Roles of Pseudo-Closed s² Orbitals for Different Intrinsic Hole Generation between Tl–Bi and In–Bi Bromide Double Perovskites

Journal Article · Thu Dec 21 00:00:00 EST 2017 · Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/acs.jpclett.7b02949· OSTI ID:1593889

Xiao, Zewen  ^[1]; Yan, Yanfa  ^[2]; Hosono, Hideo ^[3]; Kamiya, Toshio ^[3]

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1. Tokyo Inst. of Technology (Japan). Materials Research Center for Element Strategy
2. Univ. of Toledo, OH (United States). Dept. of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization (PVIC)
3. Tokyo Inst. of Technology (Japan). Materials Research Center for Element Strategy and Lab. for Materials and Structures

Although metal halide double perovskites A₂B(I)B(III)X₆ are expected as nontoxic alternatives for lead halide perovskites, recent studies have shown that only Tl(I)–Bi(III) and In(I)–Bi(III) bromides are thermodynamically stable and possess optoelectronic properties suitable for photovoltaic absorbers. In this work, we show, through density functional theory calculations, that Tl–Bi and In–Bi bromide double perovskites exhibit significantly different semiconducting behaviors due to the different energy levels of the highest-occupied pseudoclosed s² orbitals of Tl(I) and In(I). While Tl–Bi double perovskites can exhibit semiconducting $$p$$-type properties, In–Bi bromide double perovskites exhibit metallic $$p$$-type ones regardless of the synthesis condition due to the extremely low formation energy of In vacancy. Such difference makes Tl–Bi bromide double perovskites suitable for optoelectronic applications, but not In–Bi bromide double perovskites. Furthermore, there is a high probability for In to substitute a Bi site, forming a local In–In bromide double perovskite structure with a lower local conduction band minimum, detrimentally affecting the open circuit voltage of In–Bi bromide double perovskite-based thin film solar cells.

• Research Organization: Duke Univ., Durham, NC (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE); Ministry of Education, Culture, Sports, Science and Technology (MEXT); National Science Foundation (NSF)
• Grant/Contract Number: EE0006712; CHE-1230246; DMR-1534686
• OSTI ID: 1593889
• Journal Information: Journal of Physical Chemistry Letters, Vol. 9, Issue 1; ISSN 1948-7185
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY