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Organic materials have found widespread applications but require doping to overcome their intrinsically low carrier concentration. Doping injects free carriers into the polymer, moving the position of the Fermi level, and creates coulombic traps, changing the shape of the electronic density of states (DOS). We develop equations to explicitly map the DOS parameters to the Seebeck vs conductivity relationship. At low carrier concentrations, this relationship is a universal slope - k B / q , while at higher carrier concentrations, the slope becomes dependent on the shape of the DOS. We conclude that, at high doping, a heavy-tailed DOS leads to higher thermoelectric power factors. [ABSTRACT FROM AUTHOR]

This work comprehensively studies the electronic, structural, optical, thermodynamic and thermoelectric properties of the Co2CrBi Heusler compound for both ferromagnetic and antiferromagnetic phases. The calculation is based on the Full-potential Linearized Augmented Plane-Wave (FP-LAPW) method by using the "WIEN2k" code, with the Generalized Gradient Approximation (PBE-GGA) for the exchange–correlation potential. The calculations reveal that Co2CrBi exhibits metallic behavior due to the spin polarization at the Fermi level. Further calculations were performed using GGA + SOC + U and hybrid functional HSE06 approximations to confirm this metallic nature. The antiferromagnetic phase is more stable than the ferromagnetic phase, although it cannot be regarded as a hard material. Various properties, including electron energy loss, refractive index, extinction coefficient, optical conductivity, Seebeck coefficient, electrical conductivity, and thermal conductivity are also computed and discussed for both ferromagnetic and antiferromagnetic phases. Additionally, this investigation is extended to encompass the unexplored properties of Co2CrBi, including both thermodynamic and thermoelectric. [ABSTRACT FROM AUTHOR]

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Abstract The conversion efficiency of a thermoelectric power generator depends on the dimensionless figure-of-merit (ZT) of the constituent thermoelectric materials, which is mainly determined by their Seebeck coefficient as well as the electrical and thermal conductivity. ZnO holds promise for thermoelectric applications, yet its use is currently limited by low electrical conductivity and high thermal conductivity. Herein, we demonstrate how thermal conductivity of ZnO can be significantly reduced by intelligently combining it with a cellulose-based Ag fabric using a one-step hydrothermal method, and how different ratios of zinc nitrate hexahydrate (ZNH) to hexamethylenetetramine (HMT) can be used to fine-tune the thermoelectric performance of the resulting composite. We show that as-prepared samples have a composite structure of Ag, Zn and O without any other impurity phases. We propose that the facet dependent crystal growth orientation, from the c-axis in (101) planes to the a-axis in (100) plane, amplify phonon scattering within the material, impeding effective heat transfer and thereby lowering overall thermal conductivity to 0.046 W/mK at room temperature for composites with a 1:1 ZNH to HMT ratio.

Abstract Ab-initio simulations using density functional theory (DFT) were employed to investigate the structural, mechanical, electronic, magnetic, optical, and thermoelectric properties of halide perovskites $$\hbox {BaCoX}_3$$ (X = Cl, Br, I). Structural optimization and mechanical stability assessments confirm the reliability of these perovskites in a hexagonal P $$6_3$$ mc symmetry. The stability of the ferromagnetic phase was validated through total crystal energy minimization via Murnaghan’s equation of state. Electronic band structures and density of states, derived from the generalized gradient approximation (GGA), reveal a semiconducting ferromagnetic nature in the spin up channel, spotlighting their potential in semiconductor spintronic applications. Phonon dispersion analysis of $$\hbox {BaCoCl}_3$$ and $$\hbox {BaCoBr}_3$$ revealed positive phonon modes throughout the entire Brillouin zone, confirming their dynamical stability. In contrast, $$\hbox {BaCoI}_3$$ demonstrated dynamical instability. The elastic constants confirm the mechanical stability and ductile nature of the perovskites. Optical and dielectric properties of these perovskites show significant UV absorption and photoconductivity, making them highly suitable for optoelectronic and solar cell applications. Finally, transport properties, such as the Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and figure of merit (ZT) unveil their exceptional thermoelectric performance. Combining half-metallic ferromagnetic traits with superior thermoelectric and optoelectronic performance positions $$\hbox {BaCoX}_3$$ compounds as exceptional candidates for applications in spintronics, optoelectronics, and thermoelectrics. This comprehensive investigation demonstrates their ability to excel across a diverse array of advanced technological applications.

As a new type of inorganic ductile semiconductor, silver sulfide (α-Ag2S) has garnered a plethora of interests in recent years due to its promising applications in flexible electronics. However, the lack of detailed defect calculations and chemical intuition has largely hindered the optimization of material's performance. In this study, we systematically investigate the defect chemistry of extrinsic doping in α-Ag2S using first-principles calculations. We computationally examine a broad suite of 17 dopants and find that all aliovalent elements have extremely low doping limits (

Abstract Lead-free double perovskite halides are attracting considerable interest in the optoelectronics sector due to their remarkable electronic, optical, and transport properties. These materials are not only stable and easy to synthesize but also present a wide range of potential applications. This study investigates the fascinating characteristics of Rb₂LiGa(Br/I)₆, focusing on its structural, electronic, optical, transport, and photovoltaic attributes. Our findings indicate that Rb₂LiGaBr₆ and Rb₂LiGaI₆ have band gaps of 1.19 eV and 1.13 eV, respectively, highlighting their versatility for various applications. Both compounds exhibit exceptional optical properties, featuring high absorption coefficients and optical conductivity, along with low reflectivity throughout the UV-visible spectrum, positioning them as excellent candidates for solar cell technologies. Moreover, Rb₂LiGa(Br/I)₆ demonstrates impressive thermoelectric performance, with high figure-of-merit (ZT) values between 200 K and 800 K, indicating their potential as effective thermoelectric materials. Consequently, this study offers valuable insights for the development of efficient double perovskite-based solar cells. Encouraged by the outstanding absorption and optical conductivity of Rb₂LiGa(Br/I)₆, we simulated an Au/Cu₂O/Rb₂LiGa(Br/I)₆/TiO₂/FTO solar cell. Our results reveal that the modeled solar cell, Au/Cu₂O/Rb₂LiGaI₆/TiO₂/FTO, achieves an efficiency of 26.48%, surpassing previous reports. This research sets a new benchmark for high-performance double perovskite-based solar cells and lays the foundation for future advancements in this exciting area.

