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In this work, we report the thermoelectric behaviour of flexible fabric-based Mo doped CuAl 2 O 4. The doped Mo atom occupies the interstitial positions of the spinel lattice of CuAl 2 O 4. This results the lattice expansion and also provides the carrier electrons. Initially, the pristine CuAl 2 O 4 has the carrier concentration of 2.81 × 1014 cm−3, while doping with molybdenum, it not only increases the concentration of the carriers (about −7.65 × 1015 cm−3), but also changes the carrier type. The minimum doping (2 %) of molybdenum to spinel CuAl 2 O 4 (CuAl 2 O 4 Mo 0.02) creates the fermi level near to the conduction band, which reduces the band gap and results in the effective electrical conductivity as 0.69 Scm−1 at 340 K. The heavy doping enhances the scattering process. This leads to deduction of mobility and lower the electrical conductivity. The highest power factor of 0.0599 μWcm−1K−2 is achieved for the CuAl 2 O 4 Mo 0.06 sample at 300 K. This is due to the high Seebeck coefficient value of the sample and has an ultralow thermal conductivity value of 0.056 W/mK. The highest output voltage of 3.9 mV is achieved for parallelly connected p-type CuAl 2 O 4 -n-type CuAl 2 O 4 Mo 0.02 thermoelectric device at the temperature difference of ΔT = 4.1 K. This research findings justify, the doping of molybdenum in the spinel lattice effectively enhances the thermoelectric properties of CuAl 2 O 4 and provide the new ideas for the flexible, wearable fabric based thermoelectric research. [Display omitted] [ABSTRACT FROM AUTHOR]

So far, the method of optimizing the thermoelectric properties of skutterudite CoSb 3 is usually to achieve a breakthrough in high-properties thermoelectric merit by selecting excellent doping atoms and determining a reasonable percentage of atoms. In this study, we achieved the preparation of small atomic radius Al-filled Co 4 Sb 11.5 Te 0.5 compounds by high-temperature and high-pressure (HTHP) synthesis methods. The thermoelectric properties of the samples Al x Co 4 Sb 11.5 Te 0.5 were optimized from two dimensions: synthesis pressures (1.0 GPa, 1.5 GPa, 2.0 GPa) and Al filling concentration (x = 0.1, 0.2, 0.3, 0.5), ultimately achieving effective decoupling of electron-phonon transport properties. The experimental results show that Al doping can optimize the electrical transport properties of materials effectively, rapid synthesis method of HTHP can introduce abundant grain boundaries, diversification of grain sizes, a large number of dislocations and widely distributed nano second phase, etc. These microstructures in bulk materials form a multi-scale phonon scattering network in situ, which can effectively scatter phonons and reduce the lattice thermal conductivity effectively. After optimizing the synthesis pressure and Al filling concentration through orthogonal transformation, the sample Al 0.3 Co 4 Sb 11.5 Te 0.5 prepared at a synthesis pressure of 1.5 GPa obtained a minimum lattice thermal conductivity value of 0.88 W m−1 K−1, a maximum power factor of 40.96 μ W cm−1 K−2 and a maximum zT value of 1.18 at 773.15 K. [ABSTRACT FROM AUTHOR]

The development of Ga-doped Zinc Oxide (GZO) films from nontoxic, abundant elements using a cost-effective and scalable approach is crucial for the profitability and sustainability of thermoelectric applications. Challenges in formulating GZO film inks have led to extensive experimentation to enhance their thermal, structural, mechanical, and room-temperature thermoelectric properties by adjusting ink concentration and annealing treatment. Increasing the GZO nanoparticle concentration reduced the melting temperature and crystallinity, whereas annealing at 200 °C decomposed the polyethylene oxide (PEO) binder. TEM analysis revealed the polycrystalline structure of the GZO nanoparticles and their interaction with the binder, while XRD patterns confirmed the characteristic peaks of the GZO films; annealing effectively eliminated the PEO diffraction peaks. The GZO films from the concentrated 1.24M ink exhibited minimal grain growth, reduced lattice strains, uniform elemental distribution, and enhanced surface texture and conductivity, which were further improved by annealing. Increasing the GZO nanoparticle concentration facilitated the formation of a conductive network, while annealing enhanced the conductivity by promoting the formation of a cohesive, interconnected network through impurity removal, nanoparticle redistribution, and coalescence. Consequently, the annealed 1.24M film demonstrated the highest nanohardness of 791 MPa and a thermoelectric power factor of 1.78 nW/m∙K2 at room temperature, which were attributed to enhanced electrical conductivity and Seebeck coefficient through concentration and annealing synergies. [ABSTRACT FROM AUTHOR]

Heat is produced by all machinery, including microprocessors and jet engines, as well as by industrial processes that produce goods from steel to food. There is still a strong desire for alternative energy sources in this day of ecologically conscious and sustainable energy needs. The recovery of heat from waste heat into beneficial electrical energy provides a simple energy source with enormous potential. Thermoelectrics is one of the popular technologies, which can convert heat into electricity, making them useful for power generation. Tin telluride (SnTe), a significant type of newly developed thermoelectric material, has drawn a lot of attention due to its low toxicity and environmentally friendly characteristics. Here, we synthesize Bi/Se co-doped SnTe (Sn 1-x Bi x Te 0.97 Se 0.03 (x = 0, 0.02, 0.04, 0.06)) samples by employing the solid-state metathesis route. The results of this work suggest that the combined action of cationic and anionic substitution of Bi and Se to SnTe matrix could potentially modify the microstructure and band structure of SnTe, thereby effectively improving its electronic, mechanical, and thermal transport properties. In line with the experimental findings, the samples show degenerate semiconducting electronic transport behaviour throughout the temperature range. The maximum Seebeck coefficient is found to be ∼84 μV/K and the total thermal conductivity is reduced to 1.6 W/mK at 573 K in a 6 % Bi-doped sample, which is 2.2 times less than the pristine sample. The Sn 0.94 Bi 0.06 Te 0.97 Se 0.03 sample has a maximum ZT of approximately 0.23 at 573 K, which is three times higher than the pristine sample because of the combined regulation of cation-anion co-doping and an elevated power factor of 936 μW/K2m in Sn 0.96 Bi 0.04 Te 0.97 Se 0.03 sample at 573 K, which is 1.82 times higher than that of pristine SnTe. Considering these findings, it appears that Bi-Se co-doped SnTe is a promising material for thermoelectric applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This work presents a comparative analysis of pure and Ag-intercalated Ca 3 Co 4 O 9 multilayer thermoelectric materials prepared through the hot-uniaxial pressing technique. Samples were prepared by attrition milling and hot-pressed at 900 °C and 55 MPa for 1 h. They were mirror polished, and some of them were stacked with and without intermediate Ag foil and hot-pressed again at 900 °C and 52 MPa for 1 h. Out-of-plane XRD showed that samples are nearly single-phase, and the grains are well oriented with their ab-plane perpendicular to the pressure direction. Microstructural studies confirmed perfect welding in the multilayer samples accompanied by the formation of a very thin layer containing larger grains and notable Ag diffusion close to the Ca 3 Co 4 O 9 /Ag interface. Three-point bending stresses have been increased in Ag-containing samples, while microhardness has been raised in all samples hot-pressed twice. Thermoelectric measurements showed a decrease of thermal gradient along the Ag-containing sample, together with a drastic decrease of electrical resistivity when compared to the Ag-free ones. However, the Ag-layers have promoted a drastic decrease in the Seebeck coefficient, reflected in a notable reduction of the power factor of Ca 3 Co 4 O 9 /Ag multilayer composites. Nevertheless, these results show that it is possible to use these materials to reduce Joule heating and increasing the compatibility with the welding compounds when building thermoelectric modules. Moreover, they open a new research line searching for larger S compounds to be intercalated with Ag foils. [ABSTRACT FROM AUTHOR]

