scholarly journals Simultaneous improvement in electrical conductivity and Seebeck coefficient of PEDOT:PSS by N2 pressure-induced nitric acid treatment

RSC Advances ◽  
2018 ◽  
Vol 8 (64) ◽  
pp. 36563-36570 ◽  
Author(s):  
May Thu Zar Myint ◽  
Masaki Hada ◽  
Hirotaka Inoue ◽  
Tatsuki Marui ◽  
Takeshi Nishikawa ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Nitric Acid ◽  
Seebeck Coefficient ◽  
Acid Treatment ◽  
Waste Heat ◽  
Seebeck Effect ◽  
Te Material

As a thermoelectric (TE) material suited to applications for recycling waste-heat into electricity through the Seebeck effect, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) (PEDOT:PSS) is of great interest.

The effect of nitric acid (HNO3) treatment on the electrical conductivity and stability of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) thin films

2017 ◽  
Vol 37 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Suhana Mohd Said ◽  
Shahriar Mufid Rahman ◽  
Bui Duc Long ◽  
Subramanian Balamurugan ◽  
Norhayati Soin ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Nitric Acid ◽  
Acid Treatment ◽  
Base Material ◽  
Operating Conditions ◽  
Organic Polymer ◽  
Visible Range ◽  
Infrared Analysis ◽  
Conductivity Enhancement ◽  
Improved Stability

Abstract In this work, the posttreatment of an organic polymer is performed using an inorganic acid, nitric acid (HNO3). We picked poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the base material and improved its electrical conductivity by acid treatment with different concentrations of HNO3. The acid treatment was able to achieve the optimum electrical conductivity of 197 S/cm, which is 115.5 times higher than the base material when treated with an aqueous solution containing 65% of HNO3. Moreover, the films showed higher transparency in the visible range while conducting Fourier transform infrared analysis. In addition, the treated films showed improved stability against outdoor operating conditions in terms of sheet resistance compared with untreated PEDOT:PSS films. We tried to develop a hypothesis to describe the reason behind the electrical conductivity enhancement by studying the thicknesses of all the samples at different acid concentration levels. The results from atomic force microscopy, the Hall effect, and the trend of film thickness suggest that the conformational change, the removal of excess PSS from the polymer, and the increase in carrier concentration are the reasons behind the improvement in electrical conductivity.

Effect of TiO2 additive on thermoelectric properties of SrTiO3

2019 ◽  
Vol 13 (02) ◽  
pp. 2051001
Author(s):  
Wei-Ying Yang ◽  
Ke-Xian Wang ◽  
Zheng Cao ◽  
Hao-Yang Yu ◽  
Xiao-Bo Ma ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Strontium Titanate ◽  
Thermoelectric Properties ◽  
Waste Heat ◽  
Molar Ratio ◽  
Composite Powders ◽  
The Impact

Strontium titanate ([Formula: see text] has the advantages of being non-toxic, environmentally friendly and high-temperature stable, and has potential application in waste heat power generation at medium and high temperature. To explore the impact of TiO2 on the thermoelectric properties of SrTiO3, we synthesized TiO2/La10Nbb10-STO composite powders by hydrothermal method using precursor solution of 10[Formula: see text]mol.% La and 10[Formula: see text]mol.% Nb co-doped STO (La10Nb10-STO) containing TiO2 nanopowders with different molar ratio. After cold pressing and sintering, composite bulk materials were obtained, and their microstructure and thermoelectric transport properties were analyzed. With the increasing TiO2, although the thermal conductivity of TiO2/La10Nb10-STO composite decreased and the Seebeck coefficient increased, the minimum thermal conductivity and the maximum Seebeck coefficient were 2.54[Formula: see text][Formula: see text][Formula: see text] and 215[Formula: see text][Formula: see text]V[Formula: see text][Formula: see text], respectively, at 1000[Formula: see text]K, but the power factor decreased at high temperature due to the apparent decrease of electrical conductivity, resulting in the ZT values being lower than that of La0Nb10-STO without TiO2 addition at high temperature. Significantly, the addition of TiO2 can improve the thermoelectric performance of strontium titanate at low temperature. This approach is expected to improve the ZT of SrTiO3-based thermoelectric material through additional controlling of electrical conductivity.

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 Synthesis and Characterization of Thermoelectric Co2XSn (X = Zr, Hf) Heusler Alloys

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 624
Author(s):  
Alessandro Difalco ◽  
Francesco Aversano ◽  
Stefano Boldrini ◽  
Alberto Ferrario ◽  
Marcello Baricco ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Curie Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Power Factor ◽  
Electronic Transport ◽  
Waste Heat ◽  
Heusler Alloys ◽  
Secondary Phases ◽  
Electronic Transport Properties

In this work, we report the results of an experimental investigation on the synthesis, structure, microstructure, mechanical, electrical conductivity, and Seebeck coefficient of Co2XSn (X = Zr, Hf) alloys. In both the alloys, the main constituent is a full Heusler-type compound that coexists with small amounts of secondary phases. Both alloys show a rather high Vickers hardness (around 900 HV) and an indentation fracture toughness typical of ceramics (around 2 MPa·m1/2). The electronic transport properties of the two alloys were measured for the first time. The temperature dependence of both the Seebeck coefficient and the electrical conductivity of the two alloys shows a change in correspondence of the Curie temperature. The Seebeck coefficient reaches a constant plateau, while the electrical conductivities show a transition from metallic to semiconductor behavior. As a consequence, almost constant values of the power factor have been obtained for the power factor above the Curie temperature, which is promising for an efficient exploitation of thermal gradients of several hundreds of degree in waste heat harvesting applications. Finally, on the basis of results from this work and from the literature, the effect of the substitution of the X element on the electronic transport properties in the series Co2XSn (X = Ti, Zr, Hf) is discussed.

