Enhancing the thermoelectric performance of gamma-graphyne nanoribbons by introducing edge disorder

Abstract

Structure disorder especially edge disorder is unavoidable during the fabrication of nanomaterials. In this paper, using the non-equilibrium Green's function method, we investigate the influence of edge disorder on the thermoelectric performance of gamma(γ)-graphyne nanoribbons (GYNRs). Our results show that the high Seebeck coefficient in pristine γ-GYNR could still be preserved although edge disorder is introduced into the structure. Meanwhile, in these edge-disordered nanoribbons the suppression of thermal conductance including electronic and phononic contributions outweighs the reduction of electronic conductance. These two positive effects combine together, and finally boost the thermoelectric conversion efficiency of γ-GYNRs. The thermoelectric figure of merit ZT in the edge-disordered γ-GYNRs (the length and width are about 55.68 and 1.41 nm) could approach 2.5 at room temperature, and can even reach as high as 4.0 at 700 K, which is comparable to the efficiency of conventional energy conversion methods. The findings in this paper indicate that the edge-disordered γ-GYNRs are a promising candidate for efficient thermoelectric energy conversion and thermal management of nanodevices.

Thermoelectric Properties of Pristine Graphyne and the BN-Doped Graphyne Family

“…This wide band gap indicates that double vacancy in γ-graphyne will lead to a large Seebeck coefficient. Literature survey also reveals that the introduction of the defective environment in the γ-graphyne nanoribbon system significantly enhances the thermoelectric performance of the material. − Therefore, we expect further enhancement with defects in our structures too.…”

Thermal Transport in Two-Dimensional Heterostructures

“…On the other hand, (Tran et al, 2015) found the phonon conductance is significantly inhibited in GNRs with BNNRs branches, but the electron transmission is equivalent to that in pristine GNRs, similar to that in vdW graphene junction (Hung Nguyen et al, 2014). Moreover, (Cui et al, 2018b) reported that the ZT value of graphyne nanoribbons with edge disorder can achieve 2.5 because of the strong phonon-boundary scatterings. Along the way, the MoS2/WSe 2 (Jia et al, 2019) and graphene/ MoS 2 vdW heterostructures (Sadeghi et al, 2016) have been proposed to construct thermoelectronic devices with excellent performance.…”

Graphyne and graphdiyne nanoribbons: from their structures and properties to potential applications

“…Edge disorder can greatly improve the thermoelectric conversion rate of g-GYNRs. 121,122 Different defect structures and different defect locations also have a critical effect on the power factor and thermal conductivity suppression of GYNRs and GDYNRs. Researchers can significantly enhance the thermoelectric properties of g-GYNRs, through edge defect modulation (by a factor greater than 1.2 at room temperature) (Fig.…”

“…(e) The maximum value of the edge disordered g-GYNR thermoelectric superiority is a function of the length of the central region (M = 0.3, the central region width is fixed at 1.41 nm) and the width (M = 0.3, the central region length is fixed at 13.92 nm), where the shaded part is an error bar. The dashed lines represent the corresponding values of the original g-GYNR 122. (f) Thermal power (ZT) and phonon thermal conductance (P) after the original and edge defect modulation g-GYNR (W = 3) 111.…”