Thermoelectric Applications Research Articles

A strategy towards fabrication of thermoplastic-based composites with outstanding mechanical and thermoelectric performances

Compared to the great achievements in enhancing thermoelectric (TE) performance, little attention is paid to the mechanical (ME) performance of polymer composites although it is a prerequisite for practical applications. However, how to improve a trade-off between TE and ME performance is a great challenge, as the increase in ME performance is always along with the decrease in TE performance and vice versa. Herein, an enhanced trade-off is realized for ionic liquid (IL)-modulated flexible poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/ single-walled carbon nanotube (SWCNT)/polycarbonate (PC) composites. It shows a maximum power factor value of 8.5 ± 2.1 μW m−1 K−2 and a strong mechanical robustness is also achieved for the composite with a fracture strength of 43.4 ± 5.4 MPa and a tensile modulus of 3.8 ± 0.4 GPa. The TE and ME performances are superior to other thermoplastics-based TE composites, and even comparable to some conducting polymers and their composites. The high electrical conductivity of PEDOT:PSS/SWCNT and their strong interfacial interaction with PC are responsible for the enhanced trade-off between ME and TE performances. This work provides a new avenue to endow polymer composites with high TE and ME performances simultaneously and will promote their versatile TE applications.

Tuning of power factor in bismuth selenide through Sn/Te co doping for low temperature thermoelectric applications

The physical parameters of solid-state produced tin and tellurium co-doped bismuth selenide polycrystalline crystals were described. Powder X-ray diffraction revealed the hexagonal structure in the samples’ phase domination. A field emission scanning electron microscope was used to analyze the surface microstructure. Thermoelectric properties such as Seebeck coefficient, electrical resistivity, and thermal conductivity were analyzed in the temperature range 10–350 K. The electrical resistivity of (Bi0.96Sn0.04)2Se2.7Te0.3 was found to be four times lower than that of pure Bi2Se3. Due to donor-like effects and antisite defects, the Seebeck coefficient demonstrates a p- to n-type semiconducting transition. When compared to pure Bi2Se3, power factor and thermoelectric figure of merit of (Bi0.96Sn0.04)2Se2.7Te0.3 is found to increase by 15 and 9 times respectively. Tellurium excess boosts tin vacancies, promoting the p to n-type transition in (Bi0.96Sn0.04)2Se2.7Te0.3, making it a good option for low temperature thermoelectric and sensor applications.

High thermoelectric power factor of SbPbTe thin alloy film grown by thermal evaporation and post-annealing treatment

Simple chemical compositions are frequently preferred in practical thermoelectric material applications due to their high growth success rates and increased stability. In this study, an n-type SbPbTe thin alloys film with equal amounts of all elements was grown, and the effect of equal contributions on thermoelectric properties and post-annealing treatment for 1–4 h was investigated. The as-grown SbPbTe thin alloys film and post annealed sample exhibited uniform composition distributions, single-phase microstructures, and non-uniform grain sizes at both micro- and nanoscales. The 4-h post annealed SbPbTe thin alloys film demonstrated maximum thermoelectric power factor of 21.2 μWcm−1K−2 at 500 K. This improvement was attributed to a decrease in electrical conductivity and the maintenance of a relatively maximum Seebeck coefficient achieved through the adjustment of carrier concentrations. The small grain size distribution over the surface contributed to strengthened grain boundary scattering, enhanced the charge carrier density and energy filtering effect. The thermoelectric power factor for the 4-h annealed sample peaks at 500 K, indicating optimal thermoelectric performance, as calculated from the Seebeck coefficient and electrical conductivity values. These findings provide insights into the structural and thermoelectric properties of SbPbTe thin alloy films, pointing to potential ways to improve their thermoelectric efficiency.

