Honeycomb-like puckered PbSe with wide bandgap as promising thermoelectric material: a first-principles prediction

Motivated by the superior thermoelectric performance of two-dimensional (2D) materials, the thermoelectric properties of honeycomb-like puckered PbSe monolayer are theoretically evaluated using the first-principles calculation and the semiclassical Boltzmann transport theory. The computational results show that the puckered PbSe monolayer is an indirect semiconductor with a wide bandgap of 2.31 eV within Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional in combination with spin-orbital coupling (SOC) effect. The phonon dispersion spectrum and mechanical stabilities show that the PbSe monolayer is thermodynamically and mechanically stable without negative frequencies and elastic constants. The Seebeck coefficients corresponding to the maximum figure of merit (ZT) at 900 K are ∼ 234 and ∼ 280 μV/K along the armchair and zigzag directions, respectively, which are highly correlated to the special band structure and density of states of PbSe monolayer. Along the armchair and zigzag directions, strong anisotropy in the thermoelectric properties is discovered for the p-type PbSe monolayer. The maximum ZT for optimal p-type doping PbSe monolayer at 900 K approaches to ∼ 1.3 along the zigzag direction. Our present work would provide a deep insight into the thermoelectric transport in the low dimensional system and explore a new PbSe-based with wide bandgap thermoelectric material.