Microstructures and thermoelectric properties of porous Ca 3 Co 4 O 9 ceramics were investigated, which were prepared by tert-butanol alcohol (TBA)-based freeze casting method. The honeycomb-like porous Ca 3 Co 4 O 9 ceramic presented an average pore diameter of 2.5 μm and the porosity of 65 %. The excellent low total thermal conductivity of 0.354 W (m K)−1 was obtained along the parallel channel direction, which was attributed to the oriented pores and isolated pores dispersed in ceramics matrix. The compositing thermal conductivity behavior of porous Ca 3 Co 4 O 9 ceramics was jointly regulated by the parallel and Maxwell-Eucken (ME-1) models. The ZT value reached 0.37 at 1073 K. This work provides an effective strategy to improve thermoelectric properties of oxides thermoelectric ceramics, which can complete the decoupling of electrical and thermal properties. [ABSTRACT FROM AUTHOR]

Cu 3 SbSe 4 is recognized for its abundant elemental availability, cost-effectiveness, and non-toxic properties, making it a promising candidate for thermoelectric applications at medium temperatures. This study explored the preparation of Bi/Fe, Ag/Fe, and Ag/Bi double-doped Cu 3 SbSe 4 ceramics using vacuum melting and cold isostatic pressing techniques. The focus was on examining the influence of these dopants on the microstructural and thermoelectric performances of Cu 3 SbSe 4. The analysis revealed the presence of Cu 3 SbSe 4 and Cu 2− x Se phases in the doped samples. Double doping optimized the carrier concentration, increased the effective mass, and significantly enhanced the electrical conductivity from 12.45 to 64.01 S cm−1. Notably, the power factor of the Cu 2.85 Ag 0.15 Sb 0.985 Bi 0.015 Se 4 sample reached 649.1 μWm−1K−2 at 573 K. Furthermore, the thermal conductivity was significantly reduced to 0.73 W/mK. The maximum ZT value of the Cu 2.85 Ag 0.15 Sb 0.985 Bi 0.015 Se 4 sample was 0.47 at 573 K. These breakthrough results demonstrate that dual doping markedly enhances the thermoelectric properties of the Cu 3 SbSe 4 system. [ABSTRACT FROM AUTHOR]

Besides excellent thermoelectric properties, composed of earth-abundant elements and featuring simple chemical compositions are more conducive to the practical fabrication and utilization of thermoelectric materials. In this study, a tellurium-free thermoelectric compound, AgSbSe 2 , was synthesized, and the impact of Ag deficiencies on its thermoelectric performance was examined. It was found that the density of charge carriers of AgSbSe 2 can be effectively modulated by introducing slight Ag deficiencies, thereby significantly optimizing its electrical transport performance. A peak power factor of 6.63 μWcm−1K−2 @623 K is achieved in the sample with a composition of Ag 0.99 SbSe 2 , which is similar to the maximum value observed in Pb doped samples prepared by the same experimental production. Meanwhile, extremely low thermal conductivity was restrained in AgSbSe 2 with Ag deficiencies due to the effect of phonon scattering caused by crystal defects, which offsets the increased electrical thermal conductivity. Finally, a maximum zT value of 0.97 @623 K is obtained for Ag 0.99 SbSe 2 , which is comparable to that of heavily doped AgSbSe 2 with the conventional divalent cations doping at the Sb site. [ABSTRACT FROM AUTHOR]

The prime goal of this novel work is to investigate the efficacy of spinel zinc ferrite as a thermoelectric material and its performance enhancement for high temperature applications. Zn 1-x Ni x Fe 2 O 4 (0 ≤ x ≤ 0.2) were prepared by sol-gel method and their structural, morphological, and thermoelectric behaviours were examined as functions of composition and temperature. Among the studied compositions, Zn 0.8 Ni 0.2 Fe 2 O 4 exhibits the highest electrical conductivity (σ) of 49.83 S/m, the largest power factor of 6.66 μW/mK2, and the lowest thermal conductivity (κ) of 0.36 W/mK at 947 K, thus extending to an overall enhancement in the thermoelectric figure of merit (zT). Conduction through electron hopping is proven to be the main driving force for the enhancement in electrical and thus thermoelectric properties. Results reveal that thermoelectric properties of ZnFe 2 O 4 can potentially be enhanced by the doping Ni at Zn site and opens up an exciting opportunity for the utilization of this spinel ferrite as a novel thermoelectric material for applications involving elevated temperatures. [Display omitted] • Thermoelectric figure of merit of ZnFe 2 O 4 was considerably enhanced by doping Ni. • Electron hopping is found to be one of the major contributors for the enhancement of electrical conductivity. • The dopant is also effective in reducing the thermal conductivity of ZnFe 2 O 4 at higher temperatures. • The results indicate that the studied material is suitable for high temperature (>700K) thermoelectric applications. [ABSTRACT FROM AUTHOR]

Donor-doped SrNb 2 O 6 -based materials are regarded as highly promising candidates for high-temperature thermoelectric applications. The Sr 0.6 La 0.4 Nb 2 O 6-δ /x wt% Ti (x = 1, 5, 10, 15) composite ceramics thermoelectric materials were prepared and the mechanism for enhancing their thermoelectric properties was investigated. The experimental results demonstrate that during sintering, nano-additive titanium powder undergoes oxidation to form TiO 2. The inclusion of a secondary phase ultimately leads to successful reduction in electrical resistivity within the composite oxides. Due to crystal defects, complex structure and phonon scattering at grain boundaries, the samples consistently exhibit low thermal conductivity values below 3.0 W m−1K−1. Among them, the sample doped with 10 wt% Ti shows the highest PF value (470.0 μW/mK2 at 1073 K), demonstrating a significant increase in power factor of 280 % compared to Sr 0.6 La 0.4 Nb 2 O 6 without the Ti composite. Consequently, the Sr 0.6 La 0.4 Nb 2 O 6-δ /10 wt% Ti composite material achieved a maximum ZT value of 0.20, representing a fifty-three percent enhancement compared to the undoped sample. [ABSTRACT FROM AUTHOR]

High-pressure effects can be used to effectively optimize the thermoelectric performance of wide-bandgap oxides. We build upon this finding to show that the synergistic effects of doping with aluminum and graphene composite give excellent thermoelectric performance under high pressure. By employing the parabolic band model, the Pisarenko curves are derived at different pressures, coupled with the band structure of Al-doped ZnO. An analysis indicates that pressure-induced narrowing of the bandgap in Al-doped ZnO reduces the electron excitation energy, thereby optimizing the electrical properties of the samples. The Debye Callaway model is also used to fit the lattice thermal conductivity of the samples, thus enabling an in-depth analysis of the phonon scattering mechanisms. Our analysis suggests that graphene composites significantly enhance point defect scattering and Umklapp scattering, thus increasing the phonon relaxation time and effectively reducing the lattice thermal conductivity of the samples. The improvement in the figure of merit (zT) of ZnO is attributed to the simultaneous enhancement of its electrical properties under high pressure and the synergistic optimization of reducing the lattice thermal conductivity through doping and composites. In this work, we consider a fixed doping ratio of Al and a constant proportion of graphene composite, and analyze the microstructure and thermoelectric properties of 0.1C–ZnAl 0.04 O (C–ZnAlO) samples synthesized under pressures ranging from 1 to 5 GPa, with the aim of elucidating the influence of pressure and graphene composite on the electro-acoustic transport properties of ZnO. We find that the zT value for a sample synthesized at 5 GPa is increased to 0.27 at 973 K. [ABSTRACT FROM AUTHOR]

