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Lead‐free double perovskites are unique materials for transport and optoelectronic applications that use clean resources to generate energy. Using first‐principle computations, this study thoroughly investigates the structural, thermoelectric, and optical attributes of A2TlAgF6 (A = Rb, Cs). Tolerance factor and formation energy estimates are used to verify that these materials exist in the cubic phase. Elastic constants with high melting temperature values are ductile when evaluated for mechanical stability using the Born stability criterion. The optical absorption band is adjusted from 2 to 4 eV via band gaps of 1.88 and 1.99 eV, as indicated by band structures. Analysis of optical properties reveals perfect absorption in the visible spectrum, whole polarization, and low optical loss. Furthermore, thermoelectric properties are assessed at 300, 500, and 700 K in the range of −0.5 to 3 eV for chemical potential (μ). The materials exhibit significant improvements in the Figure of Merit scale due to their elevated electrical conductivity, Seebeck coefficient, and extremely low thermal conductivity values. [ABSTRACT FROM AUTHOR]

Ultra‐broadband photodetectors based on semimetal crystals have recently become popular because of their gapless band structures. In particular, semimetal crystals have large carrier mobility or high Seebeck coefficient; this almost eliminates the possibility of using semimetal crystals as photodetectors. In addition, a larger temperature gradient can cause photocurrent generation based on the photothermoelectric effect. Surprisingly, the TaTe2 crystal has a huge absorption coefficient (≈104 cm−1), a minimal specific heat (≈0.172 J g−1 K−1), and a low thermal conductivity (0.3 W m−1 K−1), which is beneficial for generating a high photothermal conversion efficiency of 30.2%, despite its small Seebeck coefficient, and achieving a large temperature gradient occurs for the heat generated by external illumination. Herein, the possibility of photoresponse based on the TaTe2 detector is explored, which has a low carrier mobility (≈10 cm2 V−1 s−1) and a small Seebeck coefficient (≈7.1 µV K−1). The self‐powered TaTe2 photodetector can also provide a competitive photoresponse range from 355 to 2715 nm and exhibit a maximum responsivity of 1.1 mA W−1 with a detectivity of 4.7 × 108 Jones at 455 nm. This study provides a new design scheme and operating mechanism for semimetal photodetectors and enriches semimetal crystal photodetectors. [ABSTRACT FROM AUTHOR]

Thermoelectric materials are of tremendous interest due to their capacity to convert waste heat into useful electrical energy. Bismuthene nanosheets (BiNS) have recently emerged as a promising material for thermoelectric applications because of their unique two‐dimensional structure and low thermal conductivity. However, the development of efficient and scalable methods for preparing BiNS‐based thermoelectric composites with improved performance remains a challenge. In this study, we reported a novel approach to preparing a thin film BiNS‐based thermoelectric composite with UV‐curing 3D printing technology. The composite was prepared using BiNS as the filler and a UV‐sensitive resin as the matrix, which contained 5 vol% graphene as the third phase to enhance the thermoelectric performance of the composite. The results showed that the prepared composite exhibited stable thermoelectric performance, with a maximum power factor of 311.79 ± 13.90 μW/mK2 when the volume fraction of BiNS reached 95 vol%. The electrical conductivity of the composite improved significantly as the volume fraction of BiNS increased from 75 to 95 vol%. The Seebeck coefficient remained essentially unchanged in the range of 70.1–70.7 μV/K. These findings demonstrate the potential of BiNS‐based thermoelectric composites prepared by UV‐curing 3D printing technology for practical applications in energy harvesting and cooling devices. Highlights: A simple, efficient and scalable method for BiNS thermoelectric composites.UV‐curing 3D printing technology was used for fabrication.The BiNS composite exhibited stable thermoelectric performance.The electrical conductivity of the composite improved significantly.This BiNS composite showed great potential in thermoelectric application. [ABSTRACT FROM AUTHOR]

Exploring N‐type High‐entropy materials with both high thermoelectric and mechanical properties is highly desirable for all‐high‐entropy thermoelectric generators (TEGs) since the thermoelectric and mechanical properties of N‐type one are largely behind its P‐type counterparts. Herein, a new rock‐salt structure N‐type high entropy thermoelectric AgBiPbSe2S is introduced with a bandgap of ≈0.43 eV. The atomic radii difference of each component results in a large lattice distortion of 0.246, leading to a low thermal conductivity of 0.36 W m−1 K−1 at 823 K. The figure of merit (ZT) reaches 0.6 for AgBiPbSe2S at 823 K. Moreover, Ag2Se precipitates are included in AgBiPbSe2S to filter low energy carriers for high Seebeck coefficients and to scatter phonons with nanoscale wavelength for ultralow lattice thermal conductivities. Consequently, a peak ZT of ≈1.18 at 823 K and an average ZT of 0.60 at 400–823 K are obtained for Ag1.02BiPbSe2S. More importantly, high mechanical properties are also obtained in Ag1.02BiPbSe2S, of which the Vickers hardness and flexural strength are ≈209 Hv and 32 MPa, respectively, originating from the enhanced lattice friction by chemical short‐range disorder (i.e., high entropy effect) and dispersion strengthening caused by Ag2Se nanoprecipitates. [ABSTRACT FROM AUTHOR]

Metal‐backboned polymers (MBPs), with a unique backbone consisting of bonded metal atoms, are promising for optic, electric, magnetic, and thermoelectric fields. However, the application of MBP remains relatively understudied. Here, we develop a shear‐induced orientation method to construct a flexible nickel‐backboned polymer/carbon nanotube (NBP/CNT) thermoelectric composite fiber. It demonstrated a power factor of 719.48 μW ⋅m−1 K−2, which is ca. 3.5 times as high as the bare CNT fiber. Remarkably, with the regulation of carrier mobility and carrier concentration of NBP, the composite fiber further showed simultaneous increases in electrical conductivity and Seebeck coefficient in comparison to the bare CNT fiber. The NBP/CNT fiber can be integrated into fabrics to harvest thermal energy of human body to generate an output voltage of 3.09 mV at a temperature difference of 8 K. This research opens a new avenue for the development of MBPs in power supply. [ABSTRACT FROM AUTHOR]

Cu2Se‐based binary compounds have recently fetched the attention of researchers due to their remarkable electrical and extremely low thermal properties. In addition, Cu2Se‐based quaternary chalcogenides are expected to present exceptional thermoelectric performance. Cu2Se1−x−ySxTey‐like compounds are synthesized via microwave‐assisted hydrothermal method and their respective thermal and electrical transport properties are studied in this research work. The phase purity and homogeneity are examined by X‐ray diffraction and energy‐dispersive X‐ray spectrometry analysis. The introduction of S and Te elements into Cu2Se matrix enhances Seebeck coefficient resulting in improved electrical performance illustrating a maximum power factor of 989.4 μWK−2 m−1 at 673 K. Furthermore, S‐ and Te‐co‐doped samples exhibit reduced total thermal conductivity values with lowest value of 0.808 WK−1 m−1 for Cu2Se0.96S0.02Te0.02 sample in comparison to 1.18 WK−1 m−1 for the pristine sample. The simultaneous improvement in electrical and thermal properties results in enhanced figure of merit of 0.82 for Cu2Se0.96S0.02Te0.02 sample at 673 K. [ABSTRACT FROM AUTHOR]

