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Chalcogenide perovskites, renowned for their low lattice thermal conductivity, have emerged as promising candidates for thermoelectric applications. Hence, we leveraged first-principles high-throughput calculations to investigate the electrical and thermal transport properties, as well as the ductility, of the chalcogenide perovskites ABX3 (X = S, Se, Te). Candidates with 30 combinations were initially screened by bandgap screening (Eg > 0.1 eV), stability assessment (Born–Huang criterion), and ductility evaluation (Pugh's ratio: G/K < 0.571, the ratio of shear modulus G to bulk modulus K) from the MatHub-3d database (176 ABX3 crystal structures, 32 kinds of space groups, and number of atoms Natom < 40). Intriguingly, weaker chemical bonding between the A and X site atom pairs gives rise to a higher ductility in the screened quasi-ductile perovskites. Furthermore, it should be noted that the low phonon group velocities confirmed the low lattice thermal conductivity of the materials. In consequence, the identification of quasi-ductile thermoelectrics, characterized by six n-type and six p-type candidates with ZT > 0.3 at 300 K, stands as the most promising candidates for application in thermoelectrics. [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]

Currently, the efforts to find materials with high κ anisotropy ratios mainly focus on layered materials, however, the limited quantity and lower workability comparing to non‐layered ones boost the exploration of non‐layered materials with high κ anisotropy ratios. Here, taking PbSnS3, a typical non‐layered orthorhombic compound, as an example, we propose that maldistribution of chemical bond strength can lead to large anisotropy of κ in non‐layered materials. Our result reveals that the maldistribution of Pb−S bonds lead to obvious collective vibrations of dioctahedron chain units, resulting in an anisotropy ratio up to 7.1 at 200 K and 5.5 at 300 K, respectively, which is one of the highest ever reported in non‐layered materials and even surpasses many classical layered materials such as Bi2Te3 and SnSe. Our findings can not only broaden the horizon for exploring high anisotropic κ materials but also provide new opportunities for the application of thermal management. [ABSTRACT FROM AUTHOR]

Many Zintl phases are promising thermoelectric materials owning to their features like narrow band gaps, multiband behaviors, ideal charge transport tunnels, and loosely bound cations. Herein we show a new Zintl phase NaCdSb with exceptional intrinsic thermoelectric performance. Pristine NaCdSb exhibits semiconductor behaviors with an experimental hole concentration of 2.9×1018 cm−3 and a calculated band gap of 0.5 eV. As the temperature increases, the hole concentration rises gradually and approaches its optimal one, leading to a high power factor of 11.56 μW cm−1 K−2 at 673 K. The ultralow thermal conductivity is derived from the small phonon group velocity and short phonon lifetime, ascribed to the structural anharmonicity of Cd−Sb bonds. As a consequence, a maximum zT of 1.3 at 673 K has been achieved without any doping optimization or structural modification, demonstrating that NaCdSb is a remarkable thermoelectric compound with great potential for performance improvement. [ABSTRACT FROM AUTHOR]

Thermoelectric performance of p-type skutterudites currently lags that of the corresponding n-type materials, and improvement of this important class of materials has become the focus of considerable research effort world-wide. Recent calculations find promising band structure features in p-type skutterudite materials of the type AFe3NiSb12 (A = Ca, Sr, or Ba), which could potentially lead to excellent thermoelectric properties. Recent work on the Yb-filled analogs of these formulations (YbFe3NiSb12) however, finds that the onset of intrinsic conduction at lower than expected temperatures deteriorates the performance above 500 K. This leads to performance in the temperature range of interest for automotive waste heat recovery applications. We, therefore, seek a way to increase the band gap in order to find a way to minimize the deleterious effects of intrinsic conduction on thermoelectric performance. Here, we present ab initio band structure calculations, the synthesis and thermoelectric properties of YbxFe4-yPtySb12 (0.8 ≤ x ≤ 1, y = 1 and 0.5). Ab initio calculations find that the band gap increases for YbFe3PtSb12 as compared to the Ni-containing analog, though no such increase in the band gap energy was found for YbFe3.5Pt0.5Sb12 as compared to YbFe3.5Ni0.5Sb12. The y = 1 sample shows a characteristic transition to intrinsic conduction with a decrease in the Seebeck coefficient at temperatures above 700 K. The increased carrier concentration in y = 0.5 virtually eliminates any evidence of intrinsic conduction, and the Seebeck coefficients for these samples increase monotonically up to 750 K, resulting in power factors approaching 27 μW/cm·K2 at 750 K. These power factors combined with low thermal conductivity result in a ZT = 0.9 at 750 K for Yb0.95Fe3.5Pt0.5Sb12. [ABSTRACT FROM AUTHOR]