Thermoelectric materials with high electrical conductivity and low thermal conductivity (e.g., Bi2Te3) can efficiently convert waste heat into electricity; however, in spite of favorable theoretical predictions, individual Bi2Te3 nanostructures tend to perform less efficiently than bulk Bi2Te3. We report a greater-than-order-of-magnitude enhancement in the thermoelectric properties of suspended Bi2Te3 nanoribbons, coated in situ to form a Bi2Te3/F4-TCNQ core-shell nanoribbon without oxidizing the core-shell interface. The shell serves as an oxidation barrier but also directly functions as a strong electron acceptor and p-type carrier donor, switching the majority carriers from a dominant n-type carrier concentration (∼1021 cm-3) to a dominant p-type carrier concentration (∼1020 cm-3). Compared to uncoated Bi2Te3 nanoribbons, our Bi2Te3/F4-TCNQ core-shell nanoribbon demonstrates an effective chemical potential dramatically shifted toward the valence band (by 300-640 meV), robustly increased Seebeck coefficient (∼6× at 250 K), and improved thermoelectric performance (10-20× at 250 K).

The perception of light is crucial for humans to explore the external world. However, challenges of current planar photosensors include inherent limitations in depth of field and field of view. Flexible electronic devices offer a solution to this issue by allowing adaptation to curved surfaces, ensuring stable interfaces and excellent signal quality. Compared to photoelectric sensors, flexible photosensors based on photothermal conversion can respond to a wider spectrum of light, simplify design processes, and overcome issues such as instability and high toxicity. The review introduces progress on the flexible photosensors based on photothermal conversion, and summarizes the combination of photothermal conversion with pyroelectric, thermoelectric, and thermoresistive effects, allowing for the conversion of light signals into thermal signals and then into electric signals. Additionally, the review outlines the challenges for future research in this field.

The thermoelectric (TE) properties of Nb-doped (CuI)0.003Bi2− x Nb x Te2.7Se0.3 compounds (x = 0, 0.005, 0.01 and 0.03), were investigated at temperatures ranging from 300 to 600 K. Among the compounds studied, the lightly substituted (CuI)0.003Bi1.995Nb0.005Te2.7Se0.3 compound exhibited the best TE performance due to the improvement in its electrical conductivity and its relatively unchanged Seebeck coefficient due to Nb doping. Its figure of merit, ZT, was greater than the undoped (CuI)0.003Bi2Te2.7Se0.3 compound for the temperature range investigated. In particular, the ZT of (CuI)0.003Bi1.995Nb0.005Te2.7Se0.3 reached a value of 0.65 at 448 K in this study. [ABSTRACT FROM AUTHOR]

The thermoelectric (TE) properties of Nb-doped (CuI)0.003Bi2− x Nb x Te2.7Se0.3 compounds (x = 0, 0.005, 0.01 and 0.03), were investigated at temperatures ranging from 300 to 600 K. Among the compounds studied, the lightly substituted (CuI)0.003Bi1.995Nb0.005Te2.7Se0.3 compound exhibited the best TE performance due to the improvement in its electrical conductivity and its relatively unchanged Seebeck coefficient due to Nb doping. Its figure of merit, ZT, was greater than the undoped (CuI)0.003Bi2Te2.7Se0.3 compound for the temperature range investigated. In particular, the ZT of (CuI)0.003Bi1.995Nb0.005Te2.7Se0.3 reached a value of 0.65 at 448 K in this study. [ABSTRACT FROM AUTHOR]

Atmospheric Water Generation assumes substantial significance as an innovative remedy for addressing water scarcity and augmenting water resilience. This technology facilitates water extraction directly from the atmosphere, presenting a sustainable and decentralized approach to water supply. The investigation into the feasibility of attaining the dew point temperature for a heatsink operating in the climatic conditions of Basra was conducted using Fluent 22.1 software. The minimum dew point temperature under extreme conditions was determined to be 10.52℃. A thermoelectric device was a primary component in cooling the moisture-laden air to produce water from atmospheric air. Simulations were executed using two complementary and two integrated heatsinks under turbulent airflow conditions ranging from 4 to 20 m/s. The results indicated an inverse relationship between heat distribution within the heatsink and fluid flow velocity, emphasizing the crucial role of airflow passage arrangement in the condensation process. Enhancing the heatsink's surface area and reducing airflow quantity proved effective in achieving the dew point temperature. The lowest temperature attained was 9.2℃, featuring intersecting heat exchangers with a flow velocity of 4 m/s. The result indicated that altering the flow pattern affects the condensation process's surface temperature by as much as 38%, while the rise in pressure difference can reach 20%. Under the same operational conditions, the difference in thermal conductivity between two distinct heat exchanger configurations, attributed to pressure variations, is notably 8%. The study concludes that the Qurna region benefits from favorable weather conditions, encompassing temperature and relative humidity, thereby enabling water generation from atmospheric air, notwithstanding the consideration of the dew point temperature as a limiting factor.

Abstract Exploration of metastable phases holds profound implications for functional materials. Herein, we engineer the metastable phase to enhance the thermoelectric performance of germanium selenide (GeSe) through tailoring the chemical bonding mechanism. Initially, AgInTe2 alloying fosters a transition from stable orthorhombic to metastable rhombohedral phase in GeSe by substantially promoting p‐state electron bonding to form metavalent bonding (MVB). Besides, extra Pb is employed to prevent a transition into a stable hexagonal phase at elevated temperatures by moderately enhancing the degree of MVB. The stabilization of the metastable rhombohedral phase generates an optimized bandgap, sharpened valence band edge, and stimulative band convergence compared to stable phases. This leads to decent carrier concentration, improved carrier mobility, and enhanced density‐of‐state effective mass, culminating in a superior power factor. Moreover, lattice thermal conductivity is suppressed by pronounced lattice anharmonicity, low sound velocity, and strong phonon scattering induced by multiple defects. Consequently, a maximum zT of 1.0 at 773 K is achieved in (Ge0.98Pb0.02Se)0.875(AgInTe2)0.125, resulting in a maximum energy conversion efficiency of 4.90% under the temperature difference of 500 K. This work underscores the significance of regulating MVB to stabilize metastable phases in chalcogenides.

Highlights The flexible single-walled carbon nanotube/titanium carbide composite films exhibit excellent thermoelectric (TE), high-temperature stable and flame-retardant properties. The assembled TE device achieves an ultrafast fire warning response time of ~ 0.1 s with a threshold voltage of 1 mV. The fire warning device demonstrates exceptional repeatability and long-term stability. The designed intelligent system is promising for next-generation self-powered remote IoT fire warning applications.

