High Seebeck Coefficient Research Articles

Introduction of interstitial Cu atoms is beneficial to improving the thermoelectric performance of TiNiSn

The effect of interstitial Cu on the thermoelectric properties of TiNiSn was evaluated by microwave and spark plasma sintering. It is demonstrated that the interstitial Cu optimize the carrier concentration and mobility, and that segregation of Cu at grain boundaries makes an additional contribution to the electrical conductivity. The goal of great increasing the electrical conductivity while maintaining a high Seebeck coefficient is realized, resulting in a maximum of 3703.6 μWm−1K−2 at 673 K. Furthermore, the samples enhance the high-frequency phonon scattering by introducing more point defects. And the mass fluctuation scattering and stress field fluctuation scattering induced by the interstitial Cu further decrease the lattice thermal conductivity to 1.91 Wm−1K−1 at 773 K, a reduction of 64.7 % compared to the pure sample. The dimensionless figure of merit (ZT) of the TiNiCu0.055Sn is even higher by 78.7 %, with a maximum of 0.62.

Defect and dopant complex mediated high power factor in transparent selenium-doped copper iodide thin films

Copper iodide (CuI) is a promising p-type transparent thermoelectric material for near-room temperature energy harvesting. We report a high-power factor for selenium (Se)-doped CuI films. Ion beam-sputtered CuI films were doped using 30 keV 80Se+ implantation with Se concentration varying between 0.50% and 6.50%. Hall effect measurements showed a ∼34% increase in electrical conductivity (σ ≈ 36.1 Ω−1cm−1) due to a ∼54% increase in carrier density (pH ≈ 5.4 × 1019 cm−3) in the p-type γ-CuI film implanted with 5.0 × 1014 Se.cm−2. A high Seebeck coefficient, α ≈ 388.9 μVK−1−1, and moderate electrical conductivity, σ ≈ 29.1 Ω−1cm−1, yield a nearly 85% increase in the power factor, α2σ ≈ 439.7 μWm−1K−2, for a 1.0 × 1015 Se.cm−2 implanted film compared to the unimplanted film (α2σ ≈ 236.4 μWm−1K−2). Monte Carlo simulation and ab initio density functional theory calculations revealed that the increased displacement per atom values and the {SeI−VCu} defect complex-induced shallow acceptor could be attributed to the observed increase in hole density. Our results highlight that native defects and defect complexes are beneficial for enhancing the power factor in transparent CuI for thermoelectric applications.

Effective Self‐Powered Semimetal TaTe2 Photodetector with the Thermal Localization Photothermoelectric Effect from Ultraviolet to Mid‐Infrared Range

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

Advancing Heteroanionicity in Zintl Phases: Crystal Structures, Thermoelectric and Magnetic Properties of Two Quaternary Semiconducting Arsenide Oxides, Eu8Zn2As6O and Eu14Zn5As12O.

Two novel quaternary oxyarsenides, Eu8Zn2As6O and Eu14Zn5As12O, were synthesized through metal flux reactions, and their crystal structures were established by single-crystal X-ray diffraction methods. Eu8Zn2As6O crystallizes in the orthorhombic space group Pbca, featuring polyanionic ribbons composed of corner-shared triangular [ZnAs3] units, running along the [100] direction. The structure of Eu14Zn5As12O crystallizes in the monoclinic space group P2/m and its anionic substructure can be described as an infinite "ribbonlike" chain comprised of [ZnAs3] trigonal-planar units, although the structural complexity here is greater and also amplified by disorder on multiple crystallographic positions. In both structures, the O2- anion occupies an octahedral void with six neighboring Eu2+ cations. Formal electron counting, electronic structure calculations, and transport properties reveal the charge-balanced semiconducting nature of these heteroanionic Zintl phases. High-temperature thermoelectric transport properties measurements on Eu14Zn5As12O reveal relatively high resistivity (ρ500K = 8 Ω·cm) and Seebeck coefficient values (S500K = 220 μV K-1), along with a low concentration and mobility of holes as the dominant charge-carriers (n500K = 8.0 × 1017 cm-3, μ500K = 6.4 cm2/V s). Magnetic studies indicate the presence of divalent Eu2+ species in Eu14Zn5As12O and complex magnetic ordering, with two transitions observed at T1 = 21.6 K and T2 = 9 K.

