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In situ phase separation precipitates play an important role in enhancing the thermoelectric properties of copper sulfides by suppressing phonon transmission. In this study, Cu1.8S composites were fabricated by melting reactions and spark plasma sintering. The complex structures, namely, micron-PbS, Sb2S3, nano-FeS, and multiscale pores, originate from the introduction of FePb4Sb6S14 into the Cu1.8S matrix. Using effective element (Fe) doping and multiscale precipitates, the Cu1.8S+0.5 wt% FePb4Sb6S14 bulk composite reached a high dimensionless figure of merit (ZT) value of 1.1 at 773 K. Furthermore, the modulus obtained for this sample was approximately 40.27 GPa, which was higher than that of the pristine sample. This study provides a novel strategy for realizing heterovalent doping while forming various precipitates via in situ phase separation by natural minerals, which has been proven to be effective in improving the thermoelectric and mechanical performance of copper sulfides and is worth promoting in other thermoelectric systems.

Due to its large hole mobility, organic rubrene (C42H28) has attracted research questions regarding its applications in electronic devices. In this work, extensive first-principles calculations are performed to predict some temperature- and doping-dependent properties of organic semiconductor rubrene. We use density functional theory (DFT) to investigate the electronic structure, elastic and transport properties of the orthorhombic phase of the rubrene compound. The calculated band structure shows that the orthorhombic phase has a direct bandgap of 1.26 eV. From the Vickers hardness (1.080 GPa), our calculations show that orthorhombic rubrene is not a super hard material and can find useful application as a flexible semiconductor. The calculated transport inverse effective mass and electronic fitness function show that the orthorhombic rubrene crystal structure is a p-type thermoelectric material at high temperatures.

ABSTRACTPhotovoltaic-thermoelectric (PV-TE) tandem system has been considered as an effective way to fully utilize the solar spectrum, and has been demonstrated in a perovskite solar cell (PSC)-thermoelectric (TE) configuration. However, the conventional PSC-TE tandem architecture cannot convert infrared light transmitted through the upper PSC into heat effectively, impeding the heat-electricity conversion of TE devices. Herein, a semi-transparent PSC-photothermal-TE tandem system is designed for improved photothermal utilization. Through optimizing the buffer layer of the back transparent electrode, semi-transparent PSC with a power conversion efficiency (PCE) of 13% and an average transmittance of 53% in the range of 800–1500 nm was obtained. On this basis, a photothermal thin film was introduced between the semi-transparent PSC and the TE device, which increased the efficiency contribution ratio of the TE device from 14% to 19%, showing enhanced utilization of AM 1.5 G solar spectrum and improved photo-thermal-electric conversion efficiency.

To generate a concentrated photovoltaic–thermal (CPVT) unit system, linear Fresnel concentrators have been attached to a PV unit and a thermoelectric generator (TEG) has been combined in this work to boost productivity. In the presence of concentrators, the temperature of the silicon layer increases. While electrical output is enhanced for the CPVT unit, the non-uniform isotherms can decrease the lifetime of the panel, so confined jets of alumina–water nanofluid have been applied for cooling. To validate the numerical code, previous papers were examined and good accommodations were reported. Various values of the inlet temperature (Tin) and velocity (Vin) of jets have been analysed. The impacts of installing concentrators on overall performance and CO2 mitigation have been investigated. An increase in Vin leads to an incremental increase in thermal performance of about 4.2% and thermal uniformity is enhanced by about 13.91%. The thermal power of the system is enhanced by about 2.19 times as a result of adding concentrators. Also, the PV power is enhanced by 86.22% in the presence of the reflectors. With the increase in Tin, the thermal and electrical performance decrease by about 19.95% and 5.24%, respectively. Installing concentrators enhances the overall performance by about 6.55%. After 10 years, the amount of CO2 mitigation for the CPVT-TEG system reaches 148.28 ton.

The thermoelectric performance of SnSe strongly depends on its low-energy electron band structure that provides high density of states in a narrow energy window due to the multi-valley valence band maximum (VBM). Angle-resolved photoemission spectroscopy measurements, in conjunction with first-principles calculations, reveal that the binding energy of the VBM of SnSe is tuned by the population of Sn vacancy, which is determined by the cooling rate during the sample growth. The VBM shift follows precisely the behavior of the thermoelectric power factor, while the effective mass is barely modified upon changing the population of Sn vacancies. These findings indicate that the low-energy electron band structure is closely correlated with the high thermoelectric performance of hole-doped SnSe, providing a viable route toward engineering the intrinsic defect-induced thermoelectric performance via the sample growth condition without an additional ex-situ process.

