Thermoelectric Properties of Graphene through BN-ring Doping: A Theoretical Investigation

TL;DR

This study uses multiscale simulations to show that BN-ring doping in graphene can significantly improve its thermoelectric properties by increasing the Seebeck coefficient and reducing thermal conductance, despite some conductance reduction.

Contribution

It introduces a novel approach of BN-ring doping in graphene and analyzes its effects on thermoelectric properties through detailed theoretical modeling.

Findings

BN-ring doping enlarges graphene's bandgap and enhances thermoelectric properties.

Thermal lattice conductance is reduced by up to 40% with BN-ring doping.

The effects depend on BN concentration and rotational alignment, emphasizing precise doping control.

Abstract

Graphene has been widely studied for various applications due to its outstanding electrical and mechanical properties. However, its potential in thermoelectric applications has been limited by a low Seebeck coefficient and high thermal conductivity. Efforts to enhance its thermoelectric properties have involved the usage of carbon-based nanoribbons, strain engineering, and heteroatom co-doping, particularly with Nitrogen and/or Boron atoms. In this work, multiscale simulation approaches combining DFT calculations and semi-empirical models are used to explore the potential improvement of the thermoelectric properties via borazine (B$_3$N$_3$)-ring doping. As bandgap engineering can be obtained with this doping, the thermoelectric properties of graphene are significantly enlarged, albeit at the cost of reduced conductance. The effects observed are not only dependent on the concentration of BN within the graphene lattice but are also notably influenced by the relative rotational alignment of the BN rings. Furthermore, the effect of the distribution and rotational disorder are considered, showing reduced electronic conductance compared to the periodic case highlighting the importance of precise control over the doping parameters of BN-ring. Lastly, the thermal lattice conductance is estimated revealing a substantial reduction of up to 40$\%$ compared to pristine graphene opening up the possibility of enhancing the thermoelectric efficiency of BNC materials. The present theoretical approach highlights how BN-ring doping can refine the thermoelectric properties of 2D graphene, offering a pathway for enhancing its suitability in practical thermoelectric applications.