Improved Thermoelectric Properties of Selenium Functionalized Pedot

AbstractPolymer‐based chalcogenide composites are gaining attention for thermal energy storage thermoelectric (TE) applications due to their high Seebeck coefficient (S) and electrical conductivity (σ), compared to low thermal conductivity of polymers without electrical optimization. This combination can enhance power factor and ZT while suppressing drawbacks. The energy‐filtering effect of polymer/chalcogenide interfaces may also improve TE performance, further enhancing the potential for improved TE applications. In this work, Poly(3,4‐ethylenedioxythiophene) (PEDOT) was functionalized with selenium (Se), and its structural and thermoelectric (TE) properties were studied. The variations of σ and S, with higher percent of Se content, displays a simultaneous rise in both σ and S values, which is noteworthy. The probable reason behind this increment of both σ and S values is due to the improvement in charge transport in the composites due to a percolating network formed between the Se nanoparticles and PEDOT along with the carrier energy filtering interaction between PEDOT and Se. The highest room temperature ZT value obtained is 0.027 for 82 % of Se content in PEDOT, which is comparable with bulk nanostructured organic‐inorganic hybrid composite materials. This work presents an efficient technique for enhancing the TE properties of polymers through inorganic functionalization.

Enhanced Thermoelectric Performance of Nanostructured 2D Tin Telluride.

A lot of experimental studies are conducted on theoretically predicted thermoelectric 2D materials. Such materials can pave the way for charging ultra-thin electronic devices, self-charging wearable devices, and medical implants. This study systematically explores the thermoelectric attributes of bulk and 2D nanostructured Tin Telluride (SnTe), employing experimental investigations and theoretical analyses based on semiclassical Boltzmann transport theory. The bulk SnTe is synthesized through flame melting, while the 2D SnTe is produced via liquid phase exfoliation. The comprehensive assessment of thermoelectric properties integrated experimental measurements utilizing a Physical Property Measurement System and theoretical calculations from the BoltzTraP code. Experimental thermoelectric studies show a high ZT of 0.17 for 2D SnTe when compared to bulk (0.005) at room temperature. This rise in ZT is due to the high Seebeck coefficient and low thermal conductivity of nanostructured 2D SnTe. Density functional theory (DFT) studies reveal the contribution of the density of states (DOS) and energy bandgap in enhancing the Seebeck coefficient and lowering thermal conductivity by interface scattering.

Tuning thermoelectric performance with N-annulated perylene-based small molecules and single-walled carbon nanotube nanocomposite films

Two N-annulated perylene (NP)-based organic small molecules (OSMs) with end groups of di-p-tolylamine (DTA) and phenyl-di-p-tolylamine (PhDTA), namely DDTANP and DPhDTANP, are incorporated into single-walled carbon nanotubes (SWCNTs) to fabricate nanocomposite thin films for thermoelectric (TE) application. The weight ratios of OSMs to SWCNTs range from 1:1 to 1:4. The inherent planar structures of these novel OSMs facilitate strong π-π interactions and charge transfer with SWCNTs. Specifically, the DDTANP/SWCNT nanocomposite films, due to its lower HOMO, induces pronounced energy filtering and, thus, a high Seebeck coefficient (S). At the optimized weight ratio of 1:3, DDTANP/SWCNT nanocomposite thin film exhibits an electrical conductivity (σ) of 214.7 S cm−1, and S of 59.8 μV K−1. The flat structure of DPhDTANP enhances its adhesion to SWCNTs, thereby improving dispersion and increasing σ. Similarly, the DPhDTANP/SWCNT (1:3) nanocomposite thin film achieves 256.4 S cm−1, and an S of 55.8 μV K−1. The DPhDTANP/SWCNT (1:3) nanocomposite film exhibits higher σ, resulting in a power factor (PF) of 79.8 μW m−1 K−2, surpassing the PF of 76.7 μW m−1 K−2 for the DDTANP/SWCNT (1:3) nanocomposite film. These findings offer valuable insights into molecular design for SWCNTs-based composite TE research and contributed to enhancing TE applications.