Optimization of Wet-Spun PEDOT:PSS Fibers for Thermoelectric Applications Through Innovative Triple Post-treatments

Owing to the high flexibility, low thermal conductivity, and tunable electrical transport property, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) exhibits promising potential for designing flexible thermoelectric devices in the form of films or fibers. However, the low Seebeck coefficient and power factor of PEDOT:PSS have restricted its practical applications. Here, we sequentially employ triple post-treatments with concentrated sulfuric acid (H2SO4), sodium borohydride (NaBH4), and 1-ethyl-3-methylimidazolium dichloroacetate (EMIM:DCA) to enhance the thermoelectric performance of flexible PEDOT:PSS fibers with a high power factor of (55.4 ± 1.8) μW m−1 K−2 at 25 °C. Comprehensive characterizations confirm that excess insulating PSS can be selectively removed after H2SO4 and EMIM:DCA treatments, which induces conformational changes to increase charge carrier mobility, leading to enhanced electrical conductivity. Simultaneously, NaBH4 treatment is employed to adjust the oxidation level, further optimizing the Seebeck coefficient. Additionally, the assembled flexible fiber thermoelectric devices show an output power density of (60.18 ± 2.79) nW cm−2 at a temperature difference of 10 K, proving the superior performance and usability of the optimized fibers. This work provides insights into developing high-performance organic thermoelectric materials by modulating polymer chains.Graphical

Tailoring the physical characteristics of ScTaPd2Sn2 and ScTaPt2Sn2 double half-Heusler compound for thermoelectric applications

Due to its potential uses in thermoelectrics, spintronics, and other sectors, double half-Heusler compounds have recently attracted much attention. This study presents the first-ever report on the structural, electronic, optical, elastic, and thermoelectric characteristics of the double half Heusler (DHH) compounds ScTaPd2Sn2 and ScTaPt2Sn2, employing density functional theory (DFT). Using the EV-GGA approximation, the estimated band structures exhibit a semiconductor behavior with an indirect bandgap of 0.549 eV and 0.851 eV, respectively. In addition, we examined optical characteristics. Our material structural stability and stiffness were confirmed using elastic characteristics. Boltzmann’s semiclassical theory attempts to explain a simulation concept in the BoltzTrap software. According to the thermoelectric investigation, these DHH are a p-type material, a candidate for thermoelectric application, specifically when doped.

A First-Principles Study of 2D Bi-Based BiOClBr, BiOClI, and BiOBrI Monolayers with Ultralow Lattice Thermal Conductivities for Thermoelectric Application

A First-Principles Study of 2D Bi-Based BiOClBr, BiOClI, and BiOBrI Monolayers with Ultralow Lattice Thermal Conductivities for Thermoelectric Application

Tuning band gaps in lead chalcogenides under pressure: implications for infrared detection applications

This study employs first-principle calculations within density functional theory (DFT) to explore the structural, electronic, optical, and thermoelectric properties of lead chalcogenides (PbS, PbSe, and PbTe). The investigation focuses on their potential application as infrared photodetectors, leveraging their narrow-band gap semiconductor characteristics. The influence of pressure on the band gap and various electronic, optical, and thermoelectric properties is thoroughly analyzed. The calculated band gap values for PbS, PbSe, and PbTe are determined to be 0.29 eV, 0.18 eV, and 0.18 eV, respectively, aligning well with experimental data. Notably, the study reveals non-linear changes in band gap values under pressure, with phase transitions observed at specific pressure thresholds in PbS and PbSe, but not in PbTe. Under varying pressure conditions, the optical peaks shift towards lower energy levels with increased intensity. The static dielectric constant of PbS, PbSe, and PbTe exhibits distinct variations within pressure ranges of 0–8 GPa. Transport coefficients (S, σ, ke) are calculated using semi-classical Boltzmann theory across different temperatures and pressures, indicating that heavier compounds exhibit higher electrical and thermal conductivity values. At 300 K, the maximum ZT values are determined to be 0.85, 0.8, and 0.52 for PbS, PbSe, and PbTe, respectively. The study suggests enhanced thermoelectric properties of these structures at lower temperatures, particularly highlighting PbS and PbSe as promising candidates for thermoelectric applications below 500 K. Exploring the impact of pressure on the thermoelectric parameters of lead chalcogenides reveals interesting trends, with PbTe demonstrating higher thermoelectric efficiency under increased pressure compared to PbS and PbSe. These findings provide valuable insights into the potential applications and performance of lead chalcogenides in IR detection and thermoelectric systems.