Despite remarkable advances, high‐performance thermoelectric (TE) materials‐based thermocouples (TCs) lack mechanical robustness and flexibility. Hence, conventional low Seebeck coefficient metals (Ni, Cu, Fe) wire‐junction‐based TCs are used for temperature sensor applications. However, not only the sensitivity of the metal‐based TC sensor is low, but also it is very difficult to fabricate a pixelated sensor using the conventional approach. In this study, high‐performance (SbBi)2(TeSe)3‐based printed flexible TE materials are employed to fabricate two types of shape‐conformable TC‐based temperature sensor arrays with 25 pixels (TSA I and TSA II). Bi0.5Sb1.5Te3‐based p‐type (p‐BST) printed TE film and copper are used to fabricate TSA I, and the p‐type film together with the Bi2Te2.7Se0.3‐based n‐type (n‐BT) film is used to fabricate TSA II. A high average sensitivity (Sexp) value of ≈124 µV °C−1 for TSA I and ≈319 µV °C−1 for TSA II is attained with high linearity. [ABSTRACT FROM AUTHOR]

The structural, optoelectronics, and transport properties of TlTaO3 compounds were determined utilizing the full potential augmented plane wave approach using first‐principle method. We have considered the generalized gradient approximation for structural optimization and modified Becke–Johnson for electronic properties. The electronic properties reveal that the studied TlTaO3 possesses direct bandgap of magnitude 1.52 eV. Between 0 and 12 eV, optical spectra calculations are made, taking into account the real and imaginary parts of the dielectric function, refractive index, and loss function. The transport properties are estimated considering Boltzmann transport theory. The Seebeck coefficient, electrical conductivity, thermal conductivity, and power factor are all assessed using the Boltzmann transport theory. The optimized thermoelectric response of the examined TlTaO3 is produced by the improved carrier mobility, which also improves the thermoelectric efficiency of the TlTaO3. The obtained results will act as a theoretical road map for upcoming experimental and commercial TlTaO3 applications. [ABSTRACT FROM AUTHOR]

Although orthorhombic GeSe is predicted to have an ultrahigh figure of merit, ZT ≈ 2.5, up to now, the highest experimental value is ≈0.2 due to the low carrier concentration (nH ≈ 1018 cm−3). Improving symmetry is an effective approach for enhancing the ZT of GeSe‐based materials. With Te‐alloying, Ge4Se3Te displays the two‐dimensional hexagonal structure and high nH ≈ 1.23 × 1021 cm−3. Interestingly, Ge4Se3Te transformed from the hexagonal into the rhombohedral phase with only ≈2% I–V–VI2‐alloying (I = Li, Na, K, Cu, Ag; V = Sb, Bi; VI = Se, Te). According to the calculated results of Ge0.82Ag0.09Bi0.09Se0.614Te0.386 single‐crystal grown via AgBiTe2‐alloying, it exhibits a higher valley degeneracy than the hexagonal Ge4Se3Te. For instance, AgBiTe2‐alloying induces a strong band convergence and band inversion effect, resulting in a significantly enhanced Seebeck coefficient and power factor with a similar nH from 17 µV K−1 and 0.63 µW cm−1 K−2 for pristine Ge4Se3Te to 124 µV K−1 and 5.97 µW cm−1 K−2 for 12%AgBiTe2‐alloyed sample, respectively. Moreover, the sharply reduced phonon velocity, nano‐domain wall structure, and strong anharmonicity lead to low lattice thermal conductivity. As a result, a record‐high average ZT ≈0.95 over 323–773 K with an excellent ZT ≈ 1.30 is achieved at 723 K. [ABSTRACT FROM AUTHOR]

Making products that are affordable, environmentally friendly, and energy‐efficient is the main objective of modern production. The objective of this research is to discover compounds that meet these parameters. The full‐potential, linearized augmented plane wave program (FP LAPW) offered by Wien2K was used to examine the structural, optical, electrical, and transport aspects of SrCaGe and SrCaSn Half‐Heusler (HHs) compounds. Generalized gradient approximation (GGA) was considered for the structural optimization and computation of elastic properties signifies inherent ductility and mechanical stability of the examined SrCaGe and SrCaSn compounds. Additionally, both materials were found to possess a direct bandgap and exhibit semiconducting behavior. The bandgap magnitudes obtained utilizing the modified Becke‐Johnson (mBJ) approximation are 0.78 and 0.52 eV for SrCaGe and SrCaSn, respectively. According to their optical characteristics, SrCaGe and SrCaSn show potential for application in optoelectronic components. Furthermore, the transport properties are evaluated by BoltzTrap program, revealing that both SrCaGe and SrCaSn exhibit figures of merit (ZT) values nearly equal to one at room temperature. This suggests their potential use in creating thermoelectric devices with highly efficient performance. The simulation study demonstrates the promising attributes of SrCaGe and SrCaSn HHs materials, positioning them as viable candidates for various applications, aligned with the goals of sustainable and efficient manufacturing. [ABSTRACT FROM AUTHOR]

In the face of ever‐evolving energy and environmental challenges, tin selenide (SnSe) has garnered significant attention due to its outstanding thermoelectric performance. The article focuses on the research of easily accessible and highly practical polycrystalline SnSe thermoelectric materials, providing an overview of their crystal structure, band structure, and electrical transport performance. Compared with previous studies, this research classifies elements based on their own properties, mainly dividing them into alkali metals, transition metals, main group metals, halogens, and rare earth (Re) elements. The study systematically summarizes the experimental results of doping SnSe with these elements and analyzes the mechanisms by which different elements enhance the electrical transport performance and thermoelectric figure of merit of polycrystalline SnSe. The enhanced mechanism is mainly achieved by increasing the conductivity and Seebeck coefficient. Finally, a systematic analysis is conducted to identify the factors that improve electrical transport performance, and strategies for enhancing the electrical transport and thermoelectric properties of polycrystalline SnSe through precise doping techniques are discussed, with a prospect for their application in the future. [ABSTRACT FROM AUTHOR]

In this study, the strain‐induced effects on thermal and electrical transport properties of LaCuOSe are studied by combining first‐principles calculations with semi‐classical Boltzmann transport theory. The results show that external strain affects the crystal and electronic structures of LaCuOSe significantly. It is interesting to find that the electrical conductivity of n‐type LaCuOSe is improved by the tensile strain. In addition, the tensile strain also has positive effects on the Seebeck coefficient of p‐type doped LaCuOSe. Consequently, the power factor of p‐type doped LaCuOSe is enhanced by 18.2% under 10% tensile strain at 800 K. However, due to the obviously affected mechanical properties of LaCuOSe under external strain, the decreased Grüneisen constant and reduced Debye temperatures are resulted, and the lattice thermal conductivity of LaCuOSe at 300 K increases from 2.91 to 5.95 Wm/K with the tensile strain increasing from 0% to 10%. The sharply increased thermal conductivity finally results in the optimal ZT value of 0.076 and 0.417 for ideal p‐ and n‐type LaCuOSe at 800 K being reduced to 0.048 and 0.286 under 10% tensile strain, respectively. These results suggest that the thermoelectrical properties of LaCuOSe need to be further improved for its application under stress. [ABSTRACT FROM AUTHOR]