Two-dimensional (2D) layered dichalcogenides possess excellent thermoelectric (TE) properties. Among them, tin diselenide (SnSe2) exhibits n-type semiconducting properties with attractive TE performance near room temperature (RT). However, its high thermal conductivity and relatively low electrical conductivity have limited its TE performance for practical applications. In this study, we significantly suppressed the thermal conductivity and enhanced the TE performance of 2D layered SnSe2 polycrystalline structures by reducing the particle size to the nano-scale using the high-energy ball milling (BM) technique in a pressurised N2 atmosphere. The particle size was reduced from ∼2 μm to 100 nm after 15 h of BM. TE results of a highly pressed compact leg made from the TE-optimised BM sample (e.g. 7 h) showed that at RT, the electrical conductivity increased by a factor of 9, whereas the Seebeck coefficient was reduced by only 40%. Consequently, the power factor increased from 12 to 42 μW/m·K2. In addition, the thermal conductivity decreased from 5.72 to 0.40 W/m·K, resulting in a significant increase in the figure of merit by a factor of 40 times higher than that of the non-BM SnSe2 leg. This study also demonstrated power generation using single-leg modules made from these structures at ΔT values above and below RT. The TE power generation of the BM module was found to be much higher than that of the non-BM module, particularly below RT. The 7-h BM module generated 2600 nW at ΔT = 45 K above RT, but when the same ΔT was applied below RT, the generated power reached 8000 nW. This enhancement in power generation below RT is remarkable, suggesting that the BM SnSe2 compact may be useful for generating measurable TE power in cold environments.

Owing to promising room‐temperature thermoelectric properties, n‐type Ag2Se has been considered as an alternative for Bi2Te3. Herein, a carrier separation strategy is realized by compositing an insulating electron donor, polyethyleneimine (PEI), with the n‐type Ag2Se. Inhomogeneous distribution of PEI can attract the minority carriers (holes) in the n‐type Ag2Se matrix, while the separated minority carriers can avoid significant scattering of the main carriers based on coulomb repulsion, leading to record‐high carrier mobility of 1551.99 cm2 V−1 s−1 and an improved S2σ of 22.39 µW m−1 K−2 at 300 K for 6 mol% PEI/Ag2Se composite film. Moreover, with PEI acting as a binder, the resistance of 6 mol% PEI/Ag2Se composite film only increases by 6.5% after bending 1000 cycles at the radius of 6 mm, showing high stability. The assembled flexible device based on 6 mol% PEI/Ag2Se composite films exhibits an excellent power density of 73.93 W m−2 at a temperature difference of 50 K, showing potential applications in powering generation for wearable electronics. [ABSTRACT FROM AUTHOR]

Silver selenide (Ag2Se) flexible films are promising near‐room‐temperature thermoelectric candidates for low‐grade heat harvesting. However, existing Ag2Se films are generally attached on substrates, which impedes further flexibility improvement of the films and constrains the scenarios of applications. Here a cost‐effective and scalable strategy is presented, which combines screen printing and annealing, for synthesizing freestanding Ag2Se inorganic films with different densities of pores. High‐density pores and thin thickness endow the films with high flexibility, while films with low‐density pores obtain higher power factor. Furthermore, by utilizing the porous microstructure, a composite structure consisting of a Ag2Se conductive network and an organic polydimethylsiloxane (PDMS) skeleton is fabricated, which further improves films’ stability under bending and torsion. Finally, a flexible thermoelectric generator comprising five Ag2Se/PDMS legs and encapsulated PDMS outputs a voltage of 20.2 mV and a maximum power of 810 nW (the corresponding power density is 5.4 W m−2) at a temperature difference of 30 K, verifying potential application at near room temperature. This work offers a useful paradigm for fabricating substrate‐free Ag2Se porous films with high flexibility for near‐room‐temperature thermoelectric applications. [ABSTRACT FROM AUTHOR]

Element doping/alloying is a common strategy to tune the electrical and thermal transports of thermoelectric (TE) materials, but the doping/alloying limit of foreign elements in many TE materials is usually very low, bringing a great challenge to improve the TE performance. In this work, beyond the classic principle of “like dissolves like,” it is found that choosing the compound with a severely distorted lattice and diversified chemical bonding as the matrix also facilitates achieving a high doping/alloying limit. Taking ductile semiconductors as an example, this work shows that gold (Au) element is nearly immiscible in Ag2S and Ag2Te, but has a relatively high alloying limit in complex Ag2S0.5Te0.5 meta‐phase. Au in Ag2S0.5Te0.5 significantly decreases the carrier concentration and improves the TE performance, but scarcely changes the mechanical properties. Consequently, Ag1.99Au0.01S0.5Te0.5 demonstrates both a high figure‐or‐merit of 0.95 at 550 K and extraordinary room‐temperature ductility. This work offers an effective and general strategy to develop stabilized doped/alloyed TE materials. [ABSTRACT FROM AUTHOR]

Based on density functional theory, structural, electronic, magneto-optic, and thermoelectric properties of RbCaN2 and RbCaO2, Heuslerene compounds have been calculated. These compounds have the ground state points with total magnetic moment of 1.0 μ B , which represents their ferromagnetic behavior. The RbCaN2 Heuslerene has the half-metallic nature and RbCaO2 case is a magnetic semiconductor. The Kerr angle of the RbCaN2 Heuslerene has two relatively peaks at the energies of 5.5 eV to 7.0 eV, but for the RbCaO2 compound, this diagram is wider in a larger energy range. Faraday angle peaks occurred at 6.2 eV and 6.8 eV for RbCaN2 and RbCaO2 compounds, which indicates the polarization of the light irradiated to them at these energies. It was observed that both compounds show high thermoelectric quality at temperatures higher than the room-temperature, and both compounds are suitable for power generator applications. [ABSTRACT FROM AUTHOR]

Copper (Cu)‐based thermoelectric (TE) materials have attracted great attention from both scientific and industrial societies, but for a long time, their real applications are greatly limited by the lack of high‐performance n‐type Cu‐based TE materials. Most recently, the novel n‐type Cu‐based TE material, CuIn5Se8, has been discovered to show a record‐high TE figure‐of‐merit (zT) to match the state‐of‐the‐art p‐type Cu‐based TE materials. However, the physical origin of such high zT is still unclear due to its complex phase compositions and crystal structures. In this work, it is revealed that the excellent TE performance is mainly contributed by the intrinsically ultralow lattice thermal conductivity originating from the unique all‐scale hierarchical architecture. It covers the ranges from atomic‐scale cation disorder in the tetragonal CuIn5Se8 phase and nanoscale diversified stacking units and stacking sequences in the hexagonal CuIn5Se8 phase, to mesoscale grain boundaries between the tetragonal phase and hexagonal phase. Doping Br at the Se‐sites can largely tune the electrical transports of CuIn5Se8 while maintaining the ultralow lattice thermal conductivity, leading to high zT reaching the optimal value predicted by the single parabolic model. This work will guide the investigation of n‐type Cu‐based TE materials in the future. [ABSTRACT FROM AUTHOR]

