Enhanced thermoelectric performance of SWNT/organic small molecule (OSM) hybrid materials by tuning of the energy level of OSMs

2020 ◽  
Vol 8 (37) ◽  
pp. 12795-12799
Author(s):  
Tae-hoon Kim ◽  
Jae Gyu Jang ◽  
Jong-In Hong
Keyword(s):  
Energy Level ◽  
Seebeck Coefficient ◽  
Hybrid Materials ◽  
Small Molecule ◽  
Power Factor ◽  
Thermoelectric Performance

The SWNT/dmBT hybrid with a low barrier of 0.06 eV between SWNT and dmBT showed a maximum Seebeck coefficient of 78.5 μV K−1 and a power factor of 183.9 μW m−1 K−1, 1.5 and 4.6 times higher compared to the SWNT/dCNBT with a high barrier of 0.64 eV.

Significant enhancement in the Seebeck coefficient and power factor of thermoelectric polymers by the Soret effect of polyelectrolytes

2018 ◽  
Vol 6 (40) ◽  
pp. 19347-19352 ◽  
Author(s):  
Xin Guan ◽  
Hanlin Cheng ◽  
Jianyong Ouyang
Keyword(s):  
Seebeck Coefficient ◽  
Power Factor ◽  
Soret Effect ◽  
Ion Accumulation ◽  
Thermoelectric Performance ◽  
Significant Enhancement ◽  
Energy Filtering ◽  
Polyelectrolyte Layer

The thermoelectric performance of PEDOT:PSS can be significantly enhanced by energy filtering arising from ion accumulation in the polyelectrolyte layer.

scholarly journals Improving the Thermoelectric Properties of the Half-Heusler Compound VCoSb by Vanadium Vacancy

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1637 ◽  
Author(s):  
Lihong Huang ◽  
Junchen Wang ◽  
Xiaobo Mo ◽  
Xiaobo Lei ◽  
Sude Ma ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Secondary Phase ◽  
Thermoelectric Performance ◽  
Heusler Compound

The effects of V vacancy on the thermoelectric performance of the half-Heusler compound VCoSb have been investigated in this study. A certain amount of CoSb secondary phase is generated in the VCoSb matrix when the content of V vacancy is more than 0.1 at%. According to the results, a ZT value of 0.6, together with a power factor of 29 μW cm−1 K−2 at 873 K, were achieved for the nonstoichiometric sample V0.9CoSb. This proved that moderate V vacancy could improve the thermoelectric (TE) properties of VCoSb. The noticeable improvements are mainly owing to the incremental Seebeck coefficient, which may benefit from the optimized carrier concentration. However, too much V vacancy will result in more CoSb impurity and deteriorate the TE performances of VCoSb owing to the increased thermal conductivity.

Carrier dilution in TiSe2 based intergrowth compounds for enhanced thermoelectric performance

2015 ◽  
Vol 3 (40) ◽  
pp. 10451-10458 ◽  
Author(s):  
S. R. Bauers ◽  
D. R. Merrill ◽  
D. B. Moore ◽  
D. C. Johnson
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Thermoelectric Performance ◽  
Thermoelectric Power Factor

Synthesis and electrical properties of kinetically stabilized (PbSe)1+δ(TiSe2)n thin-film intergrowths are reported for 1 ≤ n ≤ 18. The carriers donated to the TiSe2 from PbSe are diluted with increasing n, leading to a systematic increase in the Seebeck coefficient and thermoelectric power factor.

scholarly journals High Thermoelectric Performance Achieved in Sb-Doped GeTe by Manipulating Carrier Concentration and Nanoscale Twin Grains

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 406
Author(s):  
Chao Li ◽  
Haili Song ◽  
Zongbei Dai ◽  
Zhenbo Zhao ◽  
Chengyan Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
High Power ◽  
Hole Concentration ◽  
Thermoelectric Performance ◽  
Significant Suppression ◽  
Valence States ◽  
High Power Factor ◽  
Sb Doping