Nanostructuring is important for designing thermoelectrics. Yet, nanoprecipitates are thermodynamically unstable and coarsen through Ostwald ripening. Here, the Ostwald ripening of Ag2Te in PbTe and its resulting impact on thermoelectric performance is investigated. Numerous Guinier‐Preston zones and platelet Ag2Te precipitates in the sample quenched from a single‐phase region is observed. Upon annealing, these platelet precipitates grow into big lath‐shaped second phases by consuming small Ag‐rich clusters. The crystallographic orientation relationships between Ag2Te and PbTe are unraveled by scanning transmission electron microscopy and modeled by first‐principles calculations. The interfaces with low lattice mismatch determine the morphology of Ag2Te in PbTe. Atom probe tomography reveals different chemical bonding mechanisms for PbTe and Ag2Te, which are metavalent and iono‐covalent, respectively. This leads to an acoustic phonon mismatch at the precipitate‐matrix interface. Yet, the electrons are also scattered by these interfaces, resulting in poor electrical properties in the as‐quenched sample. In contrast, the annealed sample contains abundant Ag‐decorated dislocations by activating the Bardeen‐Herring source. These dislocations strongly scatter phonons while maintaining a good electron transmission, contributing to a higher thermoelectric performance. This work demonstrates the complex role of microstructure morphologies, compositions, and bonding mechanisms in thermoelectric response, providing insights into structural design for thermoelectrics. [ABSTRACT FROM AUTHOR]

The crystal structure and transport properties of GeBi2Te4 are investigated as a layered compound with potential applications as thermoelectric materials. A disordered arrangement of Ge and Bi atoms in a septuple‐layer structure is discovered through synchrotron radiation X‐ray diffraction and transmission electron microscopy. Neutron pair distribution function analysis revealed the presence of discordant Ge atoms with an off‐centering distance of 0.12 Å at 300 K. The thermal conductivity of GeBi2Te4 is very low due to the strong phonon scattering. This is a result of the three Einstein local oscillators coupled with the disordered arrangement of atoms. This study also explores further the structural characteristics of these materials and their associated phonon scattering processes. The effect of Sb substitution for Ge on the electrical transport properties of the sample is profound, resulting in a change from p‐type to n‐type conduction. An enhanced thermoelectric figure of merit (ZT) of 0.45 at 523 K in the in‐plane direction is obtained. This research provides valuable insights into the crystal structure and transport properties of GeBi2Te4, showcasing its promising role as a thermoelectric material with potential for near‐room‐temperature applications. [ABSTRACT FROM AUTHOR]

The mechanical, electronic, magneto-optic and thermoelectric properties of CeBiPt compound have been calculated based on density functional theory (DFT) calculations. This compound has ground state point in the ferromagnetic phase with elastic stability by large bulk modulus of 88.565 GPa. Poisson's coefficient of 0.257 represents the ionic bonds between atoms, while the anisotropy coefficient indicates the elastic isotropic nature of this compound. Also, phonon dispersion emphasizes to the dynamic stability of this compound. By the mBJ approximation, this case exhibits ferromagnetic behavior with a magnetic moment of 0.98 μ B . Based on the magnetic behavior of this crystal, the Kerr effect angles ( θ k ) are 3.6∘ at 3 eV and − 3. 5 ∘ at 5.4 eV, respectively, therefore, the rotation angle of the ellipse light polarization ( γ k ) in the edge of ultraviolet region shows a large polarization of light in the visible region. The negative Seebeck coefficient of CeBiPt compound at low temperature refers to the hole transfer, also the magnitude of the power factor at higher temperatures indicates this compound is suitable for use in power generator applications. [ABSTRACT FROM AUTHOR]

Thermoelectric power can convert heat and electricity directly and reversibly. Low-dimensional thermoelectric materials, particularly thin films, have been considered a breakthrough for separating electronic and thermal transport relationships. In this study, a series of Bi0.5Sb1.5Te3 thin films with thicknesses of 0.125, 0.25, 0.5, and 1 μm have been fabricated by RF sputtering for the study of thickness effects on thermoelectric properties. We demonstrated that microstructure (texture) changes highly correlate with the growth thickness in the films, and equilibrium annealing significantly improves the thermoelectric performance, resulting in a remarkable enhancement in the thermoelectric performance. Consequently, the 0.5 μm thin films achieve an exceptional power factor of 18.1 μWcm−1K−2 at 400 K. Furthermore, we utilize a novel method that involves exfoliating a nanosized film and cutting with a focused ion beam, enabling precise in-plane thermal conductivity measurements through the 3ω method. We obtain the in-plane thermal conductivity as low as 0.3 Wm−1K−1, leading to a maximum ZT of 1.86, nearing room temperature. Our results provide significant insights into advanced thin-film thermoelectric design and fabrication, boosting high-performance systems. [ABSTRACT FROM AUTHOR]

