Comparative study of functionalized MXenes Mn+1CnO2 (M = Ti, Zr and Hf, n = 1, 2 and 3): A proposal for renewable energy applications

Using first-principles calculations, we studied the electronic, structural and thermoelectric properties of two-dimensional (2D) MXenes [Formula: see text] ([Formula: see text] = Ti, Zr and Hf, [Formula: see text], 2 and 3). The calculations are carried out within the generalized gradient approximation (GGA). We have calculated the Boltzmann transport equation for finding the thermoelectric properties such as power factor, Seebeck coefficient and electrical conductivity. For [Formula: see text], these materials behave as semiconductors having an indirect bandgap nature. In contrast, for [Formula: see text] these materials show metallic behavior. Out of these MXenes, we found that Ti2CO2 has a high Seebeck coefficient value, whereas the electrical conductivity of Ti4C3O2 is exceptionally high. While among all these compounds, Ti2CO2 and Hf4C3O2 have a high power factor in the 300–1200-K temperature range.

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Preparation and Thermoelectric Properties of Graphite/poly(3,4-ethyenedioxythiophene) Nanocomposites

Energies ◽

10.3390/en11102849 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2849 ◽

Cited By ~ 5

Author(s):

Yong Du ◽

Haixia Li ◽

Xuechen Jia ◽

Yunchen Dou ◽

Jiayue Xu ◽

...

Keyword(s):

Electrical Conductivity ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Power Factor ◽

Oxidative Polymerization ◽

Polymerization Process ◽

Measurement Temperature ◽

Temperature Range ◽

Different Content

Graphite/poly(3,4-ethyenedioxythiophene) (PEDOT) nanocomposites were prepared by an in-situ oxidative polymerization process. The electrical conductivity and Seebeck coefficient of the graphite/PEDOT nanocomposites with different content of graphite were measured in the temperature range from 300 K to 380 K. The results show that as the content of graphite increased from 0 to 37.2 wt %, the electrical conductivity of the nanocomposites increased sharply from 3.6 S/cm to 80.1 S/cm, while the Seebeck coefficient kept almost the same value (in the range between 12.0 μV/K to 15.1 μV/K) at 300 K, which lead to an increased power factor. The Seebeck coefficient of the nanocomposites increased from 300 K to 380 K, while the electrical conductivity did not substantially depend on the measurement temperature. As a result, a power factor of 3.2 μWm−1 K−2 at 380 K was obtained for the nanocomposites with 37.2 wt % graphite.

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DFT study of structural, elastic, electronic, magnetic, thermal and transport properties of new multifunctional NiVSn half-Heusler for spintronic and thermoelectric applications

International Journal of Modern Physics B ◽

10.1142/s0217979221502027 ◽

2021 ◽

pp. 2150202

Author(s):

Y. Bouldiab ◽

S. terkhi ◽

Z. Aziz ◽

F. Bendahma ◽

M. A. Bennani ◽

...

Keyword(s):

Transport Properties ◽

Thermoelectric Properties ◽

Density Functional ◽

Extreme Temperature ◽

Ferromagnetic State ◽

Debye Model ◽

Generalized Gradient ◽

Metallic Behavior ◽

Half Metallic ◽

High Seebeck Coefficient

In this work, the first-principles density functional calculations of the structural, elastic, electronic, magnetic, thermal and thermoelectric properties of NiVSn half-Heusler compound are carried out. The exchange and correlation potential are treated by using Generalized Gradient approximation of Perdew, Burke and Ernzerhof (GGA-PBE), GGA plus Tran–Blaha-modified Becke–Johnson (mBJ-GGA) approach and mBJ-GGA+U where U is the Hubbard on-site Coulomb interaction correction (mBJ-GGA+U). Structural calculations revealed that NiVSn is stable in type 1 structure ferromagnetic state. Elastic properties show that our compound is mechanically stable, ductile and anisotropic. The results of the band structures and density of states display a half metallic behavior of NiVSn with an indirect bandgap of 0.476, 0.508 and 0.845 eV by using GGA-PBE, mBJ-GGA, and mBJ-GGA+U, respectively. The total magnetic moment calculated is integer of 1 [Formula: see text]B confirming a half metallic behavior of NiVSn and follows the well-known Slater–Pauling rule ([Formula: see text]); therefore, the studied compound is suitable for application in spintronic fields. The thermodynamic properties such as bulk modulus, the heat capacity, the Debye temperature, and the thermal expansion coefficient are investigated using quasi-harmonic Debye model (QHDM). The thermal results show that NiVSn can be applied in extreme temperature and pressure conditions. The thermoelectric properties are studied employing the BoltzTrap code. The calculated transport properties are very interesting for the spin-down channel with high electrical conductivity, high Seebeck coefficient, and figure of merit value approaching unity. As a result, the half-Heusler alloy NiVSn is a promoter for conventional thermoelectric materials.

