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zT = 1.1 in CuInTe <sub/>2</sub> Solid Solutions Enabled by Rational Defect Engineering
摘要： In this study, the synthesis and thermoelectric performance of CuInTe2?In2Te3 and Cu0.85Ag0.15InTe2?In2Te3 solid solutions are reported. The experimental results associated with model fitting reveal that the cation vacancies generated by creating solid solutions with a compound with a smaller cation-to-anion ratio can strongly scatter phonons with high frequency, which remarkably decrease the total as well as lattice thermal conductivity of the CuInTe2 system and finally realize an enhanced thermoelectric properties compared to the pristine sample. Furthermore, substitutional Ag/Cu defects integrated with vacancies lead to a further reduction in lattice thermal conductivity. With the benefit from the rational defect design, a high figure of merit of 1.1 is gained at 840 K for the sample (Cu0.85Ag0.15InTe2)0.98?(In2Te3)0.02. In addition, a 188% improvement on average zT is obtained. This work provides an effective method for boosting thermoelectric performance of chalcopyrite compounds by defect engineering on multiple types of defects.
关键词： defect engineering,thermoelectric performance,vacancy phonon scattering,thermal conductivity,CuInTe2
更新于2025-09-12 10:27:22
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Experimental Realization of a Quantum Dot Energy Harvester
摘要： We demonstrate experimentally an autonomous nanoscale energy harvester that utilizes the physics of resonant tunneling quantum dots. Gate-defined quantum dots on GaAs=AlGaAs high-electron-mobility transistors are placed on either side of a hot-electron reservoir. The discrete energy levels of the quantum dots are tuned to be aligned with low energy electrons on one side and high energy electrons on the other side of the hot reservoir. The quantum dots thus act as energy filters and allow for the conversion of heat from the cavity into electrical power. Our energy harvester, measured at an estimated base temperature of 75 mK in a He3=He4 dilution refrigerator, can generate a thermal power of 0.13 fW for a temperature difference across each dot of about 67 mK.
关键词： resonant tunneling,quantum dots,thermoelectric,energy harvester,nanoscale
更新于2025-09-11 14:15:04
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Hybrid Photovoltaic-Thermoelectric Generator Powered Synchronous Reluctance Motor for Pumping Applications
摘要： The interest in photovoltaic (PV) pumping systems has increased, particularly in rural areas where there is no grid supply available. However, both the performance and the cost of the whole system are still an obstacle for a wide spread of this technology. In this article, a hybrid photovoltaic (PV)-thermoelectric generator (TEG) is investigated for pumping applications. The electric drivetrain comprises a synchronous reluctance motor and an inverter. A control strategy for the drivetrain is employed to execute two main tasks: 1) driving the motor properly to achieve a maximum torque per Ampère condition and 2) maximizing the output power of the PV system at different weather conditions. This means that the conventional DC-DC converter is not used in the proposed system. Moreover, batteries, which are characterized by short life expectancy and high replacement cost, are also not used. It is found that the motor output power and the pump flow rate are increased by about 9.5% and 12% respectively when the hybrid PV-TEG array is used compared to only using PV array. Accordingly, the performance, cost and complexity of the system are improved. Measurements on an experimental laboratory setup are constructed to validate the theoretical results of this work.
关键词： Photovoltaic pumping system,thermoelectric generator,MPPT,motor drives,synchronous reluctance machines
更新于2025-09-11 14:15:04
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Preliminary experiment on a novel photovoltaic-thermoelectric system in summer
摘要： Compared with the PV electricity generation, the hybrid Photovoltaic-thermoelectric (PV-TE) can generate more electricity due to its ability to utilize a wider solar spectrum than the PV. The PV-TE employing micro-channel heat pipe array is a novel PV-TE-MCHP system which is capable of providing high cost performance compared to the traditional PV-TE due to the use of the micro-channel heat pipe array. In this paper, the experimental investigation of this new system in summer in Hefei city, China is presented for the first time. The comparison between this system and PV alone is made, and the details are presented. The power output, PV temperature, and the hot and cold sides temperatures of the TE are all tested. The results show that the novel system has a higher electrical output than the PV alone. The electrical efficiencies of this system during the test are all higher than 14.0% and the PV temperatures are about 20 (cid:1)C higher than the ambient temperature. Based on this experiment, the results also verify the feasibility of the new system, which will give a valuable reference for the PV-TE design.