Solution-processed MoS2 nanostructures and thermal oxidization on carbon fabric with enhanced thermopower factor for wearable thermoelectric application

Miniaturization of electronic devices has become the new phase of modern technology. Wearable Thermoelectric Generators (WTEG), being flexible, lightweight, self-sustained, and safe are the only replacement for conventional batteries for mobile applications. Molybdenum Disulfide (MoS2), a graphene akin compound having diverse transport behaviour and low thermal conductivity is one of the most preferable candidates for thermoelectric application. However, limited reports are available on MoS2 for Wearable thermoelectric applications. In this study, we have accomplished successful growth of MoS2 nanostructures on conductive carbon fabric via one step hydrothermal method and the effect of thermal oxidation of MoS2 has been studied at various annealing temperature. The structural and elemental analysis confirms the transformation of MoS2 into MoO3. Annealing creates an MoS2/MoO3 interface thus enhancing the carrier mobility resulting in enhancement of power factor (481 nW.m−1K−2) of the sample annealed at 200 °C (M1) by 1.29 times than that of pristine MoS2. The sample possessing high performance has been employed to fabricate a WTEG and its real time output has been measured. The design and operating conditions of the device is studied and optimized to obtain the output open circuit voltage as high as 6.4 mV. This paves a promising route to fabricate self- powered wearable biomedical devices.

Suppressed Lattice Thermal Conductivity in Haeckelite Compounds for High-Performance Thermoelectric Applications.

Traditional semiconductors are known to exhibit excellent electrical properties but oversized lattice thermal conductivities, thus limiting their thermoelectric performance. Herein, we have discovered a low-energy allotrope of those traditional semiconductors. Compared with the wurtzite structure, the lattice thermal conductivity is reduced by more than five times in the haeckelite structure. This is attributed to the softening of acoustic phonon modes and concurrently enhanced anharmonicity in the haeckelite structure. Benefiting from the suppressed lattice thermal conductivity while retaining the excellent electrical properties of wurtzite structure, haeckelite compounds have been proven to be a novel category of high-performance thermoelectric materials. As an excellent representative, haeckelite CdTe exhibits a peak figure of merit approaching 1.3 at n-type doping and high temperature, which experiences a 3-fold improvement compared with its wurtzite counterpart. This work provides an alternative pathway of engineering the lattice thermal conductivities of traditional semiconductors toward superior thermoelectric properties.

Atomistic simulations of coherent thermoelectric transport in ultrathin pristine and decorated noble metals nanowires

Nanowires (NWs) are envisioned to be an important component of novel nanoscale electronic devices. Here, we perform atomistic simulations of coherent thermoelectric (TE) transport in free-standing ultrathin NWs of noble metals (viz. Au, Ag, Cu, Pt) cut along the [111] crystallographic direction using a non-equilibrium Greens function based first principles approach. Effect of decorating these NWs with Au or Pt atoms in an fcc environment, is also explored. Results of the calculated electronic structure show that all considered NWs, except the Pt and Pt-decorated NWs, are metallic and non-magnetic. Interestingly, Cu@Pt NW is found to be a magnetic semiconductor with an unequal band gap in ↑− and ↓−spin energy bands, while Pt NW and other Pt-decorated NWs (viz. Ag@Pt and Au@Pt) behave like a magnetic half-metal. To explore the TE potential of as-considered NWs, electrical conductance G, thermal conductance κT, and thermopower S are computed in the linear response regime. Notably, the metallic NWs exhibit a quantized G. Among these, pristine NWs show a quantized value 3G0 up to a temperature of 200 K, while Cu@Au NW preserves its quantized value 5G0 even at T exceeding 300 K. In thermal transport, valence electrons make a dominant contribution to the room-temperature κT of pristine NWs. The phononic contribution κph, however, goes up following decoration, with Pt-decorated NWs showing a pronounced increment (by a factor of ∼2). But, these NWs undergo a simultaneous reduction in the electronic contribution κel owing to half-metallic conduction, resulting in a net suppression of total thermal conductance κT. Moreover, Pt-decorated NWs show a manifold enhancement in zero-bias S, with Ag@Pt exhibiting the highest value ∼119μV/K. However, S can be augmented considerably by adjusting the chemical potential μ of electrodes, and an overall best S∼−890μV/K is found in Au NW for μ=0.575eV. In this way, TE figure of merit ZT is tunable in pristine NWs over the range 1−3.7. Correspondingly, the decorated NWs exhibit somewhat smaller S and ZT. Furthermore, spin-asymmetric electronic transport in Pt and Pt-decorated NWs results in net spin conductance Gs and spin thermopower Ss. It is found that the spin figure of merit ZsT, as high as 3.5, can be attained in Pt NW by controlling μ. Thus, noble metals NWs can be tailored for both thermoelectric and spin-thermoelectric applications. We have also investigated TE transport for the pristine NWs in the [110] direction, and found S and ZT to be comparatively much smaller. Such NWs may be useful as interconnects for low noise applications.