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A New Challenge of Polymer Thermoelectric Materials as Ecomaterials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.2329 ◽

2007 ◽

Vol 539-543 ◽

pp. 2329-2332 ◽

Cited By ~ 1

Author(s):

Yoshikazu Shinohara ◽

Yoshio Imai ◽

Yukihiro Isoda ◽

Kentaro Hiraishi ◽

Hachiro Nakanishi

Keyword(s):

Electrical Conductivity ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Oxidative Polymerization ◽

Side Chain ◽

Side Chains ◽

Nmr Analysis ◽

Alkyl Side Chains ◽

High Seebeck Coefficient ◽

Polymer Thermoelectric

Typical conductive polymers of poly(3-alkylthiophenes) were synthesized by oxidative polymerization. Polythiophene with no side chain was also electrolyticaly polymerized. Alkyl side chains were CnH2n+1 with n=4, 6, 8, 12. The regioregularity with the HT linkage was larger than 99% based on NMR analysis. We have evaluated the effect of side chain size on the thermoelectric properties of Seebeck coefficient and electrical conductivity. The results were as follows: 1) Seebeck coefficient decreased with an increasing electrical conductivity. 2) High Seebeck coefficient >1mV/K was observed at low electrical conductivity <10-2S/cm. 3) Small side chains, especially no side chain caused higher thermoelectric properties of polythiophene series.

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Preparation and Thermoelectric Properties of (Ca1-x-yKxBiy)3Co4O9 Ceramic

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.559 ◽

2008 ◽

Vol 368-372 ◽

pp. 559-561 ◽

Cited By ~ 4

Author(s):

Hao Ming Hu ◽

Yuan Deng ◽

Jian Li ◽

Guang Sheng Wang

Keyword(s):

Electrical Conductivity ◽

Seebeck Coefficient ◽

Transport Properties ◽

Thermoelectric Properties ◽

Power Factor ◽

Room Temperature ◽

Raw Materials ◽

Sol Gel ◽

Sintering Process ◽

Conventional Sintering

The precursor of (Ca1-x-yKxBiy)3Co4O9 was synthesized by sol-gel method using nitrate salts as raw materials and citrate acid as agent. The final product was obtained after the precursor was calcined at 800°C for 4 h. The polycrystalline bulk samples were fabricated by a conventional sintering process at 900°C for 12 h. XRD and SEM were used to characterize the microstructures and the composition of the samples. The transport properties of the samples at room temperature were determined by measuring electrical conductivity and Seebeck coefficient. The Bi and K-doped samples show an excellent transport properties even at room temperature. The value of power factor of (Ca0.90K0.075Bi0.025)3Co4O9 reaches 1.42×10-4Wm-1K-2 at 293K, close to the performance of pure Ca3Co4O9 at 1000K.

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Binary treatment of PEDOT:PSS films with nitric acid and imidazolium-based ionic liquids to improve the thermoelectric properties

Materials Advances ◽

10.1039/d0ma00522c ◽

2020 ◽

Vol 1 (9) ◽

pp. 3233-3242

Author(s):

Temesgen Atnafu Yemata ◽

Yun Zheng ◽

Aung Ko Ko Kyaw ◽

Xizu Wang ◽

Jing Song ◽

...