关键词： Micro-channel heat pipe,Power output,Experimental investigation,Photovoltaic-thermoelectric
更新于2025-09-11 14:15:04
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Laser Treatment as Sintering Process for Dispenser Printed Bismuth Telluride Based Paste
摘要： Laser sintering as a thermal post treatment method for dispenser printed p- and n-type bismuth telluride based thermoelectric paste materials was investigated. A high-power fiber laser (600 W, 1064 nm) was used in combination with a scanning system to achieve high processing speed. A Design of Experiment (DoE) approach was used to identify the most relevant processing parameters. Printed layers were laser treated with different process parameters and the achieved sheet resistance, electrical conductivity, and Seebeck coefficient are compared to tube furnace processed reference specimen. For p-type material, electrical conductivity of 22 S/cm was achieved, compared to 15 S/cm in tube furnace process. For n-type material, conductivity achieved by laser process was much lower (7 S/cm) compared to 88 S/cm in furnace process. Also, Seebeck coefficient decreases during laser processing (40–70 μV/K and ?110 μV/K) compared to the oven process (251 μV/K and ?142 μV/K) for p- and n-type material. DoE did not yet deliver a set of optimum processing parameters, but supports doubts about the applicability of area specific laser energy density as a single parameter to optimize laser sintering process.
关键词： additive manufacturing,design of experiment,laser sintering,thermoelectric,antimony telluride,bismuth telluride
更新于2025-09-11 14:15:04
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Enhanced thermoelectric properties of InSb: Studies on In/Ga doped GaSb/InSb crystals
摘要： In/Ga elements were doped in GaSb/InSb crystals respectively, and their thermoelectric performances were studied. The crystals had cubic zinc blende structure with change in lattice parameters. The charge transfer occurred between all the three (In, Ga and Sb) elements when In was doped with GaSb. Whereas in Ga doped InSb crystals, the charge transfer occurred only among Ga and Sb elements. In/Ga doped GaSb/InSb crystals exhibited degenerate and non-degenerate electrical properties, respectively. Optical modes of phonon vibrations were present, and their transverse mode was dominant over longitudinal mode in all the samples. The thermoelectric ?gure of merit (ZT) of In doped GaSb crystals were low because of their low power factor and high thermal conductivity. The highest power factor (59.5 μW/cmK2) and ZT (0.56) at 573 K were achieved by Ga doped (1 × 1021/cm3) InSb crystal. The ZT 0.56 at 573 K is thus far the highest among other reported values of InSb crystals.
关键词： D. Point defect,B. Thermoelectric properties,A. Intermetallics,C. Crystal growth,G. Thermoelectric power generation
更新于2025-09-10 09:29:36
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Photoemission and Soft X-ray Absorption Spectroscopy Study of Gd-substituted Thermoelectric and Topological Bi2Te3
摘要： The electronic structures of Gd-substituted Bi2?xGdxTe3 single crystals have been investigated by employing synchrotron-radiation spectroscopies, such as soft X-ray absorption spectroscopy (XAS), soft X-ray magnetic circular dichroism (XMCD), photoemission spectroscopy (PES), and scanning photoelectron microscopy (SPEM). SPEM measurements confirm that Gd ions are substituted homogeneously in Bi2?xGdxTe3 crystals. The measured Gd 3d XAS and XMCD spectra provide evidence that the substituted Gd ions are trivalent and magnetic. The hν-dependence of the valence-band (VB) PES spectra are described well by the hν-dependent contributions of the Te 5p and Bi 6p states. A good agreement is found between the measured VB PES spectra of Bi2?xGdxTe3 and the calculated partial densities of states, revealing that the Te 5p states will play an important role in determining the thermoelectric and topological properties of Bi2?xGdxTe3.