ZnO is a promising thermoelectric ceramic material, but the low electrical conductivity and high thermal conductivity restrict its satisfactory thermoelectric performance. Chemical doping is an effective way to improve the thermoelectric properties of ZnO. Due to the valence states and similar ionic radii of Fe3+ and Zn2+, Fe was selected as the effective dopant for ZnO. In this work, Fe-doped ZnO samples were prepared using hydrothermal synthesis and microwave sintering technology under oxygen-depleted conditions. The electrical conductivity of sintered Fe-doped ZnO was greatly improved owing to the energy band adjustment. The maximum power factor of 3108 μW/mK2 at 800 K was obtained from Zn 0.997 Fe 0.003 O, which is about 4.4 times greater than that of pure ZnO. Meanwhile, the small grain size (300–500 nm) and residual pores resulted from microwave rapid sintering in an oxygen-depleted environment, as well as the point defects caused by Fe3+ substituting for Zn2+, significantly reduced the thermal conductivity. Finally, the highest ZT value of 0.91 has been achieved in Zn 0.997 Fe 0.003 O at 800 K. [ABSTRACT FROM AUTHOR]

We herein introduce a microwave-assisted solid state technique to synthesize zintl compounds YbCd 2-x Zn x Sb 2 (0.0 ≤ x ≤ 2.0) in short time of 10 min by utilizing an active carbon as a susceptor material. Here, we report an energy-saving preparation route using a domestic microwave oven. A microwave susceptor material rapidly heats the elemental starting materials inside an evacuated quartz ampoule resulting in near single phase compounds. By studying the crystal structure using X-Ray diffraction (XRD) and SEM-EDS, the hexagonal crystal structures of the prepared samples were identified. Thermoelectric characterizations have been performed for all obtained samples and among them the compound YbCd 1. 6 Zn 0.4 Sb 2 is found as the best one because it has Seebeck coefficient of −22.68 μV/k, and power factor of 8.20 μWcm−1k−2 at 523 K with carrier concentration of 3.04 × 1021 cm−3 at 300 K. [ABSTRACT FROM AUTHOR]

The Bi 2 Sr 2 Co 2 O y ceramic, known for its stability as a p-type thermoelectric material, has limited thermoelectric performance that necessitates enhancement. In this study, Bi 2- x Cu x Sr 2 Co 2 O y (x = 0, 0.025, 0.05, 0.1, 0.2) ceramic samples were synthesized using the conventional solid-state reaction method. Substitution of Cu2+ for Bi3+ in the samples increased carrier concentration, significantly reducing electrical resistivity. Utilizing the single parabolic band (SPB) model, it was determined that Cu incorporation led to an increased effective mass, thereby enhancing the Seebeck coefficient. Additionally, fine grains and lattice defects induced by Cu2+ substitution effectively scattered phonons, resulting in an ultra-low thermal conductivity of 0.59 Wm−1K−1 at 923 K for the Bi 1.8 Cu 0.2 Sr 2 Co 2 O y sample. Consequently, Cu substitution optimized both the electrical and thermal transport properties of Bi 2-x Cu x Sr 2 Co 2 O y samples. The dimensionless thermoelectric figure of merit (ZT) for Bi 1.95 Cu 0.05 Sr 2 Co 2 O y reached 0.31 at 923 K, representing a 63 % increase over the pristine Bi 2 Sr 2 Co 2 O y sample. [ABSTRACT FROM AUTHOR]

A new preparation process for silicon carbide (SiC) powder is developed. In the Si–(C) –PTFE–Ar system, the grain size and morphology of the product 3C–SiC were controlled by adding a carbon source (graphite) and changing the percentage of polytetrafluoroethylene (PTFE) (0%, 10%, and 20%). The experimental results showed that the SiC powders prepared using a molar ratio of 1:1 silicon powder to graphite, plus 20% PTFE have a uniform particle size distribution (∼130 nm), a lamellar structure made of spherical particle stacking, a small bandgap (1.80 eV), a high carrier concentration, and a large number of lattice defects. These properties are expected to increase the electrical conductivity of 3C–SiC and decrease its thermal conductivity, thus providing a promising feedstock preparation option for SiC thermoelectric materials. In addition, the mechanism of PTFE in the preparation of SiC reactions was studied in detail. [ABSTRACT FROM AUTHOR]

Highly stable thermoelectric materials based on inexpensive elements have great potential for heat recovery in high temperature applications. TiO 2-d and SrTiO 3 based thermoelectric materials are of great interest due to this reason. In this study TiO 2 –SrF 2 based compounds were produced, to study the effect of fluorine on the thermoelectric properties of TiO 2 type materials. From XPS measurements it is clear that some exchange from the TiO 2 –SrF 2 happens forming a TiO x F y type phase. The electronic properties of the compound are very similar to the electronic properties of reduced TiO 2 while some improvement is seen in the reduction of the thermal conductivity. A higher activation energy in the SrF 2 rich samples might allow for increased electronic conductivity at higher temperatures interesting for further studies. [ABSTRACT FROM AUTHOR]

The thermoelectric properties of monolayered MnBi2Te4 are investigated using first‐principles calculations based on density functional theory (DFT) and Boltzmann transport theory. Our research indicates significant thermoelectric performance in monolayered MnBi2Te4, with a maximum figure of merit (zT$zT$) and power factor (PF${\mathrm{PF}}$) ranging from approximately 3.58 to 9.267 and 0.012 W/K2m${\mathrm{W}}/{\mathrm{K}}^2{\mathrm{\ m}}$ to 0.021 W/K2m${\mathrm{W}}/{\mathrm{K}}^2{\mathrm{\ m}}$ across a temperature range of 300–700 K. The exceptional thermoelectric performance of monolayered MnBi2Te4 can be attributed to its unique structural and electronic properties, which lead to ultralow lattice thermal conductivity and high electrical transport properties. Ultralow lattice thermal conductivity as low as 0.32W/mK$0.32\ {\mathrm{W}}/{\mathrm{m\ K}}$ at 300 K is found in the monolayered MnBi2Te4, which is mainly contributed from the anharmonic scatterings of low‐frequency phonons. And high electronic conductivity and a notable Seebeck coefficient are also observed in our system, which has close relationship with its distinctive electronic band structure. Besides, the two‐dimensional structure makes it a great candidate to holding greater PF by enhancing the quantum confinement. Our findings may lay a strong theoretical groundwork for future experimental inquiries. Subsequent experimental investigations will be crucial to confirm these findings, refine synthesis methods, and explore the practical applications of monolayered MnBi2Te4 in thermoelectric devices. [ABSTRACT FROM AUTHOR]

We employ advanced first principles methodology, merging self‐consistent phonon theory and the Boltzmann transport equation, to comprehensively explore the thermal transport and thermoelectric properties of KCdAs. Notably, the study accounts for the impact of quartic anharmonicity on phonon group velocities in the pursuit of lattice thermal conductivity and investigates 3ph and 4ph scattering processes on phonon lifetimes. Through various methodologies, including examining atomic vibrational modes and analyzing 3ph and 4ph scattering processes, the article unveils microphysical mechanisms contributing to the low κL within KCdAs. Key features include significant anisotropy in Cd atoms, pronounced anharmonicity in K atoms, and relative vibrations in non‐equivalent As atomic layers. Cd atoms, situated between As layers, exhibit rattling modes and strong lattice anharmonicity, contributing to the observed low κL. Remarkably flat bands near the valence band maximum translate into high PF, aligning with ultralow κL for exceptional thermoelectric performance. Under optimal temperature and carrier concentration doping, outstanding ZT values are achieved: 4.25 (a(b)‐axis, p‐type, 3 × 1019 cm−3, 500 K), 0.90 (c‐axis, p‐type, 5 × 1020 cm−3, 700 K), 1.61 (a(b)‐axis, n‐type, 2 × 1018 cm−3, 700 K), and 3.06 (c‐axis, n‐type, 9 × 1017 cm−3, 700 K). [ABSTRACT FROM AUTHOR]