The implementation and exploration of liquid metals for soft electronics, especially electronic skins (e-skins), are fast increasing. The growing field has received special attention since research regarding gallium-based alloys has intensified as these alloys are much safer in comparison to their more hazardous counterpart, mercury. Liquid metal alloys of gallium provide unique physical and chemical properties for e-skin. These properties originate from their high thermal and electrical conductivities and the fact that the liquid metal is an electronic melt in contrast to the ionic liquid. The formation of 2-D oxides on the surface of liquid gallium alloys, with large van der Waals forces, also adds to their uniqueness. Liquid metals, whether in bulk form or particulated morphologies, provide stretchabilities that surpass any other systems, allowing for the formation of super malleable e-skins. As such, they present certain opportunities for developing elements with extraordinary softness, malleability, and skin compatibility: stretchable wires and electrodes, memories, electronic components such as resistors, coils, diodes, and transistors, soft sensors, energy harvesting/storage elements, and self-healing systems. Presence of the 2-D metal compound skin also helps in accessing the non-Newtonian characteristics of gallium-based alloys that permit the formation of microparticles/nanoparticles and specific fluidics and grant printability in three dimensions. Liquid alloys of gallium, their properties, and applications for e-skins are discussed in this review, and the wealth of opportunities for future applications within soft and stretchable electronics is explored. [ABSTRACT FROM AUTHOR]

Identifying strategies for beneficial band engineering is crucial for the optimization of thermoelectric (TE) materials. In this study, we demonstrate the beneficial effects of ionic dopants on n‐type Mg3Sb2. Using the band‐resolved projected crystal orbital Hamilton population, the covalent characters of the bonding between Mg atoms at different sites are observed. By partially substituting the Mg at the octahedral sites with more ionic dopants, such as Ca and Yb, the conduction band minimum (CBM) of Mg3Sb2 is altered to be more anisotropic with an enhanced band degeneracy of 7. The CBM density of states of doped Mg3Sb2 with these dopants is significantly enlarged by band engineering. The improved Seebeck coefficients and power factors, together with the reduced lattice thermal conductivities, imply that the partial introduction of more ionic dopants in Mg3Sb2 is a general solution for its n‐type TE performance. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The pyrochlore‐type rare‐earth oxides attract considerable attentions due to their outstanding properties and extensive applications. In this work, contour maps of mechanical/thermal properties as a function of A and B cation radii across a wide variety of A2B2O7 (A = La‐Lu and Y; B = Ti, Sn, Hf, Zr, Pr and Ce) pyrochlore oxides are studied using the first‐principles calculations. The mechanical/thermal properties vary dramatically with increasing of the B cation sizes but do not show a strong systematic dependence on the A cation sizes. Furthermore, the machine learning algorithm is performed for the large family of pyrochlores and the parameters playing key role on mechanical/thermal properties are clarified. Besides, the expressions of focused mechanical and thermal properties are constructed. These results are expected to guide the future material design through composition tailoring. [ABSTRACT FROM AUTHOR]

High-throughput first-principles calculations are performed on ABO3 perovskites for new thermal barrier coating (TBC) materials. We present systematic investigations comprised of multiple selection criteria to achieve the prediction of target materials. A database including mechanical/thermal properties of 190 perovskites is initially established. Six perovskites are proposed as novel TBC materials with predicted thermal conductivities under 1.25 W/(m·K) and good damage tolerance. The observed anisotropy of thermal conductivity provides possibilities for the performance controlling via the growth orientation design. The adopted strategy and established database are expected to inspire the design of ABO3-based TBC materials and future structural material investigations. An investigation strategy for ceramics based on high-throughput calculations is constructed. Six perovskite oxides are predicted as new thermal barrier coating materials based on the established property database of perovskites. [ABSTRACT FROM AUTHOR]

