Intrinsic thermoelectric properties in biphenylene nanoribbons and effect of lattice defects

Intrinsic thermoelectric properties in biphenylene nanoribbons (BNRs) and effect of lattice defects are investi-gated by employing the nonequilibrium Green's function. A comparative analysis on intrinsic thermoelectric properties between graphene nanoribbons (GNRs) and BNRs is performed. Results show that although the Seebeck coefficient of BNRs is lower than that of the corresponding GNRs, BNRs exhibit better thermoelectric properties than the corresponding GNRs due to the lower phonon thermal conductance of BNRs. It is also shown that the lattice defects can enhance the maximum ZT (ZTmax) in armchair BNRs (ABNRs) and zigzag BNRs (ZGNRs), where the ZTmax can be up to 1.1 and 0.4 at T = 300 K, respectively. Moreover, such the enhancement in defective ZBNRs is more remarkable than that in defective ABNRs. Theoretical analysis reveals that this enhancement of the ZTmax originates from the substantial reduction of phonon thermal conductance due to the strong backscattering by the highly localized phonon states around the lattice defects.