Effect of dual Nitrogen doping on the electronic, thermodynamic, transport and thermoelectric properties of graphene

Abstract

Electronic, thermodynamic, transport, and thermoelectric properties of pristine graphene (C8) and graphene doped with dual nitrogen (N) atoms in three different configurations were theoretically studied. All three configurations display a direct band gap and are n-type semiconductors. Notably, at room temperature, N3-doped graphene has a greater Seebeck coefficient (S) than C8, although N1 and N2 have lower S values. Furthermore, the power factor (PF) for all three structures rapidly increases, especially at high temperatures, with C8's PF decreasing at 300 K. For N1, N2, and N3, the electronic thermal conductivity (κe) follows the Wiedemann-Franz rule, increasing with increasing temperature. Due to N defect-induced heat transfer scattering, lattice thermal conductivity (κL) diminishes exponentially with temperature. The figure of merit (ZT) for N3 doping peaks at 550 K, outperforming N1 and N2 by a large margin (103-106 times) and then drops at higher temperatures due to electronic thermal conductivity impacts.