Novel penta-GeC5 nanosheet as potential candidate for efficient thermoelectric application: A DFT approach

Under the framework of density functional theory, we systematically explore the geometric, electronic, transport, and thermal properties of a novel 2D pentagonal monolayer of GeC5. Our calculations show that the structure is dynamically and mechanically stable. Simulated results indicate that the predicted monolayer is an indirect semiconductor with a band gap of 1.77 eV. Using the Bardeen and Shockley formula, the carrier mobility of the electrons is found to be 824.41 cm2 V−1 S−1, while that of holes registers a more significant value of 4433.84 cm2 V−1 S−1. The lattice thermal conductivity for the undoped system was calculated using the Slack model, recording values of 13.46 W/(m.K), 6.73 W/(m.K), and 4.49 W/(m.K) at 300K, 600K, and 900K, respectively. In the case of electron doping, the figure of merit (ZT) is only significant along the x-direction. ZT reaches a maximum value of 2.97 at T = 300K for an energy of 0.79 eV above the Fermi level. Hole doping, however, does not lead to exciting results due to the shallow ZT values. All reported results are vacuum-free, enabling an accurate and direct comparison with experimental data whenever available. The obtained electronic properties suggest that the penta-GeC5 monolayer is a promising candidate for new electronic device applications. Additionally, when appropriately doped, the figure of merit of penta-GeC5 is expected to increase with temperature, thus making it a key ingredient in producing thermoelectric devices on the nanoscale.

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.

One stone three birds: Natural mineral enhancing thermoelectric properties in Cu2Se-based composites

Copper selenide can be used in thermoelectric applications since it has the features of a superionic conductor. Nevertheless, improving its electrical and thermal transport properties using facile fabrication is challenging. Herein, a one-stone and three-bird strategy was proposed for enhancing the thermoelectric performance of Cu2Se-based composites. Natural verdigris was used as an additive to construct a porous structure simultaneously while introducing Cu vacancies and multiscale Cu2O precipitates in the Cu2-xSe material. The carrier concentration was tailored to optimize the electrical transport properties of the bulk composites. Additionally, multiple lattice defects were generated in the bulk composites, benefiting the significantly reduced thermal conductivity. Ultimately, the Cu2Se-based composite achieved a peak ZT value of 1.25 at 873 K. This study provided a simple approach of adding a natural mineral to regulate the composition and microstructure of the material, which may be worth promoting in other systems.

Computational systematic study of pressure driven changes in electronic, optical, elastic, mechanical, thermodynamic and thermoelectric properties of CaZrO3 for optoelectronic and thermoelectric applications

Calcium Zirconate Oxide (CaZrO3) was studied in this work for its electronic, optical, structural, thermoelectric and thermodynamic properties in the consistent external pressure from 0 to 100 GPa. The correlation functionals utilized have been Generalized Gradient Approximations (GGA) and Heyd-Scuseria-Ernzerhof (HSE03). The structure maintains its cubical structure for a maximum of 100 GPa, while the lattice parameters gradually decrease when exposed to external pressure. Band structure are seen an indirect band at 0–40 GPa whereas direct band at 60–100 GPa (4.737–4.629 eV). To further comprehend the band gap, decrease with the estimated partial densities of states (PDOS) for bulk CaZrO3 for Ca, Zr and O are also estimated. Optical properties such as absorption I(ω), complex optical conductivity σ (ω), complex dielectric function ε(ω), loss function L(ω), reflectivity R(ω) and complex refractive index n(ω) varies significantly with external pressure ranges from 0 to 100 GPa. Mechanical stability is only observed at pressures up to 0–100 GPa becomes stable according to elastic constants. According to Pugh's ratio, the compound is ductile at 0–100 GPa. Whereas Poisson ratio shows metallic bonding up to 100 GPa, our predicted findings show anisotropic nature. According to the thermoelectric properties, these phases could potentially beneficial for thermoelectric devices. Thermodynamic parameters with respect to both temperature and pressure, including heat capacity, thermal expansion, and Debye temperature, from 0 to 1000 K and 0–100 GPa. CZO has phonon density of states and dispersion are calculated along high symmetry directions. This structure is dynamically stable and all frequencies are in the positive phonon spectrum.