Photochromic smart windows have drawn increasing attention as an approach to improve building energy efficiency and enhance indoor daylight comfort. However, existing photochromic smart windows still block sunlight from entering the room on sunny winter days, causing additional energy consumption for heating. Herein, a dual‐mode smart window is designed with decoupled photo and thermal functions by combining colorless Fe‐doped WO3 photochromic film with window rotation. Based on this, selective heating and cooling of the room between winter and summer is achieved while maintaining the daylight comfort benefits during all seasons. As a proof of concept, the smart window reduces the temperature of a model house by up to 7.9 °C in summer mode, while in winter mode the temperature is only reduced by 0.7 °C. The proposed seasonally adaptive dual‐mode smart window obtains by window rotation overcomes the limitations of conventional photochromic smart windows, which not only achieves better energy efficiency but also retains improved daylight comfort. Furthermore, it demonstrates that the heat absorbed by the smart window can be harnessed to produce electricity through the integration of thermoelectric modules within the glazing, which enhances its impact on reducing energy consumption. [ABSTRACT FROM AUTHOR]

Manipulating the grain boundary and chiral structure of enantiomorphic inorganic thermoelectric materials facilitates a new degree of freedom for enhancing thermoelectric energy conversion. Chiral twist mechanisms evolve by the screw dislocation phenomenon in the nanostructures; however, contributions of such chiral transport have been neglected for bulk crystals. Tellurium (Te) has a chiral trigonal crystal structure, high band degeneracy, and lattice anharmonicity for high thermoelectric performance. Here, Sb‐doped Te crystals are grown to minimize the severe grain boundary effects on carrier transport and investigate the interface of chiral Te matrix and embedded achiral Sb2Te3 precipitates, which induce unusual lattice twists. The low grain boundary scattering and conformational grain restructuring provide electrical‐favorable semicoherent interfaces. This maintains high electrical conductivity leading to a twofold increase in power factor compared to polycrystal samples. The embedded Sb2Te3 precipitates concurrently enable moderate phonon scattering leading to a remarkable decrease in lattice thermal conductivity and a high dimensionless figure of merit (zT) of 1.1 at 623 K. The crystal growth and chiral atomic reorientation unravel the emerging benefits of interface engineering as a crucial contributor to effectively enhancing carrier transport and minimizing phonon propagation in thermoelectric materials. [ABSTRACT FROM AUTHOR]

Nanoscale defects can induce the effective modulation of carrier concentration, mobility, and phonon scattering to secure high thermoelectric performance in semiconductors. However, it is still limited to effectively controlling nanoscale defects in thermoelectric materials. Here, argon plasma bombardment is employed to introduce a large number of point defects and dislocations in microcrystalline SnSe powders, synthesized by a solvothermal method. After sintering these powders into polycrystalline bulk materials, bulk SnSe shows the ZT increasing by up to 66.7% (from 0.36 to 0.6 at 773 K). Through detailed micro/nanostructure characterizations and first‐principles calculations, the underlying mechanism is elucidated for the evaluation of thermoelectric performance. This work provides a deep understanding of the mechanism of nanoscale defects in modulating thermoelectric performance and presents experimental evidence and experience for the design and synthesis of efficient thermoelectric materials, making significant contributions to future green energy technologies. [ABSTRACT FROM AUTHOR]

Harvesting low‐grade waste heat into electrical energy is recognized as a promising solution for sustainable energy supply. In parallel, thermotropic smart windows have emerged as an efficient way to reduce building energy consumption. It is posit that thermotropic smart windows with inherent thermoelectric property may offer unique advantages for practical applications. Herein, the preparation and characterization of a series of ionic hydrogels that exhibit temperature‐sensitive phase transition behavior is reported, which are suitable for both thermotropic smart windows and thermoelectric generators. Notably, the lower critical solution temperature (LCST) of this ionic hydrogels can be feasibly modulated, and the thermoteopic phase transition also induces a sharp increase in their Seebeck coefficient, reaching up to 39.03 mV K−1 with a power factor (PFi) value up to 0.838 mW m−1 K−2. A prototype dual functional thermotropic smart window that simultaneously works as an ionic thermoelectric generator is further demonstrated, achieving both efficient phase transition driven by solar heat at ≈26 °C and an energy density up to 250 mJ m−2. This study offers new opportunity for the development of smart materials that can bridge the gap between thermal comfort and energy sustainability for energy harvesting and smart building applicat. [ABSTRACT FROM AUTHOR]

Doping is a key method employed in semiconductor technology for tuning the carrier‐density‐dependent electrical properties. In thermoelectric materials, which are typically heavily doped semiconductors, more impact factors are needed to be considered due to the heavy dose doping compared to normal semiconductors beyond carrier concentration optimization, such as band structure modification, carrier scattering mechanism and even thermal transport property. In this review, the doping effect determined by the intrinsic band features and vice versa the influence of dopants on band structure is first illustrated; and then introduce the approaches to overcoming the dilemma in effective doping caused by the temperature‐dependent optimal carrier concentration. Second, the strategies including rational vacancy design, proper selection of dopants and lattice purification toward high efficient doping and weakened carrier scattering strength are reviewed. Third, the recent discovery of the effect of dopant on thermal transport is highlighted covering the dopant‐induced local lattice distortion and exceptional strong electron‐phonon coupling. Finally, a perspective is given for the doping strategies to further boost the performance of thermoelectric materials. [ABSTRACT FROM AUTHOR]

A first-principle study using density functional theory (DFT) and Boltzmann transport was conducted to evaluate the thermoelectric (TE) properties of an Fe-based full-Heusler alloy. The compound studied is Fe2CuSi with a Cu2MnAltype structure. The electronic properties of Fe2CuSi were obtained using DFT calculations by running the Quantum ESPRESSO (QE) package. By contrast, TE properties, including electron thermal conductivity, electric conductivity, and Seebeck coefficient, were computed using a semi-empirical Boltzmann transport model solved through the BoltzTraP software at 50-1,500 K temperature range. The spin-orbit coupling effect on these properties was also evaluated, demonstrating notable effects on the results. Multiple electronic bands crossing the Fermi level for both spin directions were confirmed by the density of state curve, indicating the metallic behavior of Fe2CuSi. The magnitude of the figure of merit was determined by the Seebeck coefficient, electric conductivity, and electron thermal conductivity. In this study, the maximum dimensionless figure of merit was 0.027, reached at 1,000 K for the spindown channel. [ABSTRACT FROM AUTHOR]

