Abstract
Bismuth telluride (Bi₂Te₃)-based alloys are widely used for thermoelectric cooling and power generation at low temperatures, and they are the only commercially available materials for thermoelectric applications below 500 K. The rhombohedral unit cell with a large c/a lattice constant ratio consisting of - Te-Bi-Te-Bi-Te- stacked layers inevitably brings about..... More

Abstract
This study investigates the thermoelectric properties of Pb-doped p-type Bi_0.5Sb_1.5Te₃ alloys using the Single Parabolic Band (SPB) model, focusing on optimizing room-temperature performance. We systematically analyze the effects of Pb doping (0, 0.49, 0.65, 0.81, 0.97, and 1.3 at%) on key parameters including density-of-states effective mass (m_d *), non-degenerate mobility..... More

Abstract
Skutterudite compounds have excellent thermoelectric performance in the intermediate-to high temperature range. Their lattice thermal conductivity can be reduced by intensifying phonon scattering through independent vibrations of the guest atoms, by filling the voids within the lattice. Furthermore, the thermoelectric figure of merit (ZT) can be enhanced by optimizing the..... More

Abstract
In this study, thermoelectric chalcostibite (CuSbS₂) compounds were fabricated using mechanical alloying (MA) and hot pressing (HP), and phase identification, microstructural observation, and thermal analysis were conducted. The thermal properties were then measured and compared with those of other Cu–Sb–S ternary compounds synthesized by the same solid-state process, namely, skinnerite..... More

Abstract
Because n-type Bi₂Te₃-based materials exhibit lower thermoelectric performance than p-type materials and because their thermoelectric properties are sensitively changed by the composition and carrier concentration, optimizing these aspects in n-type materials is necessary to improve the thermoelectric figure of merit (ZT). In this study, the thermoelectric performance of n-type Bi₂Te₃-based..... More

Abstract
Mg₃Sb₂-based n-type materials are consisted of earth-abundant elements and possess comparable thermoelectric properties with n-type Bi₂Te₃ at low temperatures, which make them promising candidates for cooling and power generation applications in terms of cost and performance. Substitution of Sb atom with chalcogen elements (Te, Se S) is a conventional method..... More

Abstract
SnSe₂ alloys have been investigated in recent times as potential n-type thermoelectric materials. In this study, the thermoelectric transport properties of a series of Sb-doped SnSe₂, Sn(Se_1-xSb_x)₂ (x = 0, 0.015, 0.03, 0.045, 0.06) alloys are investigated. The electrical conductivity was generally enhanced with Sb doping owing to a large..... More

Abstract
Mg₃Sb₂-based materials are promising candidates to replace n-type Bi₂Te₃ for cooling and power generation at low temperatures. Generally, the thermoelectric performance of a material is sensitively affected by synthesis process parameters, and among them, sintering temperature (T_s) is a critical one. In this study, n-type Mg₃SbBi_0.99Te_0.01 polycrystalline samples were fabricated..... More

Abstract
Thermoelectric energy harvesting has attracted a lot of attention for powering self-powered devices because of the potential to generate energy anywhere with a temperature difference. In particular, a stretchable thermoelectric generator (S-TEG) can be applied to the repetitively moving parts of a machine and even a human body. Herein, we..... More

Abstract
Cu₃Sb_1–x–yGe_xIn_ySe₄ (0.02 ≤ x ≤ 0.12; 0.04 ≤ y ≤ 0.08) permingeatite compounds doped with Ge and In were prepared using solid-state synthesis. The phases and microstructures were analyzed, and the charge transport and thermoelectric properties were evaluated according to the Ge and In doping content. Most of the samples..... More

Abstract
Mg₃Sb₂-based materials are very promising for thermoelectric applications at low temperatures, and are strong candidates to replace n-type Bi₂Te₃ for cooling and power generation. Substituting Sb atoms with chalcogen elements (S, Se, Te) is a typical method of n-type doping, while doping the Mg site with Group 3 elements (Y,..... More

Abstract
The addition of Cu to layered Bi₂Te₃-based thermoelectric alloys has been studied as an effective way to enhance thermoelectric transport properties. In this study, the influence of adding Cu to Bi₂Se₃ alloys, which have the same rhombohedral crystal structure as Bi₂Te₃, was investigated by synthesizing a series of Cu_xBi₂Se₃ (x..... More

Abstract
Cu–Sb–Se ternary chalcogenide compounds composed of earth-abundant low-toxicity elements are attracting attention as economical and ecofriendly semiconductors. Among them, permingeatite (Cu₃SbSe₄) is a potential thermoelectric material with high Seebeck coefficient and low lattice thermal conductivity. However, it is necessary to improve its thermoelectric properties through doping, as it has low..... More

Abstract
Bytizite (Cu₃SbSe₃ ) has attracted interest as a promising thermoelectric material because of its ultralow thermal conductivity; however, there are few experimental studies. This study investigated the optimal processing conditions for the synthesis of Cu₃SbSe₃ using mechanical alloying (MA) and hot pressing (HP). The MA powder exhibited an orthorhombic Cu₃SbSe₃..... More

Abstract
Famatinite (Cu₃SbS₄ ) is a promising p-type thermoelectric material because of its low lattice thermal conductivity and high Seebeck coefficient. In this study, famatinite powders, double-doped with Sn (a B^IV group element) and In (a B^III group element) to give Cu₃Sb_1-x-ySn_xIn_yS₄ (0.02 ≤ x ≤ 0.12 and 0.06 ≤..... More

Abstract
Skinnerite (Cu₃SbS₃) has recently attracted attention as a promising thermoelectric material because of its low thermal conductivity. In this study, we performed the solid-state synthesis of Fe-doped skinnerite Cu₃Sb_1-yFe_yS₃ (y = 0.02−0.06) using mechanical alloying and hot pressing, and examined the samples’ thermoelectric properties relative to Fe doping content. All..... More

Abstract
Permingeatite (Cu₃SbSe₄) is a promising thermoelectric material with narrow bandgap energy and large carrier effective mass. However, doping is required to improve its electrical conductivity and thermoelectric properties. In this study, Cu₃Sb_1−y(Al/In)_ySe₄ doped with B^III-group elements (Al or In) at the Sb sites was synthesized using mechanical alloying followed by..... More

Abstract
Herein we report the optimized processing conditions of hot extrusion for fabricating an n-type Bi₂Te_2.7Se_0.3 thermoelectric compound, with high electronic transport properties as well as improved mechanical reliability. We fabricated a Bi₂Te_2.7Se_0.3 extrudate that was 3.8 mm in diameter and 700 mm in length by controlling the processing parameters of..... More

Abstract
Bi₂Te₃-based alloys have been extensively studied as thermoelectric materials near room temperature. In this study, the electrical, thermal, and thermoelectric transport properties of a series of Co-doped n-type Cu_0.008Bi₂Te_2.6Se_0.4 polycrystalline alloys (Cu_0.008Bi_2−xCo_xTe_2.6Se_0.4, x = 0, 0.03, 0.06, 0.09 and 0.12) are investigated. The electrical conductivity of the Cu_0.008Bi_1.97Co_0.03Te_2.6Se_0.4 (x =..... More

Abstract
Environmentally sustainable thermoelectric technologies can be more broadly applied in industries once the performance of thermoelectric materials is improved. Several approaches have been proposed to improve the electronic transport properties of thermoelectric materials. The effects of each approach on the electronic properties can be evaluated by changes in the band..... More

Abstract
With increasing interest in energy harvesting using heat as a next-generation eco-friendly energy source, organic-inorganic perovskite materials have emerged as promising materials for thermoelectric devices. In particular, the photo-Seebeck effect of halide perovskite materials has attracted attention due to their wide optical absorption spectrum and large diffusion length, depending on..... More

Abstract
In this study, Cu₃Sb_1-ySn_ySe₄ (0 ≤ y ≤ 0.08) permingeatites were synthesized via mechanical alloying followed by hot pressing. The phase transformation, microstructure, charge transport parameters of the permingeatites, and their thermoelectric properties were analyzed. The permingeatites were present in a single phase with a tetragonal structure, and secondary phases..... More

Abstract
We investigated the effect of Ni doping on the electrical, thermal, and thermoelectric transport properties of FeSe₂ polycrystalline alloys. FeSe₂ alloys exhibit both n-type and p-type conduction at different temperatures and thus their practicality as a thermoelectric material is somewhat limited. In this study, Fe_1-xNi_xSe₂ polycrystalline samples with x =..... More

Abstract
Re₂Te₅ is considered a potential thermoelectric material because of its intrinsically low thermal conductivity, due to its complex crystal structure. Herein, a series of Se-doped Re₂Te₅ (Re₂Te_5-xSe_x, x = 0, 0.2, 1, and 2) samples were synthesized, and their electrical and thermal transport properties were investigated. Pure orthorhombic Re₂Te₅ phases..... More

Abstract
Bi₂O₂Se oxyselenide has been actively studied as a potential n-type thermoelectric material because of its intrinsically low thermal conductivity and high Seebeck coefficient (S). However, Bi₂O₂Se has very low electrical conductivity (σ), resulting in relatively poor thermoelectric performance. Herein, we investigate the effect of Cu addition on the electrical and..... More

Abstract
NbFeSb-based alloys are promising p-type half-Heusler materials with excellent thermoelectric performance, thermal stability, and naturally abundant constituent elements. Alloying and doping are powerful techniques for enhancing the thermoelectric properties of half-Heusler materials. This study experimentally investigated the effects of V alloying in NbFeSb codoped with Ti, Zr, and Sn. As..... More

Abstract
In this study, mechanical alloying was performed to synthesize permingeatite Cu₃Sb_1-x-ySn_xBi_ySe₄ (0.02 ≤ x ≤ 0.06 and 0.02 ≤ y ≤ 0.04) doped with Sn and Bi. Hot pressing was subsequently conducted to achieve dense sintered bodies. When the Bi content was constant, the carrier concentration increased with the Sn..... More

Abstract
In this study, the effect of Sb incorporation on the thermoelectric transport properties of tetradymite-type Pb(Bi_2-xSb_x)Te₄ (0≤x≤1) compounds is presented. PbBi₂Te₄ (x = 0) possesses a high electron concentration of ~1.6×10²⁰/cm³ at room temperature and exhibits n-type degenerate semiconductor behavior, in which electrical conductivity decreases and negative Seebeck coefficient increases..... More

Abstract
We present a study on the synthesis of Bi₂Te_2.7Se_0.3 powders through an oxide reduction process and also on the effect of the oxide reduction process on the thermoelectric transport properties of the resulting Bi₂Te_2.7Se_0.3 compounds. Starting materials of Bi₂O₃, TeO₂ and SeO₂ were mechanical milled for homogeneous mixing, and then..... More

Abstract
Skinnerite Cu₃SbS₃, which consists of non-toxic and low-cost elements, is a potential thermoelectric material, however, studies on its thermoelectric properties are limited. In this study, the optimal conditions of mechanical alloying (MA) and hot pressing (HP) for the synthesis of the Cu₃SbS₃ phase were investigated, and its thermoelectric properties were..... More