Half metallic ferromagnetic and transport behavior of rare earth based CdGd2(S/Se)4 spinels

Spinel chalcogen compounds have garnered significant interest in recent ages because of their promising potential in optoelectronic and thermoelectric device applications. Here, we undertake an inclusive analysis of the structural, mechanical, electronic, magnetic, optical, and transport response of CdGd2(S/Se)4 utilizing WIEN2k code based on DFT. The determination of the crystal structure's ground state and the material's thermodynamic stability is investigated through energy vs. volume plots and ∆Hf calculation. Our analysis, including Poisson (v) and Pugh (B/G) ratios, reveals the ductile nature of the studied composition. Band gap assessments are conducted using the TB-mBJ approach, revealing the semiconducting nature of investigated compounds with direct band characteristics. Specifically, calculated band gap values are 2.2 for CdGd2S4 and 1.8 eV for CdGd2Se4. Additionally, analysis of optical properties and transport response underscores the perspective of these compositions for diverse optoelectronic and thermoelectric devices.

Enhancing n-type PbTe thermoelectric performance through Cd alloying and strategic defects management

The significant performance disparity between n-type and p-type PbTe hinders their commercial viability in thermoelectric (TE) applications. While conventional multi-element alloying has demonstrably improved n-type PbTe thermoelectrics, it introduces stability concerns and cost escalation. Here, we propose a simpler approach utilizing a single isovalent element alloying strategy with Cd and defect management to enhance the TE performance of n-type PbTe. Cd doping widens the bandgap, leading to an increased effective mass and Seebeck coefficient, particularly at higher temperatures due to improved Cd solubility. However, as documented in previous studies on the PbTe-Cd system, Cd introduction can potentially deteriorate TE performance by reducing carrier mobility. To address this, we implemented defect engineering to optimize carrier mobility. A small excess of Pb atoms was introduced to occupy intrinsic Pb vacancies, achieving a remarkable 65.5 % enhancement in carrier mobility. Consequently, the maximum power factor of Cd-alloyed Pb1.01Te samples reaches 31.5 μW cm−1 K−2, marking a significant 69.3 % improvement compared to pristine PbTe. Additionally, the Cd-induced bandgap widening effectively mitigates bipolar diffusion. This, combined with enhanced phonon scattering due to the secondary CdTe phase, results in a 34.3 % decrease in thermal conductivity. By leveraging the multifaceted effects of Cd alloying and defect management, the ZT value of Pb1.01Te-2 %Cd samples reaches 1.35 at 782 K. These findings offer a new perspective on the versatile use of single isovalent element alloying strategy and performance optimization in other TE materials.

Thermoelectric active window frame: Constructive integration and preheating analysis

Building heating and cooling systems using thermoelectricity appear to be a feasible alternative, as it presents several features including versatility and high reliance. While most applications of thermoelectricity in buildings are found in wall systems, window integration shows excellent potential for enhancing the thermal performance of buildings at the façade level, compensating heat losses that take place in windows. Combining energy efficient ventilation with heat recovery leads to a significant reduction of the required energy, keeping desired comfort conditions inside buildings. Thus, the following study presents the design of an active window frame with an integrated thermoelectric system, attaining two functions: pre-heating the supply air, while simultaneously recovering the waste heat energy from exhaust air. Two full-scale prototypes were built, each featuring a different airflow pattern, and preliminary tests for heating mode were carried out under laboratory conditions. The results revealed a similar performance comparing both prototypes, achieving a COP ranging 1.56 to 2.71 for prototype A, while prototype B ranged from 1.62 to 2.65. The results showcase superior heating efficiency compared to a previous experiments conducted by the research group, where a maximum COP of 1.91 was achieved. From a building perspective, wider adoption of thermoelectricity applied to thermal conditioning is hindered by lack of suitable products for architectural integration. Therefore, the system's innovation stems from optimized design, integrated construction, and industrialized production, enhancing energy efficiency in buildings via a compact façade integrated system without space compromise.