XCoP (XTi, Zr, Hf) half Heusler alloys are investigated through density functional theory in stable non‐magnetic phase. The exchange‐correlation functional Generalized Gradient Approximation (GGA) is used to study these alloys. The equilibrium lattice constants and corresponding ground state energies of the studied alloys are calculated in stable γ‐phase. All these three reported alloys exhibit semiconducting behavior with corresponding bandgap values of 1.40, 1.29, and 1.38 eV for TiCoP, ZrCoP, and HfCoP, respectively. The studied alloys are mechanically stable and ductile in nature. The obtained thermoelectric figure of merit for p‐type TiCoP, ZrCoP and HfCoP are 0.5, 0.6, and 0.7 at 1200 K. Similarly, the figure of merit obtained for n‐type TiCoP, ZrCoP, HfCoP are 0.54, 0.37, and 0.31, respectively, at the same temperature. The investigated favorable transport properties of these alloys show that they are the potential candidates for waste heat energy harvesting application. [ABSTRACT FROM AUTHOR]

In the current investigation, we have explored the structural, electrical, optical, thermoelectric, and elastic features of potassium(K) based halide double perovskite K2MBiBr6 (M = Na, Ag, Cu) using the WIEN2k code under the framework of density functional theory. Various factors, including negative formation energy, structural optimization, tolerance, and octahedral factors, verify the stability of perovskites. The generalized gradient approximation has been employed to investigate the structural phase and elastic properties. The Tran-Balaha modified Becke-Johnson function has been utilized to precisely evaluate the electronic, optical, and thermoelectric properties. The electronic parameters, such as band gap and density of states revealed that K2NaBiBr6, K2AgBiBr6, and K2CuBiBr6 are semiconductors, with indirect bandgaps of 4.01, 2.36, and 1.26 eV, respectively. For optical properties, the current study has examined characteristics such as energy loss, refractive index, light energy absorption, and polarization through the entire energy spectrum, which ranges from 0 to 8 eV. The BoltzTraP code is used to examine thermoelectric characteristics, revealing maximum ZT values of 0.75, 0.77, and 0.78, respectively. This study further emphasizes the elastic constants of cubic symmetry to figure out the variation between ductile and brittle nature, anisotropy, and the large melting temperature of these materials. The theoretical findings given in the present article have substantial impacts on the future renewable energy sector especially solar cells and electron transport applications. [ABSTRACT FROM AUTHOR]

SrTiO 3 (STO) is considered a promising high-temperature N-type thermoelectric material. However, its intrinsic insulating properties and high thermal conductivity limit the dimensionless quality factor (zT) due to its simple crystal structure and the existence of light elements. Along these lines, in this work, the optimization of the thermoelectric properties of STO-based materials was achieved by using the high temperature and high pressure (HPHT) method and adjusting the doping ratios of the La and Nb heavy elements. To enhance the doping effect, oxygen vacancies need to be formed within the sample. For this reason, titanium powder was added to the sample. Due to the confined environment induced by the high pressure, which can be attributed to the application of the HPHT method and the strong oxygen trapping ability of Ti at high temperatures, a reducing environment was attained for the samples, the latter, promoted the formation of oxygen vacancies in the synthesized samples, and semiconducting properties were achieved. The thermoelectric properties and microscopic morphology of the synthesized samples with different doping ratios of La and Nb were also thoroughly investigated. Finally, the maximum zT value obtained for the samples was 0.28@973 K. A fast, simple, and effective method for the preparation of oxygen-deficient packet-crystalline oxide materials was developed in this work, which paves the way for significantly improving their thermoelectric properties. [ABSTRACT FROM AUTHOR]

SrTiO 3 (STO)-based perovskite oxide is regarded as a promising high-temperature n-type thermoelectric material. However, its intrinsic high thermal conductivity leads to poor thermoelectric properties. Using entropy engineering, lower thermal conductivity can be obtained. However, the high configuration entropy can also lead to poor carrier mobility, which inhibits electron transport and consequently reduces the electrical conductivity. Along these lines, in this work, an ultra-low thermal conductivity was obtained, which is significantly lower than the majority of the values reported in the literature, and the concept of phononic glass electronic crystal was attained at the same time. The enhanced effective scattering of phonons through the multi-scale defects gives rise to a low thermal conductivity of 1.8 W m−1 K−1 at 973K. Optimization of electrical properties due to in situ reduction at high temperature and pressure，the high-entropy ceramics possess the maximum power factor of 7.03 μW cm−1 K−2 at 973K. The application of high pressure is considered an important approach for the development of new materials with special properties. A new strategy for the composition design and in-situ reduction of oxide thermoelectric materials was provided in this work, which paves the way for the optimization and application of both the electrical and thermal properties of perovskite-based materials. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Petrochemical Universities / Shiyou Huagong Gaodeng Xuexiao Xuebao is the property of Journal Editorial Department Of Liaoning Shihua University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thermoelectric (TE) materials play a crucial role in converting energy between heat and electricity, essentially for environmentally friendly renewable energy conversion technologies aimed at addressing the global energy crisis. Significant advances in TE performance have been achieved over the past decades in various TE materials through key approaches, such as nanostructuring, band engineering, and high-entropy engineering. Among them, the design of high-entropy materials has recently emerged as a forefront strategy to achieve significantly low thermal conductivity, attributed to severe lattice distortion and microstructure effects, thereby enhancing the materials' figure of merit (zT). This review reveals the progress of high-entropy TE materials developed in the past decade. It discusses high-entropy-driven structural stabilization to maintain favorable electrical transport properties, achieving low lattice thermal conductivity, and the impact of high entropy on mechanical properties. Furthermore, the review explores the theoretical development of high-entropy TE material and discusses potential strategies for future advancements in this field through interactions among experimental and theoretical studies. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of the thermoelectric properties of solid crystal YbxBi 2 − x Te3. This work presents the results of studies of the thermoelectric properties of YbxBi 2 − x Te3 (x ≤ 0. 1 0) solid solutions before and after annealing in the temperature range 300–580 K. Regularities of changes in the electrical conductivity, Seebeck coefficient, and total thermal conductivity of the samples depending on the content of ytterbium (Yb) are established. Dependences of electrical conductivity, Seebeck coefficient, and the thermal conductivity on temperature for the crystal under study are plotted. Temperature curves were recorded using a Termoscan-2 low-frequency temperature recorder at a heating rate of 283 K/min. Studies of conductivity σ , thermoelectric power (S) were carried out by the four-probe method at direct current in the temperature range of 300–600 K. Ohmic contacts were applied using alloys. It has been established that the optimal combination of these thermoelectric characteristics is achieved for the compositions x = 0. 1 , which are characterized by the maximum thermoelectric index (Z T = 0. 8 7) of the figure of merit in the temperature range of 420–500 K after annealing at 500 K for τ = 2 4 0 h. It was revealed that the YbxBi 2 − x Te3 systems under study are n-type semiconductor thermoelectric materials in the temperature range of 300–600 K. [ABSTRACT FROM AUTHOR]

