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

Polymers ◽  
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.

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

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2849 ◽  
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.

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

2008 ◽  
Vol 368-372 ◽  
pp. 559-561 ◽  
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.

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

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.

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

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1143 ◽  
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.

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

2006 ◽  
Vol 510-511 ◽  
pp. 1086-1089 ◽  
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.

The Effect of Nano-SiO2 Addition on Electrical Properties of the Thermoelectric Compound Ca3Co4O9

2012 ◽  
Vol 465 ◽  
pp. 292-295 ◽  
Author(s):  
Wei Wei Sun ◽  
Wen Hao Fan ◽  
Shao Ping Chen ◽  
Yi Yun Li ◽  
Qing Sen Meng
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Seebeck Coefficient ◽  
Electric Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Sio2 Content ◽  
Nano Sio2

Abstract. Ca3CO4O9/x wt.%SiO2 composites were prepared by using field-activated pressure-assisted synthesis(FAPAS) process. The effects of nano-SiO2 addition on the microstructure and thermoelectric properties of the Ca3CO4O9 were investigated. With an increasing of the of SiO2 content, the size of Ca3Co4O9 particles decreased. The Seebeck coefficient decreased after the doping of nano-SiO2. The electrical conductivity firstly increased and then decreased with increasing amount of nano-SiO2 and the highest value belong to the Ca3CO4O9/0.5 wt.% SiO2 - sample. With the highest electric conductivity and slightly decreased Seebeck coefficient, the Ca3CO4O9/0.5 wt.%SiO2-sample achieved the highest power factor of 0.349 mw/mk2 at 800 °C, which is 8% higher than the value of pure Ca3CO4O9 reported in the literature.

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

2021 ◽  
pp. 2150290
Author(s):  
Nasir Shehzad ◽  
Lixin Zhang ◽  
Shahzad Saeed ◽  
Anwar Ali
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Boltzmann Transport ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Energy Applications ◽  
High Power Factor ◽  
High Seebeck Coefficient

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.

scholarly journals A comparative study on thermoelectric properties of ZnO bulks and thin films

2020 ◽  
Vol 23 (4) ◽  
pp. 788-794
Author(s):  
Dai Cao Truong ◽  
Anh Tuan Thanh Pham ◽  
Oanh Kieu Truong Le ◽  
Dung Van Hoang ◽  
Truong Huu Nguyen ◽  
...  
Keyword(s):  
Thin Film ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Comparative Study ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
The Comparative Study

Introduction: Zinc oxide (ZnO) is well-known as a promising thermoelectric material owing to its safety, inexpensiveness, and thermal stability. This research provides an overview of thermoelectric potentials, including structure, electrical conductivity, Seebeck coefficient, and power factor of pure ZnO semiconductor synthesized in bulk and thin-film forms. Methods: The ZnO bulk was synthesized by solid-state reaction at high temperature, while the thin film was prepared by d.c. magnetron sputtering technique. The temperature-dependent thermoelectric properties of all the samples were measured by the Seebeck LSR-3 system. The crystallographic and surface morphological information of the samples were obtained by using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. Results: The XRD results confirm that both the bulk and thin-film have polycrystalline structure and characteristics of hexagonal-wurtzite ZnO. Through the FESEM observation, the bulk is well densified under high-temperature condition, while the thin-film achieve good orientation and close-packed grains. At 573 K, the obtained thermoelectric properties (electrical conductivity, Seebeck coefficient, and power factor) are respectively 352.4 S/cm, -89.5 µV/K and 282.5 µW/mK2 for the ZnO bulk; and 289 S/cm, -113.8 µV/K and 374.3 µW/mK2 for the ZnO film. Conclusion: The comparative study shows the good thermoelectric potential of ZnO material in both forms of bulk and thin film. Among them, the thin film has better results, especially in the Seebeck coefficient and power factor than one.

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.

The Influence of Silicon Dopant and Processing on Thermoelectric Properties of B4C Ceramics

1998 ◽  
Vol 545 ◽  
Author(s):  
Ke-Feng Cai ◽  
Ce-Wen Nan ◽  
Xin-Min Min
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Room Temperature ◽  
A Value ◽  
Si Doped

AbstractB4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity and Seebeck coefficient of the samples are measured from room temperature up to 1500K. The electrical conductivity increases with temperature, and more rapidly after 1300K; the Seebeck coefficient of the ceramics also increases with temperature and rises to a value of about 320μVK−1. The value of the figure of merit of Si-doped B4C rises to about 4 × 10−4K−1 at 1500K.

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