Understanding the lattice dynamics and phonon transport from the perspective of chemical bonds is essential for improving and finding high-efficiency thermoelectric materials and for many applications. Here, the coexistence of global and local weak chemical bonds is elucidated as the origin of the intrinsically low lattice thermal conductivity of non-caged structure Nowotny-Juza compound, α-MgAgSb, which is identified as a new type of promising thermoelectric material in the temperature range of 300-550 K. The global weak bonds of the compound lead to a low sound velocity. The unique three-centered MgAgSb bonds in α-MgAgSb vibrate locally and induce low-frequency optical phonons, resulting in 'rattling-like' thermal damping to further reduce the lattice thermal conductivity. The hierarchical chemical bonds originate from the low valence electron count of α-MgAgSb, with the feature shared by Nowotny-Juza compounds. Low lattice thermal conductivities are therefore highly possible in this series of compounds, which is verified by phonon and bulk modulus calculations on some of the compositions. [ABSTRACT FROM AUTHOR]

Contrary to the conventional belief that the consideration for topological insulators (TIs) as potential thermoelectrics is due to their excellent electrical properties benefiting from the topological surface states, this work shows that the 3D weak TIs, formed by alternating stacks of quantum spin Hall layers and normal insulator (NI) layers, can also be decent thermoelectrics because of their focus on minimum thermal conductivity. The minimum lattice thermal conductivity is experimentally confirmed in Bi14Rh3I9 and theoretically predicted for Bi2TeI at room temperature. It is revealed that the topologically 'trivial' NI layers play a surprisingly critical role in hindering phonon propagation. The weak bonding in the NI layers gives rise to significantly low sound velocity, and the localized low-frequency vibrations of the NI layers cause strong acoustic-optical interactions and lattice anharmonicity. All these features are favorable for the realization of exceptionally low lattice thermal conductivity, and therefore present remarkable opportunities for developing high-performance thermoelectrics in weak TIs. [ABSTRACT FROM AUTHOR]

Abstract: Ab-initio calculations of the resonant modes and frequencies for a number of possible fillers in p-type RFe3CoSb12 and RFe4Sb12 were carried out. The results indicate that, although the exact values of fillers’ resonant frequencies in p-type skutterudites are somewhat different from those in n-type Co-based skutterudites, the Einstein-like resonant modes of the fillers are similar to those in n-type materials. Experimentally, several pairs of the fillers were selected and double-filled p-type skutterudite compounds RxMy Fe3CoSb12 (R, M = Ba, Ce, Nd, and Yb) were successfully synthesized. The reduction in the lattice thermal conductivity was realized by extending the range of resonant frequencies. As a result, enhanced ZT values above unity were achieved in these double-filled p-type skutterudites. [Copyright &y& Elsevier]

Bi2Te3‐based compounds and derivatives are milestone materials in the fields of thermoelectrics (TEs) and topological insulators (TIs). They have highly complex band structures and interesting lattice dynamics, which are favorable for high TE performance as well as strong spin orbit and band inversion underlying topological physics. This review presents rational calculations of properties related to TEs and provides theoretical guidance for improving the TE performance of Bi2Te3‐based materials. Although the band structures of these TE materials have been studied theoretically and experimentally for many years, there remain many controversies on band characteristics, especially the locations of band extrema and the exact values of bandgaps. Here, the key factors in the theoretical investigations of Bi2Te3, Bi2Se3, Sb2Te3, and their solid solutions are reviewed. The phonon spectra and lattice thermal conductivities of Bi2Te3‐based materials are discussed. Electronic and phonon structures and TE transport calculations are discussed and reported in the context of better establishing computational parameters for these V2VI3‐based materials. This review provides a useful guidance for analyzing and improving TE performance of Bi2Te3‐based materials. [ABSTRACT FROM AUTHOR]