DFT investigation of optoelectronic and thermoelectric features of Ba2Ce(Sn,Pt)O6 double perovskites

This study explores the geometric and thermodynamic stability, optoelectronic, and thermoelectric attributes of Ba2Ce(Sn,Pt)O6 double perovskites (DPs) through first-principles calculations. Both DPs exhibit stable cubic structures. Ba2CeSnO6 displays a bandgap of approximately 2.1 eV, indicating semiconductive behavior, while Ba2CePtO6 features a narrower bandgap of around 0.41 eV. This electronic behavior of both DPs is mainly influenced by the emergence of Ce-4f flat bands. Analysis of optical properties reveals absorption peaks at 3.4 eV for Ba2CeSnO6 and 1.2 eV for Ba2CePtO6, suggesting potential applications in visible and ultraviolet light optoelectronics. Additionally, the thermoelectric (TE) investigation demonstrates promising results, with high Seebeck coefficients (S) of 170 for Ba2CeSnO6 and 221 μV/K for Ba2CePtO6 at room temperature. The computed thermoelectric figure of merit (zT) exhibits a relatively stable trend for temperatures greater than 300 K, reaching 0.66 for Ba2CeSnO6 and 0.74 for Ba2CePtO6 at 800 K. This research provides valuable insights into the potential applications of these double perovskites in emerging technologies including visible light photonics and thermoelectric generators.

Ultrahigh average zT realized in polycrystalline SnSe0.95 materials through Sn stabilizing and carrier modulation

The average zT determines the conversion efficiency, and the power factor plays an important role in average zT value. However, the inadequate electrical conductivity of SnSe materials seriously limits its application. Herein, the TaCl5-doped in polycrystalline SnSe0.95 materials synthesized using the melting method and combined with spark plasma sintering technology achieves a zT value of 1.64 at 773 K and a record zTave of 0.62 from 323 K to 773 K. The electrical conductivity increases due to the released electron carrier induced by effective TaCl5 doping. According to the DFT calculation, the energy band of TaCl5-doped samples is narrowed, which can enhance the electron transport. Besides, the Seebeck coefficient is maintained at an elevated level as a result of the incorporation of the heavy element Ta. Due to the significantly enhanced electrical conductivity and maintained high Seebeck coefficient, the power factor reaches to 622 μW·m−1·K−2 at 773 K for the SnSe0.95 + 1.75% (in mass) TaCl5 sample, which is almost 21 times higher than that of the pristine sample. Simultaneously, a high average power factor value of 334 μW·m−1·K−2 for the SnSe0.95 + 1.75% (in mass) TaCl5 sample from 323 to 773 K was obtained. It is surprisingly found that the Ta element plays another important role to improve the stability of SnSe0.95 by forming Ta2Sn3 and removing the low melting point Sn, which usually existed in n-type SnSe samples, resulting in the decreased lattice thermal conductivity. A low lattice thermal conductivity value of 0.24 W·m−1·K−1 was also obtained for the SnSe0.95 + 2.0% (in mass) TaCl5 sample at 773 K due to the multiscale defects. Consequently, the SnSe0.95 + 2.0% (in mass) TaCl5 sample obtains a peak zT value of 1.64 at 773 K and a record zTave of 0.62 from 323 to 773 K, and the theoretically calculated conversion efficiency reaches 11.2%, it can be utilized for power generation and/or cooling at a broad temperature range. This strategy of introducing high-valence halides with heavy element can optimize the thermoelectric performance for other material systems.

High Seebeck Coefficient Thermally Chargeable Supercapacitor with Synergistic Effect of Multichannel Ionogel Electrolyte and Ti3C2Tx MXene‐Based Composite Electrode

Thermally chargeable supercapacitors can collect low‐grade heat generated by the human body and convert it into electricity as a power supply unit for wearable electronics. However, the low Seebeck coefficient and heat‐to‐electricity conversion efficiency hinder further application. In this paper, we designed a high‐performance thermally chargeable supercapacitor device composed of ZnMn2O4@Ti3C2Tx MXene composites (ZMO@Ti3C2Tx MXene) electrode and UIO‐66 metal–organic framework doped multichannel polyvinylidene fluoridehexafluoro‐propylene ionogel electrolyte, which realized the thermoelectric conversion and electrical energy storage at the same time. This thermally chargeable supercapacitor device exhibited a high Seebeck coefficient of 55.4 mV K−1, thermal voltage of 243 mV, and outstanding heat‐to‐electricity conversion efficiency of up to 6.48% at the temperature difference of 4.4 K. In addition, this device showed excellent charge–discharge cycling stability at high‐temperature differences (3 K) and low‐temperature differences (1 K), respectively. Connecting two thermally chargeable supercapacitor units in series, the generated output voltage of 500 mV further confirmed the stability of devices. When a single device was worn on the arm, a thermal voltage of 208.3 mV was obtained indicating the possibility of application in wearable electronics.

