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Enhanced antimony telluride thermoelectric generators: From material synthesis to device applications
(2025-12-01)
Theekhasuk, Nattharika
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Sakdanuphab, Rachsak
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Voraud, Athorn
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Limsuwan, Pichet
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Sakulkalavek, Aparporn
This study investigates the effect of Bi₄O₄SeCl₂ (BOSC) addition (0–4 wt%) on the thermoelectric performance of p-type Bi₀.₅Sb₁.₅Te₃ synthesized via high-energy ball milling. XRD analysis revealed lattice incorporation at 1 wt% BOSC, while higher concentrations led to phase separation. The 1 wt% BOSC sample exhibited a significantly reduced total thermal conductivity of 0.28 W/m·K, compared to 0.46 W/m·K in the undoped sample, attributed to enhanced phonon scattering. Despite moderate decreases in electrical conductivity and Seebeck coefficient, a peak ZT of 1.02 at 50 °C was achieved—representing a ∼54 % improvement over the undoped material. Furthermore, a prototype thermoelectric module fabricated with BOSC-doped legs produced a power density of 17.6 mW/cm² under a 150 °C temperature gradient. These results demonstrate that BOSC is an effective additive for reducing thermal conductivity and enhancing overall thermoelectric performance, offering potential for energy harvesting applications at moderate temperatures.
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Enhanced thermoelectric properties of bismuth telluride via Ultra-Low thermal conductivity BOSC compound addition
(2024-12-01)
Theekhasuk, Nattharika
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Somdock, Nuttakrit
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Voraud, Athorn
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Limsuwan, Pichet
;
Sakdanuphab, Rachsak
This study aimed to enhance the thermoelectric properties of bismuth telluride by adding Bi<inf>4</inf>O<inf>4</inf>SeCl<inf>2</inf> (BOSC). Commercial N-type bismuth telluride was mixed with BOSC powder in varying concentrations. As the BOSC content increased, the carrier concentration also rose due to chlorine atoms acting as donor impurities. Despite this increase, the power factor values of the samples with BOSC additives did not significantly differ from those of the bare bismuth telluride sample. However, the total thermal conductivity decreased significantly with the addition of BOSC, reaching a minimum value of 0.54 W·m–1·K–1 at 150 °C for the sample with 1 wt% BOSC. Notably, the ZT value for the sample with 1 wt% BOSC was about 0.86, which is four times higher than that of the bare bismuth telluride sample. Our findings demonstrate superior thermoelectric performance, indicating a more efficient modification of thermoelectric properties through the addition of BOSC to the bismuth telluride matrix.
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Enhancing thermoelectric properties of Bi2Te3 film via CuI doping: Sputtering and solid iodination methods verified by ab initio calculation
(2024-04-01)
Khumtong, Tanakorn
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Theekhasuk, Nattharika
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Somdock, Nuttakrit
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Pluengphon, Prayoonsak
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Inceesungvorn, Burapat
We have introduced an innovative method for preparing CuI-doped Bi<inf>2</inf>Te<inf>3</inf> films for the first time, which was also validated through ab initio calculations. The chemical reaction between the Cu-Bi<inf>2</inf>Te<inf>3</inf> film and iodine was conducted using the solid iodination method at room temperature. The results from X-ray diffraction and energy-dispersive spectrometry suggest that the sputtering process, followed by the solid iodination method, holds promise for synthesizing CuI-doped Bi<inf>2</inf>Te<inf>3</inf> films. Additionally, appropriately doping Bi<inf>2</inf>Te<inf>3</inf> with CuI enhances the (00l) crystal orientation, increases carrier concentration and mobility, resulting in improved electrical conductivity. Furthermore, our calculation results align with our experimental findings. An excess of substitutional CuI dopant tends to generate secondary phases, leading to alterations in the intrinsic conductivity and a reduction in the thermoelectric properties of Bi<inf>2</inf>Te<inf>3</inf>. Leveraging the enhanced electrical transport properties achieved through CuI doping, the maximum power factor of the (CuI)<inf>0.2</inf>Bi<inf>2</inf>Te<inf>2.9</inf> film reaches approximately 2.40 × 10−3 W/mK2 at 423 K, representing a 66 % enhancement compared to that of the Bi<inf>2</inf>Te<inf>2.9</inf> film, which has a power factor of 1.44 × 10−3 W/mK2.
