Chemical Trends in the Thermodynamic Stability and Band Gaps of 980 Halide Double Perovskites: A High-Throughput First-Principles Study

Abstract

The chemical trends in the thermodynamic stability and band gaps of 980 A2B+B3+X6 halide double perovskites are revealed based on high-throughput first-principles calculations. To accurately predict the stability with respect to phase decomposition, all known metal halides in the Materials Project database are considered as the competing compounds. The energies above the convex hull show that only 112 of 980 double perovskites are stable and 27 double perovskites that had been predicted to be stable in the literature are actually unstable after considering more competing compounds. The stability of these double perovskites is determined mainly by A, X, and B+ elements and increases gradually as A becomes heavier (from Li to Cs) and X becomes lighter (from I to F). The band gaps are determined mainly by X, B+, and B3+ elements, decreasing monotonically as X becomes heavier while changing nonmonotonically as B+ and B3+ change. These chemical trends provide clear instructions for the design of double perovskites with good stability and suitable band gaps for various applications, i.e., through choosing heavier A cations (e.g., large organic cations), stable double perovskites can be designed with band gaps tunable in a wide range of 0–7 eV (infrared to ultraviolet); however, through choosing light X anions, stable double perovskites can be designed with only wide band gaps.

High throughput screening of promising lead-free inorganic halide double perovskites via first-principles calculations

“…With the changes of the constituent elements A, B, and X, the band gap shows a clear trend. From the color change of the heat map, we can easily find that, for double perovskites such as Cs 2 B 2+ B′ 2+ X 6 , the halogen atom at the X position with the element types of F, Cl, Br, and I, the band gap value gradually decreases; this follows the same trend as the A 2 B 1+ B′ 3+ X 6 double perovskites studied by Zhao et al 31 and Zhang et al 32 The band gap value is distributed uniformly in each interval, showing the advantage of the wide-range adjustable band gap of all-inorganic double perovskites, as shown in Fig. 3b.…”

“…The cation-transmutation principle enables the replacement of elements by keeping the total number of valence electrons unchanged at the B site. For example, Zhao et al 31 and Zhang et al 32 systematically screened the replacement of the B site elements with different valences, i.e. 2Pb 2+ → B + + B′ 3+ .…”

Lattice Doping of Lanthanide Ions in Cs 2 AgInCl 6 Nanocrystals Enabling Tunable Photoluminescence

“…However, those materials are either limited by stability challenges [14] or with lower electronic mobility because of the lower symmetry nonperovskite structure [15]. One different way to address the challenge is to replace two Pb 2+ ions with one monovalent cation (B + ions) and one trivalent cation (B 3+ ions), forming the three-dimensional (3D) double perovskite structure [16]. The possible combinations of various cations make the diversity of lead-free double perovskites and make them the most promising alternative for optoelectronic applications [17].…”

Lead‐Free Double Perovskite Cs2AgBiBr6: Fundamentals, Applications, and Perspectives

“…Through combining different A, B + , B 3+ and X elements (for example, A = K, Rb, Cs; B + = Li, Na, K, Rb, Cs, Ag; B 3+ = Al, Ga, In, Sb, Bi, Sc, Y, and X = F, Cl, Br, I), more than 100 double perovskites with a structural tolerance factor and octahedra factor in a reasonable range have been predicted to be thermodynamically stable. [9] Therefore, the structural and functional diversity, combined with the high stability observed in double perovskites, make them very promising lead-free candidates for a wide range of optoelectronic applications.…”