[Display omitted] In thermoelectrics, doping is essential to augment the figure of merit. Traditional strategy, predominantly heavy doping, aims to optimize carrier concentration and restrain lattice thermal conductivity. However, this tactic can severely hamper carrier transport due to pronounced point defect scattering, particularly in materials with inherently low carrier mean-free-path. Conversely, dilute doping, although minimally affecting carrier mobility, frequently fails to optimize other vital thermoelectric parameters. Herein, we present a more nuanced dilute doping strategy in GeTe, leveraging the multifaceted roles of small-size metal atoms. A mere 4% CuPbSbTe 3 introduction into GeTe swiftly suppresses rhombohedral distortion and optimizes carrier concentration through the aid of Cu interstitials. Additionally, the formation of multiscale microstructures, including zero-dimensional Cu interstitials, one-dimensional dislocations, two-dimensional planar defects, and three-dimensional nanoscale amorphous GeO 2 and Cu 2 GeTe 3 precipitates, along with the ensuing lattice softening, contributes to an ultralow lattice thermal conductivity. Intriguingly, dilute CuPbSbTe 3 doping incurs only a marginal decrease in carrier mobility. Subsequent trace Cd doping, employed to alleviate the bipolar effect and align the valence bands, yields an impressive figure-of-merit of 2.03 at 623 K in (Ge 0.97 Cd 0.03 Te) 0.96 (CuPbSbTe 3) 0.04. This leads to a high energy-conversion efficiency of 7.9% and a significant power density of 3.44 W cm−2 at a temperature difference of 500 K. These results underscore the invaluable insights gained into the constructive role of nuanced dilute doping in the concurrent tuning of carrier and phonon transport in GeTe and other thermoelectric materials. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of the thermoelectric properties of solid crystal YbxBi 2 − x Te3. This work presents the results of studies of the thermoelectric properties of YbxBi 2 − x Te3 (x ≤ 0. 1 0) solid solutions before and after annealing in the temperature range 300–580 K. Regularities of changes in the electrical conductivity, Seebeck coefficient, and total thermal conductivity of the samples depending on the content of ytterbium (Yb) are established. Dependences of electrical conductivity, Seebeck coefficient, and the thermal conductivity on temperature for the crystal under study are plotted. Temperature curves were recorded using a Termoscan-2 low-frequency temperature recorder at a heating rate of 283 K/min. Studies of conductivity σ , thermoelectric power (S) were carried out by the four-probe method at direct current in the temperature range of 300–600 K. Ohmic contacts were applied using alloys. It has been established that the optimal combination of these thermoelectric characteristics is achieved for the compositions x = 0. 1 , which are characterized by the maximum thermoelectric index (Z T = 0. 8 7) of the figure of merit in the temperature range of 420–500 K after annealing at 500 K for τ = 2 4 0 h. It was revealed that the YbxBi 2 − x Te3 systems under study are n-type semiconductor thermoelectric materials in the temperature range of 300–600 K. [ABSTRACT FROM AUTHOR]