Lead-free and eco-friendly GeTe shows promising mid-temperature thermoelectric applications. However, a low Seebeck coefficient due to its intrinsically high hole concentration induced by Ge vacancies, and a relatively high thermal conductivity result in inferior thermoelectric performance in pristine GeTe. Extrinsic dopants such as Sb, Bi, and Y could play a crucial role in regulating the hole concentration of GeTe because of their different valence states as cations and high solubility in GeTe. Here we investigate the thermoelectric performance of GeTe upon Sb doping, and demonstrate a high maximum zT value up to 1.88 in Ge0.90Sb0.10Te as a result of the significant suppression in thermal conductivity while maintaining a high power factor. The maintained high power factor is due to the markable enhancement in the Seebeck coefficient, which could be attributed to the significant suppression of hole concentration and the valence band convergence upon Sb doping, while the low thermal conductivity stems from the suppression of electronic thermal conductivity due to the increase in electrical resistivity and the lowering of lattice thermal conductivity through strengthening the phonon scattering by lattice distortion, dislocations, and twin boundaries. The excellent thermoelectric performance of Ge0.90Sb0.10Te shows good reproducibility and thermal stability. This work confirms that Ge0.90Sb0.10Te is a superior thermoelectric material for practical application.

Investigating Power Factor of CaMnO3 Added Carbon Nanotubes

2016 ◽  
Vol 675-676 ◽  
pp. 171-174 ◽  
Author(s):  
Meena Rittiruam ◽  
Arthorn Vora-Ud ◽  
Tosawat Seetawan
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Resistivity ◽  
Electronic Structure ◽  
Energy Level ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
Energy Gap ◽  
Boltzmann Distribution ◽  
Density Of State ◽  
High Electrical Resistivity

CaMnO3 (CMO) thermoelectric material is large Seebeck coefficient but high electrical resistivity. To reduce electrical resistivity by adding carbon nanotubes (CNTs) in CMO material and may be decreased Seebeck coefficient. In this work, we simulated electronic structure of CMO and CNTs-added CMO by DV-Xα method to investigation of power factor and enhance the thermoelectric performance. The Seebeck coefficient and electrical resistivity were calculated by Maxwell-Boltzmann distribution and Mott’s law to investigate power factor. The DV-Xa calculated show the energy level and density of state (DOS) of CMO and CNTs-added CMO demonstrated that the energy gap reduces from 3.33 eV to 0.19 eV affect to enhance the power factor of CMO with Seebeck coefficient and electrical resistivity are decreases. The power factor of CNTs-added CMO was increased with increasing CNTs content.

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

Materials ◽  
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.

scholarly journals Two impurity energy level regulation leads to enhanced thermoelectric performance of Ag1−xCdxIn5Se8

RSC Advances ◽  
2017 ◽  
Vol 7 (21) ◽  
pp. 12719-12725 ◽  
Author(s):  
Xingchen Shen ◽  
Nusrat Shaheen ◽  
Aijuan Zhang ◽  
Dingfeng Yang ◽  
Wei Yao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Energy Level ◽  
Thermoelectric Power ◽  
Thermoelectric Material ◽  
Power Factor ◽  
Electron Concentration ◽  
Thermoelectric Performance ◽  
Thermoelectric Power Factor ◽  
Low Thermal Conductivity

AgIn5Se8 is a promising thermoelectric material due to its low thermal conductivity. By incorporating Cd2+ ions at Ag+ lattice sites; the electron concentration is increased, resulting in greatly enhanced electrical conductivity, and a high thermoelectric power factor.

scholarly journals Impact of Fermi Surface Shape Engineering on Calculated Electronic Transport Properties of Bi-Sb-Te

2021 ◽  
Vol 59 (1) ◽  
pp. 54-60
Author(s):  
Sang-il Kim ◽  
Jong-Chan Lim ◽  
Heesun Yang ◽  
Hyun-Sik Kim
Keyword(s):  
Electrical Conductivity ◽  
Fermi Surface ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Effective Mass ◽  
Power Factor ◽  
Electronic Transport ◽  
Surface Shape ◽  
Thermoelectric Performance ◽  
Electronic Transport Properties

