A comparative study of the thermoelectric performance of graphene-like BX (X= P, As, Sb) monolayers

TL;DR

This study compares the thermoelectric properties of graphene-like BX monolayers (X= P, As, Sb), revealing that BAs and BSb exhibit high ZT values above 3.0 due to low thermal conductivity and strong electron transport, promising for thermoelectric applications.

Contribution

It provides a first-principles analysis of thermoelectric performance in BX monolayers, highlighting the impact of bond anharmonicity on phonon scattering and thermoelectric efficiency.

Findings

BAs and BSb monolayers have low lattice thermal conductivities.

Maximum ZT values above 3.0 are achievable in BAs and BSb.

BSb shows similar p- and n-type thermoelectric performance along the armchair direction.

Abstract

The electronic and phonon transport properties of graphene-like boron phosphide (BP), boron arsenide (BAs), and boron antimonide (BSb) monolayers are investigated using first-principles calculations and Boltzmann theory. By considering both the phonon-phonon and electron-phonon scatterings, we demonstrate that the strong bond anharmonicity in the BAs and BSb monolayers can dramatically suppress the phonon relaxation time but hardly affects that of electrons. As a consequence, both systems exhibit comparable power factors with that of the BP monolayer but much lower lattice thermal conductivities. Accordingly, a maximum ZT values above 3.0 can be achieved in both BAs and BSb monolayers at optimized carrier concentrations. Interestingly, very similar p- and n-type thermoelectric performance is observed in the BSb monolayer along the armchair direction, which is of vital importance in the fabrication of thermoelectric modules with comparable efficiencies.