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Enhancement of thermoelectric properties in rapidly synthesised β-Cu2Se using optimized Cu content and microwave hybrid heating
(2024-01-15)
Sakulkalavek, Aparporn
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Rudradawong, Chalermpol
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Gobpant, Jakrit
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Harnwunggmoung, Adul
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Limsuwan, Pichet
To our knowledge, this is the first study to successfully synthesise high-temperature-phase copper selenide (β-Cu<inf>2</inf>Se) at room temperature using rapid microwave hybrid heating (MHH). Controlling the starting Cu/Se ratio is the critical parameter for adjusting the content of α- and β-phases in the as-synthesised sample. The relatively low Cu composition causes impurities to form in the Cu<inf>3</inf>Se<inf>2</inf> phase, deteriorating the thermoelectric (TE) properties of the Cu<inf>2</inf>Se material. The β phase formation at room temperature promotes electrical conductivity. The thermal conductivities of the Cu<inf>2.0</inf>Se samples were 0.5–0.8 Wm−1K−1 at 303–673 K. A strong electronic-phonon interaction may potentially couple electronic thermal conductivity (κ<inf>e</inf>) and lattice thermal conductivity (κ<inf>L</inf>), resulting in incomplete separability of κ<inf>L</inf> and κ<inf>e</inf> in the β-Cu<inf>2.0</inf>Se sample. The Cu<inf>2.0</inf>Se exhibited a ZT value of 0.65 at 523 K because of its considerably lowered thermal conductivity.
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Understanding the effect of sputtering pressures on the thermoelectric properties of GeTe films
(2022-02-10)
Daichakomphu, Noppanut
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Abbas, Suman
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Chou, Ta Lei
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Chen, Li Chyong
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Chen, Kuei Hsien
In this work, we study the effect of sputtering pressures on the thermoelectric properties of GeTe films. The working pressures were differentiated from 3 to 30 mTorr, and the as-deposited films were annealed at 623 K for 10 min in Ar atmosphere. The results show that the working pressure has a significant effect on the Ge content and crystalline size. The turning trend of the Seebeck coefficient with different sputtering pressures corresponds to the Ge content. The surface morphology of annealed film will change from cracks to voids with increasing sputtering pressure. This behavior can be explained by the growth mechanisms model. The voids and relatively low crystalline size of GeTe films affect to the reduction of the electrical conductivity. In addition, the void content decreased as film thickness was increased. Therefore, controlling the working pressures in the sputtering process and film thickness is important for the thermoelectric performance of GeTe thin film. In our work, we prove that the thermoelectric properties of GeTe films could be optimized effectively by simply tuning different sputtering conditions.
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Graphene addition improved figure of merit in SnTe prepared by the rapid hybrid microwave solid-state method
(2022-02-01)
Gobpant, Jakrit
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Somdock, Nuttakrit
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Limsuwan, Pichet
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Sakulkalavek, Aparporn
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Sakdanuphab, Rachsak
We successfully synthesised SnTe-based powders (SnTe, Sn<inf>0.95</inf>Bi<inf>0.05</inf>Te, and SnTe with graphene addition) by a hybrid microwave solid-state method. This demonstrated comparable thermoelectric performance to the conventional heating method but had low energy consumption and rapid synthesis. Graphene addition to SnTe materials resulted in significant reduction of thermal conductivity. The SnTe with 5 wt% graphene exhibited a reduction in overall thermal conductivity from ∼10 W m−1 K−1 for SnTe to ∼2 W m−1 K−1 at 325 K and showed a moderate power factor. The Debye model was used to explain the origin of the effects of graphene on lattice thermal conductivity. The dimensionless figure of merit was increased by five times, from 0.07 for SnTe to 0.35 for SnTe with 5 wt% graphene. Our results demonstrated an effective method and additive material to synthesise and enhance the thermoelectric properties of SnTe materials.
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Improving the thermoelectric properties of thick Sb2Te3 film via Cu doping and annealing deposited by DC magnetron sputtering using a mosaic target
(2021-11-01)
Theekhasuk, Nattharika
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Sakdanuphab, Rachsak
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Nuthongkum, Pilaipon
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Pluengphon, Prayoonsak
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Harnwunggmoung, Adul
Thick Cu-doped Sb<inf>2</inf>Te<inf>3</inf> films were deposited on flexible substrate by DC magnetron sputtering from a mosaic Cu–Sb<inf>2</inf>Te<inf>3</inf> target. The Cu-doped Sb<inf>2</inf>Te<inf>3</inf> films were vacuum annealed to improve their thermoelectric properties. Density functional theory was used to clarify the internal mechanism of the Cu doped into the Sb<inf>2</inf>Te<inf>3</inf> system. The results showed that Cu substitution on a Sb site induced electronic states or impurity peaks of Sb<inf>2</inf>Te<inf>3</inf> at a valence band maximum. The carrier concentration of the Cu-doped Sb<inf>2</inf>Te<inf>3</inf> films increased as the Cu-doped concentration increased. However, the crystallite size and Seebeck coefficient of the Cu-doped Sb<inf>2</inf>Te<inf>3</inf> films decreased as the Cu-doped concentration increased. Post-annealing treatment improved the microstructure and thermoelectric properties of the Cu-doped Sb<inf>2</inf>Te<inf>3</inf> films. The maximum electrical conductivity and power factor values of 754.20 S/cm at 50 °C and 1.56 10−3 W/mK2 at 100 °C were obtained in the annealed film with a Cu-doped concentration of 3 at%.