Keyword(s):

Electrical Conductivity ◽

Ionic Liquids ◽

Nitric Acid ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Power Factor ◽

Post Treatment

Binary post-treatment of thermoelectric PEDOT:PSS films with nitric acid and imidazolium-based ionic liquids significantly improves the electrical conductivity and Seebeck coefficient, leading to a power factor of 152 μW m−1 K−2.

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Morphologies Tuning of Polypyrrole and Thermoelectric Properties of Polypyrrole Nanowire/Graphene Composites

Polymers ◽

10.3390/polym10101143 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1143 ◽

Cited By ~ 15

Author(s):

Yong Du ◽

Hao Niu ◽

Jun Li ◽

Yunchen Dou ◽

Shirley Shen ◽

...

Keyword(s):

Electrical Conductivity ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Power Factor ◽

Oxidative Polymerization ◽

Soft Template ◽

Ammonium Bromide ◽

Measured Temperature ◽

Cetyltrimethyl Ammonium ◽

Polymerization Method

Polypyrrole (PPy) with different morphologies (e.g., particles, nanotubes, and nanowires) were successfully prepared by adding or without adding different kinds of surfactants through a chemical oxidative polymerization method, respectively. The results show that the morphologies of PPy can be effectively controlled and have a significantly effects on their thermoelectric properties. The PPy nanowires exhibit the highest electrical conductivity and Seebeck coefficient among the various PPy morphologies, such as particles, nanotubes, and nanowires, so PPy nanowires were chosen to prepare PPy nanowire/graphene thermoelectric composites via a soft template polymerization method using cetyltrimethyl ammonium bromide as the template. Both electrical conductivity and Seebeck coefficient of the PPy nanowire/graphene composites increased as the content of graphene increases from 0 to 20 wt %, and as the measured temperature increases from 300 K to 380 K, which leds to the same trend for the power factor. A highest power factor of 1.01 μWm−1K−2 at ~380 K was obtained for the PPy nanowire/graphene composites with 20 wt % PPy nanowire, which is about 3.3 times higher than that of the pure PPy nanowire.

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Fabrication and Thermoelectric Properties of p-Type Bi1Sb4Te7.5 Alloy Doped with Fe3O4

Materials Science Forum ◽

10.4028/www.scientific.net/msf.510-511.1086 ◽

2006 ◽

Vol 510-511 ◽

pp. 1086-1089 ◽

Cited By ~ 1

Author(s):

Wang Kee Min ◽

Chang Ho Lee ◽

Yong Ho Park ◽

Ik Min Park

Keyword(s):

Thermal Conductivity ◽

Electrical Conductivity ◽

Mechanical Alloying ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Power Factor ◽

Hall Effect Measurement ◽

Small Addition ◽

Z Value ◽

P Type

We investigated the effects of Fe3O4 (0~0.1 wt.%) on the thermoelectric properties of Bi1Sb4Te7.5 alloy prepared by mechanical alloying process. The Seebeck coefficient increased with Fe3O4 content, but the power factor decreased with Fe3O4 content because of the decreased electrical conductivity. The thermal conductivity decreased with Fe3O4. The carrier concentration measured by the Hall effect measurement decreased with Fe3O4. The thermal conductivity of 0.1 wt.% Fe3O4 alloy was 0.814 W/Km, 20%lower than that of Fe3O4 free alloy. As a result, the small addition of Fe3O4 improved the Z value owing to the decreased thermal conductivity by adding Fe3O4. The Z value of 0.01 wt.% Bi1Sb4Te7.5 alloy was 3.1×10-3 /K, the highest value among the prepared alloys.