Microporous Zr-metal-organic frameworks based-nanocomposites for thermoelectric applications

In the area of energy storage and conversion, Metal-Organic Frameworks (MOFs) are receiving more and more attention. They combine organic nature with long-range order and low thermal conductivity, giving them qualities to be potentially attractive for thermoelectric applications. To make the framework electrically conductive so far, thermoelectricity in this class of materials requires infiltration by outside conductive guest molecules. In this study, an in-situ polymerization of conductive polyaniline inside the porous structure of MOF-801 was conducted to synthesize PANi@MOF-801 nanocomposites for thermoelectrical applications. The growth of polyaniline chains of different loadings inside the host MOF matrix generally enhanced bulk electrical conductivity by about 6 orders of magnitude, leading to Seebeck coefficient value of -141 µVK−1 and improved thermal stability. The unusual increase in electrical conductivity was attributed to the formation of highly oriented conductive PANi chains inside the MOF pores, besides host–guest physical interaction, while the Seebeck coefficient enhancement was because of the energy filtering effect of the developed structure. Modulating the composition of PANi@MOF-801 composites by varying the aniline: MOF-801 ratio in the synthesis bath from 2:1 and 1:1 to 1:2 leads to a change in the semiconductor properties from p-type semiconductor to n-type. Among the examined composites with n-type semiconducting properties exhibited the highest ZT value, 0.015, and lowest thermal conductivity, 0.24 Wm−1 K−1. The synthesized composites have better performance than those recently reported for a similar category of thermoelectric materials related to MOF-based composites.

Hybrid silver-graphene nanoparticles enhanced Lauric Acid phase change material for photovoltaic and thermoelectric generator applications: Experimental and simulation analysis

The global initiatives for renewable energy promote sustainable energy technologies such as photovoltaic thermal (PVT) systems and thermoelectric generators (TEGs). Latent heat energy storage is an effective method for conserving excess thermal energy and can be applied to PVT and TEG technologies. The fatty acid phase change materials (PCMs) are appealing, but their low thermal conductivity limits their practical usage. In this study, silver (Ag) and graphene (Gr) hybrid nanoparticles (NPs) are considered as additives to augment thermo-physical properties of lauric acid (LA) PCM for implementation in PVT and TEG applications. The nanocomposites are prepared by two-step technique. Additionally, implementation of composites in PVT has been evaluated experimentally and through TRNSYS simulation. Besides, composites impact on TEG application was assessed experimentally. As per results, photo-absorption analysis; nanocomposite LAG-3.5 (LA with 3.5 % hybrid Ag and Gr NPs) displayed the highest 76 % decrease in transmissibility. In addition, LAG-3.5 nanocomposite augmented thermal conductivity of LA by 57 % due to integration of high thermally conductive hybrid NPs. Further, LAG-3.5 composite reported an 8 % increment in latent heat enthalpy. As per reliability, after 500 thermal cycles, nanocomposite LAG-3.5 showed chemical stability and thermal durability. Moreover, optimal composite LAG-3.5 exhibited enhanced electrical characteristics while implementing in photovoltaic and thermoelectric generator application. Therefore, the nano-enhanced composite can be significant application prospects in the 45 °C to 50 °C melting temperature range.

First principles investigations of optoelectronic and thermoelectric properties of novel BaMg2X2 (X = P, As, Sb) alloys for renewable energy applications

Zintl phase compounds are emerging candidates for solar cells due to their unique electronic structure and favorable optoelectronic characteristics. In the present communication, we have studied the structural, electronic, optical, and transport properties of BaMg2X2 (X = P, As, Sb) Zintl compounds. The computation of formation energy and analysis of phonon dispersion spectra confirm their favorable formation and dynamic stability. Employing modified Becke-Johnson (mBJ) potential, we elucidate the band structure for BaMg2P2, BaMg2As2, and BaMg2Sb2, revealing direct band gaps of 1.80, 1.65, and 1.35 eV, respectively. Examination of DOS spectra provides better insight regarding the contribution of 6 s-Ba, 3 s-Mg, and (3p-5p)-P/As/Sb states in forming valence and conduction bands. The scrutiny of the optical characteristics indicates compelling light absorption in the visible region, suggesting promising prospects for optoelectronic applications. Thermoelectric characteristics are evaluated using classical Boltzmann transport theory. Notably, large figure of merit values of 0.99, 0.97 and 0.95 for BaMg2P2, BaMg2As2, and BaMg2Sb2, respectively, have been observed at room temperature. These exceptional optoelectronic characteristics, coupled with outstanding ZT values, suggest the potential suitability of these compositions for solar cells and thermoelectric device applications.