Non-stoichiometric permingeatites Cu3+mSbSe4 (−0.04 ≤ m ≤ −0.02) were synthesized, and their thermoelectric properties were examined depending on the Cu deficiency. Phase analysis by X-ray diffraction revealed no detection of secondary phases. Due to Cu deficiency, the lattice parameters of tetragonal permingeatite decreased compared to the stoichiometric permingeatite, resulting in a = 0.5654–0.5654 nm and c = 1.1253–1.1254 nm, with a decrease in the c/a ratio in the range of 1.9901–1.9903. Electrical conductivity exhibited typical semiconductor behavior of increasing conductivity with temperature, and above 423 K, the electrical conductivity of all samples exceeded that of stoichiometric permingeatite; Cu2.96SbSe4 exhibited a maximum of 9.8 × 103 Sm−1 at 623 K. The Seebeck coefficient decreased due to Cu deficiency, showing p-type semiconductor behavior similar to stoichiometric permingeatite, with majority carriers being holes. Thermal conductivity showed negative temperature dependence, and both electronic and lattice thermal conductivities increased due to Cu deficiency. Despite the decrease in the Seebeck coefficient due to Cu deficiency, the electrical conductivity increased, resulting in an increase in the power factor (especially a great increase at high temperatures), with Cu2.97SbSe4 exhibiting the highest value of 0.72 mWm−1K−2 at 573 K. As the carrier concentration increased due to Cu deficiency, the thermal conductivity increased, but the increase in power factor was significant, with Cu2.98SbSe4 recording a maximum dimensionless figure-of-merit of 0.50 at 523 K. This value was approximately 28% higher than that (0.39) of stoichiometric Cu3SbSe4. [ABSTRACT FROM AUTHOR]

Cu 2 Te-based compounds show promise for thermoelectric applications, but their synthesis typically involves ball milling or melting-annealing processes. Here, we present a surfactant-free microwave-assisted solvothermal method for the controlled synthesis of Cu 2 Te 1− x S x (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) nanostructures at 503 K within just 30 min. The substitution of sulfur promotes the formation of a hexagonal structure in Cu 2 Te 1− x S x with x of 0.2 – 0.5, and inhibits phase transitions during heating. Moreover, the alloying of sulfur contributes to a reduction in hole concentrations toward the optimal range, resulting in enhanced power factors (e.g. , 910 μW m−1 K−2 at 825 K for Cu 2 Te 0.9 S 0.1) and reduced thermal conductivity (e.g. , 0.53 W m−1 K−1 at 825 K for Cu 2 Te 0.5 S 0.5). Ultimately, Cu 2 Te 0.5 S 0.5 achieves a maximum dimensionless figure of merit of 0.80 at 825 K. This study offers a controllable solution-based strategy for synthesizing Cu 2 Te-based materials with tunable compositions and enhanced thermoelectric performance. [Display omitted] [ABSTRACT FROM AUTHOR]

Currently, bismuth telluride-based zone-melted ingots dominate the commercial thermoelectric (TE) market. However, bismuth telluride-based zone-melted ingots with a layered lattice structure are brittle, posing challenges for their application in miniature devices. Their polycrystalline alloys have robust mechanical strength. However, the electrical conductivity of a p -type polycrystalline BiSbTe alloy bulk deteriorates. In the current study, the Bi 0.46 Sb 1.54 Te 3 powder was from crushed zone-melted ingots. Large-sized polycrystalline (CuO) x Bi 0.46 Sb 1.54 Te 3 (x = 0, 0.003, 0.01, 0.03 and 0.1) bulks were prepared via the hot-pressing method under 65 MPa at 510°C for 15 min. The electrical conductivity was improved remarkably by the acceptor doping effect. The bipolar effect of the Seebeck coefficient and thermal conductivity at high temperatures was suppressed significantly due to increased majority carrier centration and enlarged bandgaps. Consequently, their TE performance (the dimensionless TE figure of merit, ZT) was significantly improved and the ZT max and ZT ave reached 1.4 and 1.27, respectively. [ABSTRACT FROM AUTHOR]

Hydrogels are renowned for their complex structures and unique physicochemical properties, establishing them as key materials in bioenergy harvesting applications. They are used in various applications, including triboelectric nanogenerators, piezoelectric, hydraulic, thermoelectric, and biofuel cells. Among these, hydrogels as key materials for thermoelectric applications represent a technology capable of continuously converting biological energy (thermal energy) into electrical energy. This technology shows great potential and commercial value in body monitoring, energy storage, and human‐machine interaction applications. Given its rapid development, a timely review focusing on the research progress of hydrogels and their composites in thermoelectric technology is presented. This review discusses various types of hydrogels used for thermoelectric power generation and refrigeration, their unique properties, strategies for enhancing their thermoelectric performance, and their applications in the field. Finally, the remaining challenges and feasible strategies are identified for improving the efficiency, stability, application range, and system‐level integration of next‐generation hydrogels for thermoelectric applications. [ABSTRACT FROM AUTHOR]

A flexible n‐type composite film consisting of MXene/Ag2Se nanowires (MX‐AS), is synthesized herein via a facile wet chemical sintering process. The thermoelectric properties of the composites with various MXene concentrations are systematically explored. The as‐synthesized 2D MXene exhibits homogeneous intercalation and dispersion of the Ag2Se nanowires. A comparative analysis reveals that these composite films outperform the pristine Ag2Se nanowire films fabricated using the same process. Specifically, the MX‐AS composite film containing 1.5 wt.% MXene exhibits a significant (≈1.25 times) improvement in the maximum thermoelectric power factor (PF), exhibiting a value of ≈933.4 µW m−1 K−2 at 400 K. This enhancement can be attributed to the combination of the remarkable intrinsic Seebeck coefficient of the Ag2Se and the high electrical conductivity of the MXene. Moreover, cyclic bending tests demonstrate the exceptional mechanical durability and flexibility of the composite film, with only an ≈7% decrease in the PF after 1000 cycles. In addition, the as‐prepared MX‐AS composite exhibits a high electromagnetic interference (EMI) shielding efficiency. [ABSTRACT FROM AUTHOR]

With growing concerns about building energy consumption, thermoelectric generators (TEGs) have attracted significant attention for their potential to generate clean, green, and sustainable power. This comprehensive review explores the applications of thermoelectric generators (TEGs) in building systems, focusing on recent advancements from 2013 to 2024. The study examines TEG integration in building envelopes, including façades, walls, windows, and roofs, as well as non-integrated applications for waste heat recovery and HVAC systems. Key findings highlight the potential of TEGs in energy harvesting and thermal management, with façade-integrated systems generating up to 100.0 mW/m² and hybrid LCPV/T-TEG systems achieving overall efficiencies of 57.03%. The review also identifies critical parameters affecting TEG performance, such as solar intensity, thermoelectric arm length, and PCM melting temperature. Despite promising results, challenges remain in improving overall system efficiency, cost-effectiveness, and scalability. Future research directions include developing more efficient thermoelectric materials, optimizing system designs for various climatic conditions, and exploring integration with smart building management systems. This review provides valuable insights for researchers and practitioners working towards more energy-efficient and sustainable building designs using TEG technology. [ABSTRACT FROM AUTHOR]

