbon dioxide, chlorine, density functional theory, energy, hydrogen, hydrogen production, iodine, photocatalysis
The lead-free perovskites derivatives of Cs₃Sb₂X₉ (X = Cl, Br, I) have been synthesized, but their photocatalytic properties are not explored. To evaluate the feasibility for the visible light catalytic performance, we calculate the structural, electronic, optical and charge transfer properties of Cs₃Sb₂X₉, based on the hybrid density functional theory of HSE06 with the projector augmented wave potential. The results show the decrease of band energy gaps and the redshift of absorption edges from X = Cl to I. The absolute potential of the valence band maximum and conduction band minimum is determined to justify the feasibility of the photocatalytic water splitting or CO₂ reduction. The calculated carrier mobilities reveal that the high electron mobilities of Cs₃Sb₂I₉ are beneficial to the reducing powers for hydrogen generation and CO₂ reduction. The present results indicate that Cs₃Sb₂I₉ is appropriate for the photocatalytic water splitting to produce hydrogen or the CO₂ reduction driven by the visible light.