Isovalent doping offers a method to enhance the thermoelectric properties of semiconductors, yet its influence on the phonon structure and propagation is often overlooked. Here, we take C d X ( X = T e ,   S e ) compounds as an example to study the role of isovalent doping in thermoelectrics by first-principles calculations in combination with the Boltzmann transport theory. The electronic and phononic properties of C d 8 S e 8 , C d 8 S e 7 T e , C d 8 T e 8 , and C d 8 T e 7 S e are compared. The results suggest that isovalent doping with C d X significantly improves the thermoelectric performance. Due to the similar properties of S e and T e atoms, the electronic properties remain unaffected. Moreover, doping enhances anharmonic phonon scattering, leading to a reduction in lattice thermal conductivity. Our results show that optimized p-type(n-type) ZT values can reach 3.13 (1.33) and 2.51 (1.21) for C d 8 T e 7 S e and C d 8 S e 7 T e at 900 K, respectively. This research illuminates the potential benefits of strategically employing isovalent doping to enhance the thermoelectric properties of C d X compounds. [ABSTRACT FROM AUTHOR]

Thermoelectric materials are capable of generating electrical energy in response to a temperature gradient. Non-renewable energy resources are depleting, so the development of renewable energy sources that are environmentally sustainable is essential. One potential application of these materials as an alternative energy source is in wearable electronics. Thermoelectric materials are used in common electrical devices, as well as by the military, in healthcare, and in space. As a ductile N-type semiconducting material, silver sulfide is one of the most promising materials in terms of thermoelectric potential. The properties of Ag2S can be improved by choosing the appropriate dopants. This study investigates the methods by which the thermoelectric, mechanical, and hardness properties of Ag2S are improved via Ge doping. The addition of Ge increases the Seebeck coefficient to a maximum of −87 μV·K−1 from −1051 μV·K−1 to P-type, bringing it closer to transitioning. In order to work, a thermoelectric generator requires both N- and P-type materials. By applying homojunctions made from similar materials, internal stresses caused by the varying thermal expansion rates of different materials are reduced. In order to demonstrate Ge integration, scanning electron microscopy and X-ray diffraction were applied to the sample microstructure. In addition, supplementation was used to increase the ductility and malleability of materials to make them suitable for power generation in wearable electronics. These materials showed significant power factor values according to room-temperature measurements. This proves that materials capable of generating usable voltage lie in the recommended ambient temperature range for the user's body, thus rendering them potential candidates for wearable electronics. [ABSTRACT FROM AUTHOR]

This study describes a method by which to synthesize SiO2-based graphene nanoballs (SGB) using atmospheric pressure chemical vapor deposition (APCVD) with copper vapor assistance. This method should solve the contamination, damage, and high costs associated with silica-based indirect graphene synthesis. The SGB was synthesized using APCVD, which was optimized using the Taguchi method. Multiple synthesis factors were optimized and investigated to find the ideal synthesis condition to grow SGB for thermoelectric (TE) applications. Raman spectra and FESEM-EDX reveal that the graphene formed on the silicon nanoparticles (SNP) is free from copper. The prepared SGB has excellent electrical conductivity (75.0 S/cm), which shows better results than the previous report. Furthermore, the SGB nanofillers in bismuth telluride (Bi2Te3) nanocomposites as TE materials exhibit a significant increment in Seebeck coefficients (S) compared to the pure Bi2Te3 sample from 109 to 170 μV/K at 400 K, as well as electrical resistivity decrement. This approach would offer a simple strategy to improve the TE performance of commercially available TE materials, which is critical for large-scale industrial applications. [ABSTRACT FROM AUTHOR]

In order to develop flexible thermoelectric materials with thermoelectric and mechanical properties, in this study, we designed and synthesized polythiophene derivatives with branched ethylene glycol polar side-chains named P3MBTEMT, which were used in combination with single-walled carbon nanotubes (SWCNTs) to prepare composite thin films and flexible thermoelectric devices. A comparison was made with a polymer named P3(TEG)T, which has a polar alkoxy linear chain. The UV-vis results indicated that the larger steric hindrances of the branched ethylene glycol side-chain in P3MBTEMT could inhibit its self-aggregation and had a stronger interaction with the SWCNTs compared to that of P3(TEG)T, which was also confirmed using Raman spectroscopy. When the mass ratio of SWCNTs to P3MBTEMT was 9:1 (represented as P3MBTEMT/SWCNTs-0.9), the composite film exhibited the highest thermoelectric properties with a power factor of 446.98 μW m−1 K−2, which was more than two times higher than that of P3(TEG)T/SWCNTs-0.9 (215.08 μW m−1 K−2). The output power of the thermoelectric device with P3MBTEMT/SWCNTs-0.9 was 2483.92 nW at 50 K, which was 1.66 times higher than that of P3(TEG)T/SWCNTs-0.9 (1492.65 nW). Furthermore, the P3MBTEMT/SWCNTs-0.5 showed superior mechanical properties compared to P3(TEG)T/SWCNTs-0.5. These results indicated that the mechanical and thermoelectric performances of polymer/SWCNT composites could be significantly improved by adding polar branched side-chains to conjugated polymers. This study provided a new strategy for creating high-performing novel flexible thermoelectric materials. [ABSTRACT FROM AUTHOR]