Identifying strategies for beneficial band engineering is crucial for the optimization of thermoelectric (TE) materials. In this study, we demonstrate the beneficial effects of ionic dopants on n‐type Mg3Sb2. Using the band‐resolved projected crystal orbital Hamilton population, the covalent characters of the bonding between Mg atoms at different sites are observed. By partially substituting the Mg at the octahedral sites with more ionic dopants, such as Ca and Yb, the conduction band minimum (CBM) of Mg3Sb2 is altered to be more anisotropic with an enhanced band degeneracy of 7. The CBM density of states of doped Mg3Sb2 with these dopants is significantly enlarged by band engineering. The improved Seebeck coefficients and power factors, together with the reduced lattice thermal conductivities, imply that the partial introduction of more ionic dopants in Mg3Sb2 is a general solution for its n‐type TE performance. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The low weighted carrier mobility has long been considered to be the key challenge for improvement of thermoelectric (TE) performance in BiTeI. The Rashba-effect-induced two-dimensional density of states in this bulk semiconductor is beneficial for thermopower enhancement, which makes it a prospective compound for TE applications. In this report, we show that intercalation of minor Cu-dopants can substantially alter the equilibria of defect reactions, selectively mediate the donor-acceptor compensation, and tune the defect concentration in the carrier conductive network. Consequently, the potential fluctuations responsible for electron scattering are reduced and the carrier mobility in BiTeI can be enhanced by a factor of two to three between 10 K and 300 K. The carrier concentration can also be optimized by tuning the Te/I composition ratio, leading to higher thermopower in this Rashba system. Cu-intercalation in BiTeI gives rise to higher power factor, slightly lower lattice thermal conductivity, and consequently improved figure of merit. Compared with pristine BiTe0.98I1.02, the TE performance in Cu0.05BiTeI reveals a 150% and 20% enhancement at 300 and 520 K, respectively. These results demonstrate that defect equilibria mediated by selective doping in complex TE and energy materials could be an effective approach to carrier mobility and performance optimization. [ABSTRACT FROM AUTHOR]

Intriguing experimental results raised the question about the fundamental mechanisms governing the electron-hole coupling induced bipolar thermal conduction in semiconductors. Our combined theoretical analysis and experimental measurements show that in semiconductors bipolar thermal transport is in general a 'conductivity-limiting' phenomenon, and it is thus controlled by the carrier mobility ratio and by the minority carrier partial electrical conductivity for the intrinsic and extrinsic cases, respectively. Our numerical method quantifies the role of electronic band structure and carrier scattering mechanisms. We have successfully demonstrated bipolar thermal conductivity reduction in doped semiconductors via electronic band structure modulation and/or preferential minority carrier scatterings. We expect this study to be beneficial to the current interests in optimizing thermoelectric properties of narrow gap semiconductors. [ABSTRACT FROM AUTHOR]

[Display omitted] Pursuing efficient thermoelectricity from low-dimensional materials has been highly motivated since the seminal work of Hicks and Dresselhaus. In fact, many superior thermoelectric materials like Bi 2 Te 3 , Mg 3 Sb 2 /Mg 3 Bi 2 and SnSe are quasi-two-dimensional (q2D), though the advantages of two-dimensionality appear to be diverse and sometimes controversial. Here, we report on a remarkably high thermoelectric performance in TlCu 3 Te 2 , which is quasi-one-dimensional (q1D) with a further reduced dimension. The thermoelectric figure of merit zT along its q1D axis amounts to 1.3 (1.5) at 300 (400) K, rivaling the best ever reported at these temperatures. The high thermoelectric performances benefit from, on one hand, large power factors derived from a center-hollowed, pancake-like Fermi pocket with q1D dispersion at the edge of a narrow band gap, and on the other hand, small lattice thermal conductivities caused by the large and anharmonic q1D lattice consisting of heavy, lone-pair-electron bearing (Tl+) and weakly-bonded (Cu+) ions. This compound represents the first bulk material with quasi-uniaxial thermoelectric transport of application level, offering a renewed opportunity to exploit reduced dimensionality for high-performance thermoelectricity. [ABSTRACT FROM AUTHOR]