Using thermoelectric refrigerators can address climate change because they do not utilize harmful greenhouse gases as refrigerants. To compete with current vapor compression cycle refrigerators, the thermoelectric performance of materials needs to be improved. However, improving thermoelectric performance is challenging because of the trade-off relationship between the Seebeck coefficient and electrical conductivity. Here, we demonstrate that decreasing conductivity effective mass by engineering the shape of the Fermi surface pocket (non-parabolicity factor) can decouple electrical conductivity from the Seebeck coefficient. The effect of engineering the non-parabolicity factor was shown by calculating the electronic transport properties of a state-of-the-art Bi-Sb-Te ingot via two-band model with varying non-parabolicity. The power factor (the product of the Seebeck coefficient squared and electrical conductivity) was calculated to be improved because of enhanced electrical conductivity, with an approximately constant Seebeck coefficient, using a non-parabolicity factor other than unity. Engineering the non-parabolicity factor to achieve lighter conductivity effective mass can improve the electronic transport properties of thermoelectric materials because it only improves electrical conductivity without decreasing the Seebeck coefficient (which is directly proportional to the band mass of a single Fermi surface pocket and not to the conductivity effective mass). Theoretically, it is demonstrated that a thermoelectric figure-of-merit <i>zT</i> higher than 1.3 can be achieved with a Bi-Sb-Te ingot if the non-parabolicity factor is engineered to be 0.2. Engineering the non-parabolicity factor is another effective band engineering approach, similar to band convergence, to achieve an effective improvement in power factor.

Enhanced thermoelectric performance in c-axis oriented Ca3Co4O9 films by Ag addition through multiple annealing

2016 ◽  
Vol 30 (15) ◽  
pp. 1650202
Author(s):  
Shengman Liu ◽  
Caixia Zhu ◽  
Xianghong Ge ◽  
Tingtai Wang ◽  
Junlan Feng ◽  
...  
Keyword(s):  
Seebeck Coefficient ◽  
Single Crystal ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Chemical Solution Deposition ◽  
Thermoelectric Performance ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Ag Addition

The [Formula: see text]-axis oriented Ca3Co4O9 (CCO) films without and with 5 wt.% Ag addition were prepared by chemical solution deposition (CSD) through multiple annealing processing on single crystal LaAlO3 (001) substrates. With Ag addition, the resistivity at 300 K is decreased to 2.25 m[Formula: see text]cm, the Seebeck coefficient at 300 K is enhanced to 106 [Formula: see text]V/K and the power factor at 300 K can reach as high as 0.5 mW[Formula: see text]K[Formula: see text]m[Formula: see text], which is the highest value among CCO films prepared by CSD. The results suggest that Ag addition is a very effective route to improve the thermoelectric properties of CCO films through multiple annealing processing.

scholarly journals Formation and Evaluation of Silicon Substrate with Highly-Doped Porous Si Layers Formed by Metal-Assisted Chemical Etching

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yijie Li ◽  
Nguyen Van Toan ◽  
Zhuqing Wang ◽  
Khairul Fadzli Bin Samat ◽  
Takahito Ono
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Contact Resistance ◽  
Power Factor ◽  
Chemical Etching ◽  
Porous Si ◽  
Si Substrate ◽  
Si Substrates ◽  
Output Performance ◽  
Metal Assisted Chemical Etching

AbstractPorous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact between porous Si and metal is one reason for the reduction of electrical conductivity. In this paper, p- and n-type porous Si were formed on Si substrate by metal-assisted chemical etching. To decrease contact resistance, p- and n-type spin on dopants are employed to dope an impurity element into p- and n-type porous Si surface, respectively. Compared to the Si substrate with undoped porous samples, ohmic contact can be obtained, and the electrical conductivity of doped p- and n-type porous Si can be improved to 1160 and 1390 S/m, respectively. Compared with the Si substrate, the special contact resistances for the doped p- and n-type porous Si layer decreases to 1.35 and 1.16 mΩ/cm2, respectively, by increasing the carrier concentration. However, the increase of the carrier concentration induces the decline of the Seebeck coefficient for p- and n-type Si substrates with doped porous Si samples to 491 and 480 μV/K, respectively. Power factor is related to the Seebeck coefficient and electrical conductivity of thermoelectric material, which is one vital factor that evaluates its output performance. Therefore, even though the Seebeck coefficient values of Si substrates with doped porous Si samples decrease, the doped porous Si layer can improve the power factor compared to undoped samples due to the enhancement of electrical conductivity, which facilitates its development for thermoelectric application.

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