This study delves into the thermoelectric properties of armchair black phosphorene nanoribbons while considering the presence of line edge roughness. Employing the tight‐binding method in conjunction with non‐equilibrium Green's function techniques and Landauer formulas, the impact of various parameters on thermoelectric performance is explored. These findings reveal that the electrical conductivity and, consequently, the power factor exhibits an increasing trend with expanding ribbon length and width. This behavior can be attributed to heightened collision rates, particularly in narrow ribbons, induced by line edge roughness as length increases. Remarkably, the Seebeck coefficient at the Fermi energy corresponding to the maximum power factor remains nearly constant across different widths, lengths, temperatures, and transport regimes. Furthermore, the thermoelectric figure of merit (ZT) demonstrates a positive correlation with both ribbon length and width. In narrow widths and lengths ≈1000 nm, the power factor and figure of merit exhibit an upward trend with ribbon width. However, with further increases in ribbon width, the influence of line edge roughness on thermal conductivity diminishes. Consequently, the figure of merit decreases due to the rise in thermal conductivity. Notably, the thermoelectric figure of merit is higher for short and narrow ribbons and long and wider ribbons. [ABSTRACT FROM AUTHOR]

This study investigates the structural, mechanical, electronic, magnetic, and thermoelectric properties of ZrMnX (X = As, Sb, Te) half Heusler alloys using spin‐polarized density functional theory (SPDFT) with WIEN2K code using full potential linearized augmented plane wave(FP‐ LAPW) technique. Results indicate the ferromagnetic phase's stability over the non‐magnetic phase in all three alloys. Band structures and density of states highlight the half‐metallic nature of ZrMnX. These alloys exhibit mechanical stability, ductility, and directional properties. Magnetic moments align with the Slater–Pauling rule. Thermoelectric properties, including Seebeck coefficient, electrical and thermal conductivity, and thermoelectric figure of merit, are evaluated using semi‐classical Boltzmann theory. The Seebeck coefficient values for ZrMnX (X = As, Sb, Te) are 144.7, 123.3, and −182.6 µV K−1, respectively at 1200 K with corresponding highest figure of merit 1.0, 0.7, and 1.78. These findings suggest the suitability of these alloys for spintronic devices and high‐temperature thermoelectric applications due to their observed spin‐polarized character and high figure of merit. [ABSTRACT FROM AUTHOR]

As a highly promising thermoelectric material in the mid‐temperature region, pristine GeTe shows deteriorated thermoelectric properties due to the low Seebeck coefficient and the intrinsic high thermal conductivity. Herein, it is discovered that the introduction of strongly correlated d, f electrons by alloying rare‐earth atoms at Ge sites will increase the band effective mass and promote band convergency, which can largely improve the electric transport property. Moreover, the heavy atoms (Pb, Bi) doping induces optical phonon softening and the avoided crossing between acoustic and optical phonon branches, decelerating both optical and acoustic phonon velocities. The modulated composition wave from the fluctuated multi‐component distribution introduces a complicated hierarchical structure including point defects and nanoprecipitates, which provides all‐scale scattering sources for heat‐carrying phonons and results in low lattice thermal conductivity. Consequently, a high zT of 2.4 at 800 K can be obtained in the Ge0.86Pb0.09Bi0.03Ce0.005Te sample due to the combination of strong correlation for d, f electrons and the full‐spectrum scattering for phonons. This work provides an effective strategy to increase the thermoelectric performance of IV–VI compounds by combining the modulated band structure and the softening phonon dispersion. [ABSTRACT FROM AUTHOR]

The stabilities, mechanical, electronic, and magnetic properties of the new equiatomic quaternary Heusler alloy (EQHA) RuTiCrSi were investigated using the Kohn‐Sham DFT (KS‐DFT) calculations within the generalized gradient approach (GGA), the modified version of the exchange potential introduced by Becke and Johnson in addition to the GGA (mBJ‐GGA), and Heyd‐Scuseria‐Ernzerhof (HSE06) hybrid functional. The ground‐state equilibrium energy reveals that the ferromagnetic with type 2 structure is the more stable. The RuTiCrSi is energetically, mechanically, and dynamically stable. The calculated self‐consistent total magnetic moment is 2 μB and agrees well with the Slater‐Pauling rule of Mt=Zt−24$$ {M}_{\mathrm{t}}=\left|{Z}_{\mathrm{t}}-24\right| $$. The electronic structure results from mBJ‐GGA and HSE06 functionals show a half‐metallic behavior. A high Curie temperature is obtained using the mean‐field approximation. The thermoelectric response was calculated using the semi‐classical Boltzmann transport equation under constant relaxation time. The maximum value of Seebeck coefficient is observed at the ambient temperature of 741μVK−1$$ 741\ \upmu \mathrm{V}\ {\mathrm{K}}^{-1} $$. It was also observed that the power factor increases significantly as temperature rises. Therefore, the new EQHA RuTiCrSi seems to be a potential candidate for spintronic thermoelectric applications. [ABSTRACT FROM AUTHOR]

We present our results of the spin‐polarized calculations on the structural, magneto‐electronic, thermodynamic, and thermoelectric properties of vacancy‐ordered double perovskites A2OsX6 (A = Rb/Cs; X = Cl/Br). We utilized the Wu‐Cohen generalized gradient approximation (Wu‐GGA) and the mBJ scheme to determine a more reliable electronic structure. The compounds exhibit negative formation energy, suitable tolerance factor, and a stable phonon spectrum, indicating their stability. The compounds show half‐metallicity, acting as semiconductors with direct band gaps between 2 and 3 eV in the spin‐up orientation while metallic in the spin‐down. Each compound shows a total spin magnetic moment of 2.00 μB per formula unit, with Os‐t2g states contributing the most (~1.5 μB). The computed thermoelectric coefficient indicates the usability of these compounds across a wide temperature range (200–800 K) with high electrical conductivity and low electronic thermal conductivity. The compounds exhibit high Seebeck coefficient and figure of merit (ZT), making them suitable for thermoelectric applications. With ferromagnetic and half‐metallic characteristics, these compounds could be promising candidates for spintronics, thermoelectronic, and data storage applications. [ABSTRACT FROM AUTHOR]

Textile‐based generators that can convert low‐grade energy from the human body or environment into sustainable electricity have generated immense scientific interest in self‐powered wearable applications. However, their low power density and environmental suitability have extremely restricted their portable applications in complex and mutable environments. Herein, an asymmetric sandwich structure between molybdenum disulfide (MoS2)‐carbonized silks (MCs) and MoS2/MXene–Cottons (MMCs) to construct efficient thermo–hydroelectric generators (THEGs) that synergistically harvest heat‐moisture energy to generate considerable electricity is rationally designed. Notably, the large surface area of MoS2/MXene van der Waals heterojunctions (vdWhs) enables efficient charge collection, and the vertical MoS2 nanosheet arrays supply abundant nanochannels for a highly efficient hydration effect, generating an output power density of 32.26 µW cm−2 after wetting with deionized water. Combined with the sensitive temperature recognition ability with a Seebeck coefficient of 23.5 µV K−1, the application possibilities of these prepared THEGs in the mutual conversion of fingertip temperature/language, and the monitoring of the human physiological state is foresee. [ABSTRACT FROM AUTHOR]

