▎ 摘　　要

In view of the experimental breakthrough and unique geometric structure, through using the nonequilibrium Green's function combined with density functional based tight-binding method, in this paper we investigate the thermoelectric performance of four metastable graphene allotrope nanoribbons. Compared to graphene nanoribbon, our calculations show that the four metastable graphene allotrope nanoribbons possess larger electronic band gap and Seebeck coefficient. Meanwhile, owing to intrinsic distortion structure, the phonon transport in these metastable nanoribbons is suppressed, and gives rise to lower thermal conductance. Such synergy effects make them hosting better thermoelectric conversion efficiency, for instance, the room temperature thermoelectric figure of merits in phagraphene and tetra penta-hepta-graphene nanoribbons is about 0.32 and 0.33, while that is merely 0.1 for graphene nanoribbon. The results not only reveal the intrinsic thermoelectric properties of the four metastable graphene allotrope nanoribbons, but also provide useful guidelines in designing related thermoelectric devices. Graphic abstract