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Energy-saving synthesis and β-phase enhancement of Cu2Se thermoelectric materials via the microwave hybrid heating technique
(2021-10-25)
Rudradawong, Chalermpol
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Sukwisute, Pisan
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Limsuwan, Pichet
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Harnwunggmoung, Adul
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Horprathum, Mati
Thermoelectric generators harvest energy from waste heat and convert it to electricity. β-Cu<inf>2</inf>Se is a candidate for them due to its outstanding thermoelectric properties and its environmentally friendly component elements. A microwave hybrid heating (MHH) method was used for the fast synthesis and enhancement of β-Cu<inf>2</inf>Se materials. The effects of the MHH reaction time on the phase microstructure and thermoelectric properties of the Cu<inf>2</inf>Se material were investigated, and the MHH method was compared with the conventional heating method. The X-ray diffraction patterns of samples, synthesized via the MHH method, showed monoclinic- (α) and cubic- (β) Cu<inf>2</inf>Se crystalline structures, whereas a single monoclinic-(α) structure was identified in a sample, synthesized via a conventional heating method. In addition, the β-Cu<inf>2</inf>Se phase was enhanced with increased MHH reaction time. The carrier concentration increased with β-Cu<inf>2</inf>Se content, which increased electrical conductivity and decreased the Seebeck coefficient. The Cu+ ions in the β-Cu<inf>2</inf>Se phase led to the reduced thermal conductivity. A low thermal conductivity of 0.86 W m−1 K−1 and a maximum dimensionless figure of merit of 0.32 at 523 K were realized for 10 min MHH sample. Finally, MHH showed very low energy consumption and saved time, which are essential for industrialization.
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Management of air conditioning system in electronics housing by using thermoelectric Peltier module
(2021-09-15)
Suriyawong, Adirek
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Saisorn, Sira
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Suwanpayak, Nathaporn
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Wongwises, Somchai
The study was the conditioning system of the electronic case by using thermoelectric Peltier module. The Peltier module is used based on the temperature difference of the hot and cold sides, with input electric power in the thermoelectric Peltier module. The hot side of the Peltier module was installed on a side of the heat sinks with heat removing from a Peltier module into a surrounding while the cold side of the Peltier module was installed on the other side of the heat sinks with the heat absorption of the computer case. The electronic case volume is 450x395x240 mm³. The device of cooling loads was installed in the electronic case. The cooling loads were tested with various power of 0, 60, 120, 180, and 240 Watt. The results indicated that the coefficient of performance (COP) increased with the cooling load. Furthermore, the experimental results indicated that the temperature inside the electronic case increased with cooling load because the temperature of the electronic case increased with decreasing the temperature difference between the hot and the cold sides.
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Effect of grain boundary interfaces on electrochemical and thermoelectric properties of a Bi2Te3/reduced graphene oxide composites
(2020-08-01)
Thongsamrit, Wannisa
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Phrompet, Chaiwat
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Maneesai, Keerati
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Karaphun, Attaphol
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Tuichai, Wattana
The electrochemical and enhanced thermoelectric properties of pristine Bi<inf>2</inf>Te<inf>3</inf> and Bi<inf>2</inf>Te<inf>3</inf>/reduced graphene oxide (Bi<inf>2</inf>Te<inf>3</inf> + rGO) composites at 1%, 3% and 5% levels of rGO were synthesized via a simple ultrasonic method. The X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV–vis spectrometry (UV–vis) and their electrochemical and thermoelectric properties were measured. The ultrasonic method succeeded in producing rGO nanosheets composited with Bi<inf>2</inf>Te<inf>3</inf> forming grain boundary interfaces of rGO with Bi<inf>2</inf>Te<inf>3</inf>. The resulting samples displayed a continuous network structure of rGO nanosheets in Bi<inf>2</inf>Te<inf>3</inf> + rGO composites for electrons in the conduction band of the Bi<inf>2</inf>Te<inf>3</inf> structure. Electrons were transferred to rGO nanosheets at the interface, contributing electron charge carriers in Bi<inf>2</inf>Te<inf>3</inf> + rGO composites. This indicates band alignment between Bi<inf>2</inf>Te<inf>3</inf> and rGO nanosheets. The Bi<inf>2</inf>Te<inf>3</inf> + rGO composites exhibited an increasing storage charge mechanism of electrical double layer capacitors with greater rGO contents. The Bi<inf>2</inf>Te<inf>3</inf> + rGO composites displayed negative a Seebeck coefficient for thermoelectric materials. The highest ZT value was 0.17 in the bulk 1% Bi<inf>2</inf>Te<inf>3</inf> + rGO composite. Improved electrochemical and thermoelectric properties of the Bi<inf>2</inf>Te<inf>3</inf> + rGO 1% composite resulted from the interaction of the grain boundary interfaces of rGO nanosheets with pristine Bi<inf>2</inf>Te<inf>3</inf> following the model of band alignment between Bi<inf>2</inf>Te<inf>3</inf> and rGO nanosheets.

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