Enhancement of thermoelectric properties in graphene nanoribbons modulated with stub structures

Abstract

The thermoelectric properties in graphene nanoribbons modulated with stub structures are studied using atomistic simulation of electron and phonon transport. The results show that the phonon transport is dramatically suppressed by the elastic scattering of the stub structure; while the thermopower S can be enhanced by a few times of magnitude. This leads to a strong enhancement of the figure of merit (ZT). Moreover, it is found that the enhancement of ZT can be effectively tuned by modulating geometric parameters of the stub and edge shapes, which offers an effective way to improve the thermoelectric performance of graphene nanoribbons.

Thermal transport in nanostructures

“…[191][192][193] Benefit from the reduced thermal conductivity and/or increased power factor, enhanced thermoelectric performance have been observed in 1D NWs, [194][195][196][197] NTs 55,198 and quasi-2D nanoribbons. 97,117,[199][200][201][202] …”

“…There are rich physical phenomena about thermal property of GNRs. The effects of size, [95][96][97][98] defects, 99, 100 doping, 101,102 shape, 103,104 stress/strain,, [105][106][107][108] substrates, 109 inter-layer interactions, [110][111][112] nanoscale junctions, 113 chirality, 114 topological structure, 115 edge effect, [116][117][118][119] foldings (gradfolds), 23,120 etc. on thermal conductivity of nanoribbons [121][122][123][124][125][126][127][128] have been widely studied.…”

Atomic-Scale Mapping of Thermoelectric Power on Graphene: Role of Defects and Boundaries

“…Indeed, the thermoelectric properties of this two-dimensional material have recently been extensively studied for revealing the intrinsic properties of Dirac electrons and elucidating effects of defects on its unique electronic structures. [14][15][16][17][18][19][20][21] In those studies, thermoelectric measurements are usually carried out with a technique developed by Kim et al 22 In this technique, a local heater made of a metal line produces a temperature difference ΔT between the two ends of a sample, which gives rise to a thermoelectric voltage V th measured by electrodes defined by standard electron beam lithography and nanofabrication process. The thermopower is obtained as the ratio of V th to ΔT across a sample.…”

Recent advances in CNT/graphene based thermoelectric polymer nanocomposite: A proficient move towards waste energy harvesting

“…It has been shown that edge roughness and vacancies could reduce the thermal conductivity and thus improves the Seebeck coefficient. However, the ZT is still suppressed by the reduced electrical conductivity which suggests the use of kinked GNRs [153][154][155][156][157]. The first [158] synthesis of kinked GNRs was realized that a simple, surface-based bottom-up chemical process was introduced.…”