AbstractMiniaturization and integration of electronic equipment in aircraft have resulted in a substantial increase in thermal load. However, aircraft often experience acceleration maneuvering flights in supergravity environments, which makes comprehensive research on thermal management under supergravity conditions necessary. The influence of gravity on the thermal storage properties of composite phase change materials doped with graphene nanoparticles (GNP-PCM) was investigated in this study by simulation. Under 2g, 4g, 6g, 8g, and 10g gravity conditions, the melting time is reduced by 14.86%, 27.05%, 33.31%, 37.00%, and 39.79%, respectively, compared with normal gravity conditions. Moreover, the integration of the PCM with a thermoelectric power system facilitated waste heat utilization. Incorporating GNPs markedly enhances power generation efficiency under 10g supergravity conditions. With an open-circuit voltage of 0.8 V and a maximum output power of 0.11 W, the power generation reached 81.62 J, which is 53.91% higher than that of pure PCM. This enhancement can be attributed to the improved natural convection and accelerated melting rate facilitated by the GNPs. This study elucidates the underlying physical mechanisms affecting the melting rate of PCM under increased gravity conditions. Furthermore, coupling PCM with a thermal power generation system provides a rational approach for the reuse of waste heat. [ABSTRACT FROM AUTHOR]

The full-potential linearized augmented plane wave (FP-LAPW) approach of density functional theory has been utilized to systematically analyze the AgCoFeZ(Z = Al,Ga,Si,Ge, Sn), NiFeCrZ(Z = Al,Si,Ge,In) and NdCoMnGa materials. The electronic band structure and density of states (DOS) are determined using GGA, GGA + U, mBJ, mBJ + U and SCAN approximations. AgCoFeGe, AgCoFeSn, NdCoMnGa and NiFeCrAl exhibit half-metallic (HM) properties when their equilibrium lattice constants are optimally adjusted in the normal state and themagnetic moment of the alloys satisfies the value prescribed by the Slater-Pauling rule.We have analyzed the calculated DOS and energy bands of the alloys, and investigated the mechanism behind the formation of the HM band gap based on our research findings. The excellent HM property gives a good candidate for spin polarized material. Using spin density functional theory calculations, it is found that the given compounds are metallic in both spin channels. The thermoelectric properties have also been investigated in terms of Seebeck, electrical conductivity, thermal conductivity, power factor and figure of merit. [ABSTRACT FROM AUTHOR]

A novel ternary medium-entropy perovskite oxide, (Sr 1/3 Ba 1/3 Ca 1/3)TiO 3 , is reported for thermoelectric applications; it was synthesized via solid-state reaction and graphite burial sintering. The formation and stability of the single-phase structure were evaluated using thermodynamic calculations and the Goldschmidt's tolerance factor. The material was found to have a single-phase cubic perovskite structure with a homogeneous distribution of all elements. The medium entropy generates moderate carrier mobility, while the band flattening yields high Seebeck coefficient, resulting in a high power factor of 378.8 μW·m−1·K−2 at 773 K. The enhanced multi-phonon scattering derived from the medium entropy, oxygen vacancies, and porous structure significantly reduced the lattice thermal conductivity, with a lowest value of 1.90 W·m−1·K−1 at 773 K. As a result, a ZT max of 0.13 was attained at 773 K, which outperforms that of high-entropy SrTiO 3 -based oxides. This work provides a new direction to obtain high-performance thermoelectric materials through medium-entropy composition design. [ABSTRACT FROM AUTHOR]

New 2D layered materials WX2N4(X≐Si, Ge)1 are suitable for thermoelectric applications for a pretty good value of the figure of merit (ZT). Here, the thermoelectric properties of the 2D monolayer of WX2N4(X≐Si, Ge) using Density Functional Theory (DFT) is investigated combined with Boltzmann Transport Equation (BTE) along with spin‐orbit coupling (SOC). An excellent thermoelectric ZT$ZT$ of 0.91 (0.92 with SOC) is obtained at 900 K for p‐type WGe2N4, and a ZT$ZT$ of 0.81 (0.86 with SOC) is observed for n‐type at the same temperature. Furthermore, the WGe2N4 showed a ZT$ZT$ of more than 0.7 (0.79 with SOC) at room temperature for p‐type. On the other hand, the WSi2N4 showed a comparatively lower ZT$ZT$ at room temperature. However, the ZT$ZT$ value increases significantly at higher temperatures, reaching 0.72 (0.79 with SOC) and 0.71 (0.62 with SOC) for p and n‐type at 900 K, respectively. The electronic band structure is examined and discovered that WSi2N4 and WGe2N4 possess indirect bandgaps (BG) of 2.68 eV (2.57 eV with SOC) and 1.53 eV (1.46 eV with SOC), respectively, according to Heyd‐Scuseria‐Ernzerhof (HSE) approximation. These materials may also be useful in UV and visible range optoelectronic devices because of their strong absorption in the respective regions. [ABSTRACT FROM AUTHOR]

