IntegratedSnSSebulk and monolayer as industrial waste heat thermoelectric materials

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 robust Cm-SnSSe and P3m1-SnSeS phases was performed. These phases exhibit an intrinsically low thermal conductivity of similar to 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 factorPF > 3.0 mW K-2 m(-1). Better performances were obtained through holes doping at 10(20) cm(-3) concentration, where their ZT values reach 0.9 at 500 K and fluctuate minimally over broad temperature plateau, retaining the highPFover 3.0 mWK(-2) m(-1). Evolution into layered structure is also possible, with the calculated p-type doping of P3m1-SnSSe monolayer displaying decentZT similar to 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 E-2D 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 similar to 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.