Study of mechanical, optoelectronic, and thermoelectric properties of Rb2ScAuZ6 (Z = Br, I) for energy harvesting applications

In the current article, the structural, mechanical, optoelectronic, and thermoelectric properties of Rb2ScAuZ6 (Z = Br, I) have been predicted using the density functional theory (DFT) approach. The tolerance factor, phonopy, and formation energy analysis validated the structural, dynamic, and thermodynamic stability of Rb2ScAuBr6 and Rb2ScAuI6, respectively. Likewise, the investigated elastic properties concluded that both materials exhibit mechanical stability and possess ductile characteristics. The directional-dependent elastic moduli revealed the anisotropy features. The indirect bandgaps determined by TB-mBJ approximation are 2.1 eV and 1.6 eV for Rb2ScAuBr6 and Rb2ScAuI6, respectively. Optical absorption, reflectivity, refractive index, and dielectric constants have been assessed in the energy range between 0 and 6 eV to ensure efficient absorption in the visible spectrum. Both materials have appropriate optical parameters for utilization in photovoltaic systems. Further, using the BoltzTraP code, the thermoelectric properties have been calculated to evaluate the thermoelectric efficiency. Both perovskites have lower lattice and electronic thermal conductivity, a higher Seebeck coefficient, and a higher figure of merit, making them ideal candidates for thermoelectric applications.

A comprehensive computational investigation on the physical properties of the chalcogenide ternary Y2ZnX4 (Y = In, Ga; X = S, Se) compounds

In this study, the structural, elastic, vibrational, electronic, optical, thermodynamic, and thermoelectric properties of the chalcogenide ternary Y2ZnX4 (Y = In, Ga; X = S, Se) compounds are comprehensively investigated using the pseudopotential plane-wave (PP-PW) and full-potential linearized augmented plane wave (FP-LAPW) methods. The analysis of elastic and vibrational properties reveals the dynamic and mechanical stability of these compounds. The calculated energy band gaps, ranging from 1.47 eV (Ga2ZnSe4) to 2.55 eV (In2ZnS4) in the visible spectrum, decrease as X atoms are substituted with S to Se. All examined compounds demonstrate favorable optical absorption (α > 105 cm−1) in the ultraviolet region. Notably, Ga2ZnSe4 exhibits absorption red-shift towards the visible region at hν = 2.76 eV due to its lower energy band gap, making it a promising candidate for solar cells. The three-dimensional representation of Young's modulus indicates significant deviation from sphericity, revealing anisotropic behavior in all compounds. Pugh's ratio, Poisson's ratio, and Cauchy's pressure analysis suggest ductile behavior in all four chalcogenide ternary compounds. Additionally, all compounds, except In2ZnS4, display auxetic properties. Finally, the calculated thermoelectric properties identify Ga2ZnS4 and In2ZnS4 as promising candidates for high-performance thermoelectric applications, with high Seebeck coefficients of 1848 and 1936 μV/K, respectively, and ZT values approaching unit.

Dual Sensing Signal Decoupling Based on Thermoelectric Polymer Aerogels for Precise Temperature and Pressure Recognition

AbstractThe capability to emulate skin‐like temperature and pressure sensing is fundamental for next‐generation artificial intelligence products. However, detecting temperature and pressure simultaneously with a single sensor without signal interference is challenging. Herein, a novel PCC aerogel sensor composed of PEDOT:PSS, CNTs, and CNF via directional freezing technology is developed. The PCC sensor can decouple temperature and pressure stimuli into individual voltage and resistance signals. It exhibits high‐precision temperature sensing capabilities, boasting an exceptionally high Seebeck coefficient of 30.4 µV K‐1 and the ability to detect temperature variations as low as 0.1 K. PCC sensors show excellent sensitivity and fast response times for detecting static and dynamic pressures, as well as high stability after 1000 cycles. Its maximum pressure sensitivity can reach 159.1% kPa−1, and the lowest detection limit is 10 Pa. Additionally, its excellent thermoelectric properties also enable to generating thermopower from human skin for self‐powered pressure sensing. A 3×3 PCC sensor array has been proposed to simulate the unique features of human skin in temperature and pressure recognition. This work provides a scalable manufacturing strategy for multi‐functional tactile sensors.

Understanding the origin of the high thermoelectric figure of merit of Zintl-phase KCaBi.