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Thermoelectric (TE) technology can effectively alleviate energy shortage and environmental pollution problems and has thus attracted extensive attention. In this work, we designed two unexplored two‐dimensional materials, Ba2ZnAs2 and Ba2ZnSb2, and investigated their stability, mechanical characteristics, and TE properties using first‐principles calculations and by solving the Boltzmann transport equation. We revealed that the two materials possess high stability and moderate cleavage energies of 0.84 and 0.76 J m−2. Moreover, they are indirect semiconductors with band‐gaps of 1.26 and 0.97 eV and show flat energy dispersion near the valence band maximum, resulting in a high p‐type Seebeck coefficient of approximately 0.72 and 0.29 mV K−1 at 300 K. Furthermore, they have significant anisotropic TE power factor along the a‐ and b‐axis, with maxima of 1.19 and 0.75 mW m−1 K−2 at 300 K. Owing to the strong coupling between the acoustic and optical phonons, as well as the low frequency for low‐lying phonons, the materials have high phonon scattering rates and low lattice thermal conductivities of 0.54/0.52 and 0.81/0.43 W mK−1 along the a‐/b‐axis. Ultimately, Ba2ZnAs2 and Ba2ZnSb2 can deliver high‐performance TE transport with high figures‐of‐merit of 0.32 and 0.19 at 300 K, which increase further to 1.67 and 0.91, respectively, at 700 K. [ABSTRACT FROM AUTHOR]

The thermoelectric properties of Bi 0.5 Sb 1.5 Te 3 synthesized through the low-temperature liquid phase sintering (LPS) method can be significantly improved by employing a synergistic approach. During the heat treatment, excess Te undergoes self-swelling under optimal sintering pressure, facilitating the slip of matrix grains perpendicular to the applied pressure and subsequent recrystallization, leading to enhanced electrical properties. Building upon this basis, the heightened Seebeck coefficient and power factor of the thermoelectric matrix stem from the incorporation of 0.6 vol% B 4 C nanoparticles. Simultaneously, lattice thermal conductivity experiences notable suppression due to enhanced phonon scattering induced by additional interfaces, defects, and second-phase. Lastly, a markedly improved maximum ZT value of 1.30 at 333 K is achieved when the volume percentage of B 4 C nanoparticles is 0.6 vol%, representing a remarkable 23% enhancement compared to the untreated sample. These results indicate that the LPS method, coupled with the enhanced second nanophase scattering mechanism, is beneficial to enhancing the thermoelectric properties of Bi 2 Te 3 -based materials. [Display omitted] [ABSTRACT FROM AUTHOR]

(Cu,Te) co-doped CoSb 3 -based thermoelectric compounds Cu 0.3 Co 4 Sb 12-x Te x were synthesized rapidly by solid-state reaction method with the sintering temperature∼923 K and holding time ∼20 min. XRD analysis showed that the prepared samples Cu 0.3 Co 4 Sb 12-x Te x were single-phase skutterudite structure in the range of x < 0.7 %. SEM and EDS analyses show that the sample grains are fine with an average diameter of micro-nanometer and the sample contains many micro-pores inside and the grains have a relatively uniform distribution of elements. The lattice thermal conductivity at high temperature of Cu 0.3 Co 4 Sb 12-x Te x (x = 0,0.3,0.5, 0.7,0.9) significantly reduced by ∼50 % when compared to the samples at room temperature due to enhanced scattering of fine grains, micro porosity and grain boundary. The maximum power factor ∼2824 μWm−1K−2 was obtained for Cu 0.3 Co 4 Sb 11.5 Te 0.5 at 769 K and a maximum ZT value of ∼0.83 at 623 K are obtained from (Cu,Te) co-doped CoSb 3 material. [ABSTRACT FROM AUTHOR]

Thermoelectric (TE) technology can effectively alleviate energy shortage and environmental pollution problems and has thus attracted extensive attention. In this work, we designed two unexplored two‐dimensional materials, Ba2ZnAs2 and Ba2ZnSb2, and investigated their stability, mechanical characteristics, and TE properties using first‐principles calculations and by solving the Boltzmann transport equation. We revealed that the two materials possess high stability and moderate cleavage energies of 0.84 and 0.76 J m−2. Moreover, they are indirect semiconductors with band‐gaps of 1.26 and 0.97 eV and show flat energy dispersion near the valence band maximum, resulting in a high p‐type Seebeck coefficient of approximately 0.72 and 0.29 mV K−1 at 300 K. Furthermore, they have significant anisotropic TE power factor along the a‐ and b‐axis, with maxima of 1.19 and 0.75 mW m−1 K−2 at 300 K. Owing to the strong coupling between the acoustic and optical phonons, as well as the low frequency for low‐lying phonons, the materials have high phonon scattering rates and low lattice thermal conductivities of 0.54/0.52 and 0.81/0.43 W mK−1 along the a‐/b‐axis. Ultimately, Ba2ZnAs2 and Ba2ZnSb2 can deliver high‐performance TE transport with high figures‐of‐merit of 0.32 and 0.19 at 300 K, which increase further to 1.67 and 0.91, respectively, at 700 K. [ABSTRACT FROM AUTHOR]

The pursuit of high‐power factor and low lattice thermal conductivity simultaneously in thermoelectric research is longstanding. Herein, great success has been achieved in SnTe‐based materials by employing a proposed strategy of entropy engineering involving vacancies, thus leveraging the promising cocktail effect. Significant band convergence and flatness effects have given rise to exceptionally high density of state carrier effective mass and Seebeck coefficients. These effects have also led to the theoretical optimal carrier concentration closely aligning with the actual carrier concentration. Furthermore, the entropy engineering involving vacancies has induced pronounced lattice disorder and a wealth of nanostructures, facilitating multi‐scale phonon scattering. Consequently, impressive thermoelectric performance is realized in AgSb3Pb2Ge2Sn6Te15: room‐temperature ZT of ≈0.4, peak ZT of ≈1.3 at 623 K, and average ZT of ≈1.0 (300–773 K). A thermoelectric module, comprising this p‐type material and the homemade n‐type PbTe, is assembled, demonstrating a competitive conversion efficiency of 9.3% at a temperature difference of 478 K. This work not only provides valuable insights into the modulation of electron/phonon transports but also establishes an effective paradigm of entropy engineering involving vacancies. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskite compounds attract tremendous research attention due to their remarkable and interesting optoelectronic properties and high power conversion efficiency (PCE). This work aims to predict various properties of some new halide perovskites RbKTiX6 (X = Cl, Br, I) to investigate their feasibility as active materials for energy storage and photovoltaic application. The Density Functional Theory (DFT) implemented in the Quantum Espresso code was applied to calculate the materials' properties, including the optoelectronic and transport properties. The evaluation of their calculated structural parameters reveals that the perovskites are highly stable, both chemically and mechanically and that there is a decline in the lattice constant and the Ti-X bond length when the I anion is substituted with its isoelectronic i.e. Br and Cl. From their electronic band structure, the materials are projected to be direct-gap semiconducting materials with energy gap ranging from 0.77 eV to 2.3 eV. Strong light absorption (up to 105 cm−1) in ultraviolet–visible regions is predicted for all studied perovskites, which is crucial for solar cell applications. This is also supported by their low reflectivity (below 23%). To investigate the power conversion efficiency (PCE) of these materials, we suggest n-i-p solar cells diagram, using RbKTiX6 (X = Cl, Br, I) as the light absorber. The calculated PCE values of RbKTiCl6, RbKTiBr6 and RbKTiI6 are ƞ = 10.03%, ƞ = 7.21% and ƞ = 4.18%, respectively. Finally, it is found that the perovskites exhibit high thermo-power convergence efficiency, as indicated by their thermoelectric figure of merit which is near unity. [ABSTRACT FROM AUTHOR]