We have introduced an innovative method for preparing CuI-doped Bi 2 Te 3 films for the first time, which was also validated through ab initio calculations. The chemical reaction between the Cu-Bi 2 Te 3 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 2 Te 3 films. Additionally, appropriately doping Bi 2 Te 3 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 2 Te 3. Leveraging the enhanced electrical transport properties achieved through CuI doping, the maximum power factor of the (CuI) 0.2 Bi 2 Te 2.9 film reaches approximately 2.40 × 10−3 W/mK2 at 423 K, representing a 66 % enhancement compared to that of the Bi 2 Te 2.9 film, which has a power factor of 1.44 × 10−3 W/mK2. [ABSTRACT FROM AUTHOR]

This work covers a numerical analysis of the design and optimization of a thermoelectric cooler (TEC) operated by a thermoelectric generator (TEG). The aim of the work was to design the optimum mini refrigerator for tractors and also to provide cooling using the energy produced in the TEG used in the tractor. Thanks to the TEC powered with the TEG system, farmers will be able to preserve their food during working hours without additional fuel consumption. When the literature is examined, no study has been found in which cooling is done by using the compressor air of turbocharged systems. Therefore, this work will make an important contribution to the literature. According to the numerical results obtained, while the electrical power requirement was 34.78 W at an outdoor temperature of 30 °C, it was 26.54 W at an outdoor temperature of 15 °C. In other words, while the coefficient of performance was obtained as 0.301 at 15 °C, it was determined as 0.219 at 30 °C. In addition, while the electrical power value produced by the TEG system used in the tractor for an outdoor temperature of 15 °C was 50.71 W, it was 38.84 W at an outdoor temperature of 30 °C. [ABSTRACT FROM AUTHOR]

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In this work, a simple, cost-effective successive ionic layer adsorption and reaction (SILAR) deposition technique has been used to deposit a high-quality tin selenide (SnSe) thin film onto a glass substrate. Structural, morphologic, and thermoelectric properties have been characterized for the prepared thin film. X-ray diffraction (XRD) results of the SnSe thin film reveal an orthorhombic structure phase. The morphological properties of the prepared thin films have been studied using field emission scanning electron microscopy (FESEM). The stoichiometric composition of the deposited thin film and the elemental binding energies of the Sn and Se elements have been investigated with energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The Fourier transformation infrared (FTIR) spectrum of the SnSe thin film displays vibrational modes of chalcogenides bonds. These results suggest that the developed thin film is crystalline, uniform, and without impurities and is appropriate for energy harvesting applications. The prepared thin film's Seebeck coefficient and electrical resistivity were estimated through ZEM-3 from room temperature to 600 K. The power factor was evaluated. A substantially high electrical conductivity is observed, which decreases somewhat with temperature, suggesting a semimetal conducting transport—the absolute values of the Seebeck coefficient increase with temperature. The resulting power factor showed the highest values near room temperature and a somewhat decreasing trend as the temperature increased. Despite lower values of the Seebeck coefficient, the substantially enhanced power factor is due to the higher electrical conductivity of the thin film, superior to that reported previously. This precursor study demonstrates promising results for developing high-performance flexible thermoelectric devices via a simple and facile SILAR strategy. [ABSTRACT FROM AUTHOR]

Finding a real thermoelectric (TE) material that excels in various aspects of TE performance, mechanical properties, TE power generation, and cooling is challenging for its commercialization. Herein, we report a novel multifunctional Ge0.78Cd0.06Pb0.1Sb0.06Te material with excellent TE performance and mechanical strength, which is utilized to construct candidate TE power generation and cooling devices near room temperature. Specifically, the effectiveness of band convergence, combined with optimized carrier concentration and electronic quality factor, distinctly boosts the Seebeck coefficient, thus greatly improving the power factor. Advanced electron microscopy observation indicates that complex multi‐scale hierarchical structures and strain field distributions lead to ultra‐low lattice thermal conductivity, and also effectively enhance mechanical properties. High ZT ~ 0.6 at 303 K, average ZTave ~ 1.18 from 303 to 553 K, and Vickers hardness of ~200 Hv in Ge0.78Cd0.06Pb0.1Sb0.06Te are obtained synchronously. Particularly, a 7‐pair TE cooling device with a maximum ΔT of ~45.9 K at Th = 328 K, and a conversion efficiency of ~5.2% at Th = 553 K achieving in a single‐leg device. The present findings demonstrate a unique approach to developing superior multifunctional GeTe‐based alloys, opening up a promising avenue for commercial applications. [ABSTRACT FROM AUTHOR]

Selenium selenide (SnSe) has attracted widespread attention because of its environmental friendliness and ultra-low lattice thermal conductivity. Single-crystal SnSe has been discovered to exhibit a high ZT value, but its mechanical qualities are weak and its manufacturing process is complicated, rendering it unsuitable for commercial usage. Polycrystalline SnSe is facile to synthesis; however, due to its weakened electrical performance, it has a poor thermoelectric property. In this study, polycrystalline SnSe samples are prepared using hydrothermal synthesis combined with vacuum sintering, and their thermoelectric properties are modulated using alkali metal element doping. [ABSTRACT FROM AUTHOR]