[Display omitted] A Fortran code named TTEP (Thermal Transport from constant Electron-Phonon coupling approximation) is presented in this work. Within the framework of first-principles calculation, this code utilizes the deformation potential approximation to replace the electron–phonon (EP) coupling matrix element in the phonon scattering due to EP interaction. By adopting this approximation, our method achieves a balance between computational efficiency and accuracy, enabling the exploration of the thermal transport from EP interaction with much reduced computational consumption. One of the key features of TTEP is its versatility in handling a broad range of carrier concentration, including both hole and electron doping. We also extend the applicability of TTEP to actual doping case and capture EP effect over a wide temperature range. Other scattering mechanisms, such as grain boundary scattering and phonon–phonon interaction, have been included in the calculation of lattice thermal conductivity through the Matthiessen's rule. Several test cases are presented in this work to demonstrate the above features. [ABSTRACT FROM AUTHOR]

A key driver of cost for a thermoelectric generator is the thermoelectric materials themselves, and the heavy reliance on rare earth (RE) elements as fillers, particularly for p -type formulations, represents a strategic risk. In the present study, we have investigated fully filled p -type skutterudites with nominal compositions CaFe x Co 4 − x Sb 12 (2 ⩽ x ⩽ 3.5) using both experimental and theoretical methods. High purity samples were successfully synthesized using a combined melt-spinning (MS) and spark plasma sintering (SPS) technique. Structural analysis confirmed phase-pure samples with high filling fraction (>90%), homogeneous filler and transition metal distribution, and exceptionally low levels of oxygen contamination. Electrical and thermal transport property measurements revealed large power factors and unexpectedly low thermal conductivities. Electronic band structure calculations found a rapid increase in the density of states at the Fermi level with increasing Fe content. The large power factors observed in this system are attributable to this effect. Maximum zT of 0.9 was achieved in CaFe 3 CoSb 12 at 773 K. To understand the low lattice thermal conductivity in these compounds, lattice dynamics calculations were performed. The small size of Ca atoms and their concomitantly weak interactions with the surrounding Sb atoms result in a small force constant between fillers and the host, giving rise to a heretofore unreported low frequency optical phonon mode. This low frequency mode at 7 meV is in addition to the previously described mode at 17 meV identified by modeling the Ca as a simple harmonic oscillator. The lower energy phonon mode imparted by Ca filling results in a comparable lattice thermal conductivity reduction to early lanthanide species such as La. [ABSTRACT FROM AUTHOR]

Non-toxic and low-cost ZnO ceramic is a promising high-quality thermoelectric material with high Seebeck coefficient, but its high thermal conductivity leads to poor thermoelectric performance. The introduction of point defects is an effective approach to reduce the thermal conductivity of thermoelectric materials. In this study, high temperature and high pressure sintering method was used to regulate the concentration of oxygen vacancies in bulk ZnO crystal. Electron spin resonance showed an increase in concentration of oxygen vacancies with sintering temperature at high pressure. High temperature and high pressure process induced oxygen vacancies coupled with dislocations and micro-nano holes, thereby enhancing the phonon scattering and remarkably reducing the thermal conductivity. In sum, high temperature and high pressure method looks promising for effective regulation of defects and improving the thermoelectric performance of ZnO and other important thermoelectric materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag 3 SbSe 3 , Cu 3 BiSe 3 and Cu 3 SbTe 3 show lower lattice thermal conductivities than prototype Cu 3 SbSe 3. • All these compounds exhibit abnormally low lattice thermal conductivities due to their low group velocities and Debye temperatures. • Cu 3 BiSe 3 and Cu 3 SbTe 3 reduce the band gaps, which are expected to be beneficial to higher electrical conductivities than that of prototype Cu 3 SbSe 3. Abstract Understanding the thermal transport in solids has been an emerging topic since its importance in many fields, such as thermoelectrics. Some typical thermoelectric compounds which has unique vibrational characteristics have been investigated, such as Cu 3 SbSe 3. Experiments have shown that Cu 3 SbSe 3 exhibits abnormally low and nearly temperature-independent lattice thermal conductivity. In this work, we theoretically studied the vibrational characteristics of Ag 3 SbSe 3 , Cu 3 BiSe 3 and Cu 3 SbTe 3 , which are the substitution of prototype Cu 3 SbSe 3 with heavier elements on each atomic sites. These compounds all exhibit low bulk moduli and group velocities; Ag 3 SbSe 3 and Cu 3 BiSe 3 show larger atomic displacement parameters than Cu 3 SbSe 3 and thus lower Debye temperatures. Both results lead to abnormally low lattice thermal conductivities of these compounds. Furthermore, heavier element substitutions Cu 3 BiSe 3 and Cu 3 SbTe 3 reduce the band gaps, which are expected to be beneficial to higher electrical conductivities than that of Cu 3 SbSe 3. Therefore, due to the lower lattice thermal conductivities and favourable electrical transport properties, Ag 3 SbSe 3 and Cu 3 BiSe 3 are promising thermoelectric candidates. [ABSTRACT FROM AUTHOR]

[Display omitted] • α -BaCu 2 Se 2 is a wide-band-gap semiconductor with orthorhombic structure. • Cu vacancy engineering was applied in Zintl α -BaCu 2 Se 2 aiming to improve the thermoelectric properties. • The Cu vacancy can realize the temperature-dependent hole concentration to the optimal one. • Cu vacancy engineering signifies the enlargement of average zT in a wide temperature range. Vacancy engineering offers an alternative route to aliovalent and interstitial doping for optimization of the carrier concentration in thermoelectric materials. For the wide-bandgap semiconductor BaCu 2 Se 2 , the Cu vacancy is dynamically stable; this feature can be rationally manipulated to maximize the thermoelectric figure of merit zT. In this work, we show that at room temperature, Cu-deficient BaCu 2− x Se 2 samples exhibit increased hole effective mass and mobility, attributed to the energy band modulation, which are favorable for improved electrical transport properties. More importantly, the defect energy level resulting from the Cu vacancies continually contributes holes at high temperature, thereby allowing the hole concentration to approach an optimal concentration. This effect leads to an increase of the power factors over a wide temperature range. The artificial reduction of the Cu content in BaCu 2 Se 2 results in the strengthened point-defect scattering, suppressing the lattice thermal conductivity. This strategy allows simultaneous optimization of the electrical and thermal transport properties, with a thermoelectric figure of merit zT = 1.08 achieved for BaCu 1.94 Se 2 at 823 K, which is 38% higher than that of stoichiometric BaCu 2 Se 2. Within the measured temperature range, the average zT value for BaCu 1.94 Se 2 is 0.494, which is 52.9% higher than that of BaCu 2 Se 2. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ba8Au x Ga16 − 3xGe30+2x were prepared, and the solubility limit of Au is x =5.4. [•] Glass like thermal conduction at low temperature was found for p-type materials. [•] Higher DOS effective masses carriers were found in higher Au content samples. [•] Au was found to preferentially substitute at the 6c Wyckoff site. [•] ZT=0.6 at 750K was found for Ba8Au x Ga16 − 3xGe30+2x (x =1, 5, and 5.33). [ABSTRACT FROM AUTHOR]

Due to the lone-pair-induced anharmonic rattling, InTe exhibits intrinsically ultralow thermal conductivity, which was considered as a candidate for thermoelectric application. However, the poor electrical transport properties result in low thermoelectric conversion efficiency. In this work, Cd doping in InTe have been performed with the aim to optimize the carrier concentration and increase the power factor. Furthermore, an essential enhancement of carrier mobility can be realized via prolonging the annealing time, leading to improved thermoelectric performance. As a result, the maximum thermoelectric figure of merit zT of 0.87 at 773 K has been achieved for In 0.98 Cd 0.02 Te undergoing 7 days annealing treatment (In 0.98 Cd 0.02 Te-7days), which is 67% higher than the value of InTe after 2 days annealing (InTe-2days, zT = 0.52@773 K). The average zT increases significantly from 0.26 for InTe-2days to 0.53 for In 0.98 Cd 0.02 Te-7days in the temperature range of 323–823 K. Thus, both introducing Cd dopant and regulating the annealing time have obvious effects on improving the thermoelectric performance of InTe. Image 1 • The carrier concentration can be increased via Cd substitution In3+ in InTe. • Prolonged annealing time is beneficial for increasing the carrier mobility. • A peak zT value of ∼0.87 at 773 K and an average zT of ∼0.53 for In 0.98 Cd 0.02 Te-7 days are achieved. [ABSTRACT FROM AUTHOR]