In this study, by utilizing the first-principles calculation coupled with the Boltzmann transport theory, we comprehensively study the thermoelectric (TE) properties of the Sb2C monolayer. The calculated results show that the Sb2C monolayer owns an inherent ultra-low lattice thermal conductivity of 0.88 W m−1 K−1 at 300 K, which originates from small phonon group velocities, large Grüneisen parameters, and short phonon lifetimes. The Sb2C monolayer also exhibits excellent electrical transport properties mainly due to the degeneration of the bottom conduction bands, which increases the Seebeck coefficient of the n-type doped samples and thus yields a larger power factor. Based on the extremely low lattice thermal conductivity and superior electrical transport performance, a large ZT value of 2.71 for the n-type doped Sb2C monolayer at 700 K is obtained. Our results quantify Sb2C monolayers as promising candidates for building outstanding thermoelectric devices.

Two-dimensional (2D) materials exhibit enhanced thermoelectric (TE) performance compared to bulk materials, which relies heavily on lattice thermal conductivity. Penta-X2C (X = P, As, and Sb) is a newly predicted 2D material family with promising potential applications in photocatalytic water splitting and photovoltaic and optoelectronic devices. To achieve a combination of photovoltaic and TE technologies and further boost the energy utilization rate, in this paper, we systematically investigate the thermal transport of the penta-X2C family. Density functional theory combined with semiclassical Boltzmann transport approach was used to evaluate the thermal transport. Interestingly, the calculated lattice thermal conductivities (kl) of penta-Sb2C are two orders of magnitude smaller than that of penta-P2C, despite that they share similar atomic structure. The calculated kl of penta-P2C, penta-As2C, and penta-Sb2C are 75.27 W m−1 K−1, 19.11 W m−1 K−1, and 0.72 W m−1 K−1, respectively. Penta-Sb2C also exhibits low average acoustic group velocity, large Grüneisen parameters, strong optical–acoustic phonon coupling, and short phonon mean free path. These results qualify penta-Sb2C as a promising candidate for building outstanding TE devices.

Thermoelectric (TE) materials as one of the effective solutions to the energy crisis are gaining more and more interest owing to their capability to generate electricity from waste heat without generating air pollution.

Black Arsenic-phosphorus (AsP) monolayer is a novel two-dimensional nanomaterial with the characteristics of modest direct bandgap and superhigh carrier mobility. However, little is known about how the surface adsorption affects the property of AsP monolayer. Motivated by this, we researched systematically the geometry, adsorption energy, magnetic moment and electronic structure of 11 different adatoms adsorbed on AsP monolayer using first-principles calculations. The adatoms used in this study include light nonmetallic (C, N, O) adatoms, period-3 metal (Na, Mg, Al) adatoms, and transition-metal (Ti, V, Cr, Mn, and Fe) adatoms. The adatoms cause an abundant variety of structural, magnetic and electronic properties. This study shows that AsP binds strongly with all adatoms under study and the adsorption energies in all systems are much stronger than that on graphene, SiC, BN, or MoS2. The semiconductor property of AsP is affected by the introduction of adsorbed atoms, which can induce mid-gap states or cause n-type doping. Moreover, the adatom adsorptions cause various spintronic characteristics: N-, Ti-, and Fe-adsorbed AsP become bipolar semiconductors, while the Mn-decorated AsP becomes a bipolar spin-gapless semiconductor. Our results suggest that atomic adsorption on AsP monolayers has potential application in the field of nanoelectronics and spintronics.

The CaAs3 monolayer is a newly predicted two-dimensional material with attractive properties, such as a moderate direct bandgap, high carrier mobility, prominent visible-light absorption, etc.