Transport and thermoelectric properties of penta-Sb2X monolayers

Thermoelectrics enable direct conversion between heat and electricity, with broad implications for energy and nano-technologies. A key challenge is improving the efficiency of devices, which depends on improved thermoelectric materials. Here we investigate the novel penta-Sb2X (X = Si, Ge, Sn) 2D materials as potential thermoelectrics, using first-principles methods and Boltzmann transport theory. All the three monolayer structures are semiconducting. Sb2Si is found to have excellent electric conductivity with high electron mobility of 4010 cm(2) V-1 s(-1). Sb2Ge and Sb2Sn have very low lattice thermal conductivity of 2.34 and 0.94 W m(-1) K-1. Optimization of the carrier concentration leads to high estimated values of the figure of merit, ZT. We predict the ZT of n-type Sb2Si to be as high as 4.38, while the ZT values of p-type Sb2Ge and Sb2Sn at 700 K are up to 7.37 and 8.0. These results suggest experimental investigation of the semiconducting and thermoelectric properties of these monolayers.

Automated summary

It is found that the novel penta-Sb2X (X = Si, Ge, Sn) 2D materials exhibit excellent thermoelectric properties, which can improve the efficiency of thermoelectric devices. Sb2Si shows remarkable electrical conductivity and electron mobility, while Sb2Ge and Sb2Sn have low lattice thermal conductivity. Optimized carrier concentration leads to high values of the figure of merit, ZT. Experimental investigation of the semiconducting and thermoelectric properties of these materials is suggested.