This study introduces Sn-substituted higher manganese silicides (MnSi1.75, HMS) synthesized via an arc-melting process followed by spark plasma sintering (SPS). The influences of Sn concentrations on the thermoelectric performance of Mn(Si1−xSnx)1.75 (x = 0, 0.001, 0.005, 0.01, 0.015) are systematically investigated. Our findings reveal that metallic Sn precipitates within the Mn(Si1−xSnx)1.75 matrix at x ≥ 0.005, with a determined solubility limit of approximately x = 0.001. In addition, substituting Si with Sn effectively reduces the lattice thermal conductivity of HMS by introducing point defect scattering. In contrast to the undoped HMS, the lattice thermal conductivity decreases to a minimum value of 2.0 W/mK at 750 K for the Mn(Si0.999Sn0.001)1.75 sample, marking a substantial 47.4% reduction. Consequently, a figure of merit (ZT) value of ~0.31 is attained at 750 K. This considerable enhancement in ZT is primarily attributed to the suppressed lattice thermal conductivity resulting from Sn substitution. [ABSTRACT FROM AUTHOR]

Bismuth sulfide (Bi2S3) is a promising thermoelectric material with earth‐abundant, low‐cost, and environment‐friendly constituents. However, it shows poor thermoelectric performance due to its extremely low electrical conductivity derived from the low electron concentration. Here, a high‐performance Bi2S3‐based material is reported to benefit from the Fermi level tuning by Ag and Cl co‐doping and defect engineering by introducing dense low‐angle grain boundaries. Both Ag and Cl act as donors in Bi2S3, upshifting the Fermi level. This increases the electron concentration without degrading the electron mobility, thereby obtaining improved electrical conductivity. The electron localization function (ELF) contour map indicates that interstitial Ag causes electron delocalization, showing higher electron mobility in Bi2S3. More importantly, dense low‐angle grain boundaries block phonon propagation, yielding an ultralow lattice thermal conductivity of 0.30 W m−1 K−1. Consequently, a record ZT value of ≈0.9 at 676 K is achieved in the Bi2Ag0.01S3‐0.5%BiCl3 sample. [ABSTRACT FROM AUTHOR]

The discovery of ductile Ag2(S, Se, Te) materials opens a new avenue toward high‐performance flexible/hetero‐shaped thermoelectrics. Specifically, the cubic‐structured materials are quite attractive by combining remarkable plasticity, decent thermoelectric figure of merit (zT), and no phase transition above room temperature. However, such materials are quite few and the understanding is inadequate on their mechanical and thermoelectric properties. Enlightened by the high‐entropy principles, a series of pseudo‐ternary Ag2S‐Ag2Se‐Ag2Te alloys is designed and comprehensive diagrams of composition‐structure‐plasticity‐zT are compiled. Subsequently, the compositional region for the cubic phase is outlined. As a high‐entropy example featuring with anion‐site alloying and disordered Ag ions, Ag2‐xS1/3Se1/3Te1/3 materials exhibit impressively large elongations of 60–97%, ultralow lattice thermal conductivities of ≈0.2 W m−1 K−1, and decent zT values of 0.45 at 300 K, 0.8 at 460 K. The materials can be readily rolled into thin foils, showing excellent flexibility. Finally, a six‐leg in‐plane device is fabricated, achieving an output voltage of 13.6 mV, a maximal power of 12.8 µW, and a power density of 14.3 W m−2 under the temperature difference of 30 K, much higher than the organic counterparts. This study largely enriches the members of cubic ductile inorganic materials for the applications in flexible and hetero‐shaped energy and electronic devices. [ABSTRACT FROM AUTHOR]

Bismuth sulfide (Bi2S3) is a promising thermoelectric material with earth‐abundant, low‐cost, and environment‐friendly constituents. However, it shows poor thermoelectric performance due to its extremely low electrical conductivity derived from the low electron concentration. Here, a high‐performance Bi2S3‐based material is reported to benefit from the Fermi level tuning by Ag and Cl co‐doping and defect engineering by introducing dense low‐angle grain boundaries. Both Ag and Cl act as donors in Bi2S3, upshifting the Fermi level. This increases the electron concentration without degrading the electron mobility, thereby obtaining improved electrical conductivity. The electron localization function (ELF) contour map indicates that interstitial Ag causes electron delocalization, showing higher electron mobility in Bi2S3. More importantly, dense low‐angle grain boundaries block phonon propagation, yielding an ultralow lattice thermal conductivity of 0.30 W m−1 K−1. Consequently, a record ZT value of ≈0.9 at 676 K is achieved in the Bi2Ag0.01S3‐0.5%BiCl3 sample. [ABSTRACT FROM AUTHOR]