Zintl materials have received enormous attention in recent time due to their unique structure and thermoelectric efficiency. In this work, quaternary Zintl compounds LaAgZnX2 (X = P, As) have been comprehensively investigated using the FP-LAPW + lo method through first principles approximation. The dynamic stability of the samples is performed through phonon analysis. Birch–Murnaghan equation of states is used to determine ground state parameters. The lattice constant increases while formation energy and bulk modulus B(GPa) decrease by anion replacement from P to As. Band structure calculation shows that LaAgZnP2 is an indirect bandgap semiconductor while LaAgZnAs2 is a direct bandgap semiconductor. The density of states (DOS) demonstrates that the valence band (V.B) is mainly comprised of Zn-d and X-p states while the La-f state is in the conduction band (C.B) along with the minor contribution of the La-d state. Substantial absorption is observed in the low-frequency ultraviolet and visible spectrums for these compounds. Red shifting of the hallmark optic peak occurs due to the anion replacement from P to As. To investigate the electric and thermal conductivities, Seebeck coefficients, and thermopower factor, the Boltzmann transport theory is used to quantify them for these materials. High absorption peaks and figures of merits of these compounds highlight their potential usage in optoelectronics and thermoelectric systems. [ABSTRACT FROM AUTHOR]

Herein, the structural, mechanical, optoelectronic, and transport properties of double perovskites A2ScCuCl6 (A = K, Rb, and Cs) have been determined through simulations using density functional theory. The stability of K2ScCuCl6, Rb2ScCuCl6, and Cs2ScCuCl6 compounds is supported by the optimization of structural configuration and estimation of negative formation energy. The mechanical parameters are computed to quantify mechanical strength, stability, and anisotropy. The compounds that were investigated exhibit semiconductor properties, with an indirect bandgap of 1.55, 1.43, and 1.30 eV using TB-mBJ potential, respectively. The density of states also reveals the band gap and semiconductor properties of the materials. The optical characteristics of the materials have been analyzed in terms of the dielectric function, absorption, reflectance, and optical loss. The projected low excitons binding energy, high absorbance in visible and ultraviolet regions, minimal reflectivity, and energy loss suggest that these materials are highly recommended for utilization in solar energy technology. We examined the transport characteristics that vary with temperature. The combination of high electrical conductivity, moderate thermal conductivity, and higher ZT values of 0.81, 0.86, and 0.77 makes them promising candidates for thermoelectric applications. This analysis ensures that these materials can be utilized in energy conversion applications. [ABSTRACT FROM AUTHOR]

A series of Cu12-xGaxSb4S13 (x=0,0.05,0.1 and 0.15) samples were synthesized through high-temperature melting method and heat annealing technique combined with spark plasma sintering (SPS). The phase composition, band structure and thermoelectric properties of the samples were characterized and analyzed. The results show that Ga doping can introduce impurity band near the conduction band, acting as donor energy level, thus reducing the hole carrier concentration and increasing the Seebeck coefficient of the samples. At the same time, with the increase of Ga doping content, the thermal conductivity of Ga-doped samples decreases significantly. When the temperature is 770 K, the thermal conductivity of Cu11.85Ga0.15Sb4S13 sample decreases to 1.20 W/mK, which is 29% lower than that of the intrinsic material. Finally, the maximum ZT value of 0.7 is achieved for Cu11.9Ga0.1Sb4S13 sample at 770 K, a 40% improvement over the intrinsic Cu12Sb4S13. [ABSTRACT FROM AUTHOR]

Precise positioning is a never‐ending goal in both fundamental science and technology. Recent decades of advancements in high‐precision position detection have predominantly relied on photoelectric effects for light detection in semiconductors. Herein, a different approach is proposed: The thermoelectric‐based position‐sensitive detector (T‐PSD) concept is designed to detect single heat spots arising from various energy sources, including electromagnetic radiation, electrons, and macroscopic mechanical heat. The T‐PSD concept is initially derived mathematically from the fundamental principles of heat conduction and the Seebeck effect. Subsequently, it is proved by finite element simulation in both 1D and 2D configurations. Following this theoretical groundwork, T‐PSD prototypes are fabricated and subjected to positional detection using various stimuli such as CO2 laser beam, hot soldering tip, and electron beam. In the prototypes, structured aluminum‐doped zinc oxide thermoelectric thin films, prepared via atomic layer deposition, are outfitted with voltage probes, enabling the measurement of thermoelectric voltages as a function of position and the intensity or temperature of the heat spot. Furthermore, practical decoding strategies are introduced to infer the position from the measured signals. The T‐PSD in this article showcases considerable promise in high‐precision position detection such as (quasi‐)particle tracking and precision machinery, offering an alternative concept in PSD design. [ABSTRACT FROM AUTHOR]

It is of great significance to develop high‐performance thermoelectric (TE) materials, because they can be used to harvest waste heat into electricity and there is abundant waste heat on earth. The conventional TE materials are inorganic semimetals or semiconductors like Bi2Te3 and its derivatives. However, they have problems of high cost, scarce/toxic elements, high thermal conductivity, and poor mechanical flexibility. Organic TE materials emerged as the next‐generation TE materials because of their merits including solution processability, low cost, abundant element, low intrinsic thermal conductivity, and high mechanical flexibility. Organic TE materials are mainly conducting polymers because of their high conductivity. Both the conductivity and Seebeck coefficient depend on the doping level, and they are interdependent. Hence, the TE properties of polymers can be improved through doping/dedoping engineering. There are three types of doping forms, oxidative (or reductive) doping, protonic acid doping, and charge transfer doping. Accordingly, they can be dedoped by different approaches. In this article, we review the methods to dope and dedope p‐type and n‐type TE polymers and the combination of doping and dedoping to optimize their TE properties. Secondary doping is also covered, since it can significantly enhance the conductivity of some TE polymers. [ABSTRACT FROM AUTHOR]