Herein, we have investigated the unexplored thermoelectric properties of Zintl-phase KCaBi using first-principles calculation and the solution of the Boltzmann transport equation. KCaBi shows intrinsically very low lattice thermal conductivities (κl) along the (x(y), and z)-directions of (1.78, 0.68) and (1.15, 0.43) W m-1 K-1 at 300 and 800 K, respectively. Along with the effect of very low κl, the high figure of merit (ZT) for p-type KCaBi results from the high Seebeck coefficients (S) and optimal electrical conductivities (σ), which originate from the high and steep total density of state (TDOS) at the valence band edge and the less dispersed multi-valley nature of the valence band edge in the band structure. On the other hand, large ZT for n-type KCaBi results from moderate S and high σ caused by the sloped TDOS at the conduction band edge and the highly dispersed nature of the conduction band edge in the band structure, and very low values of κl. The highest ZT of KCaBi that we obtained at 800 K along the (x(y), and z)-directions was (1.83, 0.80) for the p-type case at a hole concentration of 1021 cm-3 and (1.36, 1.22) for the n-type case at electron concentration 7 × 1018 cm-3. Our study demonstrates that both p-type and n-type KCaBi have the potential to be promising thermoelectric materials.

Band gap engineering of vacancy-ordered halide perovskite Cs2SnCl6 from substitutional doping of Pt (Cs2Sn(1-x)PtxCl6 where x = 0, 0.25, 0.50, 0.75 and 1.00) and its effects on thermoelectric properties using the first-principles approach

Researchers have shown substantial interest in vacancy-ordered halide perovskites for non-traditional energy harvesting applications including solar cells and thermoelectric generators. In this study we performed band gap engineering of vacancy-ordered halide perovskite Cs2SnCl6 from substitutional doping of Pt (Cs2Sn(1-x)PtxCl6 where x = 0, 0.25, 0.50, 0.75 and 1.00) and studied its effects on thermoelectric properties using first-principles approach. Thermodynamic stability has been proven by computing the formation energies and the tolerance factors. The band gaps were efficiently reduced to 2.50 eV from 3.61 eV by the band gap engineering approach of Pt doping. Consequently, the materials exhibited improved thermoelectric properties, including low thermal conductivities, high Seebeck coefficients, and high values of ZT. The maximum value of ZT = 2.27 was estimated for x = 1.00. The Pt doping technique can be deemed effective based on the enhanced structural and thermoelectric performance parameters.

Boosting thermoelectric performance of single-walled carbon nanotubes-based films through rational triple treatments

Single-walled carbon nanotubes (SWCNTs)-based thermoelectric materials, valued for their flexibility, lightweight, and cost-effectiveness, show promise for wearable thermoelectric devices. However, their thermoelectric performance requires significant enhancement for practical applications. To achieve this goal, in this work, we introduce rational “triple treatments” to improve the overall performance of flexible SWCNT-based films, achieving a high power factor of 20.29 µW cm−1 K−2 at room temperature. Ultrasonic dispersion enhances the conductivity, NaBH4 treatment reduces defects and enhances the Seebeck coefficient, and cold pressing significantly densifies the SWCNT films while preserving the high Seebeck coefficient. Also, bending tests confirm structural stability and exceptional flexibility, and a six-legged flexible device demonstrates a maximum power density of 2996 μW cm−2 at a 40 K temperature difference, showing great application potential. This advancement positions SWCNT films as promising flexible thermoelectric materials, providing insights into high-performance carbon-based thermoelectrics.

Ultra-Low Thermal Conductivity and Improved Thermoelectric Performance in Tungsten-Doped GeTe.

Compared to SnTe and PbTe base materials, the GeTe matrix exhibits a relatively high Seebeck coefficient and power factor but has garnered significant attention due to its poor thermal transport performance and environmental characteristics. As a typical p-type IV-VI group thermoelectric material, W-doped GeTe material can bring additional enhancement to thermoelectric performance. In this study, the introduction of W, Ge1-xWxTe (x = 0, 0.002, 0.005, 0.007, 0.01, 0.03) resulted in the presence of high-valence state atoms, providing additional charge carriers, thereby elevating the material's power factor to a maximum PFpeak of approximately 43 μW cm-1 K-2, while slightly optimizing the Seebeck coefficient of the solid solution. Moreover, W doping can induce defects and promote slight rhombohedral distortion in the crystal structure of GeTe, further reducing the lattice thermal conductivity κlat to as low as approximately 0.14 W m-1 K-1 (x = 0.002 at 673 K), optimizing it to approximately 85% compared to the GeTe matrix. This led to the formation of a p-type multicomponent composite thermoelectric material with ultra-low thermal conductivity. Ultimately, W doping achieves the comprehensive enhancement of the thermoelectric performance of GeTe base materials, with the peak ZT value of sample Ge0.995W0.005Te reaching approximately 0.99 at 673 K, and the average ZT optimized to 0.76 in the high-temperature range of 573-723 K, representing an increase of approximately 17% compared to pristine GeTe within the same temperature range.

