Integrated SnSSe bulk and monolayer as industrial waste heat thermoelectric materials

Abstract

Summary New, nontoxic and earth‐abundant materials for heat‐energy interconversion are urgently required to mitigate the over‐reliance on finite fossil fuels supply. Herein, using ab initio quantum mechanical calculations and Boltzmann theory, optimization of thermoelectric performances instable, mechanically robustCm‐SnSSe and P3m1‐SnSeS phases was performed. These phases exhibit an intrinsically low thermal conductivity of ~1.00 W m−1 K−1 at room temperature. Beyond 400 K, both phases display satisfactory thermoelectric performances, namely figure of merit ZT > 0.7 and power factor PF > 3.0 mW K−2 m−1. Better performances were obtained through holes doping at 1020 cm−3 concentration, where their ZT values reach 0.9 at 500 K and fluctuate minimally over broad temperature plateau, retaining the high PF over 3.0 mWK−2 m−1. Evolution into layered structure is also possible, with the calculated p‐type doping of P3m1‐SnSSe monolayer displaying decent ZT ~ 0.7 and very high PF > 6.0 mWK−2 m−1 beyond 300 K. In bulk form, the study specimens display superior machinability and mechanical properties, as evidenced by the approximately 8‐fold increase in their Vickers hardness when compared to PbTe and Bi2Te3 materials, while maintaining their plasticity characteristic. The computed E2D of 55.50 N m−1 is relatively low, which means Sn‐S‐Se alloy remains ductile when progressing to 2D state. Biaxial strain‐induced results show enhanced anharmonicity phonon scattering and thermopower increment, enabling maximum ZT ~ 1.0 and PF > 7.0 mW m−1 K−2 to be achieved in the appealing industrial waste heat akin 373 ≤ T ≤ 773 K range under 10% tensile strain.

The Thermal Stability of Janus Monolayers SnXY (X, Y = O, S, Se): Ab-Initio Molecular Dynamics and Beyond

“…Unlike graphene, our systems possessed a sandwiched structure (X−Sn−Y) with the space group of P 3 m 1, and they lacked both the inversion center and out-of-plane mirror symmetry. As can be found from Table 1 , the lattice constant ( ), the layer thickness ( ), and the bond length ( , ) increased with the radii of X and Y atoms, which are in good agreement with those reported previously [ 21 , 22 , 23 , 24 ]. If we focus on the difference ( ) between and , we found that was the largest for the Janus SnOSe, smallest for the SnSSe, with the SnOS in between.…”

“…Using first-principles calculations, Yuan et al [ 20 ] found that the formation energies of Janus MnSTe, MnSeTe, MnSSe, and VSeTe can be comparable to those of the parents MnS 2 , MnSe 2 , MnTe 2 , VSe 2 , and VTe 2 . In addition, previous ab-initio studies confirmed the chemical, dynamical, and mechanical stability of Janus monolayer SnSSe, which exhibits promising optoelectronic properties for solar cells applications and can be also used as appealing industrial waste thermoelectric materials [ 21 , 22 , 23 ].…”

“…Although many Janus monolayers have been proposed to be energetically and dynamically stable in recent years [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ], less is known about their thermal stability and an explicit understanding is therefore quite necessary, especially considering various application potentials at different temperature regions. In this work, using the Janus monolayers SnXY (X, Y = O, S, Se) as a prototypical class of examples, we focus on their thermal stability by performing ab-initio molecular dynamics (AIMD) simulations at a series of temperatures.…”

Quartic anharmonicity and ultra‐low lattice thermal conductivity of alkali antimonide compounds M 3 Sb ( M = K, Rb and Cs)

“…49 If these factors are included in the estimation of lattice thermal transport, the temperature dependence of the κ L of M 3 Sb may be different from the above results, which indicates a potential limitation of the method used in the present calculation. 50 The lattice thermal conductivity results are shown in Figure 3, from which we can capture the following information: first, these alkali antimonide compounds have ultra-low lattice thermal conductivity with a value of 1.26, 0.63 and 0.52 Wm −1 K −1 of K 3 Sb, Rb 3 Sb and Cs 3 Sb at a temperature of 300 K, respectively, which is much smaller than the typical thermoelectric material PbTe (κ L 2 Wm −1 K −1 ) [51][52][53] and comparable to the cubic antiperovskites A 3 BO (A = K, Rb; B = Br, Au) (κ L 0.73-1.7 Wm −1 K −1 ), 37 Cm-SnSSe and P3m1-SnSeS (κ L 1.00 Wm −1 K −1 ), 54 57 and based on the ultra-low lattice thermal conductivity, these materials may exhibit good thermoelectric properties. We calculated their Seebeck coefficient, electrical conductivity and showed them in S3, and the results indicate that the Seebeck coefficients of these alkali antimonide compounds M 3 Sb are larger than that of thermoelectric materials such as Na-doped PbTe (S 0.3 mV/K), 58 Li 3 Bi (S 0.25 mV/K) 59 and BP bilayer (S 0.3 mV/K) 60 at the appropriate doping concentration.…”

Low lattice thermal conductivity and high figure of merit in n‐type doped full‐Heusler compounds X 2 YAu (X = Sr, Ba; Y = as, Sb)

“…With the fossil fuel supply decreases and the world energy demand increases, the search for sustainable and clean energy has become a crucial social issue in the 21 st century. 1,2 Over these years, thermoelectric (TE) materials have received widespread attention, and the combination of thermal and electrical as well as semiconductor properties of TE materials make them useful for using heat to generate electricity. TE materials have an important effect on solving the international energy shortage problem.…”