The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure. Designing thermoelectric materials with a simple, structurally‐uniform interface provides a facile way to understand how these interfaces influence the transport properties. Here, we synthesized Bi2−xSbxTe3 (x = 0, 0.1, 0.2, 0.4) nanoflakes using a hydrothermal method, and prepared Bi2−xSbxTe3 thin films with predominantly (0001) interfaces by stacking the nanoflakes through spin coating. The influence of the annealing temperature and Sb content on the (0001) interface structure was systematically investigated at atomic scale using aberration‐corrected scanning transmission electron microscopy. Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the (0001) interface. As such it enhances interfacial connectivity and improves the electrical transport properties. Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient. Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient, the maximum power factor of the Bi1.8Sb0.2Te3 nanoflake films reaches 1.72 mW m−1 K−2, which is 43% higher than that of a pure Bi2Te3 thin film. [ABSTRACT FROM AUTHOR]

The emergence of new functionalities in transition metal oxides and their interfaces poses an important challenge. Many recent discoveries regarding the polar/nonpolar interface between perovskite oxides open new avenues for modern applications. SrTiO3/LaCrO3 heterostructures are particularly intriguing due to a polar discontinuity along the [001] direction, giving rise to two distinct and controllable interface structures, TiO2-LaO and SrO-CrO2, which exhibit new and promising electronic and thermoelectric transport properties. Through a combination of first-principles simulations based on density functional theory and the Boltzmann transport equation, we have calculate and discuss the structural, electronic, valence band offset, and thermoelectric properties of SrTiO3, LaCrO3, and SrTiO3/LaCrO3 heterostructures. The temperature dependence of the Seebeck coefficient, electrical conductivity, electronic thermal conductivity, and figure of merit is determined. Furthermore, we highlight the effect of the interface between the polar perovskite LaCrO3 and the nonpolar SrTiO3(001) on the thermoelectric properties, wherein we observed a change in the metal–semiconductor transport behavior. These results constitute an important advancement in our understanding of the thermoelectric properties at polar/nonpolar perovskite oxide interfaces. [ABSTRACT FROM AUTHOR]

Copper selenide (Cu2Se) has attracted extensive research interest in the field of thermoelectricity due to its large abundance of constituent elements, environmental friendliness, and excellent thermoelectric properties. In this study, a facile and low-cost hydrothermal synthesis method combined with vacuum sintering was used for Cu2Se-based sample preparation, and the possibility of improving the thermoelectric properties of Cu2Se by doping with rare earth elements (Tm, Er, Lu) was explored using experimental tests and density functional theory calculations. The electronic structure calculations show that the electrical conductivity is increased due to the increased electron density after rare earth element doping. At the same time, the sharp increase in the density of states at the Fermi level after rare earth element doping enhances the Seebeck coefficient of the Cu2Se matrix. The experimental results show that the thermoelectric properties of all the samples doped with rare earth elements (Tm, Er, Lu) were improved compared to the Cu2Se matrix. The doping of rare earth elements led to an increase in point defects and the formation of pores in the samples, which play an important role in reducing the thermal conductivity. Among them, the Tm-doped Cu1.995Tm0.005Se sample reached a maximum ZT value of 0.80 at 773 K, which is a nearly 43% increase compared to the Cu2Se matrix (ZTmax = 0.56). [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) GeTe is a popular medium-temperature thermoelectric material, but few studies have focused on strategies for improving its thermoelectric performance. To further investigate the thermoelectric properties of two-dimensional GeTe, different atomic defects are introduced, and the electronic structure and thermoelectric properties are systematically investigated via first-principles calculations and the semiclassical Boltzmann theory. Compared with that of three-dimensional (3D) GeTe, the Seebeck coefficient of 2D GeTe increases from 144 μV K−1 to 560 μV K−1 at 700 K, and the thermal conductivity decreases from 3.3 W m−1 K−1 to 2.3 W m−1 K−1. Thus, the ZT value increases from 0.8 to 1.14. On the basis of these results, the influence of vacancy atomic defects on the thermoelectric performance is investigated. With single-atom defects (SV-Ge and SV-Te), the ZT value increases at constant temperature. However, for double-atom defects in monolayer GeTe, the ZT value increases when DV-585 defects are present but decreases to varying degrees when DV-Ge and DV-Te defects are present. The ZT value of monolayer GeTe with DV-585 defects has an average increase of 0.56 at 300–800 K, which accords well with the experimental results. This study indicates that introducing single-atom vacancy defects somewhat improves the thermoelectric performance of monolayer GeTe, which provides an important point of reference for the development of GeTe in the two-dimensional materials field. [ABSTRACT FROM AUTHOR]

The thermoelectric properties of monolayered MnBi2Te4 are investigated using first‐principles calculations based on density functional theory (DFT) and Boltzmann transport theory. Our research indicates significant thermoelectric performance in monolayered MnBi2Te4, with a maximum figure of merit (zT$zT$) and power factor (PF${\mathrm{PF}}$) ranging from approximately 3.58 to 9.267 and 0.012 W/K2m${\mathrm{W}}/{\mathrm{K}}^2{\mathrm{\ m}}$ to 0.021 W/K2m${\mathrm{W}}/{\mathrm{K}}^2{\mathrm{\ m}}$ across a temperature range of 300–700 K. The exceptional thermoelectric performance of monolayered MnBi2Te4 can be attributed to its unique structural and electronic properties, which lead to ultralow lattice thermal conductivity and high electrical transport properties. Ultralow lattice thermal conductivity as low as 0.32W/mK$0.32\ {\mathrm{W}}/{\mathrm{m\ K}}$ at 300 K is found in the monolayered MnBi2Te4, which is mainly contributed from the anharmonic scatterings of low‐frequency phonons. And high electronic conductivity and a notable Seebeck coefficient are also observed in our system, which has close relationship with its distinctive electronic band structure. Besides, the two‐dimensional structure makes it a great candidate to holding greater PF by enhancing the quantum confinement. Our findings may lay a strong theoretical groundwork for future experimental inquiries. Subsequent experimental investigations will be crucial to confirm these findings, refine synthesis methods, and explore the practical applications of monolayered MnBi2Te4 in thermoelectric devices. [ABSTRACT FROM AUTHOR]

Doping narrow‐gap semiconductors is a well‐established approach for designing efficient thermoelectric materials. Semiconducting half‐Heusler (HH) and full‐Heusler (FH) compounds have garnered significant interest within the thermoelectric field, yet the number of exceptional candidates remains relatively small. It is recently shown that the vacancy‐filling approach is a viable strategy for expanding the Heusler family. Here, a range of near‐semiconducting Heuslers, TiFexCuySb, creating a composition continuum that adheres to the Slater‐Pauling electron counting rule are theoretically designed and experimentally synthesized. The stochastic and incomplete occupation of vacancy sites within these materials imparts continuously changing electrical conductivities, ranging from a good semiconductor with low carrier concentration in the endpoint TiFe0.67Cu0.33Sb to a heavily doped p‐type semiconductor with a stoichiometry of TiFe1.00Cu0.20Sb. The optimal thermoelectric performance is experimentally observed in the intermediate compound TiFe0.80Cu0.28Sb, achieving a peak figure of merit of 0.87 at 923 K. These findings demonstrate that vacancy‐filling Heusler compounds offer substantial opportunities for developing advanced thermoelectric materials. [ABSTRACT FROM AUTHOR]

