TY - JOUR

T1 - Novel 3D photoactive direct bandgap perovskites CsBiPbX6

T2 - Ab initio structure and electronic properties

AU - Kevorkyants, R.

AU - Bahnemann, D.W.

AU - Emeline, A.V.

N1 - Funding Information: The authors acknowledge St. Petersburg State University for the research grant (Pure ID 39054581). The authors also thank the Center for Computational Resources of St. Petersburg State University (Peterhof campus) for the provided CPU time.

PY - 2020/10

Y1 - 2020/10

N2 - We present DFT study on hypothetical 3D all-inorganic metal halide perovskites CsBiPbX 6 (X = Cl, Br, I). According to the calculations, the perovskites form cubic, orthorhombic, monoclinic, and trigonal phases which are all direct bandgap semiconductors. Typical of metal halide perovskites, valence bands of the considered species are composed of halide anions’ occupied p-orbitals. Their conduction bands contain about equal contributions from vacant p-orbitals of both Bi 3+ and Pb 2+ cations. Electronic bandgaps of the studied perovskites range from 1.05 eV to 2.10 eV, whereas estimated optical bandgaps of their cubic F43m phase equal 1.50 eV (CsBiPbI 6), 1.87 eV (CsBiPbBr 6), and 2.40 eV (CsBiPbCl 6). The perovskites’ electronic properties can be fine-tuned by mixing of halide anions. Mixed-halides CsBiPbBr nI (6-n), (n = 1–5) are considered here as an example. Majority of these compounds are direct bandgap semiconductor as well with electronic bandgaps falling in the range [1.08–1.72] eV. Their optical bandgaps are expected to exceed the corresponding electronic ones by a few tenths of an electronvolt. Owing to relatively low lead content, direct electronic transitions, and remarkable tunability of electronic properties the proposed materials may find applications in photovoltaics.

AB - We present DFT study on hypothetical 3D all-inorganic metal halide perovskites CsBiPbX 6 (X = Cl, Br, I). According to the calculations, the perovskites form cubic, orthorhombic, monoclinic, and trigonal phases which are all direct bandgap semiconductors. Typical of metal halide perovskites, valence bands of the considered species are composed of halide anions’ occupied p-orbitals. Their conduction bands contain about equal contributions from vacant p-orbitals of both Bi 3+ and Pb 2+ cations. Electronic bandgaps of the studied perovskites range from 1.05 eV to 2.10 eV, whereas estimated optical bandgaps of their cubic F43m phase equal 1.50 eV (CsBiPbI 6), 1.87 eV (CsBiPbBr 6), and 2.40 eV (CsBiPbCl 6). The perovskites’ electronic properties can be fine-tuned by mixing of halide anions. Mixed-halides CsBiPbBr nI (6-n), (n = 1–5) are considered here as an example. Majority of these compounds are direct bandgap semiconductor as well with electronic bandgaps falling in the range [1.08–1.72] eV. Their optical bandgaps are expected to exceed the corresponding electronic ones by a few tenths of an electronvolt. Owing to relatively low lead content, direct electronic transitions, and remarkable tunability of electronic properties the proposed materials may find applications in photovoltaics.

KW - Crystal structure

KW - DFT

KW - Electronic properties

KW - Metal halide perovskites

KW - Photovoltaics

UR - http://www.scopus.com/inward/record.url?scp=85085487122&partnerID=8YFLogxK

U2 - 10.1016/j.commatsci.2020.109819

DO - 10.1016/j.commatsci.2020.109819

M3 - Article

VL - 183

JO - Computational materials science

JF - Computational materials science

SN - 0927-0256

M1 - 109819

ER -