关键词： Gd-substituted Bi2Te3,XAS,thermoelectric,topological,XMCD,PES,SPEM
更新于2025-09-10 09:29:36
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Structural and thermoelectric properties of Se doped In <sub/>2</sub> Te <sub/>3</sub> thin films
摘要： The Se-Te based chalcogenides exhibit novel property of Phase Change Memory (PCM) which has potential applications in electrical non-volatile memories. These materials are also suitable in thermal to electrical energy conversions and, hence, of potential interest in energy sustainability as thermoelectric devices. In this study, the Se doped In2Te3 thin films were prepared by thermal evaporation and were annealed at 250 ?C and 300 ?C in Argon gas. The X-ray diffraction spectra show that thermal annealing leads to the phase transitions in Se doped In2Te3 into binary phases of In2Se3 and In2Te3. The surface morphology of the films exhibits the grains of spherical nature. Annealing also decreases the energy band gap due to the presence of two phases. From the four probe and photoconductivity measurements, a large contrast in electrical resistance between the amorphous and crystalline states is found with a variation of a few orders of magnitude. The electrical transport properties such as the electrical resistivity, Seebeck coefficient and the power factor were measured in the temperature range from 300 K to 430 K. All the deposited and annealed thin films exhibit n-type conductivity with the Seebeck coefficient ranging from -338 μVK-1 to -510 μVK-1. An increase in thermoelectric power of 25% is observed in the 300 ?C annealed films in comparison to the as-deposited films. Moreover, the lower Se doped In2(Te0.96Se0.04)3 compound exhibits a better thermoelectric performance compared to the In2(Te0.90Se0.1)3 composition. This study shows the multifunctional nature of Se doped In2Te3 both for PCM and thermoelectric applications.
关键词： power factor,Seebeck coefficient,Phase Change Memory,X-ray diffraction,thermal evaporation,Se-Te based chalcogenides,electrical resistance,thermoelectric devices
更新于2025-09-10 09:29:36
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[IEEE 2018 Open Innovations (OI) - South Africa (2018.10.3-2018.10.5)] 2018 Open Innovations Conference (OI) - Prospective Use of Thermoelectric Device for PV Panel Cooling
摘要： The electrical efficiency of a photovoltaic panel is influenced by the rise in the panel’s temperature, especially at temperatures from and above 25 °C. For cooling a photovoltaic panel, a thermoelectric module operated as a thermoelectric cooler (TEC) attached at the back of a photovoltaic panel is a practical solution. The TEC module is used to absorb the heat generated on the surface of the photovoltaic panel, which is then dispersed by a heat-sink mounted on the opposite side of a TEC. This paper deals with the development of a mathematical model to optimally control a TEC and take into account the amount of energy used to cool down a photovoltaic panel.
关键词： Photovoltaic cooling,Solar energy,Thermoelectric cooler,Photovoltaic panel
更新于2025-09-10 09:29:36
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A Narrowband Photo-Thermoelectric Detector Using Photonic Crystal
摘要： Here, a wavelength-specific photo-thermoelectric (PTE) device is reported that achieves narrowband optical absorption and thermoelectric conversion functions using a stack of thin films on a grating-patterned substrate. Conventional PTE devices are broadband with the absorption of electromagnetic radiation from ultraviolet to terahertz. There are demands for PTE devices that can exhibit narrowband response at a desired wavelength. Here, the narrowband PTE device consists of a photonic crystal (PC) filter with metal cladding and a thin-film thermocouple. The PC-PTE design is investigated numerically to illustrate the underlying energy conversion mechanism. The device is fabricated using nanoreplica molding followed by coating of thin films. The fabricated metal-cladding PC resonator exhibits a narrowband optical absorption with a resonant absorption coefficient of 85.4% and full-width-half-maximum of 14.8 nm in the visible wavelength range. The PTE measurements show that the thermoelectric output is sensitive to the coupling of incident light and guided-mode resonance modes. Illuminated under the resonant condition, the PTE device exhibits a responsivity and noise equivalent power of 0.26 V W?1 and 7.5 nW Hz?1/2, respectively. This PC-PTE technology has the unique attributes of narrowband detection, large surface area, and low cost for the potential application in sensors, optical spectroscopy, and imaging.
关键词： photo-thermoelectric effect,photonic crystals,guided-mode resonance,narrowband filters
更新于2025-09-10 09:29:36