Phosphorene nanoribbon as a promising candidate for thermoelectric applications

TL;DR

This study explores the electronic and thermoelectric properties of phosphorene nanoribbons, revealing their potential for high-efficiency thermoelectric devices due to tunable band gaps, enhanced Seebeck coefficients, and low thermal conductivity.

Contribution

It provides a comprehensive analysis of how nanoribbon width and edge passivation affect electronic and thermoelectric properties, highlighting phosphorene nanoribbons as promising thermoelectric materials.

Findings

Armchair nanoribbons are semiconducting; zigzag are metallic.

Hydrogen passivation increases band gaps and Seebeck coefficients.

Achieved a ZT value of 4.0 at room temperature.

Abstract

In this work, the electronic properties of phosphorene nanoribbons with different width and edge configurations are studied by using density functional theory. It is found that the armchair phosphorene nanoribbons are semiconducting while the zigzag nanoribbons are metallic. The band gaps of armchair nanoribbons decrease monotonically with increasing ribbon width. By passivating the edge phosphorus atoms with hydrogen, the zigzag series also become semiconducting, while the armchair series exhibit a larger band gap than their pristine counterpart. The electronic transport properties of these phosphorene nanoribbons are then investigated using Boltzmann theory and relaxation time approximation. We find that all the semiconducting nanoribbons exhibit very large values of Seebeck coefficient and can be further enhanced by hydrogen passivation at the edge. Taking armchair nanoribbon with width N=7 as an example, we calculate the lattice thermal conductivity with the help of phonon Boltzmann transport equation. Due to significantly enhanced Seebeck coefficient and decreased thermal conductivity, the phosphorene nanoribbon exhibit a very high figure of merit (ZT value) of 4.0 at room temperature, which suggests its appealing thermoelectric applications.