Effect of lattice defects on electronic structure and thermoelectric properties of 2D monolayer MoS2

Molybdenum disulfide (MoS2) is considered as a promising economical and non-toxic thermoelectric material due to its low thermal conductivity and high Seebeck coefficient. However, its power factor is not ideal, which limits its energy conversion efficiency in thermoelectric applications. In this paper, the electronic structure of pure and lattice-defect MoS2 2D monolayer is studied by using the first principles method and non-equilibrium Green's function (DFT-NEGF). The effects of atom substitution and vacancy defect on the thermoelectric properties of MoS2 2D monolayer are also investigated. The result shows that the S-vacancy changes the bandgap by introducing donor and acceptor levels, while the substitution of Se and Te atoms slightly increases the bandgap value. In the case of n-type doping, the ZT value of the S atom substituted MoS2 reaches 1.19 at 300 K, while the Te atom substitution MoS2 has a higher ZT value of almost 2.26 at 800 K. The analysis shows that the thermal conductivity of MoS2 decreases due to the presence of S-vacancy, while the atomic substitution of Se and Te increases the power factor of MoS2. This work may provide a new method and theoretical guidance for achieving high performance of thermoelectric devices in the energy industry.

Stable, Self‐Adhesive, and High‐Performance Graphene‐Oxide‐Modified Flexible Ionogel Thermoelectric Films

AbstractIonic thermoelectric materials have attracted increasing attention because of their high flexibility and high Seebeck coefficient. However, their insufficient thermoelectric performance and long‐standing processing limit their practical applications. To achieve exotic ionic thermoelectric materials, here, a graphene oxide (GO) modified acrylamide ionogel is designed with high thermoelectric performance and flexibility. Detailed structural characterizations confirm that the uniform dispersion of GO particles in the ionogel structure enables a power factor of 753.0 µW m−1 K−2 and a promising ZT value of 0.19. Additionally, the as‐prepared ionic thermoelectric thin film shows excellent flexibility, stretchability, and self‐adhesiveness. An integrated device, assembled by the as‐prepared ionogel films, can generate an optimal output power density of 1.32 mW cm−2 with a temperature difference of 20 K, indicating great potential for wearable electronics. This work provides insight for searching long‐term, high‐performance ionic thermoelectric materials.

Simultaneous Enhancement of Electrical Conductivity and Porosity of a Metal–Organic Framework Toward Thermoelectric Applications

AbstractMetal–organic frameworks (MOFs) exhibit large surface areas and low thermal conductivity, making them promising for thermoelectric generation. However, their limited electrical conductivity poses a significant hurdle to be practically useful. Traditionally, enhancing the electrical conductivity of MOFs typically comes at the cost of reducing surface area, thereby increasing thermal conductivity. This study introduces an approach to simultaneously boost the electrical conductivity and porosity of a MOF‐based material while maintaining remarkably low thermal conductivity. The electrically conductive poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) is deployed to nucleate the growth of Cu3(BTC)2 (or simply CuBTC, where BTC = benzene‐1,3,5‐tricarboxylic acid), resulting in the synthesis of composites labeled CPP‐y (where y denotes wt% PEDOT:PSS). Predictably, the CPP‐y composites are more electrically conductive than pure CuBTC, achieving an electrical conductivity exceeding 1.40 S cm−1 at room temperature. Furthermore, the CPP‐y composites exhibit consistently high Brunauer–Emmett–Teller (BET) surface areas of ≈1600 m2 g−1, comparable to pristine CuBTC, while maintaining thermal conductivities below 0.04 W m−1 K−1 at room temperature. With a high Seebeck coefficient in the range 180–373 µV K−1, CPP‐15 and CPP‐23 demonstrate a figure‐of‐merit (zT) of 0.25 and 0.11, respectively, at 285 K, marking a substantial achievement for MOF‐based materials.