High energy‐conversion efficiency (ZT) of thermoelectric materials has been achieved in heavy metal chalcogenides, but the use of toxic Pb or Te is an obstacle for wide applications of thermoelectricity. Here, high ZT is demonstrated in toxic‐element free Ba3BO (B = Si and Ge) with inverse‐perovskite structure. The negatively charged B ion contributes to hole transport with long carrier life time, and their highly dispersive bands with multiple valley degeneracy realize both high p‐type electronic conductivity and high Seebeck coefficient, resulting in high power factor (PF). In addition, extremely low lattice thermal conductivities (κlat) 1.0–0.4 W m−1 K−1 at T = 300–600 K are observed in Ba3BO. Highly distorted O–Ba6 octahedral framework with weak ionic bonds between Ba with large mass and O provides low phonon velocities and strong phonon scattering in Ba3BO. As a consequence of high PF and low κlat, Ba3SiO (Ba3GeO) exhibits rather high ZT = 0.16–0.84 (0.35–0.65) at T = 300–623 K (300–523 K). Finally, based on first‐principles carrier and phonon transport calculations, maximum ZT is predicted to be 2.14 for Ba3SiO and 1.21 for Ba3GeO at T = 600 K by optimizing hole concentration. Present results propose that inverse‐perovskites would be a new platform of environmentally‐benign high‐ZT thermoelectric materials. [ABSTRACT FROM AUTHOR]

In the search for new and novel materials for various thermo‐physical applications, we have reported the magnetic, electronic, mechanical, thermal, and thermoelectric transport properties of two full Heusler alloys (HAs), Ru2MnV and Ru2MnNb. In order to obtain a stable structure, volume optimization was carried out in the Fm‐3m (225) and F43‐m (216) space groups. The Fm‐3m space group was found to be a stable phase for both alloys. Electronic results show the metallic nature of these alloys. Ferromagnetic moments of 4.06 and 4.18 μB were obtained for Ru2MnV and Ru2MnNb, respectively. Mechanical results show a brittle nature for Ru2MnV and a ductile nature for Ru2MnNb with a high melting temperature for Ru2MnV. Thermoelectric properties such as figure of merit along with Seebeck coefficient, electrical conductivity, power factor, and thermal conductivity have also been calculated. Furthermore, the thermodynamic results of the studied materials have also been evaluated to understand the nature of various thermodynamic parameters with respect to temperature and pressure. [ABSTRACT FROM AUTHOR]

Herein, the synthesis of high‐entropy wolframite oxide (CoCuNiFeZn)1‐xGaxWO4 through standard solid‐state route followed by spark plasma sintering and their structural, microstructural, and thermoelectric (TE) properties are investigated. X‐ray diffraction pattern followed by patterns matching refinement shows a monoclinic structure with the volume of the unit cell decreasing with increasing Ga content. The optical bandgap for these oxides shows a cocktail effect in high‐entropy configuration. The Seebeck coefficient indicates electrons as dominating charge carriers with a nondegenerate behavior. The electrical resistivity decreases with increasing temperature depicting a semiconducting nature. Thermal conductivity in high‐entropy samples (κ ≈ 2.1 W m−1 K−1 @ 300 K) is significantly lower as compared to MgWO4 (κ ≈ 11.5 W m−1 K−1 @ 300 K), which can be explained by the strong phonon scattering due to large lattice disorder in high‐entropy configuration. The TE figure of merit zT increases with Ga doping via modifying all three TE parameters positively. [ABSTRACT FROM AUTHOR]

The field of electronic textiles currently lacks n‐type polymer fibers that can complement the more established p‐type polymer fibers. Here, a highly conductive n‐type polymer fiber is obtained via wet‐spinning of n‐doped poly(3,7‐dihydrobenzo[1,2‐b:4,5‐b']difuran‐2,6‐dione) (n‐PBDF). The electrical conductivity of the fibers increases from 1000 to 1600 S cm−1 with increased draw during processing and correlates well with Young's modulus. Wide‐angle X‐ray scattering reveals the existence of a bimodal orientation of the polymer chains, favoring parallel alignment to the fiber axis with increased draw. After 14 d in 80% humid air, fiber conductivity stabilizes maintaining 81% of the initial conductivity. Although the electrical conductivity drops slightly over time, the Seebeck coefficient increases, resulting in the highest thermoelectric power factor being measured at 91 µW m−1 K−2 for the most drawn fiber 14 d after its fabrication. A proof‐of‐concept two‐couple thermoelectric textile is crafted by embroidering bundles of n‐type PBDF fibers and p‐type PEDOT:PSS fibers. The device generates 2.40 nW at a 22 °C temperature gradient. This work represents the initial steps and a crucial advancement toward fabricating high‐performance n‐type polymer fibers that can complement their p‐type counterparts to close the existing performance gap. [ABSTRACT FROM AUTHOR]

Organic thermoelectric (TE) materials are regarded as the next‐generation TE materials because of their merits including low cost, high mechanical flexibility, and low intrinsic thermal conductivity. However, their Seebeck coefficient is usually quite low. Herein, a new strategy is demonstrated to greatly enhance the Seebeck coefficient of poly(3,4‐ethylenedioxy‐thiophene):poly(styrenesulfonate) (PEDOT:PSS), which is the most popular TE polymer, through polaron level splitting via π–π overlapping with nonpolar small aromatic molecules including anthracene, naphthalene, and pyrene. Although these aromatic molecules are neither oxidizing nor reducing agent, they can greatly enhance the Seebeck coefficient of PEDOT:PSS films pre‐treated with dimethyl sulfoxide, acid, or acid then base, while they do not lower the electrical conductivity too much. Through such a treatment with anthracene, the Seebeck coefficient can be up to 45.5 µV K−1, and the ZT value can be up to 0.27. The enhancement is ascribed to the splitting of the lower polaron energy level of PEDOT, which is induced by the π–π overlapping between the aromatic compounds and conjugated PEDOT. This can shift up the Fermi level, thereby enhancing the Seebeck coefficient. [ABSTRACT FROM AUTHOR]

Group IV‐VI van der Waals crystals (MX, where M = Ge, Sn, and X = S, Se) are receiving increasing attention as semiconducting thermoelectric materials with nontoxic, earth‐abundant composition. Among them, SnSe is considered the most promising as it exhibits a remarkably high thermoelectric figure of merit (ZT), initially attributed to its low lattice thermal conductivity. However, it has been shown that the electronic band structure plays an equally important role in thermoelectric performance. A certain band shape, described as a "pudding mold" and characteristic for all MXs, has been predicted to significantly improve ZT by combining good electrical conductivity with high Seebeck coefficient. This subtle feature is explored experimentally for GeS, SnS, and SnSe by means of angle‐resolved photoemission spectroscopy. The technique also allows for the determination of the effective mass and Fermi level position of as‐grown undoped crystals. The findings are supported by ab initio calculations of the electronic band structure. The results greatly contribute to the general understanding of the valence band dispersion of MXs and reinforce their potential as high‐performance thermoelectric materials, additionally giving prospects for designing systems consisting of van der Waals heterostructures. [ABSTRACT FROM AUTHOR]

As an energy harvesting device, the newly emerged thermocell has attracted great interest. However, it requires an additional energy storage device to complete a functional recycling system. As the core part of energy harvesting and storage devices, the design of electrodes with both high thermoelectric and electrochemical conversion efficiencies is particularly important. Herein, a high‐performance thermocell and supercapacitor device are constructed by employing the same mix‐phase MoSe2‐NiSe/NF electrode for both energy harvesting and storage. The thermocell exhibits an enhanced Seebeck coefficient of −1.69 mV K−1 and a superior output of 0.58 mW m−2 K−2 for low‐grade heat harvesting. Meanwhile, the supercapacitor device shows a great energy density of 54 Wh kg−1 at a power density of 806 W kg−1 and excellent cycling stability with a 92.8% retention rate after 50 000 cycles. This work offers a universal approach for the rational design of synergistic electrode materials to simultaneously achieve high‐energy harvesting and storage devices and lays a foundation for the recycling system of thermoelectric harvesting, conversion, and storage. [ABSTRACT FROM AUTHOR]