High‐performance polycrystalline calcium cobaltite ceramic was synthesized via electrospinning of nanoribbons, followed by dual‐process compaction using spark plasma sintering and edge‐free spark plasma texturing. The combination of nanoribbon electrospinning and this multistage sintering technique was employed for the first time and resulted in exceptionally well‐textured thermoelectric ceramics. The textured ceramic had excellent thermoelectric properties. At 1073 K, the ceramic exhibited an electrical conductivity of 268 S cm−1, a Seebeck coefficient of 247 µV K−1 and a heat conductivity of 3.3 W m−1 K−1. In addition, the power factor and figure‐of‐merit reached enormously high values of 16.3 µW cm−1 K−2 and 0.53, respectively. This represents the highest thermoelectric performance reported to date not only for electrospun, polycrystalline calcium cobaltite fiber ceramics, but also for undoped polycrystalline calcium cobaltite ceramics. [ABSTRACT FROM AUTHOR]

SnTe has emerged as a non-toxic and environmentally friendly alternative to the high-performance thermoelectric material PbTe, attracting significant interest in sustainable energy applications. In our previous work, we successfully synthesized high-quality SnTe with reduced thermal conductivity under high-pressure conditions. Building on this, in this work, we introduced indium (In) doping to further decrease thermal conductivity under high pressure. By incorporating resonance doping into the SnTe matrix, we aimed to enhance the electrical transport properties while maintaining low thermal conductivity. This approach enhances the Seebeck coefficient to an impressive 153 μVK−1 at 735 K, marking a notable enhancement compared to undoped SnTe. Furthermore, we noted a substantial decrease in total thermal conductivity, dropping from 6.91 to 3.88 Wm−1K−1 at 325 K, primarily due to the reduction in electrical conductivity. The synergistic impact of decreased thermal conductivity and heightened Seebeck coefficient resulted in a notable improvement in the thermoelectric figure of merit (ZT) and average ZT, achieving approximately 0.5 and 0.22 in the doped samples, respectively. These advancements establish Sn1−xInxTe as a promising candidate to replace PbTe in thermoelectric applications, providing a safer and more environmentally sustainable option. [ABSTRACT FROM AUTHOR]

This study introduces the synthesis of a hybrid thermoelectric material with enhanced conductivity and a high Seebeck coefficient, leveraging the properties of Te nanowires (NWs) and the conductive polymer PEDOT:PSS. Te NWs were synthesized using the galvanic displacement reaction. To further enhance conductivity, Ag-Te NWs were synthesized under optimized conditions via the Ag topotactic reaction, achieving desired results within 7 min using ethylene glycol and AgNO3. This hybrid material exhibited an electrical conductivity of 463 S/cm, a Seebeck coefficient of 69.5 μV/K at 300 K, and a power factor of 260 μW/mK2. These metrics surpassed those of conventional Te/PEDOT:PSS hybrids by a factor of 3.6, highlighting the superior performance of our approach. This study represents a significant advancement in thermoelectric materials, improving both conductivity and efficiency. [ABSTRACT FROM AUTHOR]

The performance of high-temperature thermoelectric material CaMnO 3 is primarily limited by its high electrical resistivity and thermal conductivity. In this study, we synergistically optimized its electrical and thermal transport properties by employing a combination of doping and compositing strategies. The results suggest that Yb doping promotes the transfer of electrons to the Mn d orbital and facilitates the double exchange interactions between neighbor Mn3+ and Mn4+, leading to decreased electrical resistivity and a transition of electron transport mechanism from semiconductor to metal. The further addition of CoAl 2 O 4 nanoparticles improves the Seebeck coefficient by reducing carrier concentration and increasing electron scattering, ultimately enhancing the power factor. Meanwhile, the fluctuations in atomic mass and increased interface density strengthen the interface phonon scattering, which results in a significant reduction in lattice thermal conductivity. As a result, the Ca 0.95 Yb 0.05 MnO 3 with 2 wt % CoAl 2 O 4 nanoparticles exhibits a maximum ZT value of 0.12 at 850 K, representing a 180 % improvement compared to the pristine material. This study highlights the effectiveness of the combined doping and compositing strategy in enhancing the thermoelectric performance of CaMnO 3 materials and offers a promising approach for optimizing other oxide thermoelectric materials. [ABSTRACT FROM AUTHOR]

The synthesis of transparent thermoelectric materials, particularly at low processing temperature possesses a good promise for future power generation by renovating waste heat into electrical energy. The fabrication of invisible thermoelectric module is hindered by limited choices of appropriate p-type transparent thermoelectric materials so far. The present study deals with the growth and characterization of optically transparent p-type copper iodide (γ-CuI) thin films. Thermal annealing (maximum up to 200 °C) was performed to tune the electrical and optoelectronic properties for nurturing the thermoelectric performance. Annealing induced microstructural modifications instigated the preferential crystal growth by regulating the surface morphology. Low thermal conductivity is credited to strong phonon scattering leading to improved thermoelectric performance. Consequently, we attain a record Seebeck coefficient of ∼270 μV/K and power factor of ∼20 μW/(m·K2) that is almost two-order of magnitude higher as compared to conventional p-type transparent TE materials, indicating the potential of transparent γ-CuI thin films regarding its practical applicability in transparent thermoelectric devices. [ABSTRACT FROM AUTHOR]

Thin film thermoelectric technology has immense potential to become a next-generation power source for small-scale electronics. However, the rapid development of thin film thermoelectric still lacks a controllable structural design to improve the performance of thermoelectric devices for required temperature applications. This work presented a controlled thermoelectric design of ZnO-based thin films by Al and Mg co-doping using ALD. Herein, the Mg-doped ZnO sample exhibits the highest Seebeck coefficient of −311.83 μVK−1 at 500oC, while the maximum thermoelectric power factor of 3.68 μWcm−1K−2 is obtained at 300oC, which drops for higher temperatures. This decrease in power factor resulted from the reduction in electrical conductivity above 300oC. Similarly, the Al and Mg co-doped ZnO sample (Mg/Al ≈2 at%) exhibits a high thermoelectric power factor of 3.85 μWcm−1K−2 for ZnO based material due to its moderate electrical conductivity and Seebeck coefficient value at 325oC and behave monotonically for elevated temperatures. Scanning electron microscope (SEM) images show the formation of wedge-shaped structures for Al-incorporated samples, which helps to boost the overall thermoelectric performance. Additionally, we performed XRD, UV–Vis, Hall, and AFM analysis to get a deep insight into structural, optical, electrical, and surface features of the grown thin films and their linkage with the thermoelectric properties. [Display omitted] • Growth of Al and Mg co-doped ZnO thin films on quartz substrate using ALD. • SEM measurements reveal the formation of Wedge-shaped morphology for co-doped thin films. • Thermoelectric properties have been improved by tuning the Mg/Al concentration. • The highest thermoelectric power factor of 3.85 μWK−1cm−2 was obtained for the ZMA2 sample at 325oC. [ABSTRACT FROM AUTHOR]

