Enhanced thermoelectric figure of merit in edge-disordered zigzag graphene nanoribbons

The thermoelectric properties of zigzag graphene nanoribbons (ZGNRs) are sensitive to chemical modification. In this study, we employed density functional theory (DFT) combined with the nonequilibrium green’s function (NEGF) formalism to investigate the thermoelectric properties of a ZGNR system by impurity substitution of single and double nitrogen (N) atoms into the edge of the nanoribbon. N-doping changes the electronic transmission probability near the Fermi energy and suppresses the phononic transmission. This results in a modified electrical conductance, thermal conductance, and thermopower. Ultimately, simultaneous increase of the thermopower and suppression of the electron and phonon contributions to the thermal conductance leads to the significant enhancement of the figure of merit in the perturbed (i.e., doped) system compared to the unperturbed (i.e., nondoped) system. Increasing the number of dopants not only changes the nature of transport and the sign of thermopower but also further suppresses the electron and phonon contributions to the thermal conductance, resulting in an enhanced thermoelectric figure of merit. Our results may be relevant for the development of ZGNR devices with enhanced thermoelectric efficiency.

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Enhancement of thermoelectric figure of merit in zigzag graphene nanoribbons with periodic edge vacancies

International Journal of Modern Physics B ◽

10.1142/s0217979217501247 ◽

2017 ◽

Vol 31 (15) ◽

pp. 1750124 ◽

Cited By ~ 3

Author(s):

D. V. Kolesnikov ◽

O. G. Sadykova ◽

V. A. Osipov

Keyword(s):

Seebeck Coefficient ◽

Figure Of Merit ◽

Nearest Neighbor ◽

Graphene Nanoribbons ◽

Tight Binding ◽

Dynamical Matrix ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure ◽

Tight Binding Approximation ◽

Zigzag Graphene Nanoribbons

The influence of periodic edge vacancies and antidot arrays on the thermoelectric properties of zigzag graphene nanoribbons (ZGNRs) are investigated. Using Green’s function method, the tight-binding approximation for the electron Hamiltonian and the 4th nearest neighbor approximation for the phonon dynamical matrix, we calculate the Seebeck coefficient and the thermoelectric figure of merit. It is found that, at a certain periodic arrangement of vacancies on both edges of zigzag nanoribbon, a finite band gap opens and almost twofold degenerate energy levels appear. As a result, a marked increase in the Seebeck coefficient takes place. It is shown that an additional enhancement of the thermoelectric figure of merit can be achieved by a combination of periodic edge defects with an antidot array.

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Enhancing the thermoelectric figure of merit in engineered graphene nanoribbons

nano Online ◽

10.1515/nano.bjneah.6.119 ◽

2016 ◽

Author(s):

Hatef Sadeghi ◽

Sara Sangtarash ◽

Colin Lambert

Keyword(s):

Figure Of Merit ◽

Graphene Nanoribbons ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure

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Enhancing the thermoelectric figure of merit in engineered graphene nanoribbons

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.6.119 ◽

2015 ◽

Vol 6 ◽

pp. 1176-1182 ◽

Cited By ~ 43

Author(s):

Hatef Sadeghi ◽

Sara Sangtarash ◽

Colin J Lambert

Keyword(s):

Thermoelectric Properties ◽

Fermi Energy ◽

Figure Of Merit ◽

Graphene Nanoribbons ◽

The Other ◽

Monolayer Graphene ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure ◽

Inner Surface ◽

Current Flows

We demonstrate that thermoelectric properties of graphene nanoribbons can be dramatically improved by introducing nanopores. In monolayer graphene, this increases the electronic thermoelectric figure of merit ZT e from 0.01 to 0.5. The largest values of ZT e are found when a nanopore is introduced into bilayer graphene, such that the current flows from one layer to the other via the inner surface of the pore, for which values as high as ZT e = 2.45 are obtained. All thermoelectric properties can be further enhanced by tuning the Fermi energy of the leads.

