Enhancement of thermoelectric performance in graphenylene nanoribbons by suppressing phonon thermal conductance: the role of phonon local resonance.

Based on the method of non-equilibrium Green's function, we investigate the thermal transport and thermoelectric properties of graphenylene nanoribbons (GRNRs) with different width and chirality. The results show that the thermoelectric (TE) performance of GRNRs significantly increases with decreasing ribbon width, which stems from the reduction of thermal conductance. In addition, by changing the ribbon width and chirality, the figure of merit (ZT) can be controllably manipulated and maximized up to 0.45 at room temperature. Moreover, it is found that theZTvalue of GRNRs with branched structure can reach 1.8 at 300 K and 3.4 at 800 K owing to the phonon local resonance. Our findings here are of great importance for thermoelectric applications of GRNRs.