Due to the intrinsic contradiction of electrical conductivity and Seebeck coefficient in thermoelectric materials, the enhancement for the power factor (PF) is limited. Since the PF decides the output power, strategies to the enhancement of PF are of paramount importance. In this work, Bi2Te3/Sb and Bi2Te3/W multilayer films are proposed to enhance the thermoelectric properties. Both systems possess extremely high conductivity of ≈5.6 × 105 S m−1. Moreover, the electrical conductivity and Seebeck coefficient simultaneously increase as temperature rising, showing the overcome of the intrinsic contradiction. This results in ultrahigh PFs of 1785 µWm−1 K−2 for Bi2Te3/W and of 1566 µWm−1 K−2 for Bi2Te3/Sb at 600 K. Thermal heating of the Bi2Te3/Sb multilayer system shows compositional changes with subsequent formation of Bi‐Te‐Sb phases, Sb‐rich Bi‐Te precipitates, and cavities. Contrary, the multilayer structure of the Bi2Te3/W films is maintained, while Bi2Te3 grains of high‐crystalline quality are confined between the W layers. In addition, bilayer defects in Bi2Te3 and smaller cavities at the interface to W layers are also observed. Thus, compositional and confinement effects as well as structural defects result in the ultrahigh PF. Overall, this work demonstrates the strategies on how to obtain ultrahigh PFs of commercial Bi2Te3 material by microstructure engineering using multilayer structures. [ABSTRACT FROM AUTHOR]

We investigated the magnetic and thermoelectric properties of REMoN3 (RE = La, Ce, Pr, Nd, Sm) perovskites using the full potential linearized augmented plane wave (FP‐LAPW) method. To overcome the problem of underestimation of electronic interaction, we employed the DFT + U approach to accurately map the electronic structure of these compounds. Our study shows an increasing trend in the magnetic moments with the increasing number of unpaired electrons in RE. Among these compounds, SmMoN3 possesses a large magnetic moment, which is suitable for applications such as memory devices and sensors. Interestingly, all these perovskites display ferromagnetic behavior except CeMoN3, which exhibits an antiferromagnetic nature. Furthermore, our analysis indicates n‐type thermoelectric behavior in all these materials. The compound, namely PrMoN3, exhibits a high figure of merit among REMoN3, which can be improved by modifying the lattice sites. [ABSTRACT FROM AUTHOR]

In the past two decades or so, thermoelectricity has made considerable progress with several new materials discovered and significant improvement in the performance of already‐existing materials. Among the different classes of materials, skutterudites have emerged as materials having tremendous potential for mid‐temperature thermoelectric applications such as energy harvesting, waste heat recovery, etc. Herein, the authors discuss the thermoelectric properties and latest research developments that have led to significant improvement in the thermoelectric performance of skutterudites by reducing their otherwise high thermal conductivity to a greater extent. The enhancement of the thermoelectric performance of skutterudites by various techniques such as nanostructuring and filling of voids is also briefly discussed. [ABSTRACT FROM AUTHOR]

π‐Conjugated polymers can be manipulated at the molecular and thin‐film levels to strengthen thermoelectric performance. Herein, two distinctive polymers—PBDP‐T and PBDB‐T with respective outstanding Seebeck coefficient (S) and electrical conductivity (σ) are selected and their functional units are integrated to synthesize random terpolymers via the ′backbone sequence′ strategy. The resulting disordered π‐backbones of terpolymers however lead to an unsuccessful acquisition of high power factor (PF). Alternately, the ′film sequence′ strategy is utilized and representative high‐σ P2F and high‐S PTB7‐Th polymers are blended. Note that 3D conductive paths are generated in the blend films when the PTB7‐Th content falls between 35–80 wt%, which favors charge transportation and yields high σ. At an optimal 65 wt% PTB7‐Th, a maximum PF of 145.5 µW m−1 K−2 is obtained, far surpassing that of each parent polymer, which marks a breakthrough of the ′two‐phase combination′ rule. The peak PF achieved in medium PTB7‐Th content is attributed to the coexistence of bilayered and mixed morphologies, the former of which delivers slowly declining σ while the latter results in greatly elevated S with increasing PTB7‐Th. Given the notably lower thermal conductivity acquired in blend than neat polymers, the room‐temperature thermoelectric figure‐of‐merit as high as 0.15 is achieved. [ABSTRACT FROM AUTHOR]

Partial laser treatment is introduced to carbon‐based microfibers to generate excellent photon sensing capability without bias. This treatment brings about a Seebeck coefficient distribution along the sample's length, out of which a photovoltage with no external bias is generated and sensed. Using a line‐shaped laser spot, carbon microfiber (CMF), graphene microfiber (GMF), and graphene aerogel fiber (GAF) are investigated for their response to µm‐scale photon irradiation. A higher sensitivity for the incident photon is found for the GAF with no position sensitivity. More Seebeck coefficient variation is also observed for the GAF considering the amount of laser power used for the laser treatment. A weaker Seebeck coefficient spatial variation is observed for the GMF compared with the GAF. However, its photovoltage shows an abrupt magnitude change from the laser‐treated region to the non‐treated one. Despite the low spatial variation of the Seebeck coefficient for the CMF, it features an excellent and accurate position‐sensitive photoresponse with polarization change over a distance of ≈100 µm. Such unique capability prompts novel applications in using partially annealed CMF for sensing the position of optical beams at the microscale. [ABSTRACT FROM AUTHOR]

Introducing nanostructures into bulk thermoelectric materials is an effective strategy for reducing lattice thermal conductivity (κlat). However, large numbers of hanging bonds emerge on account of lattice mismatch usually at the interfaces between nanostructures and matrix, thereby significantly deteriorating carrier mobility (µH) and seriously limiting thermoelectric performance. Here, utilizing the cointroduction of Gd‐Cu2Te into n‐type PbSe as a paradigm, the zT could be greatly improved. The conduction band flattening caused by Gd doping can successfully compensate for the small Seebeck coefficient in n‐type PbSe, thus achieving extraordinary electrical performance. Further advanced electron microscopy and X‐ray absorption fine structure spectra directly demonstrate that most of the Cu forms nanoscale Cu2Se precipitates, especially a unique semi‐coherent interface between the PbSe matrix and the Cu2Se nanoprecipitate is observed for the first time. Such nanoprecipitate accompanied by the semi‐coherent interface not only ensures higher µH as an excellent charge transfer mediator but also collectively scatters the heat‐carrying phonons over a wide frequency range to obtain the ultralow κlat, resulting in the prominent improvement of the ratio µH/κlat. The present finding represents an important step forward in electron–phonon decoupling via constructing semi‐coherent nanostructure and interface engineering, which should be applicable for other thermoelectric materials. [ABSTRACT FROM AUTHOR]

