Improve thermoelectric properties of graphene nanoribbons based on resonant structure engineering

Resonant graphene nanoribbons (GNRs), consisting of GNRs with engineered resonant side structures, offer a promising route to suppress low-frequency phonon transport and significantly reduce lattice thermal conductivity, thereby enhancing thermoelectric performance. In this work, we investigate the thermoelectric properties of resonant GNRs using molecular dynamics simulations combined with the linear-scaling quantum transport (LSQT) method, explicitly accounting for electron–phonon coupling. Our results indicate that while resonance structures moderately degrade the electrical conductivity and Seebeck coefficient, they dramatically reduce the lattice thermal conductivity, which far outweighs the electronic transport losses and leads to an overall improvement in thermoelectric performance. By optimizing the key geometric parameters of the resonant structures — height (H_Re) and period (L_p) — we achieve a peak ZT of 0.135 at H_Re = 1.5 nm and L_p = 7 nm, representing a threefold enhancement over pristine GNRs. This improvement stems from the decoupling of phonon and electron transport, enabled by resonant phonon localization. Our findings not only elucidate the role of resonant structures in tuning thermoelectric properties but also provide a general strategy for designing high-performance low-dimensional thermoelectric materials through targeted phonon engineering.