BiCuSeO, an oxide thermoelectric material with a superlattice structure, presents the advantages of affordability, low toxicity, and environmental friendliness. However, its intrinsic low electrical conductivity has impeded its possible applications. To address this challenge, we put tiny PbZr 0.52 Ti 0.48 O 3 (PZT) with varying weight percentages (x = 0, 5, 7, 9, 11) into BiCuSeO (BCSO) to fabricate thermoelectric nanocomposites. Through the spark plasma sintering process, PZT particles underwent in-situ decomposition, generating nano-sized second phases such as PbO 2 , TiO 2 , and PbZrO 3 , which are homogenously distributed within BCSO matrix (validated by XRD and TEM). The introduced PbO 2 , TiO 2 , and PbZrO 3 second phases served a dual purpose: inhibiting the grain growth of BCSO and introducing additional nano-grain boundaries. This resulted in more effective phonon scattering sites, thereby reducing lattice thermal conductivity. Simultaneously, the Pb element derived from PZT decomposition was doped into the Bi site of the BCSO matrix, causing a reduction in the band gap of BCSO from 0.49 eV to 0.388 eV and a significant increase in carrier concentration. Consequently, this doping enhanced the electrical conductivity of BCSO-based composites, with the composite with 11 wt% PZT additive amount exhibiting a remarkable 318-fold increase, reaching 550 S/cm compared to pristine BCSO. Notably, the composite with 7 wt% PZT additive amount achieved an exceptionally low lattice thermal conductivity of 0.333 W m−1 K−1 at 823 K. Through the synergistic optimization of electrical and thermal transport properties, the BCSO-based composite with 7 wt% PZT additive amount obtained a ZT value of ∼0.9 at 873 K, representing a 2.45-fold increase compared to pristine BiCuSeO. This straightforward method presents a cost-effective and scalable approach to enhance the thermoelectric performance of various materials, opening new avenues for potential commercial applications. [ABSTRACT FROM AUTHOR]

This study introduces the synthesis of a hybrid thermoelectric material with enhanced conductivity and a high Seebeck coefficient, leveraging the properties of Te nanowires (NWs) and the conductive polymer PEDOT:PSS. Te NWs were synthesized using the galvanic displacement reaction. To further enhance conductivity, Ag-Te NWs were synthesized under optimized conditions via the Ag topotactic reaction, achieving desired results within 7 min using ethylene glycol and AgNO3. This hybrid material exhibited an electrical conductivity of 463 S/cm, a Seebeck coefficient of 69.5 µV/K at 300 K, and a power factor of 260 µW/Mk². These metrics surpassed those of conventional Te/PEDOT:PSS hybrids by a factor of 3.6, highlighting the superior performance of our approach. This study represents a significant advancement in thermoelectric materials, improving both conductivity and efficiency. [ABSTRACT FROM AUTHOR]

Context: Nowadays, Perovskite materials with diverse compositions and structures have garnered significant attention for their potential applications across various industrial and technological fields. Here, we investigated the structural, electronic, optical, thermodynamic, thermoelectric, and magnetic properties of perovskite PrFeO3 using density functional theory and Monte Carlo simulations. The optimization results demonstrate that the ferromagnetic phase is more stable than the antiferromagnetic phase. Under the GGA + SOC + U and GGA + mBJ approaches, the electronic results of the PrFeO3 compound expose the half-metallic and magnetic behavior. It was also demonstrated that introducing dilatation strain can effectively enhance both the mechanical and thermal stability of PrFeO3. Additionally, the optical properties show that this material has potential uses for solar cells because of its capacity to absorb light in the ultraviolet (UV) spectrum. The maximum values of the Seebeck coefficient reach 90 µV/K at 1000 K, indicating the potential of PrFeO3 as an efficient thermoelectric material. The magnetic properties exhibit a first transition of spin reorientation (TSR) at 171.44 K, followed by a second-order transition at 707.15 K. This investigation provides valuable insights into the unstudied aspect of Perovskite PrFeO₃. Methods: To carry out this investigation, we employed the density functional theory (DFT) implemented in the Wien2k package. To determine the exchange–correlation potential, we utilized the GGA-PBE (Perdew, Burke, and Ernzerhof) approach. The SOC was included based on the second-variational method using scalar relativistic wavefunctions, and electron–electron Coulomb interactions for Fe and Pr are considered in the rotationally invariant way GGA + SOC + U. In this paper, the effective parameter Ueff = U − J was adopted, where U and J stand for the Coulomb and exchange parameters, respectively. Also, we opted for the modified Becke–Johnson potential (mBJ) for comparison. The thermodynamic properties are obtained using the quasi-harmonic Debye model via Gibbs2 software programs. For the calculation of thermoelectric coefficients, a combination of first-principles band structure calculations and the Boltzmann transport theory within the rigid band approximation (RBA) and the constant scattering time approximation (CSTA) was employed, utilizing the BoltzTrap code. Subsequently, we delve into the magneto-caloric and magnetic properties by employing Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

This scientometric study looks at the current trend in thermoelectric materials research and explores the evolving domain of thermoelectric materials research using a combination of bibliometric and scientometric methodologies. The analysis examines global research trends from a dataset of over 37,739 research articles, focusing on thematic evolution, annual growth rates, and significant contributions. Six principal research clusters were identified, encompassing energy conversion, material synthesis and nanostructures (the most prominent cluster), computational modeling and material properties, measurement and characterization, material performance enhancement, and material processing and microstructure. Each cluster highlights a critical aspect of the field, reflecting its broad scope and depth. The key findings reveal a marked annual increase in research output, highlighting the growing global importance of thermoelectric materials in sustainable energy solutions. This is especially evident in the significant contributions from China and the USA, emphasizing their leadership in the field. The study also highlights the collaborative nature of thermoelectric research, showing the impact of global partnerships and the synergistic effects of international collaboration in advancing the field. Overall, this analysis provides a comprehensive overview of the thermoelectric materials research landscape over the past decade, offering insights into trends, geographic contributions, collaborative networks, and research growth. The findings underscore thermoelectric materials' vital role in addressing global energy challenges, highlighting recent advancements and industrial applications for energy efficiency and sustainability. [ABSTRACT FROM AUTHOR]

High-conductivity tellurium-based glasses were anticipated to be the attractive candidates in chalcogenide glass systems on account of their distinctive characteristics and extensive application prospects. In this paper, the high-density (>96%) Sn8[(Ga2Te3)34(SnTe)66]92 bulk glass with the density of 5.5917 g/cm3 was successfully prepared by spark plasma sintering (SPS) technology at 460 K, using a 5 min dwell time and 450 MPa pressure. The room-temperature thermal conductivity of Sn8 bulk materials significantly decreased from 1.476 W m−1∙K−1 in the crystalline sample to 0.179 W m−1∙K−1 in the glass, and the Seebeck coefficient obviously increased from 35 μV∙K−1 in to 286 μV∙K−1, indicating that the glass transition of tellurium-based semiconductors could optimize the thermal conductivity and Seebeck coefficient of the materials. Compared to the conventional tellurium-based glassy systems, the fabricated Sn8 bulk glass presented a high room-temperature conductivity (σ = 6.2 S∙m−1) and a large glass transition temperature (Tg = 488 K), which was expected to be a promising thermoelectric material. [ABSTRACT FROM AUTHOR]

Thermoelectric materials play a crucial role in converting heat into electricity, offering significant potential for applications in waste heat recovery and cooling. Herein, an innovative approach that combines an organic–inorganic hybrid superlattice structure with nanocrystal‐amorphous composite nanolayers is introduced. The nanocrystal‐amorphous composite enhances the Seebeck coefficient resulting in a notable twofold improvement in the power factor. The superlattice, alternating self‐assembled organic monolayers and inorganic nanolayers, effectively reduces lattice thermal conductivity by creating multiple interfaces that scatter phonons effectively. The integration of the nanocrystal‐amorphous composite nanolayers into the superlattice provides a dual advantage, simultaneously boosting the power factor and suppressing thermal conductivity. This synergistic effect leads to exceptional thermoelectric performance in the 4‐mercaptophenol/Sb2Te3 superlattice, with achieved figure of merit (ZT) values of 3.48 at 300 K and reaching a peak ZT value exceeding 4.0 at 400 K while surpassing 2.5 over the temperature range from 300 to 500 K. These results suggest that this innovative approach paves the way for the development of highly efficient thermoelectric materials, propelling efforts toward more energy‐efficient and environmentally friendly solutions. [ABSTRACT FROM AUTHOR]

