The structural stability, lattice dynamics, electronic, thermophysical, and mechanical properties of the inverse perovskites A ₃ OX: A comparative first‐principles study

Abstract

Summary We present a comparative study on the structural, electronic, elastic, and thermoelectric properties of the cubic inverse‐perovskites A3OX (where A = Li, Na, K and X = Cl, Br, I) by density functional theory (DFT). The cohesive, formation, and elastic properties analysis indicates that all studied materials are chemically, thermodynamically, and mechanically stable. Electronic properties reveal that all the inverse A3OX perovskite are direct bandgap semiconductors except Li3OCl and Li3OBr with ionic nature which is confirmed by electron localization function (ELF) analysis. We have also calculated Debye temperature (ΘD) and Grüneisen parameter (γ) to determine the lattice thermal conductivity for all the A3OX materials. Furthermore, thermoelectric (TE) properties are explored by calculating the Seebeck coefficient (S), electronic thermal conductivity, power factor (PF), electrical conductivity (σ/τ), lattice thermal conductivity, and ZT value. Our investigated A3OX inverse‐perovskites provide a fertile base that can improve the overall TE performance for TE applications and green energy production.

First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

“…We started from experimentally reported atomic positions and performed structural optimizations by varying the volume until the minimum energy was reached. The obtained data was fitted into the Murnaghan's equation of state that can be expressed as: where E(V) and E o are the total energies at the deformed (V) and reference (V o ) volumes, respectively, and B o and represent the bulk modulus and its first-order pressure derivative, respectively [9,56,57]. The volume-energy optimization curve of the π-SnSe is shown in Figure 2.…”

“…To understand the thermoelectric (TE) response and applicability of the cubic π-SnSe alloy, we employed the semiclassical Boltzmann transport theory to determine the Seebeck coefficient (S), the electrical conductivity (σ/τ), as well as the electronic part of the thermal conductivity (κ e /τ) by applying the following relations [9]:…”

“…The mathematical rela-tion required to calculate the lattice thermal conductivity can be expressed as [66]: (6) where (7) In the above expressions, the A parameter is equivalent to ≈3.14 × 10 −8 , which is a dimensionless collection of physical constants. The Debye temperature is represented by θ D , V a is the volume per atom, m av is the average atomic mass, n is the total number of atoms present in the unit cell, and γ is the Grüneisen parameter [9]. We used the values of θ D = 240.86 and γ = 2.1875 at 300 K in the Slack's equation to obtain the lattice thermal conductivity.…”

“…The close interdependency of the three entities S, σ, and κ tot offer challenges in the formulation of strategies to improve the ZT values of the TE materials, particularly by utilizing affordable and Earth-abundant materials [1,6], and this is the task that may revolutionize the field of solid-state thermal energy conversion [7]. A higher value of ZT needs a large value of the power factor (PF = S 2 σ) which is connected with the electrical transport [8,9] and the lowest value of κ tot [10]. To date, a considerable amount of research has been performed to enhance the ZT value.…”

Electronic and thermo‐physical properties of double antiperovskites X6SOA2 (X = Na, K and A = Cl, Br, I): A non‐toxic and efficient energy storage materials

“…Shukla et al [13] have determined physical and thermoelectric properties of tin‐based organometallic halide perovskites (CH 3 NH 3 SnX 3 , X = Br and I) and concluded that they may also be used in thermoelectric devices at room temperature. Sattar et al [14] have investigated structural, electronic, mechanical and thermoelectric parameters of A 3 OX (where A = Li, Na and K; X = Cl, Br and I) antiperovskite compound and stated that all compounds are mechanically and thermodynamically stable and offer a fertile base that can enhance overall thermoelectric output for thermoelectric devices and renewable energy production. Goh et al [15] have studied topological and TE parameters of double antiperovskite compounds and found these materials a good candidate for TE applications.…”