ZnO is a promising high‐temperature thermoelectric (TE) material due to its superior stability and earth abundance. However, the coupling relation between Seebeck coefficient and electrical conductivity on carrier concentration limits the optimum TE performance for most TE materials, especially ZnO. Herein, enhancement of TE performance is achieved via a stepwise optimization strategy composed of carrier concentration optimization and carrier filtering effect for fabricating robust ZnO‐based composite ceramics through a self‐developed specific high‐pressure synthesis followed by spark plasma sintering. Specifically, doping SnO2 provide substantial electrons to surge the carrier concentration. The subsequent compositing Si3N4 nanoparticles results in the unique reaction‐generated Zn2SiO4 nanoprecipitates with a larger bandgap and intrinsically low thermal conductivity, which introduce an excellent carrier filtering effect to increase the Seebeck coefficient by 57.7% at 300 K without compromising electrical conductivity much and enhance phonon scattering to cause an ultralow lattice thermal conductivity of 1.39 W m−1 K−1 achieving amorphous limits of ZnO (1.4±0.1 W m−1 K−1). Consequently, a high peak ZT (figure of merit) of 0.691 at 873 K is obtained, which is higher than that of previously reported ZnO‐based TE materials. This work demonstrates a feasible and effective strategy to fabricate high‐performance TE materials, especially those with inferior electrical conductivity. [ABSTRACT FROM AUTHOR]

Silver selenide (Ag2Se) is a promising material for thermoelectric applications near room temperature. This work proposes a new fabrication route for bulk Ag2Se via a modified cold sintering process (mCSP) to enhance its figure‐of‐merit (zT). Unlike conventional CSP, mCSP employs thiol‐amine (TA) as a liquid medium that completely undissolves Ag2Se, leading to a free flow of the TA solution within interparticle channels. By sintering at temperatures above the boiling point of TA, the liquid evaporates, leaving behind a bulk Ag2Se material with a tube‐like porous structure (open pores). These induced defects strongly influence thermoelectric properties of Ag2Se, with a substantial increase in the Seebeck coefficient and decrease in electrical conductivity. The overall power factor of the mCSP sample with TA surpasses that of the control sample without TA, consistent with effective band modeling of Ag2Se. Moreover, the created micropores during mCSP effectively suppresses the thermal conductivity, leading to a maximum zT above 1.0 at 400 K by optimizing mCSP parameters. Importantly, the average zT within the 300–400 K range is around unity, representing one of the highest reported values. Further optimization of mCSP parameters can enhance average zT beyond unity, making Ag2Se more competitive with state‐of‐the‐art materials near room temperature. [ABSTRACT FROM AUTHOR]

This study employed density functional theory (DFT) embedded in Wien2K code to evaluate the physical features of the XGeCl3 (X = Rb/Cs) cubic halide perovskites. The structural optimization has been performed considering generalized gradient approximation (GGA) and electronic properties have been computed considering modified Becke‐Johnson potential (mBJ). The formation energy and phonon dispersion analysis establish the stability of the investigated compounds. Mechanical stability is further confirmed by the computed diverse elastic coefficients. It has been discovered that the examined substances are naturally ductile. The refractive index, reflectivity, and absorption coefficient, are among the optical parameters that have been estimated and analyzed. Interesting results have been obtained for the transport properties of XGeCl3 (X = Rb/Cs). The XGeCl3 (X = Rb/Cs) exhibits a high Seebeck coefficient (X = Rb/Cs) and the largest figure of merit (about 0.99), indicating significant potential for thermoelectric applications. [ABSTRACT FROM AUTHOR]

Silver selenide (Ag2Se) is a promising material for thermoelectric applications near room temperature. This work proposes a new fabrication route for bulk Ag2Se via a modified cold sintering process (mCSP) to enhance its figure‐of‐merit (zT). Unlike conventional CSP, mCSP employs thiol‐amine (TA) as a liquid medium that completely undissolves Ag2Se, leading to a free flow of the TA solution within interparticle channels. By sintering at temperatures above the boiling point of TA, the liquid evaporates, leaving behind a bulk Ag2Se material with a tube‐like porous structure (open pores). These induced defects strongly influence thermoelectric properties of Ag2Se, with a substantial increase in the Seebeck coefficient and decrease in electrical conductivity. The overall power factor of the mCSP sample with TA surpasses that of the control sample without TA, consistent with effective band modeling of Ag2Se. Moreover, the created micropores during mCSP effectively suppresses the thermal conductivity, leading to a maximum zT above 1.0 at 400 K by optimizing mCSP parameters. Importantly, the average zT within the 300–400 K range is around unity, representing one of the highest reported values. Further optimization of mCSP parameters can enhance average zT beyond unity, making Ag2Se more competitive with state‐of‐the‐art materials near room temperature. [ABSTRACT FROM AUTHOR]

Increasing valley degeneracy via doping is one approach to enhance thermoelectric performance. Herein, it is shown that reducing degeneracy can also have a positive impact on performance, particularly for materials with high degeneracy around their undoped band edges. Specifically, doping NbFeSb with Zr or Hf atoms split the valence band edge, resulting in a 1.33 reduction in hole concentration, compared with the experimental carrier concentrations. The reduction increases Seebeck coefficients and overall thermoelectric performance to better agreement with the experimental ones. Notably, for potentially effective thermoelectric materials with high degeneracy, if the doped atom has significantly lower (higher) electronegativity, it is expected to produce a high‐performance p‐type (n‐type) thermoelectric material. [ABSTRACT FROM AUTHOR]

N‐type ZrNiSn‐based alloys reach a record thermoelectric figure of merit zT ≈1.2 by increasing the carrier concentration to 4–5 × 1020 cm−3. In this work, It is reported that a comparable zT can also be realized in trace Ru‐doped ZrNiSn‐based alloy at even lower temperature by decreasing the carrier concentration. Compared to the previously reported Co doping, the doping of Ru results in a more effective reduction in carrier concentration, and thus higher Seebeck coefficient, lower electronic thermal conductivity, and enhanced thermoelectric performance. The electronic specific heat coefficient of the ZrNi1‐xRuxSn sample remains constant with increasing Ru content, indicating no obvious change in the density of states effective mass. Theoretical calculations show that the doping of Ru has negligible effect on the bottom of conduction band. The lattice thermal conductivity is further reduced by alloying Ti and Hf at the Zr site, and the bipolar diffusion is suppressed by doping of 0.5 at.% Sb. As a result, Ti0.25Zr0.5Hf0.25Ni0.99Ru0.01Sn0.995Sb0.005 reaches not only a zT value of 1.1 at 773 K but also a record average zT value of 0.8 in 300 to 873 K, demonstrating the effectiveness of trace Ru doping on boosting the thermoelectric performance of ZrNiSn‐based alloys. [ABSTRACT FROM AUTHOR]

Although ionic hydrogels have been developed recently for innovative wearable electronics, they necessitate high humidity to diffuse ions in water and fast self‐healing, which negatively impacts their performance and stability in ambient conditions (e.g., dry environments). In this study, a series of p‐ and n‐type polymeric ionic gels (PIGs) with different ratios of ionic side chains are synthesized to allow only single‐type ions to pass through them. The results demonstrate that the repeatedly stretchable PIGs are transparent, thermally robust up to 125°C, and self‐healing. Among the series of PIGs, p‐ and n‐type PIGs with 75% ion moieties (P75 and N75) exhibit the optimum ionic conductivity (σi) (4.1 × 10−4 and 2.7 × 10−4 S cm−1) and ionic Seebeck coefficients (Si) (5.84, and ‐4.18 mV K−1) under ambient conditions (25°C and relative humidity (RH) of 30%), resulting in ZTi values of 1.87 × 10−3 and 1.18 × 10−3. Moreover, the σi and Si of PIGs are almost consistent under extremely low RH 10%. Accordingly, P(([EMIM+][SPA])0.75‐r‐MA0.25) (P75) and P(([APTA][TFSI−])0.75‐r‐MA0.25) (N75) are used to achieve stretchable ionic thermoelectrics (iTEs) with stable operability under ambient conditions (RH of 30%), satisfying all of the requirements. The iTEs with five pairs of p/n couples exhibit a thermovoltage of up to ∼0.8 V. [ABSTRACT FROM AUTHOR]

