Thermoelectric Performance of Two-Dimensional AlX (X = S, Se, Te): A First-Principles-Based Transport Study

Abstract

By using the first-principles calculations in combination with the Boltzmann transport theory, we systematically study the thermoelectric properties of AlX (X = S, Se, Te) monolayers as indirect gap semiconductors. The unique electronic density of states, which consists of a rather sharp peak at the valence band maxima and an almost constant band at the conduction band minima, makes AlX (X = S, Se, Te) monolayers excellent thermoelectric materials. The optimized power factors at room temperature are 22.59, 62.59, and 6.79 mW m–1 K–2 under reasonable electronic concentration for AlS, AlSe, and AlTe monolayers, respectively. The figure of merit (zT) increases with temperature and the optimized zT values of 0.52, 0.59, and 0.26 at room temperature are achieved under moderate electronic concentration for AlS, AlSe, and AlTe monolayers, respectively, indicating that two-dimensional layered AlX (X = S, Se, Te) semiconductors, especially AlSe, can be potential candidate matrices for high-performance thermoelectric nanocomposites.

High Thermoelectric Performance in Two-Dimensional Janus Monolayer Material WS-X (X = Se and Te)

“…The single-layer MoS 2 has reported ZT values of 0.04, 0.07, and 0.11 at 300 K, 400 K, and 500 K, respectively . The ZT of 0.52, 0.59, and 0.25 at room temperature are found in AlS, AlSe, and AlTe monolayers under moderate conditions . The anisotropic materials PdS 2 , PdSe 2, and PdTe 2 show larger thermoelectric conversion performance with ZT values of 0.85, 1.18, and 2.42, respectively, compared to the commercial thermoelectric material Bi 2 S 3 (ZT = 0.80) …”

Two-dimensional boron monochalcogenide monolayer for thermoelectric material

“…Previous studies reported that group IIIA monochalcogenides such as AlX, GaX and InX (X ¼ S, Se, Te) have superior thermoelectric efficiency. [28][29][30] Motivated by such fascinating thermoelectric properties of group IIIA chalcogenide materials, we have investigated the thermoelectric properties of boron monochalcogenide BX (X ¼ S, Se, Te). Boron monochalcogenides are recently proposed materials utilizing density functional theory (DFT) which contain two phases, 1T and 2H.…”

Two‐dimensional Janus group‐III ternary chalcogenide monolayer compounds B2XY, Al2XY, and BAlX2 (X, Y = S, Se, Te) with high carrier mobilities

“…4 The semiconducting properties of 2D AlX (X = S, Se, Te) were theoretically elucidated and, in particular, AlSe was suggested as a potential candidate for outstanding thermoelectric nanocomposites. 5 As a new class of layered materials, the Janus-type compounds of 2D group-III chalcogenides, which have different atomic compositions or arrangements at both opposite sides, have recently been of interests due to their fascinating physical and chemical properties, such as enhanced piezoelectric properties and promising photocatalytic activities for water splitting. The first-principles calculations of Ga 2 STe, Ga 2 SeTe, In 2 STe, and In 2 SeTe monolayers revealed not only that their piezoelectric coefficients were four times higher than those of corresponding perfect monochalcogenides monolayers, 6 but also their band edge positions are suitable for photocatalytic water splitting based on their semiconducting nature and simulated optical absorption spectra.…”