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Enhanced thermoelectric figure of merit in assembled graphene nanoribbons

Physical Review B ◽

10.1103/physrevb.86.115438 ◽

2012 ◽

Vol 86 (11) ◽

Cited By ~ 65

Author(s):

Liangbo Liang ◽

Eduardo Cruz-Silva ◽

Eduardo Costa Girão ◽

Vincent Meunier

Keyword(s):

Figure Of Merit ◽

Graphene Nanoribbons ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure

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Spin thermoelectric effects of new-style one-dimensional carbon-based nanomaterials

Characterization and Application of Nanomaterials ◽

10.24294/can.v4i1.1323 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Yushen Liu ◽

Jinfu Feng ◽

Xuefeng Wang

Keyword(s):

Figure Of Merit ◽

Graphene Nanoribbons ◽

Thermal Conductance ◽

Transmission Function ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Effects ◽

Thermoelectric Figure ◽

One Dimensional ◽

Carbon Chains ◽

Carbon Based Nanomaterials

Based on first-principles methods, the authors of this paper investigate spin thermoelectric effects of one-dimensional spin-based devices consisting of zigzag-edged graphene nanoribbons (ZGNRs), carbon chains and graphene nanoflake. It is found that the spin-down transmission function is suppressed to zero, while the spin-up transmission function is about 0.25. Therefore, an ideal half-metallic property is achieved. In addition, the phonon thermal conductance is obviously smaller than the electronic thermal conductance. Meantime, the spin Seebeck effects are obviously enhanced at the low-temperature regime (about 80K), resulting in the fact that spin thermoelectric figure of merit can reach about 40. Moreover, the spin thermoelectric figure of merit is always larger than the corresponding charge thermoelectric figure of merit. Therefore, the study shows that they can be used to prepare the ideal thermospin devices.

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High thermoelectric figure of merit and thermopower in layered perovskite oxides

Physical Review Materials ◽

10.1103/physrevmaterials.3.022401 ◽

2019 ◽

Vol 3 (2) ◽

Cited By ~ 6

Author(s):

Vincenzo Fiorentini ◽

Roberta Farris ◽

Edoardo Argiolas ◽

Maria Barbara Maccioni

Keyword(s):

Figure Of Merit ◽

Perovskite Oxides ◽

Layered Perovskite ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure ◽

Layered Perovskite Oxides

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Extraordinary thermoelectric performance of NaBaBi with degenerate and highly non-parabolic bands compared to LiBaSb and Bi2Te3

Sustainable Energy & Fuels ◽

10.1039/d0se01817a ◽

2021 ◽

Author(s):

Enamul Haque

Keyword(s):

Fermi Level ◽

Figure Of Merit ◽

Thermoelectric Performance ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure

This article reports the extraordinary thermoelectric figure of merit (ZT) of NaBaBi: degenerate bands, instead of the valley degeneracy of Bi2Te3, highly non-parabolic bands, and low DOS near the Fermi level of NaBaBi lead to an extraordinary ZTisotropic ≈ 1.60 at 350 K.

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Influence of multi-sintering on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

Modern Physics Letters B ◽

10.1142/s0217984920500190 ◽

2019 ◽

Vol 34 (02) ◽

pp. 2050019 ◽

Cited By ~ 2

Author(s):

Y. Zhang ◽

M. M. Fan ◽

C. C. Ruan ◽

Y. W. Zhang ◽

X.-J. Li ◽

...

Keyword(s):

Thermal Conductivity ◽

Thermoelectric Properties ◽

Figure Of Merit ◽

Phonon Scattering ◽

Sintered Sample ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure ◽

The Third ◽

Ceramic Samples ◽

Optimum Formula

[Formula: see text] ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit [Formula: see text] of [Formula: see text]. The optimum [Formula: see text] value of 0.26 is achieved at 923 K by the third sintered sample.

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