This review explores the state‐of‐the‐art of thermoelectric materials, covering different crystalline structures and material families (e.g., chalcogenides, Zintl phases, skutterudites, clathrates, oxides, half‐Heusler, organic–inorganic composites, metal–organic frameworks, and silicides). It examines their corresponding thermoelectric properties while considering the synthesis methods employed, paying significant attention to those that particularly follow sustainable routes. Additionally, the work addresses current challenges in the field, such as enhancing stability at high temperatures and reducing manufacturing costs. The understanding gained in this field opens avenues for designing more efficient and sustainable devices to convert waste heat into electrical energy, thereby advancing cleaner technologies. [ABSTRACT FROM AUTHOR]

Bismuth telluride (Bi 2 Te 3) is gaining increasing attention as a material that exhibits flexo-photovoltaic effect in the infrared region, in addition to conventional thermoelectric materials and topological insulators. However, the flexo-photovoltaic effect is observed only when strains are applied to the Bi 2 Te 3 thin films by bending the substrates. To enhance the versatility of the flexo-photovoltaic effect, in this study, Bi 2 Te 3 thin films were sputtered onto a flexible substrate under a pre-curved condition, and strains were induced when the films were flattened. The crystal orientation and strains in the Bi 2 Te 3 thin films were affected by the pre-curved conditions. The Bi 2 Te 3 thin film deposited using a concave pre-curved condition exhibited an output voltage increase of approximately 15 % compared with the film deposited under a flat condition. This discovery suggests that strained Bi 2 Te 3 thin films can efficiently produce an output voltage under light irradiation without requiring a p–n junction, making them suitable for various photodetector applications. [ABSTRACT FROM AUTHOR]

The unique layered structure and intrinsically low lattice thermal conductivity of ternary compound PbBi 4 Te 7 have rendered it a promising thermoelectric material. However, the bipolar diffusion effect induced by inherent excitation results in deteriorated Seebeck coefficients and amplified thermal conductivity. In this study, the bipolar diffusion effect of PbBi 4 Te 7 is effectively suppressed through enlarging the bandgap via Se alloying, thereby facilitating its potential application as a complementary counterpart to p-type materials. A maximum ZT value of ∼0.67 is achieved in PbBi 4 (Te 0.7 Se 0.3) 7 at 723 K, signifying an impressive improvement of 121 % compared to pure PbBi 4 Te 7. This study provides a novel insight into enhancing the thermoelectric performance of ternary materials. [ABSTRACT FROM AUTHOR]

The major issue associated with thermoelectric performance is the low efficiency of power conversion. The main challenge is achieving a combination of high Seebeck coefficient, high electrical conductivity, and low thermal conductivity for a significantly improved figure of merit (ZT). Developing strategies include the production of tetrahedrites with an intrinsically low thermal conductivity through the solvothermal method, using a low reaction time and processing temperature. Here, we report on the preparation of Cu-rich tetrahedrites through the solvothermal technique at low temperature, providing a promising strategy for the preparation of materials with potential applications in thermoelectricity. The influence of synthesis reaction time and temperature on the morphological, structural, and thermoelectrical properties of the samples was investigated through different characterization techniques. Tetrahedrite synthesized at 180 °C for 19 h yielded a favorable ZT value of >0.43 and a thermal conductivity of 0.2 Wm−1 K−1 (423 K), related to the Sb3+/Sb5+ and Cu+/Cu2+ ratio, as was observed by XPS. The cubic tetrahedrite phase attributed to the (222) plane was confirmed by XRD and TEM and the intense Raman mode observed at 351 cm−1. SEM images revealed that nanotetrahedral Cu-rich tetrahedrites efficiently assemble into spherical structures, resulting in an improvement in the Seebeck coefficient (437 µVK−1) and electrical conductivity. [ABSTRACT FROM AUTHOR]

Thermoelectric materials can efficiently and cleanly convert between electrical and thermal energy, offering significant prospects in waste heat recovery and electronic cooling applications. Lead telluride(PbTe) materials were used in thermoelectric power sources for deep space exploration. Lead selenide(PbSe), a homologue of PbTe, shows potential as a more abundant and cost-effective alternative for mid-temperature thermoelectric power generation. Recently, research in PbSe thermoelectric has shifted from mid-temperature power generation to near-room-temperature cooling, driven by the growing demand for Te-free thermoelectric cooling materials and devices. This paper reviewed the typical optimization strategies used in the research of p-type PbSe, summarized the key research progress in thermoelectric devices based on this material, and highlighted its significant development prospects. Finally, we provide a personal outlook on developing the near-room-temperature thermoelectric performance of p-type PbSe materials and manufacturing high-performance cooling devices, which includes integrating various optimization strategies, optimizing device assembly techniques, identifying suitable contact materials, and developing Te-free thermoelectric devices based on PbSe, with the goal of advancing their application in critical fields such as deep space exploration and laser cooling. [ABSTRACT FROM AUTHOR]

Thermoelectric materials possess the capability to convert electricity into heat and vice versa. The utilization of chlorofluorocarbons and hydrochlorofluorocarbons as thermal carrier agents in traditional cooling and air conditioning systems has sparked a surge in exploration toward pioneering refrigeration and spatial conditioning technologies. Chalcogenides, known for their capacity to amplify the thermoelectric efficiency of materials and their adaptability across a broad spectrum of temperatures, stand out as pivotal components in thermoelectric materials. Despite their existing suboptimal performance, these materials hold substantial promise as power generators and as solid-state Peltier coolers, attracting significant attention and positioning them as subjects ripe for further investigation. Categorized into alkali or alkaline earth, transition metal, and main-group chalcogenides, these materials and their respective subclasses are meticulously scrutinized to pinpoint the most suitable thermoelectric materials for specific applications with an optimal operational temperature span. In the quest for energy-efficient technologies characterized by simple designs, absence of moving components, and superior stability, thermoelectric materials play a crucial role. This review highlights the advancements in theoretical parameters as well as the figure of merit (ZT) of chalcogenide materials, emphasizing their device applications. These insights are intended to provide viable future approaches to mainstream thermoelectric materials. This review reveals that Cu2Se achieves a maximum ZT value of 2.66 at 1039 K, marking it as the top performer among transition metal chalcogenides. Conversely, SnSe, a main-group metal monochalcogenide, exhibits a ZT value of 2.8 at 773 K, whereas nanowires of the main group of bismuth chalcogenides exhibit a ZT value of 2.5 at 350 K. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid thermoelectric (TE) materials have attracted tremendous interest for harvesting waste heat energy. Due to their mechanical flexibility, inorganic‐organic hybrid TE materials are considered to be promising candidates for flexible energy harvesting devices. In this work, enhanced TE properties of Tellurium (Te) nanowires (NWs)‐ poly (3‐hexylthiophene‐2, 5‐diyl) (P3HT) hybrid materials are reported by improving the charge transport at interfacial layer mediated via controlled oxidation. A power factor of ≈9.8 µW (mK2)−1 is obtained at room temperature for oxidized P3HT‐TeNWs hybrid materials, which increases to ≈64.8 µW (mK2)−1 upon control of TeNWs oxidation. This value is sevenfold higher compared to P3HT‐TeNWs‐based hybrid materials reported in the literature. MD simulation reveals that oxidation‐free TeNWs demonstrate better templating for P3HT polymer compared to oxidized TeNWs. The Kang–Snyder model is used to study the charge transport in these hybrid materials. A large σE0 value is obtained which is related to better templating of P3HT on oxygen‐free TeNWs. This work provides evidence that oxidation control of TeNWs is critical for better interface‐driven charge transport, which enhances the thermoelectric properties of TeNWs‐P3HT hybrid materials. This work provides a new avenue to improve the thermoelectric properties of a new class of hybrid thermoelectric materials. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the effect of strontium (Sr) doping on the thermoelectric properties of thin films made of tin telluride (SnTe). The preparation of Sn 1-x Sr x Te (x = 0, 0.1, 0.2, 0.3, 0.4) films using a straightforward thermal evaporation method and subjected them to post-annealing at 773 K. The surface morphology and crystal structure of the films have been examined by using SEM and XRD, respectively. Our findings indicate that the Seebeck coefficient value increased from 39 to 68 μV/K as the Sr doping concentration increased. This enhancement has been attributed to the energy filtering effect resulting from charge carrier dislocation. However, the electrical conductivity value decreased due to an increase in defect density. The maximum enhancement of the power factor has been observed for x = 0.3, where the value reached 38.9 μWcm−1K−2, which is greater than the pristine sample. Our results conclude that Sr 0.3 doping in Sn 0.7 Te is a valuable addition for thermoelectric applications at room temperature. Additionally, the use of the simple thermal evaporation method for film preparation highlights its potential for large-scale applications. [ABSTRACT FROM AUTHOR]