The polyoxometalates like phosphotungstic acid (PTA) (H3PW12O40) and Cesium (Cs+) doped phosphotungstic acid (Cs‐PTA) (Cs3‐PW12O40) nanocrystalline thin films were effectively deposited by microwave assisted chemical bath deposition (MA‐CBD) technique. The structural characterization of microwave aided H3PW12O40 and Cs3‐PW12O40 thin films were done by Thermo gravimetric (TG) and Differential thermal analysis (DTA) techniques, X‐ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X‐ray analysis (EDAX). The TGDTA analysis revealed that the complete decomposition process of Cs‐PTA compound is carried out at 600 °C and which is comparatively lower than that of other chemical method. The X‐ray diffractogram confirms the polycrystalline nature of the synthesized H3PW12O40 and Cs3‐PW12O40 thin films having spinel cubic crystal structure. The lattice parameter of H3PW12O40 and Cs3‐PW12O40 compound found to be in the range of 11.34 Å to 11.46 Å. The main absorption peaks observed nearly 800, 1000 and 1100 cm−1 confirms the formation of H3PW12O40 and Cs3‐PW12O40 materials. The porous structure of nanocrystalline spherical grains morphology of H3PW12O40 and Cs3‐PW12O40 films were confirmed from SEM analysis. An appropriate peaks of metal ions like P, W, O and Cs observed in EDAX spectra shows the stoichiometric formation of H3PW12O40 and Cs3‐PW12O40 thin films. [ABSTRACT FROM AUTHOR]

It is of great significance to develop high‐performance n‐type ionic thermoelectric materials. Herein, the turnover from p‐ to n‐type and great improvement in the n‐type ionic Seebeck coefficient of ionogels through synergistic dopings of cations and anions, is reported. Doping with silver trifluoromethanesulfonate (AgOTf) can turn the ionic Seebeck coefficient of the ionogels consisting of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIM:BF4) from 5.52 to −26.4 mV K−1 under a relative humidity (RH) of 75%. The TE performances can be further improved through the combination with the anti‐solvent method, and the ZTi value can be up to 1.7 under 91% RH, the highest for n‐type ionogels. Such p‐ to n‐type turnover and great improvement in the n‐type ionic Seebeck coefficient can be attributed to synergistic doping by Ag+ and OTf−. Ag+ can form a complex with BMIM+, and OTf− can have strong Coulomb interaction to BMIM+. Both can retard the migration of the BMIM+ cations and thus increase the difference in the mobilities of BMIM+ and BF4−. This is the first time that synergistic dopings by both cations and anions for ionic TE materials has been observed. [ABSTRACT FROM AUTHOR]

Calcium cobaltite Ca3Co4−xO9+δ (CCO) is a promising p‐type thermoelectric (TE) material for high‐temperature applications in air. The grains of the material exhibit strong anisotropic properties, making texturing and nanostructuring mostly favored to improve thermoelectric performance. On the one hand multitude of interfaces are needed within the bulk material to create reflecting surfaces that can lower the thermal conductivity. On the other hand, low residual porosity is needed to improve the contact between grains and raise the electrical conductivity. In this study, CCO fibers with 100% flat cross sections in a stacked, compact form are electrospun. Then the grains within the nanoribbons in the plane of the fibers are grown. Finally, the nanoribbons are electrospun into a textured ceramic that features simultaneously a high electrical conductivity of 177 S cm−1 and an immensely enhanced Seebeck coefficient of 200 µV K−1 at 1073 K are assembled. The power factor of 4.68 µW cm−1 K−2 at 1073 K in air surpasses all previous CCO TE performances of nanofiber ceramics by a factor of two. Given the relatively high power factor combined with low thermal conductivity, a relatively large figure‐of‐merit of 0.3 at 873 K in the air for the textured nanoribbon ceramic is obtained. [ABSTRACT FROM AUTHOR]

Low‐grade heat (<100 °C) energy sources possess considerable untapped potential for sustainable power generation. Liquid thermocells (LTCs) represent an innovative solution to convert low‐grade heat into electricity. The performance of LTCs relies on the combined effects of the Seebeck coefficient (Se), electrical conductivity (σeff), and thermal conductivity (κeff). While previous studies have predominantly focused on enhancing Se and σeff, κeff has received limited attention. Therefore, in this study, an electrochemically active biphasic liquid thermocell (EAB‐LTC) composed of ferrocene (Fc) and Fe(CN)63−${\mathrm{Fe}}({\mathrm{CN}})_6^{3 - }$ in an ethanol‐aqueous biphasic system is proposed. The self‐reaction of the redox couple enhances Se, while the biphasic nature of the system suppresses thermal convection, resulting in reduced κeff. Compared to the conventional single‐phase LTC utilizing Fe(CN)63−${\mathrm{Fe}}({\mathrm{CN}})_6^{3 - }$ / Fe(CN)64−${\mathrm{Fe}}({\mathrm{CN}})_6^{4 - }$, the Se is increased by nearly threefold, accompanied by a more than threefold enhancement in output power. The application of the EAB‐LTC module is successfully demonstrated in powering electronic devices, thereby establishing a novel pathway for advancing high‐performance LTCs and presenting a promising approach toward achieving carbon neutrality. [ABSTRACT FROM AUTHOR]

Hybridizing single‐walled carbon nanotubes (SWCNTs) with π‐conjugated organic small molecules (π‐OSMs) offers a promising approach for producing high‐performance thermoelectric (TE) materials through the facile optimization of the molecular geometry and energy levels of π‐OSMs. Designing a twisted molecular structure for the π‐OSM with the highest occupied molecular orbital energy level comparable to the valence band of SWCNTs enables effective energy filtering between the two materials. The SWCNTs/twisted π‐OSM hybrid exhibits a high Seebeck coefficient of 110.4 ± 2.6 µV K−1, leading to a significantly improved power factor of 2,136 µW m−1 K−2, which is 2.6 times higher than that of SWCNTs. Moreover, a maximum figure of merit over 0.13 at room temperature is achieved via the efficient TE transport of the SWCNTs/twisted π‐OSM hybrid. The study highlights the promising potential of optimizing molecular engineering of π‐OSMs for hybridization with SWCNTs to create next‐generation, efficient TE materials. [ABSTRACT FROM AUTHOR]

