Enhancement of thermoelectric performance in β-graphyne nanoribbons by suppressing phononic thermal conductance

The thermoelectric properties of the defective β-graphyne nanoribbons are investigated by using the nonequilibrium Green’s function method. The results show that the thermoelectric properties of β-graphyne nanoribbons can be enhanced observably by introducing defects. The figure of merit of defective β-graphyne nanoribbons can reach 1.64, which is about six times larger than that of perfect β-graphyne nanoribbons. This results from the rapid decrease of phononic thermal conductance in defective β-graphyne nanoribbons due to the strong phonon-defect scattering and the intensive localization of phonons.