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.

Thermoelectric properties of In-filled and Te-doped CoSb3 prepared by high-pressure and high-temperature

2015 ◽  
Vol 29 (19) ◽  
pp. 1550095 ◽  
Author(s):  
Le Deng ◽  
Li Bin Wang ◽  
Jie Ming Qin ◽  
Tao Zheng ◽  
Jing Ni ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Pressure ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Temperature Dependent ◽  
Synthesis Time ◽  
Temperature Range

A novel chemical alloying method of high-pressure and high-temperature (HPHT) has been used for the synthesis of bulk-skutterudite [Formula: see text]. Through HPHT method, the synthesis time has been shortened from a few days to 30[Formula: see text]min. The samples of [Formula: see text] skutterudites were synthesized at 1.8–3.3[Formula: see text]GPa. We have studied the phase, the microstructure, and the temperature-dependent thermoelectric properties. The Seebeck coefficient, electrical conductivity and thermal conductivity were measured in the temperature range of 295–673[Formula: see text]K. As we expected, the thermal conductivity of sample [Formula: see text] decreased with the increase of the synthetic pressure. A maximal ZT of 0.64 was achieved for the [Formula: see text] synthesized at 1.8[Formula: see text]GPa at 673[Formula: see text]K. These results revealed that HPHT method may be helpful for optimizing electrical conductivity and thermal conductivity in a comparatively independent way.

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.

High-temperature thermoelectric properties of n-type BayNixCo4−xSb12

2001 ◽  
Vol 16 (12) ◽  
pp. 3343-3346 ◽  
Author(s):  
X. F. Tang ◽  
L. M. Zhang ◽  
R. Z. Yuan ◽  
L. D. Chen ◽  
T. Goto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Electron Concentration ◽  
Lattice Thermal Conductivity ◽  
Filling Fraction ◽  
Ni Content ◽  
Increasing Temperature

Effects of Ba filling fraction and Ni content on the thermoelectric properties of n-type BayNixCo4−xSb12 (x = 0−0.1, y = 0−0.4) were investigated at temperature range of 300 to 900 K. Thermal conductivity decreased with increasing Ba filling fraction and temperature. When y was fixed at 0.3, thermal conductivity decreased with increasing Ni content and reached a minimum value at about x = 0.05. Lattice thermal conductivity decreased with increasing Ni content, monotonously (y ≤ 0.1). Electron concentration and electrical conductivity increased with increasing Ba filling fraction and Ni content. Seebeck coefficient increased with increasing temperature and decreased with increasing Ba filling fraction and Ni content. The maximum ZT value of 1.25 was obtained at about 900 K for n-type Ba0.3Ni0.05Co3.95Sb12.

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.

High Temperature Thermoelectric Properties of Oxide Ca2Co2O5

2009 ◽  
Vol 79-82 ◽  
pp. 2143-2146 ◽  
Author(s):  
Guo Jing Li ◽  
Shu Jin Zhao ◽  
Ao Mei ◽  
Jin Le Lan ◽  
Yuan Hua Lin
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
The Body ◽  
Ceramic Powders ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Maximum Power Factor ◽  
Better Than

Ca2Co2O5 ceramic powders were synthesized by the coprecipitation method and consolidated by spark plasma sintering (SPS) technique.The observation by the SEM indicated that the ceramics body showed fine and layer microstructure.The density of the body increased with an increase of the fritting temperature.XRD patterns showed that the ceramics sample exhibits inpure phase with increasing the sintering temperayure to 850°C and that the grain was preferentially oriented.The electrical conductivity was reduce and the Seebeck coefficient slightly increased with an increase of the sintering temperature.As a result,the thermoelectric properties of the sample prepared by SPS at 800 °C for 5 min was better than the sample prepared by SPS at 750 °C for 5 min at high temperature.The sample treated by the SPS process under the condition of 800 °C,40 MPa and 5 min showed the maximum power factor (PF) of 3.85×10-4W∙m-1∙K-2 at 923 K.

Synthesis and High Temperature Thermoelectric Properties of Alkaline-Earth Metal Hexaborides MB6 (M=Ca, Sr, Ba)

2003 ◽  
Vol 793 ◽  
Author(s):  
Masatoshi Takeda ◽  
Yosuke Kurita ◽  
Keisuke Yokoyama ◽  
Takahiro Miura ◽  
Tsuneo Suzuki ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Thermoelectric Device ◽  
Alloying Effect ◽  
P Type

ABSTRACTPolycrystalline alkaline-earth hexaborides (MB6: M =Ca, Sr, Ba) were synthesized and their thermoelectric and transport properties were examined to discuss their possibility as high temperature thermoelectric materials. Hall measurements showed that carrier concentration of the BaB6 was the highest among the three hexaborides and that of CaB6 was the lowest. Substitution of part of the alkaline earth metals with one of the others changed the carrier concentration of the hexaboride. As the carrier concentration increased, Seebeck coefficient increased and electrical conductivity decreased. These results suggest that the thermoelectric properties of the divalent hexaborides depend largely on the carrier concentration, and optimum carrier concentration which gives maximum power factor was estimated to be approximately 2x1026 m−3. Consequently, such a substitution enables us to control Seebeck coefficient and electrical conductivity of the hexaborides, and will also be effective to reduce the lattice heat conduction due to the alloying effect. A thermoelectric device was fabricated using SrB6 and boron carbide thin films as n-type and p-type elements, respectively. To the best of our knowledge, this is the first demonstration of a thermoelectric device composed of only boron-rich solids.

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.

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