Synthesis of Nano-Sized Co-Sb Compounds through Solvothermal Routes

2008 ◽  
Vol 136 ◽  
pp. 57-62
Author(s):  
L. Yang ◽  
H.H. Hng ◽  
T. Sun ◽  
H. Cheng ◽  
Jan Ma
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Charge Carrier ◽  
Seebeck Coefficient ◽  
Grain Boundaries ◽  
Solvothermal Synthesis ◽  
Lattice Thermal Conductivity ◽  
Processing Parameters ◽  
The Family ◽  
Te Material

Skutterudite materials have received great attention because their promising properties for thermoelectric (TE) applications. Among the family of skutterudites, CoSb3 has been intensively investigated due to its large electrical conductivity and Seebeck coefficient. However, its thermal conductivity is too high to make it an effective TE material. Nanostructuring of CoSb3 has the desirable effects of reducing its lattice thermal conductivity as the point imperfections or grain boundaries can scatter phonons (heat carrier) more effectively than electrons (charge carrier). In this study, nanostructured CoSb3 was synthesized by solvothermal routes using CoCl2·6H2O and SbCl3 as precursors dissolved in anhydrous ethanol with the reaction temperature kept at 240°C. In addition to the CoSb3 phase, other Co-Sb compounds were also formed during the reaction process. In this paper, we investigated the effects of processing parameters, such as concentration of CoCl2·6H2O, SbCl3 and NaBH4 in ethanol and thermal duration of solvothermal synthesis, on the yield of CoSb3 phase.

Effect of Plasma–Nitric Acid Treatment on the Electrical Conductivity of Flexible Transparent Conductive Films

2013 ◽  
Vol 52 (7R) ◽  
pp. 075102 ◽  
Author(s):  
Viet Phuong Pham ◽  
Young Woo Jo ◽  
Jong Sik Oh ◽  
Soo Min Kim ◽  
Jin Woo Park ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Nitric Acid ◽  
Acid Treatment ◽  
Transparent Conductive Films ◽  
Conductive Films

scholarly journals The Investigation of the Seebeck Effect of the Poly(3,4-Ethylenedioxythiophene)-Tosylate with the Various Concentrations of an Oxidant

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 21 ◽  
Author(s):  
Joon-Soo Kim ◽  
Woongsik Jang ◽  
Dong Wang
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
In Situ Polymerization ◽  
Seebeck Effect ◽  
Particle Sizes ◽  
Seebeck Coefficients ◽  
Optimal Power ◽  
Electrical Conductivities

Poly(3,4-ethylenedioxythiophene)-tosylate (PEDOT-Tos) can be synthesized through an in situ polymerization and doping process with iron(III) p-toluenesulfonate hexahydrate as an oxidant. Both the Seebeck coefficient and the electrical conductivity were modified by varying the concentration of the oxidant. We investigated the effects of varying the concentration of the oxidant on the particle sizes and doping (oxidation) levels of PEDOT-Tos for thermoelectric applications. We demonstrated that an increase in the oxidant enabled an expansion of the particle sizes and the doping levels of the PEDOT-Tos. The modification of the doping levels by the concentration of the oxidant can provide another approach for having an optimal power factor for thermoelectric applications. De-doping of PEDOTs by reduction agents has been generally investigated for changing its oxidation levels. In this study, we investigated the effect of the concentration of the oxidant of PEDOT-Tos on the oxidation levels, the electrical conductivities and the Seebeck coefficients. As loading the oxidant of PEDOT-Tos, the Seebeck coefficient was compromised, while the electrical conductivity increased.

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.

scholarly journals Approximate models for the lattice thermal conductivity of alloy thermoelectrics

2021 ◽  
Author(s):  
Jonathan Skelton
Keyword(s):  
Thermal Conductivity ◽  
Energy Efficiency ◽  
Lattice Thermal Conductivity ◽  
Waste Heat ◽  
Seebeck Effect ◽  
Thermoelectric Generators ◽  
Approximate Models

Thermoelectric generators (TEGs) convert waste heat to electricity and are a leading contender for improving energy efficiency at a range of scales. Ideal TE materials show a large Seebeck effect,...

Investigation of Thermoelectric Materials: Substitution effect of Bi on the Ag1-xPb18MTe20 (M = Sb, Bi) (x = 0, 0.14, 0.3)

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Substitution Effect ◽  
Dimensionless Figure Of Merit ◽  
The Matrix ◽  
Mass Fluctuation

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).

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