The thermoelectric figure-of-merit (zT) of p-type MNiSn (M = Ti, Zr, or Hf) half-Heusler compounds is lower than their η-type counterparts due to the presence of a donor in-gap state caused by Ni occupying tetrahedral interstitials. While ZrNiSn and TiNiSn, have been extensively studied, HfNiSn remains unexplored. Herein, this study reports an improved thermoelectric property in p-type HfNi1-xCoxSn. By doping 5 at% Co at the Ni sites, the Seebeck coefficient becomes reaching a peak value exceeding 200 μV K-1 that breaks the record of previous reports. A maximum power factor of ≈2.2 mW m-1 K-2 at 973 K is achieved by optimizing the carrier concentration. The enhanced p-type transport is ascribed to the reduced content of Ni defects, supported by first principle calculations and diffraction pattern refinement. Concomitantly, Co doping also softens the lattice and scatters phonons, resulting in a minimum lattice thermal conductivity of ≈1.8 W m-1 K-1. This leads to a peak zT of 0.55 at 973 K is realized, surpassing the best performing p-type MNiSn by 100%. This approach offers a new method to manipulate the intrinsic atomic disorder in half-Heusler materials, facilitating further optimization of their electronic and thermal properties. [ABSTRACT FROM AUTHOR]

Herein, the electrical resistivity, Seebeck coefficient, and power factor of an indium tin oxide (ITO) and nickel‐chromium (NiCr) thermocouple are investigated. The thicknesses of the ITO and NiCr are varied between 10 and 430 nm. Seebeck coefficients between 12.8 and (21.4 ± 1.5) μV K−1 are measured, respectively. The results indicate that a reduction in thickness generally leads to an increase in the Seebeck coefficient until a maximum value is reached. Among the measured samples, the optimal Seebeck coefficients are found with an ITO thickness of (111 ± 4) nm and NiCr thickness of (18 ± 2) nm. Finally, the power factor of the thermocouples is determined, with a maximum power factor of (84 ± 7) μW m−1 K−2 for the ITO thickness of (111 ± 4) nm and nickel‐chromium thickness of (42 ± 5) nm. [ABSTRACT FROM AUTHOR]

Harvesting low‐grade waste heat, which constitutes 60% of the overall waste heat, is key to halting climate change. Electrochemical waste‐heat harvesting has recently drawn attention to practical low‐grade waste‐heat harvesting. In this study, a power density maximization strategy is presented in scalable and cost‐effective aqueous redox couple‐based thermo‐electrochemical cells (TECs). The n‐type feature of the water‐soluble Fe2+/3+ redox couple is essential for constructing the TEC p–n leg device; however, it has not been investigated much so far. The modulation of the chaotropicity of counteranions enhances the absolute value of the Seebeck coefficient for the Fe2+/3+ redox couple with an inner‐sphere reaction mechanism because of the greater structural disorder in the solvation shell. Moreover, the use of a cost‐effective Fe─N─C electrocatalyst shows redox kinetics and a power density comparable to those of state‐of‐the‐art Pt electrodes, economically compensating for the sluggish charge‐transfer kinetics of the inner‐sphere redox mechanism. The Fe─N─C ‐based TEC device exhibits 1.73 W m−2 of power density at 0.1 $ W−1 of cost per power, which is 1.24% with respect to the Carnot efficiency, exceeding 0.23–0.53% compared to those reported for previous Pt‐based TEC devices with the same redox chemistry. [ABSTRACT FROM AUTHOR]

Harvesting low‐grade waste heat from the natural environment with thermoelectric materials is considered as a promising solution for the sustainable energy supply for wearable electronic devices. For practical applications, it is desirable to endow the thermoelectric materials with excellent mechanical and self‐healing properties, which remains a great challenge. Herein, the design and characterization of a series of high‐performance ionic hydrogels for soft thermoelectric generator applications are reported. Composed of a physically cross‐linked network of polyacrylic acid (PAA) and polyethylene glycol (PEO) doped with sodium chloride, the resulting PAA‐PEO‐NaCl ionic hydrogels demonstrates impressive mechanical strength (breaking stress >1.3 MPa), stretchability (>1100%), and toughness (up to 7.34 MJ m−3). Moreover, the reversible hydrogen bonding interaction and chain entanglement render the ionic hydrogels with excellent mechanical resilience, adhesion properties, and self‐healing properties. At ambient conditions, the electrochemical and thermoelectric performance of the ionic hydrogels can be restored immediately from physical damage such as cutting, and the mechanical healing can be completely restored within 24 h. At the optimized composition, the Seebeck coefficient of the ionic hydrogels can reach 3.26 mV K−1 with a low thermal conductivity of 0.321 W m−1 K−1. Considering the excellent mechanical properties and thermoelectric performance, it is believed that the ionic hydrogels are widely applicable in ionic thermoelectric capacitors to convert low‐grade heat into electricity for soft electronic devices. [ABSTRACT FROM AUTHOR]

Realizing high thermoelectric performance in CoSb3 skutterudite‐based thin films and their devices is historically challenging, especially due to the lack of high‐performing thin‐film‐based device working at medium‐to‐high temperatures. Here, a record‐high ZT of 1.1 is achieved at 683 K in an n‐type Ce0.3Ni1.5Co2.5Sb12 thin film, fabricated from a self‐designed target via advanced pulsed laser deposition. Both experimental and computational results confirm that the Ce‐filling and metal‐featured nanoinclusions such as CeSb contribute to high electrical conductivity, while the Ni‐doping and significantly strengthen the energy filtering effect that occurs at the dense interfaces between the Ce0.3Ni1.5Co2.5Sb12 matrix and the nanoinclusions which leads to a large Seebeck coefficient, giving rise to such a high ZT. In addition, a new‐type CoSb3 thin‐film‐based device is successfully fabricated, which exhibits a high output power density of 8.25 mW cm−2 at a temperature difference of 140 K and a cold‐side temperature of 573 K, indicating the potential for application to medium‐to‐high‐temperature power generation scenarios. [ABSTRACT FROM AUTHOR]

Optical, magnetoresistance, and thermoelectric properties of La1−xKxMnO3 (x = 0.05, 0.15, and 0.25) compounds have been investigated. The crystallography demonstrates that the samples x = 0.05 and 0.15 are a single‐phase rhombohedral (R3¯C$R \overset{\cdot}{3} C$) structure, while x = 0.25 is near to a single rhombohedral phase with a minor amount of Mn3O4 (with a ratio of ≈2%). The optical properties manifest that the reflectivity decreases slightly with increasing x‐doping, where the sample of x = 0.05 has the lowest reflection value, making it a promising material for photovoltaic applications. Electrical resistivity measurements show that the samples have a metal–semiconductor transition, and the transition temperature Tms decreases with the K content. The thermoelectric data show a remarkable coincidence behavior of the ρ–T relationship, which has a peak at a transition temperature (TS). Magnetic susceptibility data show that the samples undergo ferro‐paramagnetic transition at a certain temperature (Curie temperature). [ABSTRACT FROM AUTHOR]

We investigated the Ruddlesden‐Popper series CaO(CaMnO3)m with m = 1, 2, 3, ∞, to study the impact of the varying amounts of CaO layers on their thermoelectric properties. Previous studies showed that highly dense samples are difficult to obtain due to the refractory nature of these materials. In this study, we managed to obtain dense pellets during a classical hot‐pressing step, if and only if the samples were subjected to extended ball‐milling prior to pressing, resulting in crystallite sizes of 30–35 nm after hot‐pressing. The sample with the largest amount of CaO layers (m = 1) had the lowest electrical and thermal conductivity, and the highest Seebeck coefficient, as predicted. Ultimately the perovskite CaMnO3 (m = ∞, no CaO layers) exhibited the best thermoelectric properties. [ABSTRACT FROM AUTHOR]