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Thermoelectric Properties of Poly(3-Alkylthiophenes)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.492-493.141 ◽

2005 ◽

Vol 492-493 ◽

pp. 141-144 ◽

Cited By ~ 9

Author(s):

Yoshikazu Shinohara ◽

K. Ohara ◽

Hachiro Nakanishi ◽

Yoshio Imai ◽

Yukihiro Isoda

Keyword(s):

Electrical Conductivity ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Conductive Polymers ◽

Oxidative Polymerization ◽

Side Chain ◽

Side Chains ◽

Nmr Analysis ◽

Alkyl Side Chains ◽

High Seebeck Coefficient

Typical conductive polymers of poly(3-alkylthiophenes) were synthesized by oxidative polymerization. Alkyl side chains were CnH2n+1 with n=4, 6, 8, 12. The regioregularity with the HT linkage was larger than 99% based on NMR analysis. Completely regioregular head-to-tail (HT) poly(3-alkylthiophenes) were obtained. We have evaluated the effect of side chain size on the thermoelectric properties of Seebeck coefficient and electrical conductivity. The results were as follows: 1) Seebeck coefficient decreased with an increasing electrical conductivity. 2) High Seebeck coefficient >1mV/K was observed at low electrical conductivity <10-2S/cm. 3) The small side chain caused the higher electrical conductivity in the range of electrical conductivity <10- 1S/cm.

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Effects of the Interface between Inorganic and Organic Components in a Bi2Te3–Polypyrrole Bulk Composite on Its Thermoelectric Performance

Materials ◽

10.3390/ma14113080 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3080

Author(s):

Cham Kim ◽

David Humberto Lopez

Keyword(s):

Thermal Conductivity ◽

Electrical Conductivity ◽

Thermal Properties ◽

Seebeck Coefficient ◽

Power Factor ◽

Energy Band ◽

Phonon Scattering ◽

Thermoelectric Performance ◽

High Seebeck Coefficient ◽

Fabrication Condition

We provided a method to hybridize Bi2Te3 with polypyrrole, thus forming an inorganic/organic bulk composite (Bi2Te3–polypyrrole), in which the effects of energy band junction and phonon scattering were expected to occur at the interface of the two components. Bi2Te3–polypyrrole exhibited a considerably high Seebeck coefficient compared to pristine Bi2Te3, and thus it recorded a somewhat increased power factor despite the loss in electrical conductivity caused by the organic component, polypyrrole. Bi2Te3–polypyrrole also exhibited much lower thermal conductivity than pristine Bi2Te3 because of the phonon scattering effect at the interface. We successfully brought about the decoupling phenomenon of electrical and thermal properties by devising an inorganic/organic composite and adjusting its fabrication condition, thereby optimizing its thermoelectric performance, which is considered the predominant property for n-type binary Bi2Te3 reported so far.

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Enhanced Electrical Conductivity and Seebeck Coefficient in PEDOT:PSS via a Two-Step Ionic liquid and NaBH4 Treatment for Organic Thermoelectrics

Polymers ◽

10.3390/polym12030559 ◽

2020 ◽

Vol 12 (3) ◽

pp. 559

Author(s):

Jonathan Atoyo ◽

Matthew R. Burton ◽

James McGettrick ◽

Matthew J. Carnie

Keyword(s):

Electrical Conductivity ◽

Ionic Liquid ◽

Seebeck Coefficient ◽

Conformational Change ◽

Thermoelectric Properties ◽

Power Factor ◽

Molecular Orientation ◽

Combined Treatment ◽

Charge Carriers ◽

Subsequent Reduction

A two-step approach of improving the thermoelectric properties of Poly(3,4-ethylenedioxythiophene)poly(4-styrenesulfonate) (PEDOT:PSS) via the addition of the ionic liquid, 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM:TFSI) and subsequent reduction with NaBH4 is presented. The addition of 2.5 v/v% of EMIM:TFSI to PEDOT:PSS increases the electrical conductivity from 3 S·cm−1 to 1439 S·cm−1 at 40 °C. An additional post treatment using the reducing agent, NaBH4, increases the Seebeck coefficient of the film from 11 µV·K−1 to 30 µV·K−1 at 40 °C. The combined treatment gives an overall improvement in power factor increase from 0.04 µW·m−1·K−2 to 33 µW·m−1·K−2 below 140 °C. Raman and XPS measurements show that the increase in PEDOT:PSS conductivity is due to PSS separation from PEDOT and a conformational change of the PEDOT chains from the benzoid to quinoid molecular orientation. The improved Seebeck coefficient is due to a reduction of charge carriers which is evidenced from the UV–VIS depicting the emergence of polarons.

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