The inherent low thermal conductivity, low cost, and flexibility of polymeric materials make them potential candidates for thermoelectric applications. Their eco-friendliness and mechanical flexibility are useful for the design of portable and flexible self-powered electronics. However, the heat-to-electrical power conversion efficiency, also known as the figure-of-merit (ZT), of polymer TE materials is low. Research efforts are in progress to enhance the thermoelectric performance of polymers and to find new kinds of polymer composites. Recent research innovations, such as chemical doping of polymers, development of nanocomposites and hybrid composites, and nanostructuring have significantly changed the thermoelectric properties of the polymeric materials. In this article, we summarize the recent developments and achievements in polymer materials for thermoelectric applications. [ABSTRACT FROM AUTHOR]

Currently, halide perovskites with exceptional properties are the most suitable candidates for RRAM devices. In the present study, a comprehensive investigation of structural, mechanical, optoelectronic and thermoelectric properties of Cs2BSnX6 (B = Mg, Cu; X = Cl, Br, I) has been conducted for the potential application in resistive switching random access memory (RRAM) devices. Mechanical properties display that studied perovskites exhibit mechanical stability and ductile behavior with an anisotropic character. A comparison of band structure using PBE-GGA, and TB-mBJ was also made. The band structure with TB-mBJ investigation disclosed that Cs2MgSnCl6, Cs2MgSnBr6, Cs2MgSnI6, Cs2CuSnCl6, Cs2CuSnBr6, and Cs2CuSnI6 have indirect bandgaps with value of 3.64 eV, 2.87 eV, 2.05 eV, 2.30 eV, 1.50 eV and 0.90 eV respectively. These values are found to be slightly more than PBE-GGA approximations. The optical investigation illustrates that Cs2CuSnI6 can absorb a wide range of electromagnetic radiation wavelengths from ultraviolet to infrared, making it the optimal candidate for RRAM devices. Thermoelectric properties show electrical conductivity values of the 1.65 × 1019, 1.61 × 1019, 1.58 × 1019, 1.95 × 1019, 2.35 × 1019, 2.40 × 1019 (Ω.m.s)−1 for Cs2MgSnCl6, Cs2MgSnBr6, Cs2MgSnI6, Cs2CuSnCl6, Cs2CuSnBr6, and Cs2CuSnI6 respectively at 1500 K. Furthermore, the calculated optical and thermoelectric properties of Cs2BSnX6 (B = Mg, Cu; X = Cl, Br, I) compared with previously studied Cs2CaSnX6 (X = Cl, Br, I), disclosing that Mg and Cu-based perovskites display better optical and thermoelectric properties. The vital findings of this study express that Cs2CuSnI6 is the most appropriate candidate for less-energy consuming RRAM devices among all studied perovskites. [ABSTRACT FROM AUTHOR]

This study investigates the structural and electronic properties of BiSbPbTe thin films, focusing on the impact of post-annealing time and temperature. The X-ray diffraction (XRD) analysis reveals a stable rhombohedral phase formation in all samples, with no secondary phases detected within the detection limit. The high crystallinity of the films is confirmed, and post-annealing leads to an increase in peak intensity, indicating enhanced crystalline structure. Surface morphology analysis using scanning electron microscopy (SEM) demonstrates a transition from inhomogeneous features in as-grown films to homogeneous and dense formations in post-annealed films. The grain size increases with post-annealing time, attributed to diffusion, energy minimization, nucleation, growth, and thermal activation processes. The electronic transport properties, including carrier concentration and conductivity, are influenced by post-annealing temperature and duration. A stable carrier concentration is observed for films post-annealed for up to 2 h, while longer durations decrease due to reduced defect vacancies and grain boundaries. The increase in charge carrier mobility, confirmed by SEM results, contributes to enhanced electrical conductivity. The Seebeck coefficient shows an initial enhancement up to 2 h post-annealing, attributed to defect creation and increased grain boundaries. However, further increases in post-annealing duration result in a decrease in the Seebeck coefficient due to enhanced charge carrier mobility and reduced grain boundaries. The thermoelectric power factor (4.4 μW/cm1K2), determined by the square of the Seebeck coefficient and electrical conductivity, reaches its maximum value in the 2-h post-annealed sample, emphasizing the importance of optimizing post-annealing conditions for improved thermoelectric performance. [ABSTRACT FROM AUTHOR]

This study primarily focused on forming pure single-phase FeSb and explored its thermoelectric, mechanical, and electrochemical properties since no reports are available. The FeSb binary alloy has been synthesized through the vacuum melting method, and the phase formation has been confirmed through powder X-ray diffraction (PXRD). The PXRD results show that the synthesized FeSb binary alloy belongs to the hexagonal crystal structure with space group P63/mmc, which coincides with ICSD no. 53971. The pure single phase has been formed by creating a deficiency of 10 % in antimony. The High-Resolution Scanning Electron Microscopy (HR-SEM) and Energy Dispersive X-ray (EDX) analysis have been used to identify the pure single-phase and various elemental components of the hot-pressed pellet of FeSb 0.9. The atomic wt.% of iron (Fe) and antimony (Sb) have been identified through EDX spectral analysis. The highest Seebeck coefficient value of −5.4 μV/K is achieved at 497 K, and the lowest electrical conductivity value of 24049 S/m is achieved at 447 K. The hardness of the material is found to be 6.076 GPa, which is much more sufficient for thermoelectric material during industrial handling. The magnetic characteristics of the prepared pure phase FeSb compound have also been measured by Vibrating Scanning Magnetometer (VSM) analysis, which has a weak ferromagnetic nature. Furthermore, three electrodes were employed to study the electrochemical properties, and the alloy has attained the appreciable specific capacitance of 169.5 F/g at 2 A/g. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) is most widely used conductive polymer for conductive textile applications owing to its excellent electrical conductivity, good electromagnetic shielding, good anti-bacterial properties, etc. However, it has not been explored much as thermoelectric material. PPy can be coated on cotton fabric in aqueous media from its monomer to prepare electro-conductive fabrics, which will be a flexible organic thermoelectric material. In this study, PPy-coated cotton fabrics are prepared by in situ chemical polymerisations of pyrrole in presence of ferric chloride. The polymerisation process is optimised by employing Box–Behnken response surface design and method of steepest ascent to achieve minimum electrical resistivity. The lowest resistivity of PPy-coated cotton fabric is achieved to be 1.23 Ω/cm after the optimisation. The PPy-coated cotton fabric with copper thermocouple shows Seebeck coefficient as high as 11.95 µV/K, power factor 0.139 µW m−1 K−2, and thermoelectric figure of merit 1.22 × 10−4 at an absolute temperature of 300K. The thermoelectric performance of this coated fabric is found to be comparable to other costly conductive polymers and inorganic semiconductors. The surface morphology of PPy-coated cotton fabric is observed by field-emission scanning electron microscopy. Chemical interaction between cotton and PPy is investigated by FTIR spectroscopy. Analysis of semi-crystalline structure is done by X-ray diffraction and thermo-gravimetric analyser is used for analysis of thermal degradation. [ABSTRACT FROM AUTHOR]