Higher manganese silicides have evolved as an efficient thermoelectric material because of their exceptional thermoelectric performance at intermediate temperatures. In this work, we report the ultralow-thermal conductivity with improved thermoelectric properties of Mn 1-x Cr x Si 1.8 (x = 0, 0.025, 0.05 and 0.1) prepared by induction melting followed by ball milling and uni-axial induction hot-pressing. Bragg diffraction patterns confirmed that the as-synthesized compound belongs to the Mn 15 Si 26 phase along with the solid solubility of Cr in the HMS lattice. In addition, the backscattered electron micrographs revealed the precipitation of excess Si in the HMS matrix, originating from Si-rich stoichiometry. Furthermore, an elevation in electrical conductivity with increasing Cr content has been observed because of its acceptor dopant behaviour at the Mn site. On the contrary, the Seebeck coefficient decreased upon an increase in Cr content, and bulk MnSi 1.8 has shown the highest Seebeck coefficient of 220 μV/K at 773 K. Impressively, nanostructuring along with the generated point defects as a result of Cr dopant facilitates an intensified phonon scattering at the nanostructured grain boundaries that results in a very low κ total of 0.99 W/mK at 773 K for ball-milled Mn 0.9 Cr 0.1 Si 1.8 , leading to an elevated zT of 0.46 at 773 K. [ABSTRACT FROM AUTHOR]

We propose an organic thermoelectric device having a new power generation mechanism that extracts small-scale thermal energy, i.e., a few tens of millielectronvolts, at room temperature without a temperature gradient. We demonstrate a new operating mechanism based on an organic thermoelectric power generation architecture that uses the charge separation capabilities of organic charge transfer (CT) interfaces composed of copper (II) phthalocyanine and copper (II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine as the donor and acceptor, respectively. With the optimized device architecture, values of open-circuit voltage VOC of 384 mV, short-circuit current density JSC of 1.1 μA/cm2, and maximum output Pmax of 94 nW/cm2 are obtained. The temperature characteristics of the thermoelectric properties yield activation energy values of approximately 20–60 meV, confirming the low-level thermal energy's contribution to the power generation mechanism. Furthermore, from surface potential analysis using a Kelvin probe, we confirm that charges are generated at the CT interface, and the electrons and holes are diffused to the counter-electrodes with the aid of Fermi-level alignment between adjacent layers. The authors propose an organic thermoelectric device having a new power generation mechanism based on an organic charge transfer interface with carrier transport layers, extracting small-scale thermal energy, i.e., a few tens of millielectronvolts, at room temperature without a temperature gradient. [ABSTRACT FROM AUTHOR]

The research on two-dimensional materials has gained significant traction due to their potential for thermoelectric, optical, and other properties. The development of two-dimensional (2D) nanostructured-based TE generators and photodetectors has shown promising results. Over the years, researchers have played a crucial role in advancing this field, enhancing the properties of 2D materials through techniques such as doping, alloying, and various growth methods. Among these materials, black phosphorus, transition metal dichalcogenides, graphene, and IVA-VIA compounds stand out for their remarkable electronic, mechanical, and optical properties. This study presents a comprehensive review of the progress in the field, focusing on IVA-VIA compounds and their applications in TE and photodetector technologies. We summarize recent advancements in enhancing these materials' TE and optical properties and provide an overview of various synthesis techniques for their fabrication. Additionally, we highlight their potential applications as photodetectors in the infrared spectrum. This comprehensive review aims to equip researchers with a deep understanding of the TE and optical properties of 2DMs and their potential applications and to inspire further advancements in this field of research. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the possibility of modifying the physical properties of indium tin oxide (ITO) layers by annealing them in different atmospheres and temperatures. Samples were annealed in vacuum, air, oxygen, nitrogen, carbon dioxide and a mixture of nitrogen with hydrogen (NHM) at temperatures from 200 °C to 400 °C. Annealing impact on the crystal structure, optical, electrical, thermal and thermoelectric properties was examined. It has been found from XRD measurements that for samples annealed in air, nitrogen and NHM at 400 °C, the In2O3/In4Sn3O12 share ratio decreased, resulting in a significant increase of the In4Sn3O12 phase. The annealing at the highest temperature in air and nitrogen resulted in larger grains and the mean grain size increase, while vacuum, NHM and carbon dioxide atmospheres caused the decrease in the mean grain size. The post-processing in vacuum and oxidizing atmospheres effected in a drop in optical bandgap and poor electrical properties. The carbon dioxide seems to be an optimal atmosphere to obtain good TE generator parameters—high ZT. The general conclusion is that annealing in different atmospheres allows for controlled changes in the structure and physical properties of ITO layers. [ABSTRACT FROM AUTHOR]

Semiconducting clathrates have attracted considerable interest in the field of thermoelectric materials. We report here a computational study on the crystal structure, the enthalpy of formation, and the physical properties of the following type-I clathrates: (a) experimentally studied Cs8Sn44 and hypothetical Cs8Sn46 and (b) hypothetical (NH4)8Sn46−x (x = 0 or 2). The ab initio VASP calculations for the nominal stoichiometries include the geometry optimization of the initial structural models, enthalpies of formation, and the electronic and phonon density of states. Comparison of the chemical bonding of the structural models is performed via the electron localization function. The results show that the presence and distribution of defects in the Sn framework for both Cs8Sn46−x and (NH4)8Sn46−x systems significantly alters the formation energy and its electrical properties, ranging from metallic to semiconducting behavior. In particular, one defect per six-membered Sn ring in a 3D spiro-network is the thermodynamically preferred configuration that results in the Cs8Sn44 and (NH4)8Sn44 stoichiometries with narrow-band gap semiconducting behavior. Moreover, the rotation of the ammonium cation in the polyhedral cavities is an interesting feature that may promote the use of ammonium or other small molecular cations as guests in clathrates for thermoelectric applications; this is due to the decrease in the lattice thermal conductivity. [ABSTRACT FROM AUTHOR]