First-principles study of the thermoelectric properties of the two-dimensional halide GeIBr

Abstract The utilisation of thermoelectric materials facilitates a direct conversion between heat and electricity, rendering them a highly sought-after resource in the realm of green and novel energy sources in the contemporary era. In order to realise their full potential, it is necessary to improve existing material properties and to synthesise new thermoelectric materials. In this study, we employed first-principles calculations to investigate the stability, electronic properties, and thermoelectric properties of the two-dimensional halides GeIBr. Following an exhaustive examination, we have ascertained the mechanical and kinetic stability of GeIBr and elucidated their thermoelectric properties as indirect bandgap semiconductors. Furthermore, the Seebeck coefficients( s ), conductivities( σ ), power factors( PF ) and thermal conductivities( κ ) of the two-dimensional IV group halides GeIBr have been subjected to comprehensive analysis and investigation through the lens of Boltzmann theory. The ZT value of the GeIBr monolayer of p -type is superior to that of n -type, with a maximum value of 2.06. This is attributed to the enhanced effectiveness of p -type carrier concentration in achieving the optimal power factor ( PF ) compared to n -type carriers in 2D GeIBr. The results indicate that the recently predicted two-dimensional IV group halides, GeIBr, may exhibit promising thermoelectric properties within the temperature range of 300K to 900K. The main innovation of this paper is to systematically investigate the thermoelectric transport properties of 2D GeIBr and compare them with the energy band and thermoelectric properties of the parent body. This finding not only provides a new perspective for understanding the physical properties of tetrakis halides, but also provides theoretical guidance for developing novel thermoelectric devices.